Citation
Factors affecting the nutritional quality of soybean products fed to swine and chicks

Material Information

Title:
Factors affecting the nutritional quality of soybean products fed to swine and chicks
Creator:
Campbell, Donnie Ray, 1949-
White, Calvin E. ( Thesis advisor )
Combs, George E. ( Thesis advisor )
Miles, Richard D. ( Reviewer )
Myer, Robert O. ( Reviewer )
Shireman, Rachel M. ( Reviewer )
Fry, Jack L. ( Degree grantor )
Place of Publication:
Gainesville, Fla.
Publisher:
University of Florida
Copyright Date:
1986
Language:
English
Physical Description:
vii, 184 leaves ; 28 cm.

Subjects

Subjects / Keywords:
Amino acids ( jstor )
Diet ( jstor )
Fats ( jstor )
Heating ( jstor )
Mathematical dependent variables ( jstor )
Rats ( jstor )
Soybeans ( jstor )
Swine ( jstor )
Trypsin inhibitors ( jstor )
Variable coefficients ( jstor )
Chicks -- Feeding and feeds
Soybean as feed
Soybean products
Swine -- Feeding and feeds

Notes

General Note:
Typescript.
General Note:
Vita.
General Note:
Thesis (Ph. D.)--University of Florida, 1986.
General Note:
Includes bibliographical references (leaves 162-183).

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University of Florida
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University of Florida
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The University of Florida George A. Smathers Libraries respect the intellectual property rights of others and do not claim any copyright interest in this item. This item may be protected by copyright but is made available here under a claim of fair use (17 U.S.C. §107) for non-profit research and educational purposes. Users of this work have responsibility for determining copyright status prior to reusing, publishing or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder. The Smathers Libraries would like to learn more about this item and invite individuals or organizations to contact the RDS coordinator (ufdissertations@uflib.ufl.edu) with any additional information they can provide.
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FACTORS AFFECTING THE NUTRITIONAL QUALITY OF
SOYBEAN PRODUCTS FED TO SWINE AND CHICKS





By

DONNIE RAY CAMPBELL


A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE
UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY


UNIVERSITY OF FLORIDA


1986




















The author dedicates this dissertation in memory of his mother, the

late Verna Dean Campbell, and to his father, Joe Campbell, and his entire family. Their support, patience and thoughtfulness are gratefully acknowledged.















ACK NOWLEDGEMENTS

There were many people who assisted in the completion of this project. The encouragement, assistance, friendship and professional guidance of Dr. C. E. White (chairman), Dr. G. E. Combs (cochairman), Dr. R. D. Miles and Dr. R. M. Shireman are gratefully acknowledged. The helpful assistance and advice (such as teaching the art of cane pole fishing) of Dane Bernis were desperately needed to complete this project. Through numerous ichthyological expeditions, Mike Harrison is acknowledged for giving the author the pleasure of always surpassing Mike's aquatic skills. Likewise, the author is grateful for Scot Williams, the bull Gator, who provided chum for the marine species as needed. The author also extends appreciation to his fellow

graduate students and friends (Larry, Joe, Tomi, Dewie, Kelly, Amy, Britt and Bill), the swine unit crew (Torm, Denny, Shep, Kenny, Barry and John), laboratory (Al, Pam~ and Nancy) and secretarial (Kathy and Sharon) staff.

For teaching the author two important lessons the following individuals are additionally acknowledge: Mike Harrison, who demonstrated so many times that there is one step beyond knowing something like the back of your hand, and Dr. Comibs, who taught the author the way to increase the numi-ber of fish caught per cast; cast once and troll all day or until a fish is caught.

The author extends deepest appreciation to Wendy Jo who had a large part in the completion of this project. Her assistance, patience, understanding and friendship will always be remembered.

iii
















TABLE OF CONTENTS


ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . .

ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

CHAPTERS

I INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . 1

II LITERATURE REVIEW . . . . . . . . . . . . . . . . . . . . . 5

Trypsin Inhibitors . . . . . . . . . . . . . . . . . . . 5
Protein Digestibility . . . 17
Fat Absorption and Energy Digestibility . . . .
: : : : : 20
Antibiotic Supplementation . . . . . . . . . . . . . . . . 21
Mineral and Vitamin Supplementation . . . . . . . . . . . 25
Other Anti-Nutritional Factors . . . . . . . . . . . . . . 27
Soybean Processing . . . . . . . . . . . . . . . . . . . . 28
Effects of Overheating Soybeans . . . . . . . . . . . . 30
Improvement of the Nutritive Value of Soybeans by H; at
Processing . . . . . . . . . . . . . . . . . . 32
Other Methods of Processing Soybeans . . . . . . 36
Swine Feeding Trials . . . . . . . . . . . . . . 39
Poultry Feeding Trials . . . . . . . . . . . . . 44
Composition of Commercial Soybean Meal . . . . . . . . . . 45 Variation Among Soybean Varieties . . . . . . . . . . . . 53
Effect of Storage on Soybeans and Soybean Products . . . . 57 Effect of Maturity on Composition of Soybeans . . . . . . 58 Influence of Growing Conditions on Soybean Composition 59

III THE EFFECT OF INCREASING THE MOISTURE CONTENT OF WHOLE
SOYBEANS PRIOR TO ROASTING AT VARYING HEAT TREATMENTS
ON PERFORMANCE OF WEANING SWINE . . . . . . . . . . . . . . 61

Introduction . . . . . . . . . . . . . . . . . . . . . . . 61
Materials and Methods . . . . . . . . . . . . . . . . . . 62
Results and Discussicn . . . . . . . . . . . . . . . . . . 64

IV FEEDING VALUE AND COMPOSITIONAL VARIATION AND RELATIONSHIPS ASSOCIATED WITH DIFFERENT VARIETIES OF SOYBEANS . . . . . . 72

Introduction . . . . . . . . . . . . . . . . . . . . . . . 72
Materials and Methods . . . . . . . . . . . . . . . . . . 74
Trial 1 . . . . . . . . . . . . . . . . . . . . . . . 74
Trial 2 . . . . . . . . . . . . . . . . . . . . . . . 75









Trial 3 . . . . . . . . . . . . . 0 . 0 . . . . . . 75
Results and Discuss; on . . . . . . . . . . . . . . . . . . 79
Trial 1 . . . o . o . . . . . . o . . . o . . . . . . 79
Trial 2 o . . . . . . . . . . . . . . . . . . . . . . 85
Trial 3 . . . 87
Grower period . . . .
: : : : : : : : : : : : ' 87 Finisher period . . . . . . . . . . . . . . . . 90
Overall . . . . . . . . . . . . . . . . . . . . 90

V OPTIMUM HEAT PROCESSING OF DEFATTED SOYFLAKES FOR CHICKS AND
STARTING, GROWING AND FINISHING SWINE . . . . . . . . . . . 94

Introduction . . . . o . . . . . . . . . . . . . . . . . . 94
Materials and Methods . . . . . . . . o . . . . . . . . . 96
Trial 1: Chick Trial . . . . . . . . . . . . . . . o 96
Trial 2: Starter Period . . . . . . . . . . o . . . . 99
Trial 3: Grower Period . . . . . . . . . . . . . . . 99
Trial 4: Finisher Period . . . . . . . * * * ' * * o * 99 Trials 5, 6 and 7: Digestibility Trials . o . . . . 100
Results and Discussion . . . . . . . . . . . . . . . . . 101
Trial 1: Chick Trial . . . . . . . . . . . . . . . 101
Trials 2-4: Swine Trials . . . . . . . . . . . . . 104
Starter period . . . . . . . . . . . . . . . . 104
Grower period . . . . . . . . . . . . . o . . 107
Finisher period . . . . . . . . . . . . . . . 107
Trials 5, 6 and 7: Digestibility Trials . . . . . . 109 Starter period . . . . . . o . . . . . . . . . 109
Grower period . . . . . . . . . . . . . . . . 109
Finisher period . . . o . . . . . . . . . . . 113

VI CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . 116

APPENDICES

A STATISTICAL ANALYSIS TABLES . . . . . . . . . . . . . . . 122

B TRYPSIN INHIBITOR ASSAY PROCEDURE . . . . . . . . . . . . 160

LITERATURE CITED . o . . . . . . . . . . . . . o . . . . . . . . 162

BIOGRAPHICAL SKETCH . . . . . . . . . . . . . . . . . . . . . . 184
















Abstract of Dissertation Presented to the Graduate
School of the University of Florida in Partial
Fulfillment of the Requirements for the Degree of Doctor of Philosophy FACTORS AFFECTING THE NUTRITIONAL QUALITY OF
SOYBEAN PRODUCTS FED TO SWINE AND CHICKS By

Donnie Ray Campbell

December, 1986

Chairman: Dr. C. E. White
Cochairman: Dr. G. E. Combs Major Department: Animal Science

Eleven experiments were conducted to evaluate several factors that could influence the nutritional quality of soybean products fed to swine and chicks. The effects of increasing moisture content of soybeans prior to roasting and varying roasting temperature on the nutritional value of soybeans fed to starting swine (5 kg) were determined by feeding diets containing soybean meal or "full-fat" soybeans (unheated or roasted at 110 or 125 C with 0 or 10% water added prior to roasting) (Exp. 1). Growth of pigs fed the diet containing soybean meal was superior (P<.05) compared to the other treatments groups (whole soybeans). Increasing the roasting temperature from 110 to 125 C or adding 10% moisture prior to roasting soybeans augmented (P<.05) feed intake and weight gain of weaning pigs.

Comparison of the varietal differences of soybeans indicated wide variation in the fat and protein contents and trypsin inhibitor (TI)
vi









and urease activities CUA; Exp. 2 and 3). Fat concentration was negatively correlated (P<.05) with the protein concentration and positively correlated (P<.05) with the UA of the unheated soybeans. The effect of these varietal variations on the performance of growingfinishing swine (40 kg initially) was evaluated (Exp. 4). During the grower period, pigs fed the raw or roasted soybean (Bragg or Davis varieties) diets gained more slowly (P<.05) than those fed soybean meal. Growth of pigs was increased (P<.05) by roasting either variety of soybeans at 110 C. During the finisher period, utilization of roasted soybeans of either variety and raw Davis soybeans permitted pig growth and feed efficiency equal (P>.05) to pigs fed soybean meal. In addition, six trials involving crossbred pigs and one 21-day trial using day-old chicks were conducted to evaluate the utilization of defatted soybean flakes which had been subjected to varying heating times. Total gains, feed intake and feed efficiency of chicks were not influenced (P>.05) by feeding defatted soybean flakes cooked for 16, 18, 20 or 22 minutes, whereas growth rate and feed intake of weanling pigs and average daily gains of growing pigs fed defatted soybean flakes cooked for 16 minutes or less were adversely affected (P<.05) when compared to pigs fed defatted soybean flakes cooked for 22 minutes. During the grower period, feed intake and efficiency were reduced (P<.05) compared to pigs fed defatted soybean flakes cooked for 22 minutes. Finishing pigs fed defatted soybean flakes cooked for 6, 12, 16 or 22 minutes grew at a similar (P>.05) rate and required equal (P>.05) amounts of feed per body weight gain. Amino acid digestibilities at the end of the small intestine were also determined at each age group with pigs fed the defatted soy diets.

vii

















CHAPTER I
INTRODUCTION


The soybean, Glycine max. (L.) Merr., is a member of the family Leguminosae and subfamily Papilionoideae and has been consumed in the Orient since ancient times. The earliest Chinese records which mention soybeans date back to about the time of the building of the Egyptian pyramids. The Buddhist religion, because of the exclusion of meat from the diet of its people, was a major influence in the development of soybeans for food in the Oriental countries. However, the use of soybeans in the United States covers a comparatively short period with the first commercial oilmill processing plant established in 1922. The meal was regarded as a by-product initially and had little value when compared to the high quality oil.

Soybean meal (SBM) is currently the most widely used source of supplemental protein in livestock diets. This extensive usage may be attributed to the excellent amino acid profile, dependable supply and competitive price. Approximately 80% of the SBM produced in the United States is used in swine and poultry diets (Smith, 1977). When formulating present day swine and poultry diets using computer least-cost feed programs, excess nutrients may be kept to a minimum. This practice has increased the awareness of including only high quality ingredients, or at least having an analysis with the true nutritional quality of the feedstuff. With SBM it is critical to










monitor the nutritional value as well as ensure that the heat labile anti-nutritional factors found in raw soybeans have been denatured by an optimum level of heat processing.

The level of heat processing required to denature the heat labile anti-nutritional factors found in soybeans before they are marketed requires energy which appears destined to become more costly in the future. Dada (1983) estimated that conventional fuel for boilers accounts for more than half of the energy used to manufacture SBM. The desolventizer-toasting process and final drying step accounts for 50 to 70% of the total steam consumption. It is the desolventizertoasting process that is the most sensitive step in controlling the nutritional quality of SBH (Hustakas et al., 1981). The amount of heat processing of soybean products required for optimal animal performance and still ensure economical situations for both the commercial soybean meal processor and swine producers could vary in the future.

Two different SBM's (44.0 and 48.5% protein) are currently being marketed depending on whether the soybean hulls are added back to the meal after being heat processed. However, both commonly receive the same heat processing and are currently being marketed for all animal species regardless of age. There is some indication that older

(mature) animals right efficiently utilize SBI having less heat processing (Combs and Wallace, 1969). If older animals are more efficient than younger animals in their ability to utilize underprocessed SBM, then it may be more economical to also market a SBM having less heat treatment. This practice could result in a









reduction of energy usage and lower the price of the SBM fed to older animals.

During periods of low demand for soybean oil or low price for

whole soybeans, it is economical to include whole "full-fat" soybeans in nonruminant diets. Whole soybeans, if properly processed, contain not only high quality protein but are also a rich source of energy due to their high oil content. Therefore, whole soybeans have the potential of suppling major quantities of both energy and protein in nonruminant diets. Two methods of heat processing whole soybeans (roasting and extrusion) currently available on the farm have increased the feasibility of including whole soybeans in diets for nonruminant animals. Adding fat to increase dietary caloric density has been used during periods of elevated ambient temperature to increase daily energy intake. In addition, recent studies have evaluated the effect of adding fat to diets fed to sows during late gestation and lactation in an attempt to increase piglet survivability. However, liquid fat is difficult to manage without proper storage, mixing and handling facilities. These difficulties are less of a problem when adding ground whole full-fat soybeans in the diet to increase the caloric density. Also, soybean oil contains high levels of unsaturated fatty acids, and when fed to chicks (Porter and Britton, 1974) and swine (Seerley et al., 1974; Wahlstrom et al., 1971) their carcasses contain an increased quantity of unsaturated fatty acids while still maintaining favorable organoleptic qualities. This type of meat product may be more attractive to the consumer today due to the current trend to reduce saturated fat in the human diet.










Numerous new varieties of soybeans with improved agronomic

advantages over existing varieties are released annually. In soybean breeding programs, soybeans can be selected for increased protein or increased fat composition but not increases in both traits concurrently (Hartwig, 1979). Most of the anti-nutritional factors, such as trypsin inhibitors, in raw soybeans are proteins which also contain a large percentage of the sulphur amino acids. Consequently, varieties containing an increased quantity of trypsin inhibitors may contain higher contents of protein and sulphur amino acids when compared to varieties with a lower concentration of trypsin inhibitors. If the soybeans are subjected to heat processing, the higher content of trypsin inhibitors may not be detrimental, and when denatured, would provide increased amounts of available amnino acids.

The objectives of this research were:

1. Assess the effect of increasing the moistLure content of raw soybeans prior to roasting at different temperatures on their nutritional quality when fed to weanling pigs.

2. Quantitate varietal differences in nutrient composition and assess their effect on performance of growing-finishing pigs.

3. Determine if weanling pigs and day-old chicks could attain maximium performance when fed raw defatted soybean flakes subjected to varying levels of heat processing.

4. Determine the influence on pig performance of varying the level of heat processing of defatted soybean flakes as the pig matu res.















CHAPTER II
LITERATURE REVIEW


Osborne and Mendel (1917) were the first to recognize that

unheated soybeans were inferior to heated soybeans. They reported that heating the soybean protein improved the flavor and resulted in improved growth rate when fed to rats. Subsequent research by Shrewsbury et al. (1932) substantiated that heating improved the nutritional value of soybeans when fed to pigs and rats and postulated the presence of toxic factors in raw soybeans that could be removed or destroyed by heating. Since then, many workers have reported that cooking or roasting improves the nutritional value of soybeans. Several factors have been shown to contribute to the unsatisfactory performance of animals fed raw soybeans. Among these were trypsin inhibitors (Bowman, 1944), lectins (phytohemagglutinins) (Liener and Pallansch, 1952), saponins (Potter and Kummerow, 1954), goitrogenic substance (Patton et al., 1939), decreased fat absorption (Nesheim et al., 1962), and decreased amino acid availability (Borchers, 1961).

Trypsin Inhibitors

Twenty-seven years after Osborne and Mendel's initial work, soybeans were found to contain proteolytic inhibitors (Ham and Sandstedt, 1944; Bowman, 1944). Subsequently, a compound which inhibited trypsin was isolated, crystallized, and characterized from raw soybeans (Kunitz, 1945). After further investigation, another acetone insoluble trypsin inhibitor was isolated which is now referred









to as the Bowman-Birk inhibitor (Birk et al., 1963). Obara and Wajanabe (1971) confirmed that various trypsin inhibitor fractions existed and determined that they have different susceptibilities to heat inactivation. The different trypsin inhibitors are comprised of a complex mixture of proteins and have been classified broadly into two main groups (Liener and Tomlinson, 1981). One group, of which the Kunitz soybean trypsin inhibitor is the best known example, has a molecular weight in the range of 20,000 to 25,000 daltons, specifically inhibits trypsin, and is relatively heat labile. The other group, Bowman-Birk inhibitor, consists of a family of proteins having molecular weights of approximately 8,000 daltons. Because of their high cystine content, the proteins found within this family are generally considered to be relatively heat stable. The Bowman-Birk inhibitor is unique in that it inhibits chymotrypsin as well as trypsin at two independent binding sites. Further research has indicated that the Bowman-Birk group consists of ten isoinhibitors (Tan-Wilson et al., 1985) and the Kunitz group has three isoinhibitors (Orf and Hymowitz, 1979). Because of these inhibitor specificities, raw soybeans contain twice the trypsin inhibitor activity compared to the activity for inhibition of chymotrypsin (Baintner, 1981). During heat processing, trypsin inhibitor capacity is partially inactivated prior to initial inactivation of the chymotrypsin inhibitor activity. Studies with the Bowman-Birk trypsin inhibitor indicated that most of this inhibitor is degraded during its passage through the stomach and small intestine of chicks, and that there is negligible absorption of the native inhibitor with most of the degradation products being excreted in the feces (Madar et al., 1979). In addition to the









protein trypsin inhibitors, Hafez and Mohamed (1983) reported that soybeans also contain nonprotein trypsin inhibitors.

Proteolytic inhibitors are not unique to soybeans but are

somewhat ubiquitous in nature and have distinct roles. For example, in mammals, trypsin inhibitors are a component of colostrum and help prevent proteolysis of antibodies. The pancreas also secretes trypsin inhibitor to prevent activation of the proteolytic enzymes of the pancreatic juices until they are secreted into the small intestine. Likewise, researchers postulate the functions of the proteinase inhibitors in soybeans (seeds and plant) are to (1) maintain dormancy by preventing autolysis, (2) regulate protein synthesis and metabolism

and (3) prevent attack by predatory insects (Smith and Circle, 1972).

Initial studies in which partially purified preparations of

soybean trypsin inhibitor were fed to rats and chicks resulted in no significant effect on their growth rate (Borchers et al., 1948). However, subsequent research has well documented the growth depression obtained by including raw soybeans in place of heated soybeans in the diet of rats (Liener et al., 1949; Borchers, 1961), chicks (Alumot and Nitsan, 1961; Nesheim et al., 1962), and pigs (Pekas, 1966; Hooks et al., 1967a). Trypsin inhibitor concentrate or raw soybean meal also causes pancreatic hypertrophy concurrent with the significantly slower growth in chicks (Nesheim et al., 1962; Salmon et al., 1967) and rats (Brambila et al., 1961; Borchers, 1964) but not in pigs (Hooks et al., 1965; Pekas, 1966). Liener et al. (1949) fed diets containing raw soybeans, heated soybeans, and heated soybeans + 1.8% trypsin inhibitor to rats and reported a depressed protein efficiency ratio value for the heated diet containing trypsin inhibitor compared to the









heated soybean diet but a higher protein efficiency ratio value than obtained for the diet containing raw soybeans. These data provided the initial indication that trypsin inhibitors were not the exclusive anti-nutritional constituent of soybeans. The Kunitz inhibitor can account for all the pancreatic hypertrophy effects but for only about 30 to 60% of the growth-inhibiting properties of raw soybean meal fed to rats (Rackis, 1965). More recent research by Kakade et al. (1973) confirmed the 40% growth depression but also reported only 40% of the pancreatic enlargement in rats produced by the ingestion of raw soybeans was accounted for by the trypsin inhibitors.

Contrasting research has been presented to account for the

pancreatic enlargement. Kakade et al. (1967) observed hyperplasia (increase in cell number) of the pancreatic acinar cells while Konijn and Guggenheim (1967) reported hypertrophy or increased cell size. No histopathological damage was observed in rat pancreas hypertrophied for six months, and pancreatic hypertrophy was reversible in rats (Booth et al., 1964) and in chicks (Salmon and McGinnis, 1969). The ability to compensate for the proteolytic activity of raw soybeans was greater with increasing age of chicks (Nitsan and Alumot, 1964).

The efficacy of supplementing rat, chick and pig diets with trypsin to overcome the adverse effect of feeding raw soybeans has been studied. Inclusion of 5% dietary trypsin powder in a raw soybean diet improved rat growth (Borchers and Ackerson, 1951). Autoclaving the trypsin powder destroyed its proteolytic activity but did not reduce growth. Brambila et al. (1961) added a crystalline and a crude









trypsin preparation to chick diets containing raw soybeans but still obtained depressed growth. Pancreatic hypertrophy was reduced with the crude trypsin preparation but crystalline trypsin did not prevent the pancreatic enlargement. Similarly, inclusion of .5% trypsin in diets containing raw soybeans fed to pigs at 3, 9 or 16 weeks of age did not improve the rate and efficiency of gain or dry matter, protein and ether extract digestibilities (Combs and Wallace, 1969). Plasma glucose and urea nitrogen also did not differ when pigs were fed .5% trypsin in the diet.

Feeding raw soybean meal to chicks resulted in hypertrophic

pancreas with higher trypsin and lower amylase specific activities in this organ (Pubols et al., 1964). Supplemental dietary methionine increased the ratio of amylolytic to proteolytic enzymes (Nitsan and Gertler, 1972). Total secretion of trypsin nearly doubled in chicks fed raw soybean meal, whereas amylase, lipase and chymotrypsin activities were not significantly different from that of chicks fed autoclaved soybean meal (Dal Borgo et al., 1967). Further research data collected by Gertler and Nitsan (1970) indicated increased levels of trypsin, chymotrypsin, and pancreatopeptidase but decreased levels of amylase were secreted from the pancreas when raw soybeans were substituted for heated soybeans in a chick diet. However, the addition of a trypsin inhibitor in the heated soybean diet increased the quantities of all four enzymes. Soybean trypsin inhibitor activity was correlated with pancreatic trypsin activity in the chick but was not correlated with the activities of amylase, chymotrypsin or pancreatic trypsin inhibitor (Pubols et al., 1985). In addition,









feeding raw soybean meal was reported to inhibit the synthesis of pancreatic lipase while stimulating excessive secretion of intestinal lipase In chickens (Lepkovsky and Furuta, 1970).

In other studies, feeding raw soybean meal to rats also

stimulated hypersecretion of pancreatic enzymes (Borchers, 1964). Konijn et al. (1970) and Temler et al. (1984) reported increased trypsin and chymotrypsin activities and an enlarged pancreas in rats by feeding diets containing .72 and 1.08% trypsin inhibitor. Amylase, elastase and lipase activities, feed intake and body weight were not influenced. The increase in pancreatic trypsin activity due to feeding soybean trypsin inhibitor was confirmed by Fushiki et al. (1984) but the researchers also noted an increase in pancreatic lipase activity. The trypsin activity was highly correlated with the total protein output in the bile-pancreatic juice. Feeding of raw soybeans or crystalline trypsin inhibitor immediately increased amylase and lipase activities in the intestine of rats and after three hours the activities were increased three to fourfold (Lyman and Lepkovsky, 1957). The initial intestinal trypsin activity was low, apparently inactivated by the trypsin inhibitor, but increased after six hours. These researchers noted that pepsin secretion was unaffected by feeding raw soybeans. The findings by Borchers (1964) indicated that kidney transaminase activity was also reduced when rats were fed raw soybean meal but other tissue enzymes showed no change.

The physiological changes in pigs due to feeding raw soybeans do not concur with the data obtained with chicks and rats. Pancreatic juice secretion was reduced in pigs fed raw soybean meal compared to









pigs fed heated soybean meal diets (Pekas, 1966). However, the secretory response obtained by feeding raw soybean meal is related to pig maturity (Hooks et al.# 1965). Weanling pigs fed raw soybean meal had reduced pancreas weight, nitrogen content of the pancreas, and lipase activity of the intestinal fluids and pancreas compared to weanling pigs fed heated soybean meal. Protease activity of the pancreas and intestinal fluids did not differ. When growing pigs were fed raw soybean meal, their pancreatic weight* and protease and lipase activities of the pancreas and intestinal fluids were similar to pigs fed heated soybean meal. In contrast to weanling pigs, nitrogen content of the pancreas was increased when raw soybean meal was fed to growing pigs. Cell structure and zymogen content of pancreatic tissue did not differ between pigs fed heat processed or unprocessed soybean meal nor between the different ages of pigs. In another study both raw soybean and Kunitz soybean trypsin inhibitor decreased pancreatic trypsin and chymotrypsin activities of growing pigs (Yen et al., 1977). However, inhibition of intestinal trypsin and chymotrypsin activities was greater in the pigs fed the raw soybean diet. Data from a more recent study using growing pigs fitted with a pancreatic cannula indicated that feeding an unheated commercial soybean product increased the protein secretion and total activities of trypsin and chymotrypsin of the pancreas compared to pigs fed a heated soybean product (Ozimek and Sauer, 1985). In contrast, Corring et al. (1985)

fed a diet containing raw soybeans to growing pigs and observed that the total protein output from the pancreas was not affected. However, the volume of pancreatic juice secreted was increased as well









as the plasma levels of secretin when a diet containing raw soybeans was fed. Zebrowska et al. (1985) confirmed the work of Corring and also reported no differences in total and specific activities of trypsint chymotrypsin, carboxypeptidases A and B and amylase in the pancreatic juice of growing pigs fed raw or adequately heat processed

soybean meals.

Seventy percent of the protein digestion of heat treated soybean meal in the chick was found to occur in the duodenum and 20% occurred In the upper jejunum (Bieloral et al., 1973). When raw soybean meal was fed, 70% of the protein digestion took place in the duodenum and no further digestion occurred in the remaining segments of the digestive tract. The increased secretion of enzymes and bile constituents into the duodenum in response to feeding raw soybeans was inactivated in the jejunum by the anti-nutritional factors in the soybeans and further digestion did not occur. Bielorai et al. (1973) suggested that the growth depression from feeding raw soybean meal could result from the 20% reduced protein absorption and the small amount of energy needed for the increased production and secretion of enzymes into the duodenum. This helps explain why a lower concentration of free amino acids in the intestinal contents with chicks fed raw soybeans, as compared with those fed heated soybeans, was observed In an earlier study by the same group (Bielorai et al., 1972).

Numerous factors have been proposed as being responsible for the reduced animal performance when raw soybeans are fed. Alumot and Nitsan (1961) concluded that the growth retardation was attributed to









a combination of low availability of dietary protein and an increased protein requirement resulting from stimulation of the pancreatic activity to increase enzyme production to overcome the trypsin inhibitors. The excessive amount of protein secreted in the pancreas of rats was ultimately lost in the feces (Haines and Lyman, 1961). In a later study, Muelenaere (1964) reported that feeding rats a diet containing 5% trypsin inhibitor caused a slower rate of stomach emptying and interfered with amino acid absorption through the intestinal wall. Lanchantin et al. (1969) found that the Kunitz trypsin inhibitor reacted with trypsin almost instantaneously to form a complex with an extremely low dissociation constant, thus decreasing the quantity of protein being hydrolyzed. Lepkovsky et al. (1971), using rats and chicks, suggested that the trypsin inhibitor combines with protein in the intestine to form complexes which escape digestion and are subsequently lost in the feces. Green et al. (1977) substantiated that native undenatured soybean protein is capable of binding trypsin by forming an enzyme-substrate complex which can remove feedback inhibition of pancreatic secretion by trypsin. Additional research by Lepkovsky et al. (1970) has indicated that after feeding raw soybeans to chicks, the quantity of enterokinase in the intestinal juice could not be measured which could limit the quantity of trypsinogen being converted to trypsin. Singh and Krikorian (1982) reported in a more recent study that low levels of phytic acid found in raw soybeans in vitro can also inhibit trypsin activity.









Lyman et al. (1974) and Schneeman et al. (1977) attributed the stimulatory effect of raw soybean flour on the secretory activity of the pancreas to a negative feed-back regulation. The pancreas was induced to increase the output of enzymes when the levels of trypsin and chymotrypsin in the intestine fall below certain threshold values due to complexes formed with trypsin inhibitors or dietary protein. It was believed that the mediating agent between trypsin and the pancreas is the hormone cholecystokinin. The feeding of diets containing trypsin inhibitor at 6% of the protein level to rats stimulated an increase in the production of pancreatic proteases compared to the feeding of diets containing either proteins or peptides (Temler et al., 1984). Although trypsin inhibitors are potent stimulators of the secretion of cholecystokinin, they can also stimulate secretion of other unidentified gastrointestinal factors. Struthers et al. (1983) likewise previously noted that the increased secretion of cholecystokinin was not the sole mediator of effects produced by feeding raw soybean flour.

Richardson (1381) and Liener (1981) reviewed previous research

and summarized the deleterious effects of proteinase inhibitors in raw soybeans and developed the following scheme. The proteinase inhibitors and undenatured soybean protein are only partially inactivated by pepsin and entering the small intestine, form a complex with trypsin and chymotrypsin. The resulting lower concentrations of trypsin and chymotrypsin reduce proteolytic hydrolysis and stimulate secretion of cholecystokinin. The undigested protein is lost through the feces (exogenous loss). Increased secretion of pancreatic enzymes









caused the protein from body tissue to be broken down and used in increased synthesis of proteinases. Methionine in particular is used by its conversion to homocysteine then to cystathionine and cysteine. This mechanism resulted in increased quantities of proteinases in the intestine. The sulphur containing amino acids are then degraded by the micoflora in the colon and lost in the feces (endogenous loss).

The control mechanisms for synthesis of pancreatic nucleic acids and enzyme proteins are dissimilar within different mammalian species (Struthers et al., 1983). Feeding raw soybean products containing large quantities of trypsin inhibitors produced enlargement of the pancreas in rats, mice, and chicks; but not in dogs, calves, pigs, or monkeys. Pancreatic hypertrophy and increased secretion were almost immediate in rats (Lyman and Lepkovsky, 1957); whereas in chicks, hypertrophy and pancreatic juice secretions were delayed for three to eight days following the feeding of soybean trypsin inhibitor (Nitsan and Alumot, 1964; Kakade et al., 1967). The immediate response in the pancreas of rats was a decrease in protein synthesis followed by increased selective enzyme synthesis, stimulated by both the Kunitz and Bowman-Birk inhibitors which resulted utimately in hypertrophy and loss of endogenous protein (Konijn et al., 1970). Animals whose pancreas weights were greater than .3% of their relative body weight exhibited pancreatic hypertrophy when fed raw soybeans whereas animals whose pancreas weights were less then .3% of their relative body weight did not (Liener, 1977). Although pancreatic hypertrophy does not occur in all animal species, soybean trypsin inhibitors have been shown in vitro to inhibit 90 to 100% of trypsin obtained from the rat, monkey, bovine, human, porcine and mink (Struthers et al., 1983).









Additional investigations have centered on quantifying various species response to feeding raw and heated soybean products. For example, Struthers et al. (1983) fed rats, pigs and monkeys raw and heated soybean flour containing 115 to 130 and 4 to 8 units trypsin inhibitor per mg protein, respectively. Growth and nitrogen digestibility were depressed 60 and 5%, 84 and 45%, and 0 and 9% for rats, pigs, and monkeys, respectively, due to feeding the raw soybean flour. Fecal trypsin concentration was increased 300 to 400%o in rats but decreased 50% in pigs and monkeys when fed raw soybean flour. Rats and pigs consumed significantly less of the raw soybean flour diet compared to the diet containing the heated soybean flour. However, monkeys consumed equal quantities of the two diets. Other differences due to feeding raw soy flour included changes in RNA per mg pancreas and pancreatic protein concentrations with changes of +40 and +47% ,and +20 and -7% for rats and pigs, repectively. These measured criteria were nct altered in the monkeys. In other studies, Hasdai and Liener (1983) reported depressed growth, feed intake, feed efficiency, and protein digestion when raw soybean flour was included in the diet of hamsters. They also obtained increased pancreas and kidney size and elevated trypsin, chymotrypsin, amylase and lipase activities in the pancreas. Feeding raw soybeans to the mink resulted in a 20-fold increase in fecal trypsin activity when compared to that found in chick excreta (Skrede and Krugdehl, 1985). In addition, chick excreta contained a larger quantity of proteinase Inhibitors compared to mink excreta. Furthermore, Gorrill and Thomas (1967) observed poor growth in young calves fed raw soybean meal, and reduced

trypsin and chymotrypsin secretions but no pancreatic hypertrophy.









Protein Dicestibility

As previously inferred, a change in pancreatic proteolytic enzyme production and consumption of proteolytic inhibitors can combine to alter protein hydrolysis and thereby reduce the availability of and increase the requirement for the essential amino acids. Therefore, adding amino acids to diets containing raw soybeans to improve performance has been investigated. One such study by Hill et al. (1953) indicated that the addition of an amino acid mixture failed to prevent the growth depressing effect of raw soybeans when fed to chicks. However, in subsequent research, normal growth was obtained by supplementing a diet containing raw soybeans with another mixture of amino acids (Fisher and Johnson, 1958). They suggested that earlier data which did not show improved growth was a result of inadequate amino acid balance. Increasing the dietary protein content instead of adding only amino acids to the diet improved the growth rate of rats (Fisher and Shapiro, 1963) but not of pigs (Combs et al., 1967) fed diets containing unheated soybean meal. Saxena et al. (1962a) obtained increased growth and feed efficiency when adding a mixture of amino acids, varying from four to 14 amino acids to raw soybeans, but the performance was not equal to a diet containing heated soybean meal with the same amino acids. These researchers also reported that chicks fed raw soybeans consumed five times the amount of oxygen and had much lower liver and muscle glycogen content than chicks fed autoclaved soybean meal. However, when these chicks were fed the raw soybean diets containing amino acid supplements, their oxygen consumption returned to normal. More specifically, supplementation of diets for weaning rats containing raw soybeans









with methionine, threonine and valine resulted in performance that was similar to rats fed heated soybeans (Borchers, 1961). Khayambashi and Lyman (1966) confirmed Borchers' work but also reported that the increased pancreatic and intestinal protease activities and intestinal insoluble nitrogen observed in rats fed a diet containing soybean trypsin inhibitor were not reduced when methionine, threonine and valine were added. Hooks et al. (1967a) reported that methionine supplementation in diets fed to rats and chicks improved their performance but the addition of either threonine or valine to diets containing raw soybeans did not.

Dietary supplementation with methionine to overcome the growth

depressing effect when raw soybeans were fed has received a great deal of attention but results were inconclusive. Nickelson et al. (1960) fed weanling pigs and presented data indicating improved growth with as low as .1% supplemental methionine. The ameliorated effects of feeding raw soybeans to rats and chicks by supplementing diets with methionine was confirmed by Hooks et al. (1967a). However, these researchers did not obtain increased pig performance by including methionine in raw soybean diets. Similarly, more recent studies have reported that methionine supplementation of diets containing raw soybeans did not improve the performance of finishing pigs (Jensen et al., 1970) nor pigs at three, nine, or 15 weeks of age (Combs and Wallace, 1969). Although Combs and Wallace (1969) noted a increase in dry matter and protein digestibilities when methionine was added to the raw soybean diet fed to pigs at three weeks of age, these criteria were not different for pigs at nine or 16 weeks of age.









Almquist et al. (1942) fed chicks raw soybean diets and obtained increased growth with methionine supplementation but not with additions of choline or cystine. A study by Nitsan and Gertler (1972) confirmed that the addition of .3 or .6% methionine to diets containing raw soybeans would increase chick perfomance. The increase in chick growth obtained by adding methionine to a diet containing inadequately heat processed soybean flakes was confirmed by Miles and Featherston (1976). These researchers also reported that lysine supplementation alleviated the adverse effects on growth when chicks were fed soybean flakes which were overheated.

Likewise, methionine supplementation of rat diets containing raw soybean meal increased growth and feed efficiency equal to that of rats fed diets containing heated soybean meal but performance was depressed when compared to rats fed a heated soybean meal diet containing supplemental methionine (Hensley et al., 1953). In addition, the inclusion of aureomycin in the diets containing raw and heated soybean meal supplemented with methionine permitted an additional increase in growth and feed efficiency. In another study, the addition of .6% methionine improved the protein efficiency ratio of a raw soybean meal diet similar to the improvement obtained by heating the raw soybean meal (Liener, 1949). Nitrogen retention as well as performance of rats were improved when .3% methionine was included in a diet containing raw soybean meal (Yen et al., 1971). These findings are in contrast to an earlier study (Carroll et al., 1953) which indicated that methionine supplementation in rat diets containing either raw or heated soybean meal did not affect the amount







20

and site of nitrogen absorption. Subsequent research has indicated that the inhibitors in raw soybeans do not affect the availability of supplemental methionine when Included in a rat diet but these inhibitors only depressed the availability of the intact methionine (Rao et al.# 1971) . However, Liener et al. (1949) had previously reported that a preparation of trypsin Inhibitor was capable of Inhibiting rat growth even when incorporated in diets containing either predigested protein or free amino acids.

The response from adding methionine to raw soybean diets fed to

rats can be influenced by ambient temperature (Yen et al., 1971). The largest increase in growth between rats fed either a heated soybean diet or a diet containing raw soybeans supplemented with methionine when compared to rats fed a raw soybean diet was obtained when the ambient temperature was 23 C compared to 7 C. The percentage of raw soybean meal in a rat diet can also alter the response of rats from adding methionine (Barnes et al., 1962). Addition of .3% methionine

to diets containing 50%' unheated soybean flakes increased growth of rats but no growth stimulation was obtained by the addition of methionine to a diet containing 70%o unheated soybean flakes.

Fat Absorption and Energy Digestibility

Feeding raw soybean meal has also been shown to reduce fat

absorption in young chicks; this effect was found to decrease with increasing age (Nesheim et al., 1962). Borchers (1964) fed raw soybean meal to chicks, rats, and mice and also noted depressed dietary metabolizable energy and fat absorption. However, Garlich and

Nesheim (1966) fed chicks a crude trypsin inhibitor preparation or Kunitz trypsin inhibitor and reported that each product when added







21

to a diet containing heated soybean meal depressed dietary metabolizable energy but had only a small effect on fat absorption. Providing extra calories in diets containing raw soybean meal has been reported to improve rat growth (Fisher and Shapiro, 1963) but not the gains of growing pigs (Combs et al.# 1967).

Feeding raw soybean meal has been observed to greatly enhance secretion of total fatty acids, phospholipids, cholesterol and bile into the duodenum when compared to feeding heated soybean meal to chicks (Sklan et al., 1972). The high secretion rate of fatty acids was counteracted by an increase in their absorption rate; yet, the overall net absorption of fatty acids was still slightly reduced compared to chicks fed heated soybean meal. The same protein fractions that cause pancreatic hypertrophy, also contract the gallbladder, accelerate bile secretion and decrease fat absorption (Sambeth et al., 1967). Serafin and Nesheim (1970) reported that undigested protein in raw soybean meal may also bind bile acids and elevate the rate of fecal excretion thereby depressing fat absorption. It had also previously been postulated that the depression in protein digestibility may also be partially responsible for the difference In metabolizable energy values between raw and toasted soybean meals fed to chicks (Nesheim and Garlich, 1966).

Antibiotic Supplementation

The effect of dietary antibiotics in reversing the growth depression associated with feeding raw soybeans has received considerable attention. Supplementation of diets containing raw or heated soybean meal with chlortetracycline increased the growth rate









and feed efficiency in rats fed either diet, although the improvement was greater with rats fed the raw soybean meal diet (Hensley et al., 1953). Including aureomycin in raw and heated soybean meal diets also increased the absorption of nitrogen and the amino acids (lysine, leucine, methionine and cystine) in both diets (Carroll et al., 1953). Similar to the work of Hensley et al., the increased absorption was greater in pigs fed the raw soybean meal diet. Likewise, the inclusion of .1% procaine penicillin and .1% streptomycin sulfate in raw soybean diets increased the growth of rats equal to that obtained by feeding a heated soybean meal diet (Borchers, 1958).

Brahan et al. (1959) noted that the inclusion of procaine penicillin, chlortetracycline, novabiocin, zinc bacitracin or strepton:ycin increased chick growth in raw soybean diets by 31 to 51%, but only a 4 to 14% improvement was measured for chicks fed the heated soybean diets. The raw soybean diets containing the different antibiotics did not permit equal performance when compared with the unsupplemented heated soybean diet. In trials with turkey poults, the beneficial effects on growth by adding antibiotics are negatively correlated with the amount of raw soybeans contained in the diet (Linerode et al., 1961).

The inclusion of aureomycin in a diet containing underprocessed soybeans fed to pigs from weaning to market weight did not improve performance compared to pigs fed adequately processed soybean oil meal (Becker et al., 1953). Sheppard et al. (1967) fed weanling pigs diets containing raw or heated soybean meal and reported increased growth by including antibiotics in both diets. However, the smallest response









was observed with antibiotic supplementation of the diet with raw soybeans.

The poor growth associated with feeding raw soybeans has been

suggested by Borchers (1961) to be the result of enhanced deleterious bacterial activity in the intestine. The inclusion of antibiotics in the diet may counteract this condition. Growth inhibition and increased intestinal nitrogen (protein) were observed to occur in both conventional and germi-free chicks, but Coates et al. (1970) and Hewitt and Coates (1969) reported growth Inhibition in conventional chicks was significantly greater than in germ-free chicks fed raw soybean diets. However, pancreatic hypertrophy was observed in the germr-free chicks fed raw soybean meal as well as in the conventional chicks. They postulated that the intestinal microflora potentiated the anti-nutritional effects of raw soybeans by the formation of additional factors resulting from microbial action on heat-labile components in raw soybean meal. Strains of Escherichisl cIli were subsequently shown to be responsible for the adverse effects associated with the consumption of this raw soybean diet (Jayne-Williams and Hewitt, 1972).

Barnes et al. (1965), working with chicks and rats, attributed the beneficial influence of antibiotics on overcoming the growth inhibiting effects of feeding raw soybean meal to the preservation of sulfur amino acids from degradation by the intestinal microflora.

Trypsin contains 8.7% cystine and the increased trypsin synthesis and secreticn brought about by feeding raw soybeans can account for one-half of the cystine excreted by the rat (Barnes et al., 1965).









Researchers using methionine labeled with 35S isotope noted that ingested trypsin inhibitor stimulated the conversion of methionine to cystine in the pancreas since high concentrations of radioactive cystine were found in the small intestine (Barnes and Kwong, 1965). These researchers postulated that the depletion of methionine through its conversion to cystine was at least one of the mechanisms causing growth inhibition. Thus, antibiotics, possibly by reducing the bacterial degradation of cystine in the lower gut, increased the intestinal absorption of cystine sufficiently to meet the requirement for synthesis of pancreatic enzymes (Kakade et al., 1970).

The microflora spectrum in the intestinal tract, which can be modified by antibiotic supplementation, will affect flatulence production (Rackis, 1966). Pazor et al. (1962) reported that oligosaccharides comprise about 15% of the air-dried weight of soybeans with sucrose, stachyose, and raffinose present in that order of abundance. Stachyose and raffinose are thought to produce large amounts of gas in the lower digestive tract. These compounds, having low molecular weights, are comprised of a-galactosidic and c-fructosidic linkages. Since most animals do not have the digestive enzyme a-galactosidase, the intact oligosaccharides enters the lower intestine where they are metabolized to such gasses as carbon dioxide, hydrogen and to a lesser extent methane (Liener, 1981).

Another response observed from antibiotic supplementation was an alteraticn in pancreatic enzyme production (Goldberg and Guggenheim, 1964). One hour after feeding, the tryptic and amylolytic activities of the pancrease were much lower in rats fed raw compared to heated









soybean flour diets. Inclusion of aureomycin or penicillin in the diet containing raw soybean flour diminished this reduction in pancreatic enzyme activity that was brought about by feeding raw soybeans. Addition of penicillin either through the diet or by subcutaneous injection improved the protein efficiency ratio and reduced the loss of proteolytic enzymes in the gut. However, the improvement was not equal to that found with rats fed diets containing heated soybean flour without antibiotic supplementation.

Mineral and Vitamin Supplenentation

The supplementation of trace minerals to the diet has also been shown to improve the nutritional value of raw soybean products. The addition of raw soybeans to the diet consequently increased the dietary requirement of cyanocobalamine (vitamin B 12), vitamin D3, calcium, phosphorus, zinc, iron, copper and molybdenum (Rackis, 1981). In addition, Weaver et al. (1984) found that the bioavailability of iron from defatted soyflour was relatively high and addition of vitamin C did not significantly enhance absorption of iron from raw or heated soyflour.

Phytic acid is located in the 7S protein fraction of soybeans in the form of a soluble protein-phytate salt complex with significant amounts specifically deposited In the globoid inclusions of the soybean seed (Prattley and Stanley, 1982). Research has also indicated that the phytic acid content of soybeans was involved in reducing the availability of calcium, magnesium, zinc, copper and iron by the formation of complexes which are poorly absorbed (Davis et al., 1962; Liener, 1981; Ellis and Norris, 1981). However, other






26

researchers have reported that the small amount of phytate present in the soybean protein does not affect the bioavailability of copper (Grace et al., 1984), iron (Welch and Van Campen, 1975) or magnesium (Lo et al., 1980). Recent evidence has indicated that heating raw soybeans can reduce their phytic acid content (Liener, 1981).

The inclusion of unheated soybean meal in diets of chicks increased their susceptibility to rickets unless higher than recommended levels of vitamin D3were added to the diet (Carlson et al., 1964). Autoclaving the soybean meal or supplementation with calcium and phosphorus also eliminated the occurrence of rickets (Jensen and Mraz, 1966).

Raw soybeans contain a heat-labile substance that increased the requirement for vitamin B 12in rats (Edelstein and Gugjgenheim, 1970a). The metabolites associated with enzymes that require vitamin B 12as a coenzyme are also increased (Edelstein and Guggenheim, 1970b). Supplementation of raw soybean meal diets with vitamin B 12 stimulated growth of rats (Rackis, 1981). However, Ward et al. (1986)

recently reported that raw soybeans did not enhance B 12 turnover or impair B12 absorption in chicks.

Supplementing diets containing raw soybeans with other trace

minerals has been shown to improve animal performance. The addition of 125 ppm copper sulfate to diets containing raw soybeans increased average daily gain and feed efficiency of market hogs (Young et al., 1970). The researchers did not speculate whether the response was due to the copper per se or indirectly from the bacteriostatic effect of the copper sulfate. Linerode et al. (1961) obtained no nutritional







27

benefit from adding a zinc supplement in a turkey diet containing raw soybeans. Other studies utilizing iodine-deficient diets have indicated that feeding raw soybeans caused marked enlargement of the thyroid glands of rats and chicks, an effect which could be counteracted by administration of potassium iodide or partially eliminated by heat processing soybeans (Patton et al., 1939; Block et al., 1961).

Other Anti-Nutritional Factors

Other constituents of soybeans have been implicated as being responsible for the reduced performance commonly associated with feeding raw soybeans. For example, hemagglutinins, a glycoprotein (Lis et al., 1966), was isolated from soybeans in 1952 (Liener and Pallensch, 1952) and later determined to comprise an estimated 1 to 3% of the protein of defatted soybean flour (Liener and Rose, 1953). Hemagglutinins, also known as lectins, appear to function similarly to trypsin inhibitors in the soybean plant as defensive proteins that protect the plant from insect invasion and are appropriately located on the surface of the plant cell (Lehninger, 1982). Lectins bind to certain carbohydrate groups, D-galactose and N-acetyl-D-galactosamine, on the cell surface. Soybean lectins have been shown to be readily destroyed by heat treatment and their destruction was accompanied by a marked improvement in the nutritive value of the protein when fed to chicks (Liener and Hill, 1953). However, rats fed soybean extracts, from which the lectins had been removed by affinity chromatography, grew just as poorly as those consuming the original crude soybean extract (Liener, 1981). Therefore, it appears that lectins do not play a major role in reducing the nutritional quality of soybean protein.









Another anti-nutritional factor, saponin, which has been found in some plants to have an adverse effect on animal growth, is also a constituent of soybeans. However, feeding chicks, rats, and mice diets supplemented with three times the level of saponin found in soybean flour was not detrimental to performance (Ishaaya et al., 1969).

Soybean Processing

As previously discussed, heat processing inactivates several anti-nutritional factors in soybeans, such as trypsin inhibitors, hemagglutinins, goitrogens, antivitamins and phytates (Liener, 1981). However, soybeans contain other proposed anti-nutritional factors, such as saponins, estrogenic compounds, and flatulence compounds, which are heat-stable. Also, some components of raw soybeans (pyridoxine, total and free folacin) which are needed for growth are reduced when soybeans are heated (Soetrisno et al., 1982). Sugawara et al. (1985) found that the green or grassy odor of soybeans disappeared or decreased by heating but the beany odor remained even if the soybeans were heated for 8 hours.

Water-extractable proteins from soybeans can be separated into four fractions with approximate sedimentation rates of 2, 7, 11 and 15S, and comprise 22, 37, 31 and 11% of the total protein in soybeans, respectively (DeMan, 1980). Trypsin inhibitors are located in the 2S fraction. The 7S fraction contains lectins, lipoxygenase (the enzyme that catalyzes the oxidation of lipids) and 7S globulin; whereas, the 11S fraction consists mainly of 11S globulin (glycinin). The 7S and 11S (glycinin) globulins are the major storage proteins of soybean







29

seeds. The 75 globulin, a glycoprotein, is present as a monomer with molecular weight of 180,000 to 210,000 daltons. Glycinin is a large molecule of 290,000 to 320,000 dalton molecular weight composed of 12 subunits having a rigid globular conformation (Kitamura et al., 1976). The 155 fraction has proteins with molecular weights approximately 600,000 daltons.

The application of heat to soybean protein has been shown to

alter the hydrogen and hydrophobic bonds which resulted in decreased water solubility of the proteins (DeMan, 1980). Kakade et al. (1973) suggested that native undenatured soybean protein is in itself refactory to enzymatic attack unless denatured by heat. Subsequent research indicated that glycinin in raw soybeans resists proteolytic attack (Kamata et al., 1979). Heating glycinin at 100 C increased the digestibility by denaturation or unfolding the conformation of the protein (form digested at a fairly high rate). However, heating glycinin at 120 C caused decreased digestibility suggesting that excess heat causes refolding of the protein in a new conformation that is more resistant to enzymatic attack.

The heating of raw soybeans has been shown to increase the

nutritional availability of sulphur and nitrogen in diets fed to rats (Johnson et al., 1939). The availabilities of methionine and cystine in trials with chicks increased until a temperature of 120 C was obtained; after which the availabilities then decreased (Evans and McGinnis, 1946). Carroll et al. (1953) reported that proper heat treatment of soybean meal increased absorption of lysine, leucine and methionine in rats but the greatest improvement was with cystine absorption. In addition, plasma levels of threonine and trytophan in









rats were increased markedly by heating the soybeans, indicating increased digestibility and absorption of these amino acids (Rao et al., 1971).

Effects of Overheating Soybeans

Overheating soybean protein impaired its nutritional quality. Evans and associates (Evans and McGinnis, 1946; Evans and McGinnis, 1948; Evans et al., 1951; Evans et al., 1962) have conducted extensive research with overheated soybean protein. They reported that with chickens, cystine was the limiting amino acid in overheated soybeans. Methionine availability was also decreased when soybean protein was autoclaved at 120 C. These workers indicated that 31% of the total cystine was destroyed and 25% became inactivated with autoclaving. The relative availabilities of cystine and methionine by chicks were increased by autoclaving raw soybeans at 100 C for 30 minutes; but autoclaving the soybeans at 130 C for 60 minutes reduced the quantity of cystine utilized to the level equivalent of feeding raw soybeans while methionine utilization was decreased. In addition, adding sucrose or glucose to soybeans increased inactivation of cystine by four fold. Subsequent research has shown that some of the soybean proteins appear to have more heat labile cystine than other soybean proteins. Iriarte and Barnes (1966) presented data which indicated that the amount of heat required to destroy the growth inhibitors also destroyed some of the cystine; such that it was the first limiting amino acid. More recent results by Crissey and Thomas (1983) further illustrated the reduced availabilities of methionine and lysine due to extreme overheating of soybeans. These researchers fed roosters commercial soybean meal CSBM) that had received additional






31
autoclaving for one hour at 121 C then dried the meal for 30 minutes and reported a 38 and 22% increase in the excretion of methionine and lysine, respectively.

Lysine destruction can also be used as a indicator in determining the nutritive value of overheated soybeans. Evans and Butts (1948) and Evans and McGinnis (1948) reported a greater proportion of the lysine was made inactive than was destroyed. Their results showed a greater percentage of lysine inactivated with an increase in heating temperature. The addition of sucrose or glucose further increased the binding of lysine to a form which was unavailable to enzymatic digestion. In addition to cystine, methionine and lysine, other amino acids including arginine, tryptophan, histidine and serene were partially destroyed or denatured by excessive heating of soybean meal (Liener, 1958; Skrede and Krugdehl, 1985).

Kasarda and Black (1968) implied that overheating of soybean

protein was a major source of ammonia evolution which could react with the available reducing sugars to form pyrazine compounds. Scott et al. (1969) noted that soybean products contain reducing carbohydrates such as glucose and these sugars can react with the free epsilon amino group of lysine in the soybean protein. This reaction is termed the "Maillard" or "browning" reaction. Heat treatment accelerates the formation of carboydrate-amino group complexes which are resistant to enzymatic hydrolysis. The result is that amino acids (especially lysine) become nutritionally unavailable. Knipfel et al. (1975) autoclaved soybean protein with different carbohydates at 121 C for 0 to 1280 minutes. Soybean protein autoclaved with sucrose, glucose,









or fructose reduced rat growth, net protein ratio and protein digestibility more than soybean protein which was autoclaved with starch and cellulose or without the added carbohydrates. Plasma lysine was reduced more than plasma methionine when rats were fed soybean protein heated with glucose, fructose and sucrose.

Supplementation of amino acids to the diets containing overheated soybeans has been studied in trials with chicks by Evans and McGinnis (1946). The addition of cystine, lysine, and methionine to the diet improved chick growth. Single addition of any of these amino acids simply did not ameliorate the depressed growth obtained from feeding overheated soybeans.

Improvement of the Nutritive Value.of SQbeans by Heat Processing

Many factors such as heating temperature# pressures and time are very important in obtaining the maximum nutritional value from heating soybeans. Optimum chick growth required heating soybeans 30 minutes at 107 C (Carew et al., 1961). These heating conditions confirmed earlier work of Evans and McGinnis (1946) which obtained the best chick performance when feeding soybeans that were also heated for 30 minutes at 100 to 120 C, although they found that no processing temperature above 120 C further improved protein quality for chicks. Subsequent research by Arnold (1973) indicated that heating temperatures above 120 C could produce optimum chick performance. He reported that optimum performance was obtained by heating soybeans at 149 to 160 C for 10 minutes or 171 to 194 C for 5 minutes. Featherston and Rogler (1966) reported improved soybean protein utilization when compared to the other treatments in chicks fed full-fat soybean flakes heated at 133 C for 20 minutes. Simovic et






33

al. (1972) studied even higher temperatures and indicated that temperatures up to 158 C could be used satisfactorily but, above this temperature, the soybeans became charred. The temperatures were 95.5p 111.0, 127.0 and 158.0 C with heating durations of 3.0, 2.5, 1.5 to

2.0, or 1.0 minute, respectively.

Noland et al. (1966) reported the best heating treatment for

soybeans was 60 minutes at 115 C for pigs and 24 to 72 minutes at 115 C for rats. Feeding early weaned pigs, Lawrence (1967) obtained better heating results when soybeans were autoclaved for 24 to 36 minutes at 110 C than for longer or shorter periods of time. Subjecting raw defatted soybean flakes to live steam at atmospheric pressure (approximately 100 C) for 10 or 60 minutes permitted similar rate and efficiency of growth and feed intake when fed to weanling pigs (Clawson et al., 1981). Prior to heating, the raw soyflakes were mixed 5:1 (w/w) with water. Becker et al. (1953) reported superior growth of pigs from weaning to market when fed diets containing soybeans toasted in a French cooker for 38 to 55 minutes at 99 to 116 C compared to pigs fed diets containing soybeans toasted for 18 to 20 minutes or 33 to 37 minutes at 99 to 104 C.

Hayward et al. (1936a) indicated that autoclaving soybeans for one hour at 1.06 gm/cm pressure doubled the nutritive value of the protein when fed to rats. Westfall and Hauge (1948) demonstrated that soybean flour heated at 108 C for 15 to 30 minutes resulted in superior soybean protein when included in a mouse diet. Likewise, Rackis (1966) achieved maximum protein efficiency and trypsin Inhibitor Inactivation of full-fat and defatted soyflakes by steaming






34

at 100 C for only 15 minutes in trials with rats. Subsequent research using higher heat processing temperatures suggested that the optimum heating period for ground whole soybeans fed to rats was 10 to 20 minutes at 120 or 132 C compared to soybeans heated at 100 C (Seerley et al., 1974).

The oil from soybeans can be removed by various extraction

processes and the heating time required to produce a nutritionally optimum soybean meal varied among the different methods (Hayward et al., 1936b). To produce optimum quality protein, expeller processed meal needed 2 to 3 minutes at 112 to 150 C, hydraulic processed meal needed 90 minutes at 105 to 124 C, and the solvent extracted meal required 15 minutes at 98 C. Ethanol extraction of raw soybeans improved performance of pigs compared to the feeding of raw unextracted soybeans, yet the improvement was still lower when compared to soybeans that were heat-treated (Hancock et al.* 1985). Another method for extraction of the soybean oil, supercritical carbon dioxide at a temperature of 80 C for 8.3 hours, did not denature the trypsin Inhibitor activity of raw soybeans (Pubols et al., 1985). Toasting at 109 C for 5 minutes was required to inactivate the toxic factors and permit optimum chick growth (McFarland and Pubols, 1982). Renner and Hill (1960) also noted a variation in nutritive value

between extracted dehulled raw soyflakes, and ground raw soybeans when fed to chicks. The extracted dehulled raw soyflakes had received optimrum heat processing with a wide range of heating times (10 to 60 minutes) at 107 C whereas, the ground soybeans had an optimum cook of 10 minutes at 107 C. These products produced maximum metabolizable energy values and rate and efficiency of chick growth.









The moisture content of soybeans prior to heat processing greatly influences the heating time required to produce quality soybean products (Albrecht et al. 1966). Trypsin inhibitors were readily destroyed by atmospheric steaming for 20 minutes provided the soybeans contained about 25% moisture before steaming, whereas soybeans containing lower inital moisture content required a longer heating time or higher processing temperatures. However, when moisture content of the soybeans was elevated to 60% by soaking overnight then only 5 minutes of atmospheric steaming was required to inactivate the trypsin inhibitors. Likewise, Waldroup et al. (1985) reported that the addition of 12% water to soybeans prior to heating decreased the time required to produce adequate protein supplements for chicks. However, Seerley et al. (1974) fed rats soybeans which had 10 or 20% moisture added prior to heating at 118 C for 40 minutes and noted no difference in their performance that could be attributed to initial moisture level. There is evidence to suggest that moist heat can reduce the damaging effects of overheating soybean protein (Renner et al., 1953).

Other methods used to denature the anti-nutritional factors of soybeans and improve their nutritional value have been studied. For example, the addition of thiols such as cysteine and N-acetyl-cysteine facilitates heat inactivation in the temperature range of 25 to 85 C thereby decreasing the damage to heat sensitive amino acid residues such as cystine, methionine and lysine (Leir et al., 1981; Friedman et al., 1982). This method also increased the limited sulphur content of soybeans. It was postulated that the cations of thiols were involved







36

in the formation of mixed disulfide bonds between the added thiols and enzyme inhibitors and structural proteins. The addition of cysteine prior to heating can also facilitate the heat inactivation of trypsin inhibitors in both purified soybean Kunitz inhibitor and soybean extracts, thereby indicating increased protein digestibility, protein efficiency ratio and nutritive value of soybeans (Friedman et al., 1984).

Other Methods of Processing Soybeans

Germination of whole raw soybeans has also been reported to imp ove their nutritional quality by increasing the protein dispersibility index (PDI) and improving the odor and flavor scores as evaluated by an 8-member panel test (Suberbie et al., 1981). During the early phases of germination, reserve proteins were mobilized at a steady rate, but carbohydrates were quickly depleted (McAlister and Krober, 1951). Mobilization of fat began immediately after depletion of the carbohydrate in the seed. Thus, the non-protein nitrogen content doubled (Becker et al., 1940) and the level of offending oligosaccharides were reduced markedly during germination (Pazor et al., 1962; East et al., 1972). Sprouting also reduced the energy, dry matter, total lipids, starch and concentrations of the amino acids alanine, arginine, glutamic acid, threonine, glycine, lysine, proline and serine compared to ungerminated soybeans (Peer and Leeson, 1985). These researchers further noted an increased ash, aspartic acid and leucine but no change in the concentrations of histidine, isoleucine, methionine, phenylalanine and tyrosine due to germination. Since the total protein content did not change, the percentage of individual amino acids was altered.







37

The trypsin inhibitor content of soybeans during germination has been reported to change very little (Desikachar and De, 1947; Collins and Sanders, 1976). However, other researchers have noted a reduction in trypsin inhibitor as well as lipoxygenase activity during germination (Suberbie et al., 1981). Freed and Ryan (1978a) found a

13% reduction in the Kunitz trypsin inhibitor activity after seeds had been sprouting for nine days. Bates et al. (1977) obtained a 33% reduction In total trypsin inhibitor activity after only four days of sprouting and Collins and Sanders (1976) reported that up to 13% was reduced after germinating the soybeans for only three days. Likewise, Peer and Leeson (1985) reported that trypsin inhibitor activity was reduced in a cubic trend with increased sprouting time. Freed and Ryan (1978b) found that only modified forms of the Kunitz inhibitor appeared during germination.

The actual benefit of germinating soybeans per se on the

reduction of trypsin inhibitor activity in soybeans may be limited. Collins and Sanders (1976) found that soaking four different varieties of soybeans in water for one hour reduced their trypsin inhibitor activity between 3.4 to 10.2%.

Germination increased the nutritive value of soybeans fed to rats (Desikachar and De, 1947) but not for chicks (Mattingly and Bird, 1945). Everson et al. (1944) confirmed that sprouted soybeans had better feeding value for rats compared to the raw unsprouted soybeans. However, autoclaving both products provided additional growth responses.







38

Fermentation has also been used to improve the nutritional value of soybeans (Zamora and Veum, 1979). After heating whole soybeans at 121 C for 30 minutes, they were fermented with Ae il ua oryzae or Rhizopus oligosporus. During fermentation, dry matter was reduced by 3% and the percentages of lysine, leucine and methionine increased slightly. Feeding pigs a diet containing soybeans fermented with Aspergillus orzae resulted in faster growth than pigs fed an unfermented (only heated) whole soybean diet. Feed efficiency, metabolizable energy and nitrogen utilization for pigs fed the fermented soybean diets were increased compared to pigs fed soybean meal and unfermented soybean diets.

Treating raw soybean meal with formaldehyde (1% of the meal protein content) inactivated 99, 97 and 40% of the trypsin- and chymotrypsin-inhibiting and urease activities, respectively (Nitsan and Bruckental, 1977). When fed to chicks, both soybean diets (raw and heated) containing formaldehyde reduced body weight gain, feed efficiency and protein efficiency ratio compared to chicks fed either diet unsupplemented with formaldehyde. The reduction in these measured parameters due to the inclusion of formaldehyde in the diet containing heated soybeans was greater when compared to the diet containing unsupplemented raw soybeans. However, pancreatic hypertrophy and pancreatic trypsin, chymotrypsin, lipase and amylase activities were decreased by adding formaldehyde to the raw soybean diet. Also, these researchers reported that formaldehyde addition in the raw soybeans resulted in increased intestinal trypsin content but decreased amylase in both the small intestine and cecum when compared







39

to feeding the unsupplemented raw soybean diet. Cecal trypsin and chymotrypsin activities did not differ significantly between these two treatments.

Dal Borgo et al. (1967) reported that young chicks were able to utilize raw soybeans more efficiently when fed in combination with glucose or sucrose than when starch was provided as the source of carbohydrate. These effects were not obtained with heated soybean meal. Recent research by Pontif et al. (1986a) reported that changing the dietary carbohydrate source from corn to wheat in raw and heated soybean diets resulted In reduced average daily gain. No reduction was noticed when the carbohydrate source was comprised of a mixture of corn and wheat.

Swine Feeding Trials

Numerous processing methods have been reported to yield quality soybean products. Among these are autoclaving (Combs et al., 1967), roasting (Baird, 1983), extrusion (Baird, 1983), and the use of microwaves (Hafez et al., 1985; Fuller and Owingst 1986). The heat generated during the process of pelleting was not adequate to produce a quality soybean supplement (Hanke et al., 1972; Hooks et al., 1967b).

The superiority of feeding heated soybeans compared to feeding raw soybeans to pigs is well documented. Performance of 8-week-old pigs was improved by feeding soybeans heated in an autoclave (Combs et al.* 1967). Roasting and extrusion were also adequate heat processing methods of soybeans fed weanling pigs (Noland et al., 1976). However, Rust et al. (1972) reported that roasting (141 C) and extrusion (125 C) of whole soybeans were inadequate heat treatments compared to SBM







40

fed to pigs weaned at 21 days of age, although feed efficiency was similar between pigs fed the SBM and the two heated soybean diets. Similar adverse effects due to feeding roasted soybeans to weanling pigs were noted by Crenshaw and Danielson (1985a). Pelleting soybean meal or raw soybean diets fed to four-week-old pigs did not improve performance of pigs fed either diet (Crenshaw and Danielson, 1984a).

Adams and Jensen (1985) compared the feeding value of soybeans that had been extruded or roasted for weanling pigs and reported that extrusion increased digestibilities of fat, dry matter, energy and nitrogen and metabolizable energy compared to roasting. In addition, grinding the roasted soybeans through a fine as opposed through a coarse screen did not affect their feeding value. Infra-red roasting of soybeans fed to weanling pigs provided equal growth and feed efficiency but reduced digestiblities of dry matter, ether extract and energy compared to pigs fed extruded soybeans (Faber and Zimmerman, 1973). However, the biological value of the two products was equal.

Kinyamu et al. (1985) compared the performance of weanling pigs fed diets containing SBM, extruded soybeans or Jetsploded soybeans having trypsin inhibitor activities of 6.3, 8.1 and 28.0 units per milligram, respectively. The Jetsploded method requires that the soybeans be heated at a high enough temperature to cause the soybeans to burst. The extrusion method uses both steam and pressure (friction) to process the soybeans. The pigs fed the diet containing Jetsploded soybeans grew slower and were less efficient compared to pigs fed diets with soybean meal or extruded soybeans. Digestion coefficients for each diet followed a similar trend as the performance data.







41

A preponderance of research on feeding soybeans to

growing-finishing pigs has established that raw soybeans are an inadequate protein source and require heat processing for maximum performance of growing pigs. However# research on the necessity to heat soybeans for finishing pigs is inconclusive. Jimenez et al. (1963) found that the growth of growing-finishing pigs was improved by feeding whole soybeans which had received a heat treatment. Soybeans have been subjected to various methods of heat processing to produce adequate soybeans fed to growing-finishing pigs. Among the different processing methods are infra-red heating (Noland et al., 1970; Wahlstrom et al., 1971), dry-roasting (Hanke et al., 1972; Baird, 1983; Miller et al., 1985), extrusion (Noland et al., 1969; Hanke et al., 1972; Baird, 1983)p cooking in a six-stack French cooker at 110 C for 10 minutes (Seerley et al., 1974) and cooking soybeans for six hours in a 40 gallon feed cooker mixed in a 1.0:1.7 ratio with water (Young, 1969).

Chin and Diggs (1986) reported higher values for digestible and metabolizable energy, nitrogen-corrected metabolizable energy and digestible nitrogen from feeding roasted soybeans compared to raw soybeans, but the percent ;e nitrogen retained did not differ between the two protein supplements.

Roasting temperature is critical to produce a soybean product

having optimum nutritional quality for swine (Campbell et al., 1984). These researchers reported that roasting soybeans at 110 C did not permit similar growth of growing-finishing pigs fed SBM, although a roasting temperature of 125 C produced soybeans which had equal









nutritional value as that of commercial SBM. Likewise, extruding soybeans at 132 and 143 C provided equal growth to SBM yet improved growth compared to pigs fed soybeans extruded at 115 C (Seerley et al., 1974). Crenshaw and Danielson (1985b) substantiated earlier work which indicate that roasted soybeans were adequate protein supplements for growing-finishing pigs but also noted that barrows significantly utilized roasted soybeans more effectively than gilts.

Recent research has provided additional evidence that raw

soybeans are not an adequate protein supplement for growing-finishing pigs and performance was not improved when soybeans were substituted in place of SBM on a equal weight basis or when diets were reformulated to be isonitrogenous diets (Crenshaw and Danielson, 1984b). Likewise, replacing the SBM in the diet fed to growing pigs with 0, 33, 67, and 100% raw soybeans resulted in a linear decrease in average daily gain, feed efficiency, feed intake and loin-eye area (Pontif et al.* 1986b).

The age of the pig may influence the extent to which the

anti-nutritional factors in raw soybeans affect animal performance. The beneficial effects of feeding heated soybeans to swine decreased with pig maturity (Combs and Wallace, 1969). These researchers compared effects of feeding diets containing SBM, raw and autoclaved soybeans to three-, nine- and 16-week-old pigs. Performance of the three- and nine-week-old pigs was adversely affected by feeding diets containing raw soybeans. The heated soybean diet was inadequate for three-week-old pigs when compared to the SBM diet but yielded similar performance when fed to nine-week-old pigs. Sixteen week-old pigs









were able to utilize heated and raw soybeans as effectively as properly heated SBM. Recent research indicated that feeding raw soybeans to growing-finishing pigs resulted in reduced performance regardless of initial age and weight of pigs (Crenshaw and Danielson, 1985c). Likewise Pontif et al. (1986b) reported that the replacement of dietary SBM with raw soybeans when pigs weighed 59 kg decreased the rate and efficiency of growth and feed intake. However, the significance level on the growth data was between .05 and .10%. Jensen et al. (1970) and Hanke et al. (1972) reported also that raw soybeans were not an adequate protein supplement for finishing pigs and the heat generated during pelleting was not sufficient to improve

their nutritional value.

In more mature swine, gilts and sows, the data on feeding raw soybeans have been more consistent. Gestating swine were able to reproduce normally, through second and third parities, when fed diets containing raw soybeans as the only source of supplemental protein (Crenshaw and Danielson, 1983; Crenshaw and Danielson, 1985d) SBM as a protein source in gestation and lactation diets (Danielson and Crenshaw, 1984). Allee et al. (1985) confirmed that feeding raw soybeans to sows would not impair their reproductive performance but the sows fed raw soybeans lost more weight during lactation than sows fed SBM. Noland et al. (1971) reported that the whole soybean plant (pods, leaves and stems) could be pelleted to provide adequate protein supplementation for gestating swine. The plant was cut, dehydrated and pelleted when the largest pods were full grown, seeds were full size and leaves were just beginning to yellow. This soybean product,







44

supplemented with ground corn, vitamins and minerals, provided satisfactory nutrition for gilts and sows when self-fed through the

gestation period.

Poultry Feeding Trials

By comparison, the inconsistencies of feeding raw soybeans

related to swine maturity are similar to that of feeding raw soybeans to poultry. Waldroup (1982) presented an excellent review on feeding whole soybeans to poultry so the following discussion pertains only to changes in maturity. Similar to weanling pigs, the inclusion of raw soybeans to the diet of broiler chicks adversely affected growth compared to chicks fed heated soybeans. Ogundipe and Adams (1974) reported depressed body weight of pullets when feeding raw unextracted soybeans from 11 to 20 weeks of age, although Saxena et al. (1963) had previously reported that chicks 6 to 12 weeks of age could effectively utilize diets containing raw soybeans. Barnstein and Lipstein (1962) suggested that chicks of any age, when fed a diet containing raw soybeans, would have a reduction in growth but as chicks matured, the time of adaptation to raw soybeans decreased. Several researchers have indicated that raw soybeans could replace SBM in laying hen diets without a reduction in egg production (Saxena et al., 1963; Latshaw and Clayton, 1976; Latshaw, 1974). However, other researchers have reported that raw soybeans were not an acceptable protein supplement for laying hens (Fisher et al., 1957; Rogler and Carrick, 1964; Waldroup and Hazen, 1978). Thus, raw soybeans could be processed to provide an acceptable protein supplement for laying hens by roasting and extrusion (Waldroup et al., 1969; Waldroup and Hazen, 1978),







45

adequately supplementing the diet with methionine (Salmon and McGinnis, 1968) or including methionine and/or vitamin B 12in the raw soybean diet (Fisher et al., 1957). In contrast, Waldroup et al. (1969) reported that adding synthetic lysine and methionine to layer diets containing raw soybeans did not ameliorate the adverse effect on egg production.

Composition of Commercial Soybean Keal

The National Soybean Processors Association considers that SBM (48% protein) is of acceptable quality when it has less than 12% moisture, greater then 48% crude protein and less then 3.4% crude fiber (Jones, 1984). Hill and Renner (1960) reported limited variation in protein, fat, fiber, ash, and metabolizable energy content of SBM. However, a more recent study of SBM samples obtained from 18 different feed companies and five different SBM manufacturers collected during a 6-year period demonstrated that significant differences in fat and fiber content of SBM occurred among samples taken in different years (Jones, 1984). Also, moisture, protein and fiber contents were significantly different between SBM samples obtained from the different suppliers. The number of samples that did not attain the minimum acceptable quality standards increased from 39.6% in 1976 to a high of 83.3% in 1983. Upon further investigation, it was noticed that most deficiencies (40 to 60%) occurred in samples having greater then 12% moisture. Furthermore, variation has also been observed in amino acid content of SBM (Whitacre et al., 1984). The researchers found that the average content of niethionine, lysine and protein in 175 SBM samples was .6, 2.6 and 46.7%p respectively.







46

For comparison, the National Research Council (1979) considers the content of methionine, lysine, and protein to be .7, 3.2 and 48.5% respectively.

Although the nutritional composition of soybeans used in the

processing of various soybean nieals is very important, it is necessary to subject soybeans to an adequate amount of heat processing. Longenecker et al. (1964) found marked differences in manufacturing processes for soybean concentrates and reported that in most instances heat treatment was not adequate to support maximum growth when included in diets for weanling rats. Several researchers have suggested that commercial SBM is heated for much longer periods than is required to produce optimum quality protein supplements for weanling pigs (Lawrence, 1967) and rats (Noland et al., 1966). Campbell (1974) fed weanling pigs SBM which had been processed in

Arkansas and in Illinois and the rate arid efficiency of growth of pigs fed the Arkansas SBM were increased compared to pigs fed the Illinois SBM. However, neither SBM equaled the performance obtained by feeding adequately processed full-fat soyflakes. Although not neccessarily confirming SBM is overheated, research by Clawson et al. (1981) demonstrated that SBM~ was not underheated. These researchers fed weanling pigs SBM with and without 30 minutes of additional heating with live steam at atmospheric pressure (approximately 100 C), reducing the trypsin inhibitor units from 7 to 2 per mg, and reported no difference in pig performance.

Other researchers have indicated that SBM received insufficient heat processing for optimum performance of day-old chicks CMcNaughton








et al., 1981). The SBM was autoclaved at a temperature of 110 C in 5 minutes increments. Extra processing was required before the broilers could attain their genetic potential for growth. The best performance was obtained by feeding broilers SBM autoclaved an additional 10 minutes.

As previously discussed, heat processing improved the nutritive value of soybeans by inactivating anti-nutritional factors. Trypsin inhibitors are considered the most important anti-nutritional factor in soybeans. However, soybeans also contain the enzyme urease which has little nutritional importance In poultry and swine diets. It is significant that the urease content is currently used by the SBM processing plants to evaluate optimum processing conditions. The analytical method developed by Caskey and Knapp (1944) monitors the urease-urea relationship in the soybean. In this method, urea Is degraded by urease and the pH of the media rises due to formation of ammonia and the resultant change in pH is recorded as the urease activity (UA). This analysis is easier and quicker to conduct than determining the trypsin inhibitor content. Since the heat treatment of soybeans required to denature the urease content parallels the heat treatment necessary to inactivate trypsin inhibitors, the UA is considered a good indication of adequate heat processing (Caskey and Knapp, 1944; Albrecht et al., 1966; McNaughton and Reece* 1980). In addition, the inactivation of trypsin inhibitor and urease activities during heat processing precedes the destruction of lysine (McNaughton and Reece, 1980). However, Borchers et al. (1947) observed that urease was more sensitive to heat inactivation than trypsin inhibitors









and should not be regarded as being completely accurate in determining adequacy of heat processing. These researchers along with Balloun et al. (1953) reported that the UA is of little value for detecting overheated soybean meal.

The American Feed Manufacturer Association considers that SBM having UA in the range of .05 to .20 change in pH units has received adequate heat processing (Smith, 1977) which is a reduction from a UA of approximately 2.0 for raw soybeans. However, Harris (1983) reported a commercial lot of SBM with a UA of .83; thus the quality of commercial SBM being marketed does vary. Likewise, Jones (1984) assayed 1729 SBM samples taken over three years from four different suppliers for UA and reported that some SBM samples had UA higher than

1.0. There were significant differences in SBM quality manufactured by the four different suppliers, UA were .057, .074, .041 and .109, respectively. The UA value of SBM also increased according to the year it was produced, being .062, .089 and .091 for 1981, 1982 and 1983, respectively. In addition, SBM samples processed in the colder months (Oct., Nov. and Dec.) were higher in UA. Soybean meal samples (277) obtained from one source had 2.88% with UA greater than .91. In a recent study by Rudolph et al. (1983) comparing the digestibility of nitrogen and amino acids between different SBM (48.5% and 44.0%) with soybean flour, the UA of the 48.5% and 44.0% SBM was .46 and .21, respectively. Also, SBM can be overheated as indicated by Noland et al. (1976). They received SBM having a UA of .02 and reported unsatisfactory performance when fed to weanling pigs.







49

Edwards (1983) reported a range in UA between .006 and .208 in commercial SBM from different processors. One source produced SBM having consistently higher trypsin inhibitor and UA activities which

concurrently produced a higher incidence of tibial dyschondroplasia when fed to chicks. However, gains and feed efficiencies were similar in chicks fed the various SBM.

Early research data indicating optimum heating times and

temperatures without the UA and trypsin inhibitor activities in SBM are difficult to compare since the actual heat treatment cannot be determined. Different procedures for estimating trypsin inhibitor activity were, and are being, reported which hinders using the trypsin inhibitor activity to compare research data. The UA is a common analysis and allows more reliable comparison. Rackis (1968) stated that SBM with UA between 0.05 and 0.15 has been properly heated for maximum nutritional value. However, Lawrence (1967), feeding early weaned pigs, reported maximum pig performance when fed SBM with UA of

0.01 to 0.02 as contrasted to either greater, or lesser pH change. Likewise, Noland et al. (1976) reported that autoclaved full-fat soyflakes having a UA of .03 and .05 supported higher feed intake and better gains of 8.2 kg pigs than soyflakes having UA of .01 and .11 and SBM having UA of .02. In contrast, Hansen et al. (1984a) fed SBM with and without extra heat processing having UA of .02 and .11, respectively to pigs weaned at 4 weeks of age and reported no preference to either diet when given a choice and no difference in pig performance (Hansen et al., 1984b).







50

Nitrogen balance and gross energy digestibility were similar in growing pigs fed SBM with UA ranging between .01 and .19 (Chai-Ju et al., 1984). Also, apparent ileal nitrogen and individual amino acid digestibilities did not differ. Likewise, feeding defatted soyflakes ranging in UA between .05 and .48 to barrows ranging in weight from 25 to 45 kg resulted in no significant differences in nitrogen, amino acid and energy digestibilities and nitrogen retention between the different soyflake treatments (Vandergrift et al., 1983). Pig growth and feed efficiency were not influenced by the imposed dietary treatment groups. Rudolph et al. (1983) confirmed the high nutritional value of soybean products (48.5% SBM) having a high UA of .46 for 38 kg barrows. The barrows in Rudolph's and Vandergrift's studies were limit-fed. One adverse effect associated with feeding low quality soy products to swine has been depressed feed intake. Seerley et al. (1974) fed extruded soybeans to 28.9 kg pigs having a UA of .53 and reported that the growth of these pigs did not differ from pigs fed SBM. However, the amount of feed required per unit of weight gain was increased in pigs fed the soybean product having a UA of .53. The pigs were full-fed but feed intake was not reported. The extruded soybeans having a UA of 1.83 in this study were inadequate protein supplements for growing pigs.

Research on the optimum heat processing of SBM fed to chicks

indicates variation similar to that reported for pigs. McNaughton et al. (1981) fed day-old chicks commercial SBM containing a UA of .19 compared to the same SBM having additional heating to reduce the UA to .02. The best performance was obtained by feeding broilers the






51

autoclaved SBM having a UA of .02. More recent research has indicated no difference in amino acid availability in SBM with a UA of 0 and .10 (Dale et al., 1986). However, SBM having a UA below .05 was previously thought to be overheated. Also, additional research has indicated that SBM with UA as high as .50 was an adequate protein supplement for broiler chicks (Waldroup et al., 1985). Likewise, Mian and Garlich (1985) found no difference in growth of turkey poults fed SBM with UA between .14 and .90. However, soybean meals with UA of .02 and 1.50 were inferior to the other treatment groups.

Some differences in the UA of SBM being marketed may be

attributed to the percent moisture of the soybeans before processing (McNaughton and Reece, 1980). These researchers reported that increasing the moisture content of defatted soyflakes enhances the denaturation of urease and trypsin inhibitors. Mustakes et al. (1981) reported that the quality of SBM was influenced by heating time, jacket-steam pressure and moisture content. The moisture content of SBM prior to entering the toaster was directly affected by the hexane level remaining after the oil removal process.

Although the trypsin inhibitor activity of soybean meal is

considered important in livestock and poultry feeds, Gillette et al. (1978) found no correlation between growth and the trypsin inhibitor activity in commercial SBM being fed to rats. Likewise, Kakade et al. (1972) reported no correlation between trypsin inhibitor activity and protein efficiency ratio in rat diets containing over 100 different varieties of soybeans.






52

Another assay to facilitate the determination of optimum soybean processing was developed by McNaughton et al. (1981). They reported that optimum heat processing could be determined by observing the change in color of the soybeans. These researchers used a Hunterlab colorimeter on the +a band to predict the trypsin inhibitor content in autoclaved SBM. However, Rudolph et al. (1983) determined color values of various soybean products using the procedure described by McNaughton and reported the +a color values did not coincide well with the trypsin inhibitor values of the different soybean products.

A method which can be used to determine the protein quality of soybean meal and other protein sources fed to chicks is measuring the uric acid excretion (Miles and Featherston, 1976). Protein efficiency ratio and uric acid excretion were similar indicators of protein quality. This method is of value for studies in chicks where separation of urinary and fecal nitrogen determination is extremely difficult.

A recent technique to more adequately evaluate the quality of soybean products has been conducted with pigs having a cannula inserted at the end of the small intestine (Vandergrift et al., 1983; Rudolph et al., 1983; Ozimek and Sauer, 1985). Therefore, a measurement of the actual uptake of nutrients can be determined. Vandergrift et al. (1983) presented data showing that a larger quantity of nutrients from raw soyflakes is digested in the cecum and large intestine by the microflora compared to adequately heated soyflakes. The range in differences in the digestibilities of nitrogen and amino acids was 14.3 to 50.6% for raw soyflakes and .5 to






53

20.6% for soyflakes heated for 25 minutes at a maximum temperature of 100 C. Van Weerden et al. (1985) compared differences between leal and fecal digestibilities of normal toasted, slightly undertoasted and slightly overtoasted SBM fed to growing pigs. No differences were observed in fecal digestibilities among the SBM's, whereas the ileal digestibilities of organic matter, crude protein, lysine, sulfur amino acids, threonine and tryptophan were reduced in the under- and over-toasted SBM's. Ileal digestibility of the carbohydrate in the normal toasted meal was increased 35 to 50% compared to the under- and over-toasted meals.

Variation Among Soybean Varieties

One factor contributing to the variability in SBM can be

associated with different soybean varieties. Significant variation in both oil and protein contents of soybeans have been reported to be related to both variety and location grown (Caviness, 1973; Ologhobo and Fetuga, 1984; Gandhi et al., 1985). Other researchers have confirmed the large variation in protein and oil contents due to variety and found that the two components were negatively correlated (Hymowitz and Collins, 1974; Krivoruchco et al., 1979; Hartwig, 1979; Hafez, 1983). Also, the protein content was negatively correlated with the total sugar (Hymowitz and Collins, 1974) and the sucrose (Mwandemele, 1985) contents of soybeans but positively correlated with the stachyose content (Hymowitz and Collins, 1974). In addition, changes in the protein content of soybeans were not correlated with the pentosans, crude fiber, and ash contents and soybean seed size (Krober and Cartter, 1962).









Furthermore, the protein content of soybeans was found to be not correlated with their methionine (Krober and Cartter, 1966) or the non-protein nitrogen (NPN) content (Becker et al., 1940). Krober and Gibbons (1962) confirmed the absence of a correlation between NPN and the protein content and also reported that NPN was not affected by variety or location grown but appeared to be influenced by weather conditions. However, Becker et al. (1940) indicated a wide range (2.9 to 7.8%) existed in the NPN content of the 12 varieties of soybeans studied.

Several researchers have reported that the methionine content of soybeans varies having the following ranges; 1.0 to 1.7gm/16gm N (Krober and Cartter, 1966), 1.3 to 1.5gm/16gm N (Alders, 1949), and

1.3 to 1.7gm/16gm N (Krober, 1956). The methionine content was influenced by location grown and planting season (Krober, 1956).

In contrast to being negatively correlated with the protein

content of soybeans, the oil content was positively correlated with the total sugar, sucrose, and raffinose contents of soybeans (Hymowitz and Collins, 1974). The fatty acid composition was relatively constant with different varieties grown at different locations (Collins and Sedgwick, 1959) and was influenced by temperature during the growing season (Howell and Collins, 1957). However, the linolenic and linoleic acid contents of soybeans were negatively correlated (Howell and Collins, 1957).

A large variation in the raffinose and stachyose contents of

soybeans exists in different varieties (Hymowitz and Collins, 1974). Likewise, Kennedy et al. (1985) compared five different soybean







55

varieties and noted varation in sucrose (4.0 to 7.7%), stachyose (3.0 to 4.1%) and raffinose (.7 to .9%) contents. One variety had the lowest content of each of these oligosaccharides (total of all three varied between 7.6 to 12.7%). Mwandemele (1985) reported that the stachyose and raffinose contents of soybeans were positively correlated. Also, the stachyose and raffinose contents were not correlated with the protein and oil content or yield, but the sucrose content was positively correlated with yield.

Other components of soybeans have been shown to vary, such as glycinin, (31.4 to 38.3% of the total protein; Hughes and Murphy, 1983), phytin phosphorus content (.51 to .73%; Averill and King, 1926), available carbohydrates and ash (Ologhobo and Fetuga, 1984), and percentage husk and cotyledons (Gandhi et al., 1984). The minerals with the most variabilities in soybeans were iron, zinc and manganese and the lowest variabilities were in calcium and phosphorus (Ologhobo and Fetuga, 1984).

Birk and Waldman (1965) reported that no quantitative differences were found in UA of three soybean varieties. However, Smith et al. (1956) found that the UA varied according to variety and location grown. Portions of the seed also vary in UA. The hull has lower UA than the hypocotyl, and the colyledons have twofold the UA of the hypocotyl. Myer and Froseth (1983) compared extruded mixtures of beans (Phaseolus vulberis) and raw soybeans. The raw soybeans in one experiment had a UA of 1.87 whereas, the raw soybeans in the second experiment contained a UA of 1.15. The soybeans with the higher UA contained 68 units more trypsin inhibitor per mg protein than the







56

soybeans having the lower UA. A reason for the difference between the raw soybeans was not indicated by the researchers.

The amount of trypsin inhibitor activity also varies between

soybean varieties (Kakade et al., 1969; Hafez 1983). Likewise, Gandhi et al. (1984) compared the trypsin inhibitor content of eleven different varieties of soybeans and reported a range of 8.1 to 38.5 trypsin inhibitor units per mg sample. Two varieties having a black seed coat contained the highest trypsin inhibitor and UA values. Soybeans have also been found which do not contain the Kunitz trypsin inhibitor (Leiner and Tomlinson, 1981), with the total trypsin and chymotrypsin inhibitor activities being approximately one-half and three-fourths of that of commercial raw soyflour. Soybeans also contain nonprotein trypsin inhibitors and Hafez and Mohamed (1983) reported that a large difference occurred due to variety.

Kakade et al. (1972) found a seven-fold variation in lectin

content within 108 different soybean varieties evaluated. Subsequent research by Pull et al. (1978) noted the absence of lectins in five varieties of soybeans they assayed. In addition, variations in the isoflavones (compounds having estrogenic properities) and lipoxygenase (an enzyme that catalyzes the oxidation of lipids) contents have been reported due to variety and location grown (Eldridge and Kwolak, 1983).

Data on differences in feeding value between varieties of soybeans are limited. Yen et al. (1974) reported depressed performance of growing pigs fed different varieties of raw soybeans compared to SBM. However, performance of pigs fed the three varieties









of raw soybeans did not differ. Bajjalleh et al. (1980) fed chicks two raw soybean varieties Cone commercial and one which lacked the Kunitz inhibitor) compared the responses to chicks fed heated soybeans. The soybean variety lacking the Kunitz inhibitor permitted a greater growth response and smaller pancreatic weights of chicks than the commercial variety of soybeans, although this improvement was still below the response to chicks fed heated soybeans. Han and Parsons (1986) confirmed the greater nutritional value of raw soybeans containing a low trypsin inhibitor (Kunitz) content compared to a raw commerical variety. These researchers reported that the availabilities of lysine and methionine were similar in unheated soybeans having low trypsin inhibitor content and heated dehulled soybeans, and both had higher lysine and methionine availabilities compared to the raw commerical variety. Yen et al. (1971) fed a unheated variant soybean which had a greater nutritional value than other varieties of soybeans they studied and reported that the performance of rats remained adversely affected compared with rats fed heated soybeans.

Effect of Storage on Soybeans and Soybean Products

An additional factor which may alter the nutritional value of soybeans is the method and length of storage. Soybeans have been stored at 13 to 14% moisture and at 4 to 5 C for six years without deterioration (Smith and Circle, 1972). Mitchell and Beadles (1949) reported deterioration in the digestibility and biological value of soybeans which had been stored for almost three years at 25.5 C. However, pretreatment heating largely prevented this deterioration.









the loss was attributed to an enzymatic factor. Nakayama and Kito (1981) stored soybeans at 13% moisture for six months and found 45% of the total phospholipids had decomposed, 72% of the total phospholipids originally extracted with the oil were lost and phosphatidylcholine and phosphatidylethanolamine were significantly decreased. Phosphatidic acid and lysophosphatidylcholine concentrations increased. In addition, the oligosaccharide content of soybeans was decreased in storage but this reduction can be stopped by heating the soybeans prior to storage which indicates changes due to enzymatic processes (Mwandemele, 1985). Saio et al. (1980) reported that bean color darkened and acid values of extracted crude oil and acidity of beans increased as deterioation progressed. Storage temperature and relative humidity are both related to overall changes during storage but relative humidity seems to be more important. Nitrogen solubility index decreased rapidly with high temperature and relative humidity. Yao et al. (1983) reported that storage for 6 months did not affect trypsin inhibitor activity.

Whole beans were niore resistant to deterioration during storage than soybean meals (Saio et al., 1982). Also, full-fat soybean meals deteriorated more rapidly then defatted meals.

Effect of- Maturity on Composition of Soybeans

Maturity of the soybean seed can also influence soybean

composition. Fehr et al. (1971) reported that fatty acids were synthesized by the soybean plant at different rates during pod filling. Linolenic acid percentage in the seeds decreased rapidly during the first 30 days and then remained constant thoughout the







59

period of oil deposition. Immature seeds contained only 3% of the UA (Birk and Waidman, 1965) and had more available zinc (Welch and House, 1983) than mature seeds. Lipoxygenase activity, phytate content and the ratio of 7S and 11S protein were lower in immature seeds compared to mature seeds (Yao et al., 1983). Fat content was found to be higher in earlier maturing varieties than later maturing varieties (Krlvoruchco et al., 1979). Mwandemele (1985) reported positive correlation between concentrations of various oligosaccharides and day to maturity. Also, maturation was not related to the oil and protein contents (Yao et al., 1983).

Research data on the response of soybean maturity on the trypsin inhibitor activity have been inconsistent. Collins and Sanders (1976) reported that the amount of trypsin inhibitor activity increased as the soybeans matured. However, Yao et al. (1983) found that the trypsin inhibitor activity and soybean maturity were not related.

Influence of Growinc Conditions on Soybean Composition

As previously stated, location where soybeans are grown can affect their nutrient composition. The use of fertilizer and the various components of fertilizer can influence the resulting nutrient content of the harvested soybeans. Gaydou and Arrivets (1983) found that fertilizer containing a high level of phosphorus increased both the oil and protein contents of soybeans, while fertilizer comprised of a high level of potassium increased the oil content but decreased content of protein. Dolomite fertilizer which is high in both calcium and magnesium increased the oil content but did not affect protein content of soybeans. Nitrogen fertilization did not influence either







60

oil or protein content of the soybeans. In contrast, Krober and Cartter (1966) had reported that soils low in nitrogen produced soybeans with reduced protein content.

Wolf et al. (1982) grew soybeans at temperatures during the day:night of 18:13, 24:19, 27:22, 30:25 and 33:28 C and obtained a decrease in linolenic and linoleic acid, sucrose (greatly) and stachyose (slightly) with increased temperature during the growing period. Increased growing temperature also increased oleic acid, oil and protein contents. Palmitic and stearic acid, glucose, fructose and raffinose were not affected by different growing temperatures. Amino acids were generally stable except higher temperature increased methionine content. Howell and Collins (1957) had previously reported that the temperature in which the soybeans were grown affected the linolenic and linoleic acid contents of the soybean oil more than the variety. Krober and Collins (1948) reported that weather-damaged soybeans often had higher NPN content than undamaged soybeans.

















CHAPTER III
THE EFFECT OF INCREASING THE MOISTURE CONTENT OF WHOLE SOYBEANS
PRIOR TO ROASTING AT VARYING HEAT TREATMENTS ON PERFORMANCE OF WEANLING SWINE


Introduction


Whole "full fat" soybeans are an excellent source of protein and energy for swine diets. Also, soybeans contain other important components, such as trypsin inhibitors CLiener, 1981) which are considered the principle heat labile anti-nutritional factors and the enzyme urease which is monitored in soybean meal processing plants as an indication of optimum heat processing (Caskey and Knapp, 1944). Subjecting soybeans to heat processing concurrently improves their nutritional value and reduces the activities of both trypsin inhibitor and urease.

Previous research has been inconclusive on the feeding value of roasted soybeans as a protein supplement for weanling swine (Noland et al., 1976; Rust et al., 1972; Crenshaw and Danielson, 1984a). This could be due in part to the temperature and duration of heat processing and moisture content of soybeans prior to heating; all are important factors affecting the nutritional quality of soybeans (McNaughton and Reece, 1980). Likewise, previous research at the University of Florida (Campbell et al., 1984) indicated that roasting soybeans at 125 C permitted superior growth of finishing pigs compared









to pigs fed soybeans roasted at 110 C. Therefore, the objectives of this study were to determine if increasing the moisture content (10% added water) of Bragg soybeans prior to roasting at 110 or 125 C would enhance the inactivation of trypsin inhibitors, decrease urease activity and increase performance when included in diets of weanling swine.

Materials and Methods

One-hundred eight crossbred pigs with an average initial weight of 5 kg were assigned to pens containing six pigs each by initial weight, sex and litter origin. Each treatment consisted of three replicate pens. The six dietary treatments (Table 1) were corn-based diets containing the following protein supplements: (1) soybean meal;

(2) raw soybeans; (3) soybeans roasted at 110 C with no water added prior to roasting; (4) soybeans roasted at 110 C with 10% water added;

(5) soybeans roasted at 125 C with no water added and (6) soybeans roasted at 125 C with 10/%7 water added. All diets were formulated to be isonitrogenous and isocaloric. The whole soybeans used in the treatments requiring added moisture were placed into plastic containers prior to roasting and 10%. (w/w) water was added. These soybeans were then mixed periodically with the water by dumping the soybeans into other containers and then stored overnight. During the following morning, the soybeans were roasted by passing them through a Roast-A-Tron 1gas-fired roaster. Afterwards, the soybeans were ground in a hammermill before inclusion into their respective diets.

Ether extract of the raw soybeans was determined according to the procedure outlined by the AOAC (1980). Samples of raw soybeans were



1 Mix-Mill, Inc., Bluffton, IN.









TABLE 1. PERCENTAGE COMPOSITION OF EXPERIMENTAL DIETS


Ingredients Basal Soybeans
(Diet 1) (Diets 2-6)



Ground yellow corn 68.40 56.90
Soybean meal (48%) 25.40
Whole soybeans ---39.90
Corn oil 3.00--Dynafos 1.70 1.70
Limestone .80 .80
Salt a.25 .25
Trace minerals (CCCa .10 .10
Vitamin premix (UF) .10 .10
Antibiotic c *22
100.00 100.00
Calculated analyses:
Protein, % 18.00 18.00
Metabol izable energy
Kcal/kg 3310 3304


a Provided by Calcium Carbonate Company, Quincy, IL. Contained 200
mg zinc, 100 mg iron, 55 mg manganese, 11 mg copper, 1.5 mg
iodine, 1.0 mg cobalt and 20 mg calcium per kg complete diet. b Supplied 13.2 mg riboflavin; 44.0 mg niacin; 26.4 mg pantothenic
acid; 176.0 mg choline chloride; 22.0 mg vitamin B12 ; 5,500 IU
vitamin A; 880 ICU vitamin D 3and 22 IU vitamin E per kg of
complete diet.
c Provided 44 mg chlortetracycline, 44 mg sulfamethazine and 22 mg
penicillin per kg of complete diet.









obtained for nitrogen analysis prior to roasting. These raw soybeans were digested using a modification of the aluminum block digestion procedure of Gallaher et al. (1975). Ammonia in the digestate was measured by semiautomated colorimetry (Hambleton, 1977). Additionally, trypsin inhibitor activity (TI, Hamerstrand et al., 1981), urease activity (UA, Caskey and Knapp, 1944) and dry matter content (AQAC, 1980) were determined on both the raw and roasted soybeans and SBM.

All pigs were housed during the 35-day trial in an enclosed nursery building equipped with elevated pens having expanded metal floors and wire mesh sides. Feed and water were supplied ad libitum. Pigs were individually weighed and feed consumption for each pen was determined bi-weekly. The data were subjected to analysis of variance for a randomized complete block design, with blocks representing replications. Then the basal diet (Treatment 1) and the raw soybean diet (Treatment 2) were omitted thus enabling Treatments 3 through 6 to be analyzed as a 2 x 2 factorial arrangement of treatments (added moisture x roasting temperature). The GLMI procedure developed by SAS (1979) was used for compilation of analyses of variance. Duncans' multiple range test was used to interpret significant differences (SAS, 1979).

Results and Discussion

Average daily gain of pigs fed the soybean meal (SBM) basal diet was superior (P<.05) to that of the other dietary treatment groups (Table 2). Comparing the growth rate among pigs fed the diets containing full-fat soybeans, pigs fed diets supplemented with raw











TABLE 2. PERFORMANCE OF WEANLING PIGS FED DIETS CONTAINING SOYBEANS ROASTED AT 110 OR 125 C WITH
AND WITHOUT 10% WATER ADDED PRIOR TO ROASTING


SBM ~BRAGG SOYBEANS E
Temperature, C Raw 110 110 125 125
Added Moisture, % 0 0 0 10 0 10


Avg. initial weight, kg 5.04 5.03 5.02 5.03 5.03 5.03-Avg. final weight, kg 16.80 C7.87 f 7.56 f 9.75 e 11.03 e 13 71d-Avg. daily gain, kga .33 ~ 08~ d*6d 3d17ed :2 .02
Avg. daily feed, kg .59C .3 32 *4 39d .5 .02
Avg. feed/gain 1/0e 4.45Cd 5.23c 3.09d 2.33e 2.21 .41


- Least squares means for daily gain and treatment means for feed values. b Standard error of the mean.

cod,e,f Means in same row with different superscripts are different (P<.05).










(unheated) soybeans or soybeans roasted at 110 C with no water added prior to roasting were adversely (P<.05) affected. Weight gains of pigs fed the diet containing soybeans which had 10% water added prior to roasting at 110 C were augmented (P<.05) compared to pigs fed a diet with soybeans roasted at 110 C without added water and equal (P>.05) to pigs fed soybeans roasted at 125 C. Likewise, addition of 10% water prior to roasting soybeans at 125 C permitted an additional increase (P<.05) in pig growth. The decreased performance of pigs fed raw soybeans was expected and these data agree with previous research evaluating raw soybeans fed to starting, growing and finishing pigs (Jimenez et al., 1963; Combs et al., 1967; Hanke et al.P 1972; Yen et al., 1974). Also, the depressed growth of weaning pigs fed roasted soybeans is consistent with the findings of Rust et al. (1972) and Crenshaw and Danielson (1985a) but is in contrast with the work of Noland et al. (1976).

Feed consumption by pigs fed the diets containing soybean meal or soybeans having 10% water added prior to being roasted at 125 C were equal (P>.05). However, feed consumption by pigs fed these two diets was greater (P<.05) when compared to the feed consumed by pigs fed the other treatment groups. Roasting soybeans at 110 C with or without added water and at 125 C without inclusion of water did not (P>.05) increase the quantity consumed when compared to pigs fed the raw soybean diet. Similarly,, feed-to-gain ratios of pigs fed the diets containing soybean meal or soybeans roasted at 125 C with or without additional water exceeded (P<.05) the efficiency of pigs fed diets containing raw soybeans or soybeans roasted at 110 C without water







67

being added. Rust et al. (1972) reported that the growth of pigs fed roasted soybeans were depressed but the efficiency of growth was similar to pigs fed soybean meal. Noland et al. (1976) also reported similar feed efficiency when weaning pigs were fed either roasted soybeans or SBM. In contrast, Crenshaw and Danielson (1985a) obtained depressed feed efficiency when weaning pigs were fed diets containing roasted soybeans compared to SBM.

The main effects of roasting temperature and water addition are shown in Table 3. Pigs fed diets containing Bragg soybeans roasted at 125 C consumed more (P<.05) feed, grew faster (P<.05) and were more (P<.10) efficient in utilization of feed than pigs fed diets containing soybeans roasted at 110 C. Similarly, adding 10% water prior to roasting the soybeans improved (P<.05) feed intake and average daily growth of pigs compared to pigs fed roasted soybeans without added water prior to roasting. Although the feed-to-gain ratios between treatments containing 0 or 10% added water had a large numerical difference, these ratios were not different (P>.05).

The grease (UA) and trypsin inhibitor (TI) activities, indices

used to assess soybean quality, of the different soybean products are presented in Table 4. None of the heat treatments was effective in lowering the UA of the full-fat soybeans to less than .2. Soybean meal with a UA range between .05 to .2 is considered to have received optimum heat processing by commercial soybean processing plants (Smith, 1977). Roasting soybeans at 110 C without added water reduced the TI and UA by 25.9 and 7.6%, respectively. Adding 10% water prior to roasting at 110 C or roasting at 125 C without added water resulted










TABLE 3. MAIN EFFECT PERFORMANCE MEANS OF WEANLING PIGS FED DIETS


CONTAINING SOYBEANS ROASTED AT 110 10% WATER ADDED PRIOR TO ROASTING


OR 125 C WITH AND WITHOUT


Temperature Added Moisture L110 C 125 C 0% 10%


Avg. initial weight, kg 5.02 5.02 5.02 5.02 -Avg. final weight, kg 8 69 b 124 .5b 11.78 -Avg. daily gain, kg .10 . 21C12 b .l9 .04
Avg. daily feed, kg .37 d.47 . 35 .48 .03
Avg. feed/gain 4:16 2.27 3.78 2.65 .79


a Standard error of the mean.


b ,c


Column means within main effects with different superscripts are
different (P<.05).


d,e Column means within main effects
different (P<.10).


with different superscripts are










TABLE 4. UREASE AND TRYPSIN INHIBITOR ACTIVITIES
SOYBEAN PRODUCTS


OF THE DIFFERENT


Product Trypsin Inhibitor Urease Activity
mg/gm defatted sample pH change


Unheated soybeans 53.95a 1.97
Roasted 110 C; 0% water 40.00 1.82
Roasted 110 C; 10% water 24.00 1.30
Roasted 125 C; 0% water 22.88 0.55
Roasted 125 C; 10% water 9.18 0.25
Soybean meal (48%) 3.11 0.10


Larger values are indicative of less heat processing.







70

in similar reductions in TI. The inclusion of 10% water prior to roasting at 125 C resulted in the largest reductions in TI and UA (83.0 and 87.3%, respectively) yet the product still contained between two- and three-fold the TI and UA of soybean meal. Pig performance data reflect the difference in heat processing and indicate that soybean products having a UA of .25 or higher are not adequate protein supplements for weaning pigs. These results concur with the work of Albrecht et al. (1966), McNaughton and Reece (1980), and Waldroup (1985) which suggest that increasing the moisture content of soybeans prior to heating increased the inactivation of TI and UA. These data also agree with the findings of Campbell et al. (1984) in that soybeans roasted at 125 C had a higher nutritional value when compared to soybeans roasted at 110 C. In addition, the depressed performance of weaning pigs fed soybeans having a UA higher than .2 is in agreement with the optimum range of UA used by the American Feed Manufacturer Association to indicate soybean products that have received adequate heat processing (Smith, 1977).

The Bragg variety of soybeans roasted in this study had remained in the field for a longer period of time (1-2 months) than normal before being harvested. The moisture content of these soybeans was 10.331% and with the addition of 10% water was analyzed to be 20.45% prior to roasting. Roasting the soybeans at 110 C with and without added water reduced the moisture content to 13.1 and 9.0%, respectively. Further evaluation of the soybeans noted lower protein (32.7%) and higher fat (23.9%) contents than that published by the NRC (1979; 37.0 and 18.0%, respectively). However, the actual values and







71

not the NRC (1979) values were used to calculate the experimental diets. Therefore, the protein content of the experimental diets was isonitrogenous.
















CHAPTER IV
FEEDING VALUE AND COMPOSITIONAL VARIATION AND RELATIONSHIPS
ASSOCIATED WITH DIFFERENT VARIETIES OF SOYBEANS


Introduction


Full-fat soybeans can be utilized as an excellent source of both energy and protein in swine diets. However, soybeans also contain several anti-nutritional factors which require inactivation before yielding a product having the highest nutritional value. Trypsin inhibitors are considered the most important anti-nutritional factor in soybeans and subjecting soybeans to heat processing has been used satisfactorily to reduce the trypsin inhibitor activity (Liener, 1981). Heat processing has been shown to be required when soybeans are added to diets fed to young pigs and becomes less critical when soybeans are fed to finishing pigs (Combs and Wallace, 1969). Although previous research has been inconclusive on the feeding value of raw soybeans for growing-finishing swine (Combs and Wallace, 1969; Jensen et al., 1970; Crenshaw and Danielson, 1985c; and Pontif et al., 1986), raw soybeans have been found to be adequate protein supplements for gilts and sows (Crenshaw and Danielson, 1984d). Another technique that can be used to reduce the trypsin inhibitor activity of soybeans is germination (Bates et al., 1977; Suberbie et al., 1981). Collins and Sanders (1976) reported that soybeans which had been rinsed twice









daily and allowed to germinate for three days lost up to 13.2% of their trypsin inhibitor activity.

Numerous new varieties of soybeans are released annually which have improved agronomic advantages over existing varieties. However, the nutritional value of these new soybean varieties has often been a minor selection criterion. Significant variations in both oil and protein contents and urease activity WU) of soybeans have been reported to be related to both variety and location grown (Smith et al., 1956; Caviness, 1973; Ologhobo and Fetuga, 1984; Gandhi et al., 1984). Likewise, the trypsin inhibitor activity (TI) also varies among different soybean varieties (Kakade et al., 1969; Hafez, 1983). Besides the varietal differences in the constituents of soybeans, relationships among the various components do exist. Several researchers (Hymowitz and Collins, 1974; Krivoruchco et al., 1979; Hartwig, 1979; Hafez, 1983) have reported that the protein and fat components of soybeans were negatively correlated.

These varietal differences would indicate that the heat

processing required to destroy the heat labile anti-nutritional factors could vary between the different varieties of soybeans. Data on differences in feeding value among different varieties of soybeans are limited. Yen et al. (1974) reported no difference in performance of growing pigs fed either of three different varieties of raw soybeans. However, the growth of pigs fed a commercial soybean meal was superior to the pigs fed the diets containing different varieties of raw soybeans.










The objectives of these studies were: (1) to determine the

relationships of various nutritional components and evaluate their variability in different varieties of soybeans, (2) to determine variability of similar varieties of soybeans grown at different locations, (3) to evaluate the trypsin inhibitor and grease activities of soybeans which were germinated or heated in an autoclave at 110 C for 7.5 or 15.0 minutes, and (4) to evaluate the performance of growing-finishing pigs fed diets containing either Bragg (unheated and heated at 110 or 125 C) or Davis (unheated and heated at 110 C) variety of soybeans.

Materials and Methods

Trial I

Fifteen commerical varieties and three experimental strains of soybeans were obtained from the University of Florida Agronomy Department and the protein and fat contents, grease activity (UA) and trypsin inhibitor activity (TI) were determined using procedures described below. The effect of heat processing was assessed by placing approximately 25 g of whole soybeans in aluminum drying pans having a 6 cm diameter. Three replicate drying pans per soybean variety were randomly placed on a 30 X 60 cm stainless steel tray and autoclaved for 7.5 or 15.0 minutes at 110 C and 422 gm/cm 2 pressure. The soybeans from the three replicate drying pans were combined after cooling and ground prior to determination of the TI and UA. The effect of germination on TI and UA was determined by germinating the different varieties of soybeans for 7 days and then only the soybeans which had sprouted were removed, dried and ground.










Trial 2

Four commercial varieties and thirty-four experimental strains of soybeans were obtained from the same source as soybeans used in Trial

1 and analyzed for protein and fat contents and TI and UA. These soybeans were grown during the growing season subsequent to those soybeans used in Trial 1. There is a large variation in the size of soybean seeds being marketed, and the correlation of this variable with the measured parameters was determined. Soybean size was quantitated with micrometer calipers from measurements taken on the long axis directly between the cotyledons of the soybeans. Trial 3

To evaluate the effect of the varietal differences in soybeans on their feeding value, the following trial was conducted. One-hundred and eight crossbred pigs with an average weight of 40 kg were allotted on the basis of initial weight, sex and litter origin to six dietary treatment groups. Six pigs were assigned to each pen with three replicate pens per treatment. The dietary treatments (Table 5) consisted of the following protein supplements: (1) commercial soybean meal; (2) unheated Bragg soybeans; (3) Bragg soybeans roasted at 110 C; (4) Bragg soybeans roasted at 125 C; (5) unheated Davis soybeans and (6) Davis soybeans roasted at 110 C. Roasting consisted of passing whole soybeans through a Roast-A-Tron 1 gas-fired roaster. Afterwards, the roasted and unheated soybeans were ground in a hammermill before inclusion into their respective diets. The two varieties of soybeans were obtained locally from different suppliers.


1 Mix-Mill, Inc., Bluffton, IN.










TABLE 5. PERCENTAGE COMPOSITION OF EXPERIMENTAL DIETS


Grower Diets Finisher Diets
Ingredients Control Soybeans Control Soybeans


Ground yellow corn 76.80 70.30 82.65 77.35
Soybean meal 20.00 ---14.40
Whole soybeans --- 26.50 19.70
Dicalcium phosphate 1.70 1.70 1.70 1.70
Limestone 0.80 0.80 0.80 0.80
Iodized salt a0.25 0.25 0.25 0.25
Trace minerals (CC 0.10 0.10 0.10 0.10
Vitamin premix (UF) 0.10 0.10 0.10 0.10
Antibiotic premix C 025 0J.5_100.00 100.00 100.00 100.00

Calculated analyses:
Protein, % 16.00 16.00 14.00 14.00
Metabol izable energy
Kcal/kg 3250 3250 3250 3250



a Provided by Calcium Carbonate Company, Quincy, IL. Contained 200
mg zinc, 100 mg iron, 55 mg manganese, 11 mg copper, 1.5 mg
iodine, 1.0 mg cobalt and 20 mg calcium per kg complete diet.
b Supplied 13.2 mg riboflavin; 44.0 ng niacin; 26.4 mg pantothenic
acid, 176 mg choline chloride; 22 mg vitamin B 12 ; 5,500 IU
vitamin A; 880 ICU vitamin D 3and 22 IU vitamin E per kg of
complete diet.
c Provided 110 mg chlortetracycline, 110 mg sulfamethazine and 55 mg
penicillin per gm complete grower diet.










The Bragg soybeans were harvested after remaining in the field approximately one to two months longer than normal. The Davis soybeans were harvested after a normal period of time. The grower diets were fed for 28 days and then the pigs were fed their respective finishing diet.

All pigs were housed in a semi-enclosed concrete barn with

partially slotted floors. Feed and water were supplied ad libitum. Pig weights and feed consumptions were determined bi-weekly.

In all trials, the protein and fat contents (AOAC, 1980) and UA (Caskey and Knapp, 1944) of the soybeans were conducted on air dry samples. Samples for nitrogen analysis were digested using a modification of the alumimum block digestion procedure of Gallaher et al. (1975). Ammonia in the digestate was determined by semi-automatical colorimetry CHambleton, 1977). Trypsin inhibitor activity (Hamerstrand et al., 1981) was determined on defatted soybean samples. Urease activity and TI of germinated seeds were determined on samples which had both the fat and moisture removed. All analyses were conducted in duplicate. In Trials 1 and 2, the individual variety means were used to calculate the gross correlations among the various components. Correlations were considered significant if the probability level was .05 or less. In Trial 3v the growth data were analyzed by least squares analysis of variance with initial weight as a covariate. Feed intake and feed efficiency data were subjected to analysis of variance for a randomized complete block design. Duncan's multiple range test was used to determine treatment differences. All statistical analyses were conducted following the procedures developed by SAS (1979).










TABLE 6. COMPOSITION OF THE DIFFERENT VARIETIES OF SOYBEANS (TRIAL 1)


UAa, . pH TIa rim/ Gerujin ted
Protein Fat Heat Processing, minutes at 110 C UA TI
(Il) (5 ) 0.0 7.5 15.0 0.0 7.5 15.0 ( HpH) (mlg/1in)
Co rrrci a vrietiecsa
Asgrow 7372 38.42 20.21 1.44 .095 .02 45.18 8.62 4.46 1.72 35.70
Braxton 39.55 19.21 1.36 .090 .01 35.79 9.46 3.99 1.66 31.49
Coker 237 38.68 20.78 1.04 .155 .00 28.25 9.14 2.63 1.51 25.26
Coker 368 38.50 20.73 1.17 .040 .00 25.00 7.44 3.13 1.72 21.05
Coker 488 36.44 21.13 1.37 .125 .02 28.79 10.09 3.99 1.44 24.30
Cobb 37.51 19.60 1.57 .175 .00 29.82 8.65 3.59 1.96 26.00
Centennial 41.08 19.40 1.26 .095 .02 34.47 9.70 3.57 1.38 31.84
Foster 38.37 19.13 1.34 .070 .03 38.16 9.23 3.81 1.86 25.96
GaSoy-17 36.60 20.11 1.27 .085 .04 31.73 8.31 3.43 1.57 26.75
Hutton 39.58 18.80 1.14 .095 .02 35.65 10.41 3.37 .
P 604 41.50 19.44 1.54 .050 .02 35.26 10.99 4.01 1.62 33.51
RA 801 38.18 19.71 1.33 .140 .03 32.35 8.63 3.95 1.63 28.33
Wright 38.22 19.48 1.25 .100 .08 32.10 12.63 5.05 1.33 29.21
Grown at different locLtions
Bragg No. 1 37.86 20.24 1.46 .135 .09 40.53 14.28 5.32 1.82 33.60
Bragg No. 2 32.74 23.92 1.81 .140 .05 53.95 11.80 3.11 . .
Kirby No. 1 36.94 19.85 1.69 .165 .04 40.26 12.95 3.03 Kirby No. 2 39.24 19.03 1.35 .110 .02 35.39 11.67 4.07 . .
E'perirental strains
F80-6717 38.38 20.90 1.71 .170 .06 40.53 8.49 4.30 2.04 35.09
F80-6950 37.35 20.69 1.76 .370 .05 46.05 11.87 3.64 2.03 33.60
F81-9202 38.186 20.84 1.70 .345 .08 61,84 16.87 4.94 2.04 49.74
Mean 38.17 20.16 1.43 .137 .03 37.55 10.56 3.87 1.70 30.70
S.E.M. .41 .25 .05 .02 .01 1.99 .52 .16 .06 1.65
C,V. 4.76 5.61 15.46 61.33 78.69 23.75 22.20 18,03 13.76 21.52
a UA-Urease Activity; TI-Trypsin Inhibitor Activity; RA-Ring Around; F-Florida.









Results and Discussion

Trial 1

A summary of the protein, fat, and trypsin inhibitor (TI) and urease activities (UA) of the soybeans is shown in Table 6. The percentage of protein and fat in the various soybean varieties studied ranged between 32.74 to 41.50% and 18.80 to 21.13% with an average of 38.17 and 20.16%, respectively. The UA, used in commercial soybean meal processing plants to indicate adequacy of heat processing, averaged 1.43 in the unheated soybeans. After heat processing the soybeans at 110 C for 7.5 and 15.0 minutes, the average UA was reduced to .14 and .03, respectively. The American Feed Manufacturers Association considers that soybeans have received adequate heat processing if the UA is between .05 and .2 (Smith, 1977). Therefore, heating the different varieties of soybeans for 7.5 minutes at 110 C was adequate for all varieties except for two of the experimental strains (F80-6950 and F81-9202). A wide variation among the different varieties of soybeans (approximately 2.5 fold) was observed in the TI values, ranging from 25.00 to 61.84 mg/gm of sample with a coefficient of variation of 23.75%o. Autoclaving the soybeans for 7.5 or 15.0 minutes reduced the average TI activity to 10.56 and 3.87 mg/gm of defatted soybean sample, respectively. These data are in agreement with previous research reporting a wide range in oil and protein concentrations (Caviness, 1973; Ologhobo and Fetuga, 1984; Ghandhl et al., 1984), TI (Kakade et al.,1968; Hafez, 1983; Ghandi et al., 1984) and UA (Smith et al., 1956). The wide range in UA is in contrast with









Waldman (1965). However, these researchers only compared a limited number (3) of soybean varieties.

Germinating the seeds for seven days reduced the average TI activity to 30.70 mg/gm of defatted soybean sample. The largest reductions in TI activity were with the soybean varieties initially having the highest TI activity.

Two varieties (Bragg and Kirby) were grown in different areas which permitted an evaluation of the effects of location on the compositional variability of soybeans. Variation in most of the

constituents was observed in the same variety grown in different locations. Several factors other than variety such as growing temperature (Wolf et al., 1982), type of fertilizer applied to the soil (Gaydor and Arrivets, 1983) and plant maturity (Fehr et al., 1950; Birk and Waldman, 1965; Yao et al., 1983) have been reported to alter soybean composition.

The experimental strains of soybean used in this study were

classified as being of the vegetable type of soybeans. This type of

soybean is noted for having a bland flavor and large seeds (Hinson, 1986). All soybeans had a yellow seed coat except for the F80-6717 strain which had a black seed coat. Ghandi et al. (1984) compared the TI of eleven different varieties of soybeans of which only two varieties had black seed coats. The soybeans with the black seed coats had the highest TI contents. The F80-6717 strain (black seed coat) studied in this trial had a increased TI activity compared to the average of all varieties but was not the strain with the highest TI activity. The percentage reduction in TI and UA in the different










varieties of soybeans by heat processing or germination are presented in Table 7. Heating the soybeans at 110 C for 7.5 or 15.0 minutes reduced their TI activity by 71.36 and 89.34%, respectively. Whereas the UA activity was reduced 90.62 and 97.73% by heat processing the soybeans for 7.5 and 15.0 minutes respectively. The increased inactivation of UA compared to TI concur with data of Borchers et al. (1947) and McNaughton and Reece (1980). Germinating the soybean seeds for seven days only lowered the TI content by 15.44o. Previous research has been inconsistent on the reduction of TI by germinating soybeans. Desikachar and De (1947) and Collins and Sanders (1978) reported little change in TI by germinating soybeans. However, Bates (1977) found a 33% reduction in TI by sprouting soybeans for 4 days. Similarly, Collins and Sanders (1976) obtained up to 13.27 reduction in TI after germinating seeds for only 3 days.

Gross correlations associating protein and fat with UA and TI activities are shown in Table 8. The initial TI activity of the soybeans (unheated) was positively correlated with the percent inactivation of TI by heating the soybeans for 7.5 (P<.046) or 15.0 minutes (P<.001). The UA prior to heating the soybeans was also positively correlated with the percentage TI inactivation by heating the soybeans for 15.0 minutes (P<.027). However the initial UA (prior to heating the soybeans) was not correlated (P>.05) with the percent reduction of their UA by heating for either 7.5 or 15.0 minutes. Furthermore, the protein and fat concentrations of the soybeans were not correlated (P>.05) with the percent reduction of TI or UA.










TABLE 7. PERCENT REDUCTION OF TRYPSIN INHIBITOR AND UREASE ACTIVITIES
BY HEAT PROCESSING AND GERMINATION (TRIAL 1)


Trypsin inhibitor Urease activity Germination
Heat Processing, minutes at 110 C Variety a (7.5) (15.0) (7.5) (15.0)
Commercial varieties

Asgrow 7372 80.9 90.1 93.4 98.6 21.0
Braxton 73.6 88.9 93.4 99.3 12.0
Coker 237 67.7 90.7 85.1 100.0 10.6
Coker 368 70.2 87.5 96.6 100.0 15.8
Coker 488 65.0 86.1 90.9 98.5 15.6
Cobb 71.0 88.0 88.9 100.0 12.8
Centennial 71.9 89.8 92.5 98.4 7.6
Foster 75.8 90.0 94.8 97.8 32.0
GaSoy-17 73.8 89.2 93.3 96.9 15.7
Hutton 70.8 90.6 91.7 98.3 --RA 604 68.8 88.6 96.8 98.7 5.0
RA 801 73.3 87.8 89.5 97.7 12.4
Wright 60.7 84.3 92.0 94.0 9.0
Grown at different iccations

Bragg No. 1 64.8 86.9 90.8 93.8 17.1
Bragg No. 2 78.1 94.2 92.3 97.2 --Kirby No. 1 67.8 92.5 90.2 97.6 --Kirby No. 2 67.0 88.5 91.9 98.5 --Experirental strains

F80-6717 79.1 89.4 90.1 96.8 13.4
F80-6950 74.2 92.1 79.0 97.2 27.0
F80-9202 72.7 92.0 79.7 95.3 20.0

Mean 71.4 89.3 90.6 97.7 15.4

a RA-Ring around; F-Florida.










TABLE 8. GROSS CORRELATIONS OF PROTEIN AND FAT CONTENTS WITH TRYPSIN
INHIBITOR AND UREASE ACTIVITIES (TRIAL 1)


Urease actvityva


. Trypsin inhibitora


Protein.% 0fl


Heat Processing, minutes


Proei 17, 0 nq


Fat, %


-.776
P<.0O01


Protein, % UA, 0.0 min UA, 7.5 min UA, 15.0 min TI, 0.0 min TI, 7.5 min


.475 .295
P<.034 P<.207


.244 P<.299


-.441 -.264 -.295 P<.051 P<.261 P<.160


.461 .724
P<.006 P<.041


.438 .135 -.181
P<.054 P<.570 P<.444

-.328 -.132 -.176 P<.157 P<.578 P<.458

.446 .186 .186
P<.0003 P<.049 P<.432


.440 .615
P<.0522 P<.004


.608 P<.004


.547 .143 P<.013 P<.546

.738 .669 P<.0002 P<.O01

.667 .320 P<.O01 P<.169


.489 P<.029


a Urease activity (UA,ApH); Trypsin inhibitor activity (TI, mg/gm).


N










The protein concentration was negatively correlated with the fat concentration (P<.0001) and UA of the unheated soybeans (P<.052) but was not correlated (P>.05) with the UA after heat processing or the TI prior or after heat processing. The negative correlation in the protein and fat concentrations of soybeans has previously been well documented (Hymowitz and Collins, 1974; Krivoruchco et al.# 1979; Hartwig, 1979; Hafez, 1983). The fat concentration was positively correlated with the UA (P<.034) and TI (P<.054) activity prior to heat processing; whereas after heat processing, there was no correlation (P>.05) between these components. The TI was positively correlated (P<.0003) with the UA of the unheated soybeans. Both the TI and UA of the unheated soybeans were positively correlated (P<.05) with the UA of the soybeans which had received heat processing for 7.5 or 15.0 minutes and the TI activity of soybeans heated for 7.5 minutes. The TI and UA of the unheated soybeans were not correlated (P>.05) with the TI activity of the soybeans heated for 15.0 minutes.

Several researchers (Caskey and Knapp, 1944; Albrecht et al.,

1966; McNaughton and Reece, 1980) have reported that the UA is a good indicator of adequately heat processed soybeans. The positive correlation in the present study between TI and UA would confirm these data. The UA was correlated with the TI of the unheated soybeans or soybeans heated for 7.5 minutes but was not correlated to the TI of soybeans heated for 15.0 minutes. A reason for the lack of correlation of UA with TI of soybeans heated for 15.0 minutes may be because these soybeans would be considered overheated (UA less than .05) by the American Feed Manufacturer Association (Smith, 1977).









Balloun et al. (1953) reported that the UA is of little value for detecting overheated soybean meal. Tihl

The seed size, protein, fat, UA and TI analyses are presented in Table 9. The average size of the soybean seeds studied was 7.15 mm with a range between 5.68 and 10.32 mm. The percentages of protein and fat in the various soybean varieties ranged between 37.09 to 43.62% and 17.19 to 22.81% with averages of 39.39 and 20.46%, respectively. The averages of the UA and TI activity (1.52 and 37.24 mg/gm, respectively) are similar to the values obtained in Trial 1.

However, the range in UA (.56-2.05) was greater whereas the range in TI (23.06-60.05 mg/gm) was similar to what was observed in Trial 1.

The majority of the soybean varieties utilized in this study were used to confirm trends noticed in Trial 1. The Late Giant variety is the parent stock for some vegetable types of soybeans. The F83 experimental strains of -7895, -7923, -7959 and -7962 are closely related to the F81-9202 of Trial 1 which had an extremely high activity of TI (61.84 mg/gm sample). Likewise, these strains also contained a high activity of TI with one strain (F83-7923) containing 60.05 mg TI/gm. The isolines are strains which have similar genetic material except for only one trait and in most cases the composition was similar. In addition, there are several different trypsin inhibitors present in soybeans. The first trypsin inhibitor isolated from soybeans has been referred to as the Kunitz inhibitor. The two L81 strains are from genetic lines noted for the absence of the Kunitz inhibitor but their overall TI activity was not reduced compared to









TABLE 9. COMPOSITION OF THE DIFFERENT VARIETIES OF SOYBEANS (TRIAL 2)


Varietya ize, m Commercial varieties


Seed Coat


Bragg 7.40 Y
Kanrich 7.85 Y
Kirby 6.93 Y
Late Giant 10.00 B
Experimental strains
BR6 6.96 Y
D82-3332 (IR) 6.82 Y
F85-11346 (VT) 10.17 Y
F85-11349 (VT) 10.32 B
F80-6692 (VT) 7.85 Y
F83-7895 (VT) 7.58 Y
F83-7923 (VT) 8.02 Y
F83-7959 (VT) 8.18 Y
F83-8177 (VT) 9.61 B
F85-494 (IL-I) 6.01 Y
F85-495 (IL-I) 6.29 Y
F85-606 (IL-2) 6.54 Y
F85-604 (IL-2) 6.18 Y
F85-2297 (LM) 6.69 Y
F85-2773 (IR) 6.29 Y
F85-2757 (IR) 6.37 Y
F85-2853 (IR) 5.68 Y
F85-2892 (IR) 5.92 Y
F85-2927 (IR) 5.68 Y
F85-2983 (IR) 6.95 Y
F85-3093 (IR) 6.66 Y
F85-3182 (IR) 5.92 Y
F85-3208 (IR) 6.18 Y
F85-3229 (IR) 6.43 Y
F85-3981 (HS) 6.08 Y
F85-7356 (HS) 7.29 Y
F85-7433 (HS) 6.64 Y
L81-4387 (AK) 6.23 Y
L81-4590 (AK) 7.09 Y
UFV-1 (LM) 6.53 Y
Grown at different locations
F85-994 (IL-G) 7.73 Y
F85-994 (IL-PR) 7.08 Y
F85-998 (IL-G) 7.04 Y
F85-998 (IL-PR) 8.09 Y
Means 7.15
S.E.M. .19
C.V. 16.59


Protein,%


Fat,% UAa, LpH4 TI n


39.37 20.93 1.64 36.73 21.23 1.81 40.19 21.46 1.59 40.40 19.87 1.88


38.36 37.86 37.09 35.48
40.83 42.16 37.84 42.88 37. 73 40.76
39.53 41.41
37.69 39.93 40.85 39.23 38.76
38.54 39.74 40.45
39.21 39.85 37.88 43.62
39.79 38.86 37.61 34.52 38.01 39.89

39.91
42.52 41.50 40.65
39.39
.30 4.81


20.75 22.37 21.11 21.31 22.81
19.76 22.30 21.30 20.19 20.96 19.86 21.14 20.32 20.53 19.64 19.07 17.19 19.15 18.06 21.12 20.17 20.41 22.42 18.68 19.26 20.04 20.55 21.80 22.54 20.08

19.63 18.13 19.80
20.16
20.46
.20 5.62


1.61 1.53 1.80
1.83 1.85 1.92 1.88 2.00
1.63 1.81 1.78 1.67
1.87 1.13 1.41 0.56 0.95 0.99 0.79 1.38 1.00 0.91 0.88 1.70 0.77 1.61 1.92 1.13 1.67 1.83

1.66 1.87 1.65
1.83
1.52
.06 26.91


36.75 37.54 38.95 37.89

42.65 36.84 47.10
57.00 38.53 42.89 60.05
58.42 35.17 33.85 33.54 23.14 27.04 23.06
39.21 33.51
38.60 30.68 29.72 41.67
37.72 32.74
32.30 43.07 32.69
37.98 34.82 39.25
33.95 31.14

30.42 33.85 38.33
32.82
37.24
1.28
21.74


a IR-insect resistant; VT-vegetable type; LM-late maturing;
IL-isolines; HS-hard seed coat; AK-absence of the Kunitz inhibitor; G-grown in Gainesville, Florida; PR-grown in Puerto Rico; Y-yellow;
B-black; UA-urease activity; TI-trypsin inhibitor activity.










the average TI activity. These results are in contrast with those of Leiner and Tomlinson (1981) who reported a 50% reduction in the TI activity of soybeans in which the Kunitz TI was absent.

Coefficients and probability levels of gross correlations are given in Table 10. Size of the soybeans was not significantly correlated with the protein (P>.336) and fat (P>.119) concentrations but was positively correlated with the UA (P<.0002) and TI (P<.0005). The lack of a significant correlation between the size of the seeds and their protein concentration is in agreement with the findings of Krober and Cartter (1962). Similar to Trial 1, the fat concentration was negatively correlated with the protein content (P<.014) and positively correlated with the UA (P<.054) of the unheated soybeans. Likewise, the TI activity was not correlated with the protein concentration (P<.232) but was positively correlated with the UA (P<.015). However, inconsistent with Trial 1, the protein concentration was not correlated with the UA (P<.372) and the fat concentration was not correlated with the TI activity (P<.130). Trial 3

Grower period. Average daily gain and feed efficiency of pigs

fed unheated Bragg soybeans were depressed (P<.05) and growth of pigs fed soybean meal was superior (P<.05) when compared to pigs fed the other dietary treatments (Table 11). The Bragg soybeans required roasting at 110 C to permit growth and feed efficiency similar (P>.05) to that of pigs which received the unheated Davis soybeans. Similarly, to equal the growth of pigs fed Davis soybeans roasted at 110 C, the Bragg soybeans had to be roasted at 125 C. Roasting either variety of soybeans at 110 C improved (P<.05) pig growth and feed










GROSS CORRELATIONS OF PROTEIN AND FAT WITH TRYPSIN INHIBITOR AND UREASE ACTIVITIES (TRIAL 2)


Prntf~in.


-. p. I F- l I'.41 'alll


.2503 P<.119

-.387
P<.014


-.156
P<.336


Protein, %


Urease activity, ApH .383
P<.015

a Urease activity (UA, ApH); Trypsin inhibitor activity (TI, mg/gm).


TABLE 10.


Size, mm


IIAa A nL-J TTa mn/rn,


Fat, %


.559 P<.0002

.145 P<.372

.306 P<.054


.523 P<.0005

-.193
P<.232

.244
P<.130










PERFORMANCE OF GROWING-FINISHING PIGS FED DIETS VARIETIES OF SOYBEANS (UNHEATED OR HEATED)


CONTAINING SOYBEAN MEAL OR DIFFERENT


Soybean Varieties
Bragg Davis
Control Unheated 110 C 125 C Unheated 110 C SEMa

Grower Periodb

Avg. initial weight, kg 40.03 39 95 40.00 40.0 39.98 39 98 --Avg. daily gain, kg .86c *47f 56e 7 f5.76d .04
Avg. feed/gain 2.8W 4.43c 3.60e 322e' f 3.84 . 3.2 .08
Avg. daily feed intake, kg 2.48c 2.10 2.02d 2.47c 2:20c'a 2.48c .08
Finisher Period

Avg. initial weight, kg 64.31 53.19d 55 74cd 61.54_ 56.09 61.16 --Avg. daily gain, kg .69, .56 63d .68d 65 :.68d .04
Avg. feed/gain 3.84e 5.20c 4.10 4.04 4.35 3.96 .11
Avg. daily feed intake, kg 2.83 2.70 2.47 2.85 2.71 2.81 .09
Overall

Avg. initial weight, kg 40.03 39.95 40.00 40.00 39.98 39.98
Avg. final weight, kg 11486 88.43e 96 .7d .72c 9852d 10957c
Avg. daily gain, kg 77e 59de 61d 72d,e 04
Avg. feed/gain 3.53 4.99C 3.96d 3.78d 4.21 3.81 .11
Avg. daily feed intake, kg 2.73 2.52 2.34 2.74 2.56 2.76 .09


a Standard error of the mean.

b Least squares means for daily gain and treatment means for feed values. c,d,e,f Means in same row with different superscripts are different (P<.05).


TABLE 11.










efficiency when compared to pigs fed the unheated soybeans. Increasing the roasting temperature of the Bragg soybeans from 110 C to 125 C permitted an additional increase (P<.05) in pig growth but feed-to-gain ratio was not improved (P>.05).

Feed intake of the diets containing Bragg soybeans (unheated or roasted at 110 C) was depressed (P<.05) compared to the consumption of the diets containing either soybean meal, Bragg soybeans roasted at 125 C, or Davis soybeans roasted at 110 C. Daily intake of the diets containing the unheated soybeans did not differ (P>.05).

Finisher period. The average daily gain data were adjusted for the large difference in initial weight due to simultaneously switching each treatment group to their respective finisher diet. Pigs fed the diets containing unheated Bragg soybeans continued to have inadequate growth and feed efficiency. However, growth and feed-to-gain ratio of pigs fed the diet containing unheated Davis soybeans were equal (P>.05) to pigs fed diets containing soybean meal or roasted soybeans of either variety. Roasting the Bragg soybeans at 110 C improved (P<.05) their utilization but did not provide (P>.05) an additional

increase in growth compared to pigs fed the unheated Bragg soybeans. Increasing the roasting temperature of Bragg soybeans from 110 to 125 C did not improve (P>.05) their feeding value. There were no differences (P>.05) in feed intake between the dietary treatments during the finisher period.

Overall. Pigs fed unheated Bragg soybeans during both the grower and finisher periods had poorer gain (P<.05) and were less (P<.05) efficient than any other treatment group. Average daily gain of pigs









was improved (P<.05) by feeding either variety of soybeans roasted at 110 C when compared to pigs fed the unheated soybeans. Feed-to-gain ratio was improved (P<.05) by roasting the Bragg soybeans at 110 C but feed efficiency of pigs fed Davis soybeans roasted at 110 C did not improve (P>.05) compared to pigs fed unheated soybeans. Roasting the Bragg soybeans at 125 C permitted an additional increase (P<.05) in pig growth but feed efficiency (F/G) was similar to pigs fed Bragg soybeans roasted at 110 C. Feed intake during the entire growing-finishing period did not differ (P>.05) between the different

treatment groups.

The TI and UA of the different soybean products are presented in Table 12. None of the heat treatments was sufficient to lower the UA of either variety of soybeans to less than .2 which is considered by commercial soybean processing plants as indicative of optimum heat processing (Smith, 1977). The UA is an indication of the anti-nutritional factors contained in soybean products (Caskey and Knapp, 1944; Albrecht et al., 1966; McNaughton and Reece, 1980). The unheated Davis soybeans had lower UA and TI activities compared to the Bragg soybeans (unheated or roasted at 110 C). Similarly, the Davis soybeans roasted at 110 C contained lower UA and TI activities then the Bragg soybeans roasted 110 C. The Davis soybeans roasted at 110 C also had a lower TI activity compared to the Bragg soybeans roasted at 125 C. Pig performance data reflect this varietal difference in UA and indicate that soybean products having a UA higher than .2 can be adequate protein supplements for growing-finishing swine diets. These results agree with Vandergrift et al. (1983), Rudolph et al. (1983)










TABLE 12. UREASE INDEX AND TRYPSIN INHIBITOR CONTENT OF THE DIFFERENT
SOYBEAN PRODUCTS


Soybean product Urease index a Trypsin inhibitor,
A pH mg/gm sample


Bragg soybeans, unheated 1.97 53.95
Bragg soybeans roasted at 110 C 1.80 44.08
Bragg soybeans roasted at 125 C .52 15.10
Davis soybeans, unheated 1.47 36.97
Davis soybeans roasted at 110 C .84 11.42

a Index used by commercial soybean processing plants to monitor
quality of heat processing of soybeans. An index less than .20 is
associated with soybeans that have received adequate heat
processing.










and Seerley et al. (1974) that soybean products having UA higher than .2 can still be satisfactory protein supplements for growing-finishing swine.

These data indicated that the extent of heat treatment required to destroy the heat labile anti-nutritional factors found in raw soybeans can differ among varieties of soybeans. These varietal differences could account for contrasting data reported for the feeding value of unheated or roasted soybeans obtained in previous studies. Similar performance of finishing pigs fed unheated Davis soybeans or soybean meal is in agreement with data of Combs and Wallace (1969) who reported that finishing pigs could efficiently utilize raw soybeans; whereas the reduced performance of pigs fed unheated Bragg soybeans in the present study is consistent with data indicating that feeding raw soybeans would reduce pig performance regardless of Initial age or weight of pigs (Crenshaw and Danielson, 1985c; Pontif et al., 1986). However, Combs and Wallace (1969) along with Jimenez et al. (1963), Hanke et al. (1972) and Yen et al. (1974) have noted that raw soybeans are not a satisfactory protein supplement for growing pigs. The results of the present study are in agreement with these findings.

As previously stated, the Bragg soybeans remained in the field for one to two months longer than the Davis soybeans before being harvested. The influence of this additional variable on the results of this study cannot be determined but requires further assessment.




Full Text

PAGE 1

FACTORS AFFECTING THE NUTRITIONAL QUALITY OF SOYBEAN PRODUCTS FED TO SWINE AND CHICKS By DONNIE RAY CAMPBELL A DISSERTATION P R ESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLO RID A 1986

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The author dedicates this dissertation in memory of his mother, the late Verna Dean Campbell, and to his father, Joe Campbell, and his entire family. Their support, patience and thoughtfulness are grate fully acknowledged.

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ACKNOl/LEDGEMENTS There were many people who assisted in the completion of this project. The encouragement, assistance, friendship and professional guidance of Dr. C. E. \'/hite (chairman), Dr. G. E. Combs (cochairman), Dr. R. D. Miles and Dr. R. M. Shireman are gratefully acknowledged. The helpful assistance and advice (such as teaching the art of cane pole fishing) of Dane Bernis were desperately needed to complete this project. Through numerous ichthyological expeditions, Mike Harrison is acknowledged for giving the author the pleasure of always sur passing Mike's aquatic skills. Likewise, the author is grateful for Scot Williams, the bull Gator, who provided chum for the marine species as needed. The author also extends appreciation to his fell01-1 graduate students and friends (Larry, Joe, Tom, D e wie, Kelly, Amy, Britt and Bill), the swine unit crew (Tom, Denny, Shep, Kenny, Barry and John), laboratory (Al, Pam and Nc.ncy) and secretarial (Kathy and Sha ran) staff. For teachin g the author two i m portant l e ssons the following individuals are additionally ac k nowled ge d: M ike Harrison, who demonstrated so many times that there is one step beyond knowing something like the back of your hand, and Dr. Cori1bs, who taught the author the way to increase the numb e r of fish caught per cast; cast once and troll all day or until a fish is caught. The author extends deepest appreciation to Wendy Jo who had a large part in the completion of this project. Her assistance, patience, understanding and friendship will always be remembered. i i i

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TABLE OF CONTENTS ACKNO\vLEDGEMENTS ABSTRACT CHAPTERS i ii vi I I NT ROD UCTI ON II LITERATURE REVIEW . . . . . . . . . . 1 5 Trypsin Inhibitors. 5 Protein Digestibility 17 Fat Absorption and Energy Digestibility 20 Antibiotic Supplen~ntation 21 Mineral and Vitamin Supplementation 25 Other Anti-Nutritional Factors. 27 Soybean Processing. 28 Effects of Overheating Soybeans 30 Improvement of the Nutritive Value of Soybeans by Heat Processing 32 Other Methods of Processing Soybeans 36 Swine Feeding Trials. 39 Poultry Feeding Trials 44 Composition of Commercial Soybean Meal 45 Variation Among Soybean Varieties 53 Effect of Storage on Soybeans and Soybean Products 57 Effect of Maturity on Composition of Soybeans 58 Influence of Growing Conditions on Soybean Composition 59 III THE EFFECT OF INCREASING THE MOISTURE CONTENT OF SOY B EANS PRIOR TO ROASTING AT VARYING HEAT TREATMENTS ON PERFOR MAN CE OF I V EANLHJ G SWHIE 61 Introduction 61 Materials and Methods 62 Results and Discussi c n. 64 IV FEEDING VALUE AND COMPOSITIONAL VARIATION AND RELATIONSHIPS ASSOCIATED WITH DIFFERENT VARIETIES OF SOYBEANS 72 Introduction 72 Materials and Methods 74 Trial 1. ................. 74 Trial 2 75 iv

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Trial 3 ....................... 75 Results and Discussion. 79 Trial 1 ....................... 79 Trial 2 85 Trial 3. 87 Grower period 87 Finisher period 90 Overall ................ 90 V OPTIMUM HEAT PROCESSING OF DEFATTED SOYFLAKES FOR CHICKS AND STARTING, GROWING AND FINISHING SWINE 94 Introduction. 94 Materials and Methods 96 Trial 1: Chick Trial 96 Trial 2: Starter Period 99 Trial 3: Grower Period 99 Trial 4: Finisher Period. 99 Trials 5, 6 and 7: Digestibility Trials 100 Results and Discussion. . . 101 Trial 1: Chick Trial 101 Trials 2-4: Swine Trials 104 Starter period. 104 Grower period . 107 Finisher period 107 Trials 5, 6 and 7: Digestibility Trials. 109 Starter period. . 109 Grower period . 109 Finisher period 113 VI CONCLUSIONS APPENDICES . . . . A STATISTICAL ANALYSIS TABLES B TRYPSIN INHIBITO R ASSAY PROCEDU R E LITERATURE CITED . BIOGRAPHICAL SKETCH V . . 116 122 160 162 184

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Abstract of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy FACTORS AFFECTING THE NUTRITIONAL QUALITY OF SOYBEAN PRODUCTS FED TO SWINE AND CHICKS By Donnie Ray Campbell December, 1986 Chairman: Dr. C. E. White Cochairman: Dr. G. E. Combs Major Department: Animal Science Eleven experiments were conducted to evaluate several factors that could influence the nutritional quality of soybean products fed to swine and chicks. The effects of increasing moisture content of soybeans prior to roasting and varying roasting temperature on the nutritional value of soybeans fed to starting swine (5 kg) were determined by feeding diets containing soybean meal or "full-fat" soybeans (unheated or roasted at 110 or 125 C with O or 10% water added prior to roasting) (Exp. 1). Growth of pigs fed the diet containing soybean meal was superior (P<.05) compared to the other treatments groups (whole soybeans). Increasing the roasting temperature from 110 to 125 C or adding 10% moisture prior to roasting soybeans augmented (P<.05) feed intake and weight gain of weanling pigs. Comparison of the varietal differences of soybeans indicated wide variation in the fat and protein contents and trypsin inhibitor (TI) vi

PAGE 7

and urease activities CUA; Exp. 2 and 3). Fat concentration was negatively correlated (P<.05) with the protein concentration and positively correlated (P<.05) with the UA of the unheated soybeans. The effect of these varietal variations on the performance of growing finishing swine (40 kg initially) was evaluated (Exp. 4). During the grower period, pigs fed the raw or roasted soybean (Bragg or Davis varieties) diets gained more slowly (P<.05) than those fed soybean meal. Growth of pigs was increased (P<.05) by roasting either variety of soybeans at 110 C. During the finisher period, utilization of roasted soybeans of either variety and raw Davis soybeans permitted pig growth and feed efficiency equal (P>.05) to pigs fed soybean meal. In addition, six trials involving crossbred pigs and one 21-day trial using day-old chicks were conducted to evaluate the utilization of defatted soybean flakes which had been subjected to varying heating times. Total gains, feed intake and feed efficiency of chicks were not influenced (P>.05) by feeding defatted soybean flakes cooked for 16, 18, 20 or 22 minutes, whereas growth rate and feed intake of weanling pigs and average daily gains of growing pigs fed defatted soybean flakes cooked for 16 minutes or less were adversely affected (P<.05) when compared to pigs fed defatted soybean flakes cooked for 22 minutes. During the grower period, feed intake and efficiency were reduced (P<.05) compared to pigs fed defatted soybean flakes cooked for 22 minutes. Finishing pigs fed defatted soybean flakes cooked for 6, 12, 16 or 22 minutes grew at a similar (P>.05) rate and required equal (P>.05) amounts of feed per body weight gain. Amino acid digestibilities at the end of the small intestine were also determined at each age group with pigs fed the defatted soy diets. vii

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CHAPTER I I NT ROD UCTI ON The soybean, Glycine max. CL.) Merr., is a member of the family Leguminosae and subfamily Papilionoideae and has been consumed in the Orient since ancient times. The earliest Chinese records which mention soybeans date back to about the time of the building of the Egyptian pyramids. The Buddhist religion, because of the exclusion of meat from the diet of its people, was a major influence in the development of soybeans for food in the Oriental countries. However, the use of soybeans in the United States covers a comparatively short period with the first commercial oilmill processing plant established in 1922. The meal was regarded as a by-product initially and had little value when compared to the high quality oil. Soybean meal (SBM) is currently the most widely used source of supplemental protein in livestock diets. This extensive usage may be attributed to the excellent amino acid profile, dependable supply and competitive price. Approximately 80% of the SBM produced in the United States is used in swine and poultry diets (Smith, 1977). When formulating present d ay swine and poultry diets using computer least-cost feed programs, excess nutri e nts may be kept to a minimurn. This practice has increased the awareness of including only high quality ingredients, or at least having an analysis with the true nutritional quality of the feedstuff. With SBM it is critical to 1

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2 monitor the nutritional value as well as ensure that the heat labile anti-nutritional factors found in raw soybeans have been denatured by an optimum level of heat processing. The level of heat processing required to denature the heat labile anti-nutritional factors found in soybeans before they are marketed requires energy which appears destined to become more costly in the future. Dada (1983) estimated that conventional fuel for boilers accounts for more than half of the energy used to manufacture SBM. The desolventizer-toasting process and final drying step accounts for 50 to 70% of th e total steam consumption. It is the desolventizer toasting process that is the most se nsitive step in controlling the nutritional quality of SBM ( M ust akas e t al., 1981). The amount of heat processing of soybean products required for optimal animal performance and still e nsur e economica l situations for bo th the co mm ercial soyb e an r nea l processo r a nd sw in e producers cou l d vary in the futur e. Two diffe r e nt S BM 1 s (44.0 and 48.5% protein) are curr e ntly being marketed depending on wheth e r the soybean hulls are added back to the meal aft e r being h e at process ed However bo th co m~ only r e ceive the same heat processing and are curr e ntly be in g ma r ke ted for a ll a ni ma l species regardl e ss of age Th e r e is some in d ic a tion that older ( mat ure) a nimals m i ght eff ici e ntl y utili ze SBM l1avin g l e ss heat processin g (C ombs and ~va llac e 1969). If older a nimals are more efficient than youn ge r animals in their ability to utilize underproc es sed SBM, then it may be more ec ono m ical to also market a SO M havin g less heat treatment. This practice could result in a

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3 reduction of energy usage and lower the price of the SBM fed to older animals. During periods of low demand for soybean oil or low price for whole soybeans, it is economical to include whole "full-fat" soybeans in nonruminant diets. Whole soybeans, if properly processed, contain not only high quality protein but are also a rich source of energy due to their high oil content. Therefore, whole soybeans have the potential of suppling major quantities of both energy and protein in nonruminant diets. Two methods of heat processing whole soybeans (roasting and extrusion) currently available on the fann have increased the feasibility of including whole soybeans in diets for nonruminant animals. Adding fat to increase dietary caloric density has been used during periods of elevated ambient temperature to increase daily energy intake. In addition, recent studies have evaluated the effect of adding fat to diets fed to sows durin g late gestation and lactation in an attempt to increase pi g let survivability. However, liquid fat is difficult to manage without proper storage, mixing and handling facilities. These difficulties are less of a problem when adding ground whole full-fat soybeans in the diet to increase the caloric density. Also, soybean oi l contains high levels of unsaturat e d fatty aci d s, and when fed to chicks (Porter and Britton, 1974) and swine (Seerley et al., 1974; Wahlstrom et al., 1971) their carcasses contain an increased quantity of unsaturated fatty acids while still maintainin g favorable organoleptic qualities. This type of meat product may be more attractive to the consumer today due to the current trend to reduce saturated fat in the human diet.

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4 Numerous new varieties of soybeans with improved agronomic advantages over existing varieties are released annually. In soybean breeding programs, soybeans can be selected for increased protein or increased fat composition but not increases in both traits concurrently (Hartwig, 1979). Most of the anti-nutritional factors, such as trypsin inhibitors, in raw soybeans are proteins which also contain a large percentage of the sulphur amino acids. Consequently, varieties containing an increased quantity of trypsin inhibitors may contain higher contents of protein and sulphur amino acids when compared to varieties with a lower concentration of trypsin inhibitors. If the soybeans are subjected to heat processing, the higher content of trypsin inhibitors may not be detrin~ntal, and when denatured, would provide increased a~ounts of available amino acids. The objectives of this research were: 1. Assess the e ffect of increasing the moistur e content of raw soybeans prior to roasting at different taroperatures on their nutritional quality when fed to weanling pigs. 2. Quantitate varietal differences in nutrient composition and assess their effect on perforn1ance of growing-finishing pigs. 3. Determine if weanling pigs and day-old chic k s could attain maximium performance when fed raw defatted soybean flakes subjected to varying levels of heat processing. 4. Determine the influence on pig performance of varying the level of heat processing of defatted soybean flakes as the pig matures.

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CHAPTER II LITERATURE REVIEW Osborne and Mendel (1917) were the first to recognize that unheated soybeans were inferior to heated soybeans. They reported that heating the soybean protein improved the flavor and resulted in improved growth rate when fed to rats. Subsequent research by Shrewsbury et al. (1932) substantiated that heating improved the nutritional value of soybeans when fed to pigs and rats and postulated the presence of toxic factors in raw soybeans that could be removed or destroyed by heating. Since then, many workers have reported that cooking or roasting improves the nutritional value of soybeans. Several factors have been shown to contribute to the unsatisfactory performance of animals fed raw soybeans. Among these were trypsin inhibitors (Bowman, 1944), lectins (phytohemagglutinins) (Liener and Pallansch, 1952), saponins (Potter and Kummerow, 1954), goitrogenic substance (Patton et al., 1939), decreased fat absorption (Nesheim et al., 1962), and decreased amino acid availability (Borchers, 1961). Trypsin Inhibitors Twenty-seven years after Osborne and Mendel's initial work, soybeans were found to contain proteolytic inhibitors (Ham and Sandstedt, 1944; Bowman, 1944). Subsequently, a compound which inhibited trypsin was isolated, crystallized, and characterized from raw soybeans (Kunitz, 1945). After further investigation, another acetone insoluble trypsin inhibitor was isolated which is now referred 5

PAGE 13

6 to as the Bowman-Birk inhibitor (Birk et al., 1963). Obara and Wajanabe (1971) confirmed that various trypsin inhibitor fractions existed and determined that they have different susceptibilities to heat inactivation. The different trypsin inhibitors are comprised of a complex mixture of proteins and have been classified broadly into two main groups (Liener and Tomlinson, 1981). One group, of which the Kunitz soybean trypsin inhibitor is the best known example, has a molecular weight in the range of 20,000 to 25,000 daltons, specifically inhibits trypsin, and is relatively heat labile. The other group, Bowman-Birk inhibitor, consists of a family of proteins having molecular weights of approximately 8,000 daltons. Because of their high cystine content, the proteins found within this family are generally considered to be relatively heat stable. The Bowman-Birk inhibitor is unique in that it inhibits chymotrypsin as well as trypsin at two independent binding sites. Further research has indicated that the Bowman-Birk group consists of ten isoinhibitors (Tan-Wilson et al., 1985) and the Kunitz group has three isoinhibitors (Orf and Hymowitz, 1979). Because of these inhibitor specificities, raw soybeans contain twice the trypsin inhibitor activity compared to the activity for inhibition of chymotrypsin (Baintner, 1981). During heat processing, trypsin inhibitor capacity is partially inactivated prior to initial inactivation of the chymotrypsin inhibitor activity. Studies with the Bowman-Birk trypsin inhibitor indicated that most of this inhibitor is degraded during its passage through the stomach and small intestine of chicks, and that there is negligible absorption of the native inhibitor with most of the degradation products being excreted in the feces (Madar et al., 1979). In addition to the

PAGE 14

7 protein trypsin inhibitors, Hafez and Mohamed (1983) reported that soybeans also contain nonprotein trypsin inhibitors. Proteolytic inhibitors are not unique to soybeans but are somewhat ubiquitous in nature and have distinct roles. For example, in mammals, trypsin inhibitors are a component of colostrum and help prevent proteolysis of antibodies. The pancreas also secretes trypsin inhibitor to prevent activation of the proteolytic enzymes of the pancreatic juices until they are secreted into the small intestine. Likewise, researchers postulate the functions of the proteinase inhibitors in soybeans (seeds and plant) are to Cl) maintain dormancy by preventing autolysis, (2) regulate protein synthesis and metabolism and (3) prevent attack by predatory insects (Smith and Circle, 1972). Initial studies in which partially purified preparations of soybean trypsin inhibitor were fed to rats and chicks resulted in no significant effect on their growth rate (Borchers et al., 1948). However, subsequent research has well documented the growth depression obtained by including raw soybeans in place of heated soybeans in the diet of rats (Liener et al., 1949; Borchers, 1961), chicks (Alumot and Nitsan, 1961; Nesheim et al., 1962), and pigs (Pekas, 1966; Hooks et al., 1967a). Trypsin inhibitor concentrate or raw soybean m eal also causes pancreatic hypertrophy concurrent with the significantly slower growth in chicks (N e sheim et a l., 1962; Salmon et al., 1967) and rats (Brambila et al., 1961; Borchers, 1964) but not in pigs (Hooks et al., 1965; Pekas, 1966). Liener et al. (1949) fed diets containing raw soybeans, heated soybeans, and heated soybeans+ 1.8% trypsin inhibitor to rats and reported a depressed protein efficiency ratio value for the heated diet containing trypsin inhibitor compared to the

PAGE 15

8 heated soybean diet but a higher protein efficiency ratio value than obtained for the diet containing raw soybeans. These data provided the initial indication that trypsin inhibitors were not the exclusive anti-nutritional constituent of soybeans. The Kunitz inhibitor can account for all the pancreatic hypertrophy effects but for only about 30 to 60% of the growth-inhibiting properties of raw soybean meal fed to rats (Rackis, 1965). More recent research by Kakade et al. (1973) confirmed the 40% growth depression but also reported only 40% of the pancreatic enlargement in rats produced by the ingestion of raw soybeans was accounted for by the trypsin inhibitors. Contrasting research has been presented to account for the pancreatic enlargement. Kakade et al. (1967) observed hyperplasia (increase in cell number) of the pancreatic acinar cells while Konijn and Guggenheim (1967) reported hypertrophy or increased cell size. No histopathological damage was observed in rat pancreas hypertrophied for six months, and pancreatic hypertrophy was reversible in rats (Booth et al., 1964) and in chicks (Salmon and McGinnis, 1969). The ability to compensate for the proteolytic activity of raw soybeans was greater with increasing age of chicks (Nitsan and Alumot, 1964). The efficacy of supplementing rat, chick and pig diets with trypsin to overcome the adverse effect of feeding raw soybeans has been studied. Inclusion of 5% dietary trypsin powder in a raw soybean diet improved rat growth (Borchers and Ackerson, 1951). Autoclaving the trypsin powder destroyed its proteolytic activity but did not reduce growth. Brambila et al. (1961) added a crystalline and a crude

PAGE 16

9 trypsin preparation to chick di e ts cont a ining raw soybeans but still obtained depressed growth. Pancreatic hypertrophy was reduced with the crude trypsin preparation but crystalline trypsin did not prevent the pancreatic enlargement. Similarly, inclusion of .5% trypsin in diets containing raw soybeans fed to pigs at 3, 9 or 16 weeks of age did not improve the rate and efficiency of gain or dry matter, protein and ether extract digestibilities (Combs and Wallace, 1969). Plasma glucose and urea nitrogen also did not differ when pigs were fed .5% trypsin in the diet. Feeding raw soybean meal to chicks resulted in hypertrophic pancreas with higher trypsin and lower amylase specific activities in this organ (Pubols et al., 1964). Supplemental dietary methionine increased the ratio of amylolytic to proteolytic enzymes (Nitsan and Gertler, 1972). Total secretion of trypsin nearly doubled in chicks fed raw soybean meal, whereas amylase, lipase and chymotrypsin activities were not significantly different from that of chicks fed autoclaved soybean meal (Dal Borgo et al., 1967). Further research data collected by Gertler and Nitsan (1970) indicated increased levels of trypsin, chymotrypsin, and pancreatopeptidase but decreased levels of amylase were secreted from the pancreas when raw soybeans were substituted for heated soybeans in a chick diet. However, the addition of a trypsin inhibitor in the heated soybean diet increased the quantities of all four enzymes. Soybean trypsin inhibitor activity was correlated with pancreatic trypsin activity in the chick but was not correlated with the activities of amylase, chymotrypsin or pancreatic trypsin inhibitor (Pubols et al., 1985). In addition,

PAGE 17

10 feeding raw soybean meal was reported to inhibit the synthesis of pancreatic lipase while stimulating excessive secretion of intestinal lipase in chickens (Lepkovsky and Furuta, 1970). In other studies, feeding raw soybean meal to rats also stimulated hypersecretion of pancreatic enzymes (Borchers, 1964). Konijn et al. (1970) and Temler et al. (1984) reported increased trypsin and chymotrypsin activities and an enlarged pancreas in rats by feeding diets containing .72 and 1.08% trypsin inhibitor. Amylase, elastase and lipase activities, feed intake and body weight were not influenced. The increase in pancreatic trypsin activity due to feeding soybean trypsin inhibitor was confirmed by Fushiki et al. (1984) but the researchers also noted an increase in pancreatic lipase activity. The trypsin activity was highly correlated with the total protein output in the bile-pancreatic juice. Feeding of raw soybeans or crystalline trypsin inhibitor immediately increased amylase and lipase activities in the intestine of rats and after three hours the activities were increased three to fourfold (Lyman and Lepkovsky, 1957). The initial intestinal trypsin activity was low, apparently inactivated by the trypsin inhibitor, but increased after six hours. These researchers noted that pepsin secretion was unaffected by feeding raw soybeans. The findings by Borchers (1964) indicated that kidney transaminase activity was also reduced when rats were fed raw soybean meal but other tissue enzymes showed no change. The physiological changes in pigs due to feeding raw soybeans do not concur with the data obtained with chicks and rats. Pancreatic juice secretion was reduced in pigs fed raw soybean meal compared to

PAGE 18

11 pigs fed heated soybean meal diets (Pekas, 1966). However, the secretory response obtained by feeding raw soybean meal is related to pig maturity (Hooks et al., 1965). Weanling pigs fed raw soybean meal had reduced pancreas weight, nitrogen content of the pancreas, and lipase activity of the intestinal fluids and pancreas compared to weanling pigs fed heated soybean meal. Protease activity of the pancreas and intestinal fluids did not differ. When growing pigs were fed raw soybean meal, their pancreatic weight, and protease and lipase activities of the pancreas and intestinal fluids were similar to pigs fed heated soybean meal. In contrast to weanling pigs, nitrogen content of the pancreas was increased when raw soybean meal was fed to growing pigs. Cell structure and zymogen content of pancreatic tissue did not differ between pigs fed heat processed or unprocessed soybean meal nor between the different ages of pigs. In another study both raw soybean and Kunitz soybean trypsin inhibitor decreased pancreatic trypsin and chymotrypsin activities of growing pigs (Yen et al., 1977). However, inhibition of intestinal trypsin and chymotrypsin activities was greater in the pigs fed the raw soybean diet. Data from a more recent study using growing pigs fitted with a pancreatic cannula indicated that feeding an unheated commercial soybean product increased the protein secretion and total activities of trypsin and chymotrypsin of the pancreas compared to pigs fed a heated soybean product (Ozimek and Sauer, 1985). In contrast, Corring et al. (1985) fed a diet containing raw soybeans to growing pigs and observed that the total protein output from the pancreas was not affected. However, the volume of pancreatic juice secreted was increasd as well

PAGE 19

12 as the plasma levels of secretin when a diet containing raw soybeans was fed. Zebrowska et al. (1985) confirmed the work of Corring and also reported no differences 1n total and specific activities of trypsin, chymotrypsin, carboxypeptidases A and Band amylase in the pancreatic juice of growing pigs fed raw or adequately heat processed soybean meals. Seventy percent of the protein digestion of heat treated soybean meal in the chick was found to occur in the duodenum and 20% occurred in the upper jejunum (Bielorai et al., 1973). When raw soybean meal was fed, 70% of the protein digestion to o k place in the duodenum and no further digestion occurr e d in the remaining segments of the digestive tract. The increased secretion of enzymes and bile constituents into the duodenum in response to feeding raw soybeans was inactivated in the jejunum by the anti-nutritional factors in the soybeans a nd further digestion did not occur. Bielorai et al. (1973) suggested that the growth depression from feeding raw soybean meal could result from the 20 % reduced protein absorption and the small amount of energy needed for the increased production and secretion of enzymes into the duodenum. This helps explain why a lower concentr a tion of free amino acids in the intestinal contents with chicks fed raw soybeans, as compared with those f e d heated soybeans, was observed in an ea r lier study by the same group (Bielorai et al., 1972). Numerous factors have been proposed as being responsible for the reduced animal performance when raw soybeans are f e d. Alumot and Nitsan (1961) concluded that the growth retardation was attributed to

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13 a combination of low availability of dietary protein and an increased protein requirement resulting from stimulation of the pancreatic activity to increase enzyme production to overcome the trypsin inhibitors. The excessive amount of protein secreted in the pancreas of rats was ultimately lost in the feces (Haines and Lyman, 1961). In a later study, Muelenaere (1964) reported that feeding rats a diet containing 5% trypsin inhibitor caused a slower rate of stomach emptying and interfered with amino acid absorption through the intestinal wall. Lanchantin et al. (1969) found that the Kunitz trypsin inhibitor reacted with trypsin almost instantaneously to form a complex with an extremely low dissociation constant, thus decreasing the quantity of protein being hydrolyzed. Lepkovsky et al. (1971), using rats and chicks, suggested that the trypsin inhibitor combines with protein in the intestine to form complexes which escape digestion and are subsequently lost in the feces. Green e t al. (1977) substantiated that native undenatured soybean protein is capable of binding trypsin by forming an enzyme-substrate complex which can remove feedback inhibition of pancreatic secretion by trypsin. Additional research by Lepkovsky et al. (1970) has indicated that after feeding raw soybeans to chicks, the quantity of enterokinase in the intestinal juice could not be measured which could limit the quantity of trypsinogen being converted to trypsin. Singh and Krikorian (1982) reported in a more recent study that low levels of phytic acid found in raw soybeans in vitro can also inhibit trypsin activity.

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14 Lyman et al. (1974) and Schneeman et al. (1977) attributed the stimulatory effect of raw soybean flour on the secretory activity of the pancreas to a negative feed-back regulation. The pancreas was induced to increase the output of enzymes when the levels of trypsin and chymotrypsin in the intestine fall below certain threshold values due to complexes formed with trypsin inhibitors or dietary protein. It was believed that the mediating agent between trypsin and the pancreas is the hormone cholecystokinin. The feeding of diets containing trypsin inhibitor at 6% of the protein level to rats stimulated an increase in the production of pancreatic proteases compared to the feeding of diets containing either proteins or peptides (Temler et al., 1984). Although trypsin inhibitors are potent stimulators of the secretion of cholecystokinin, they can also stimulate secretion of other unidentified gastrointestinal factors. Struthers et al. (1983) likewise previously noted that the increased secretion of cholecystokinin was not the sole mediator of effects produced by feeding raw soybean flour. Richardson (1981) and Liener (1981) reviewed previous research and summarized the deleterious effects of proteinase inhibitors in raw soybeans and developed the following scheme. The proteinase inhibitors and undenatured soybean protein are only partially inactivated by pepsin and entering the small intestine, form a complex with trypsin and chymotrypsin. The resulting lower concentrations of trypsin and chymotrypsin reduce proteolytic hydrolysis and stimulate secretion of cholecystokinin. The undigest e d protein is lost through the feces (exogenous loss). Increased secretion of pancreatic enzymes

PAGE 22

15 caused the protein from body tissue to be broken down and used in increased synthesis of proteinases. Methionine in particular is used by its conversion to homocysteine then to cystathionine and cysteine. This mechanism resulted in increased quantities of proteinases in the intestine. The sulphur containing amino acids are then degraded by the micoflora in the colon and lost in the feces (endogenous loss). The control mechanisms for synthesis of pancreatic nucleic acids and enzyme proteins are dissimilar within different mammalian species (Struthers et al., 1983). Feeding raw soybean products containing large quantities of trypsin inhibitors produced enlargement of the pancreas in rats, mice, and chicks; but not in dogs, calves, pigs, or monkeys. Pancreatic hypertrophy and increased secretion were almost immediate in rats Clyman and Lepkovsky, 1957); whereas in chicks, hypertrophy and pancreatic juice secretions were delayed for three to eight days following the feeding of soybean trypsin inhibitor (Nitsan and Alumot, 1964; Kakade et al., 1967). The immediate response in the pancreas of rats was a decrease in protein synthesis followed by increased selective enzyme synthesis, stimulated by both the Kunitz and Bowman-Birk inhibitors which resulted utimately in hypertrophy and loss of endogenous protein (Konijn et al., 1970). Animals whose pancreas weights were greater than .3% of their relative body weight exhibited pancreatic hypertrophy when fed raw soybeans whereas animals whose pancreas weights were less then .3% of their relative body weight did not (Liener, 1977). Although pancreatic hypertrophy does not occur in all animal species, soybean trypsin inhibitors have been shown in vitro to inhibit 90 to 100% of trypsin obtained from the rat, monkey, bovine, human, porcine and mink (Struthers et al., 1983).

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16 Additional investigations have centered on quantifying various species response to feeding raw and heated soybean products. For example, Struthers et al. (1983) fed rats, pigs and monkeys raw and heated soybean flour containing 115 to 130 and 4 to 8 units trypsin inhibitor per mg protein, respectively. Growth and nitrogen digestibility were depressed 60 and 5%, 84 and 45%, and O and 9% for rats, pigs, and monkeys, respectively, due to feeding the raw soybean flour. Fecal trypsin concentration was increased 300 to 400% in rats but decreased 50% in pigs and monkeys when fed raw soybean flour. Rats and pigs consumed significantly less of the raw soybean flour diet compared to the diet containing the heat e d soybean flour. However, monkeys consumed equal quantities of the two diets. Other differences due to feeding raw soy flour included changes in RNA per mg pancreas and pancreatic protein concentrations with changes of +40 and +47% ,and +20 and -7% for rats and pigs, repectively. These measured criteria were not altered in the monkeys. In other studies, Hasdai and Liener (1983) reported depressed growth, feed intake, feed efficiency, and protein digestion when raw soybean flour was included in the diet of hamsters. They also obtained increased pancreas and kidney size and elevated trypsin, chymotrypsin, amylase and lipase activities in the pancreas. Feeding raw soybeans to the mink resulted in a 20-fold increase in fecal trypsin activity when compared to that found in chick excreta (Skrede and Krugdehl, 1985). In addition, chick excreta contained a larger quantity of proteinase inhibitors compared to mink excreta. Furthermore, Gorrill and Thomas (1967) observed poor growth in young calves fed raw soybean meal, and reduced trypsin and chymotrypsin secretions but no pancreatic hypertrophy.

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17 Protein Di ges tibility As previously inferred, a change in pancreatic proteolytic enzyme production and consumption of proteolytic inhibitors can combine to alter protein hydrolysis and thereby reduce the availability of and increase the requirement for the essential amino acids. Therefore, adding amino acids to diets containing raw soybeans to improve performance has been investigated. One such study by Hill et al. (1953) indicated that the addition of an amino acid mixture failed to prevent the growth depressing effect of raw soybeans when fed to chicks. However, in subsequent research, normal growth was obtained by supplementing a diet containing raw soybeans with another mixture of amino acids (Fisher and Johnson, 1958). They suggested that earlier data which did not show improved growth was a result of inadequate amino acid balance. Increasing the dietary protein content instead of adding only amino acids to the diet improved the growth rate of rats (Fisher and Shapiro, 1963) but not of pigs (Combs et al., 1967) fed diets containing unheated soybean meal. Saxena et al. (1962a) obtained increased growth and feed efficiency when adding a mixture of amino acids, varying from four to 14 amino acids to raw soybeans, but the performance was not equal to a diet containing heated soybean meal with the same amino acids. These researchers also reported that chicks fed raw soybeans consumed five times the amount of oxygen and had much lower liver and muscle glycogen content than chicks fed autoclaved soybean meal. However, when these chicks were fed the raw soybean diets containing amino acid supplements, their oxygen consumption returned to normal. More specifically, supplementation of diets for weanling rats containing raw soybeans

PAGE 25

18 with methionine, threonine and valine resulted in performance that was similar to rats fed heated soybeans (Borchers, 1961). Khayambashi and Lyman (1966) confirmed Borchers' work but also reported that the increased pancreatic and intestinal protease activities and intestinal insoluble nitrogen observed in rats fed a diet containing soybean trypsin inhibitor were not reduced when methionine, threonine and valine were added. Hooks et al. (1967a) reported that methionine supplementation in diets fed to rats and chicks improved their performance but the addition of either threonine or valine to diets containing raw soybeans did not. Dietary supplementation with methionine to overcome the growth depressing effect when raw soybeans were fed has received a great deal of attention but results were inconclusive. Nickelson et al. (1960) fed weanling pigs and presented data indicating improved growth with as low as .1% supplemental methionine. The ameliorated effects of feeding raw soybeans to rats and chicks by supplementing diets with methionine was confirmed by Hooks et al. (1967a). However, these researchers did not obtain increased pig performance by including methionine in raw soybean diets. Similarly, more recent studies have reported that methionine supplementation of diets containing raw soybeans did not improve the performance of finishing pigs (Jensen et al., 1970) nor pigs at three, nine, or 15 weeks of age (Combs and Wallace, 1969). Although Combs and Wallace (1969) noted a increase in dry matter and protein digestibilities when methionine was added to the raw soybean diet fed to pigs at three weeks of age, these criteria were not different for pigs at nine or 16 weeks of age.

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19 Almquist et al. (1942) fed chicks raw soybean diets and obtained increased growth with methionine supplementation but not with additions of choline or cystine. A study by Nitsan and Gertler (1972) confirmed that the addition of .3 or .6% methionine to diets containing raw soybeans would increase chick perfomance. The increase in chick growth obtained by adding methionine to a diet containing inadequately heat processed soybean flakes was confirmed by Miles and Featherston (1976). These researchers also reported that lysine supplementation alleviated the adverse effects on growth when chicks were fed soybean flakes which were overheated. Likewise, methionine supplementation of rat diets containing raw soybean meal increased growth and feed efficiency equal to that of rats fed diets containing heated soybean meal but performance was depressed when compared to rats fed a heated soybean meal diet containing supplemental methionine (Hensley et al., 1953). In addition, the inclusion of aureomycin in the diets containing raw and heated soybean meal supplemented with methionine permitted an additional increase in growth and feed efficiency. In another study, the addition of .6% methionine improved the protein efficiency ratio of a raw soybean meal diet similar to the improvement obtained by heating the raw soybean meal (Liener, 1949). Nitrogen retention as well as performance of rats were improved when .3% methionine was included in a diet containing raw soybean meal (Yen et al., 1971). These findings are in contrast to an earlier study (Carroll et al., 1953) which indicated that methionine supplementation in rat diets containing either raw or heated soybean meal did not affect the amount

PAGE 27

20 and site of nitrogen absorption. Subsequent research has indicated that the inhibitors in raw soybeans do not affect the availability of supplemental methionine when included in a rat diet but these inhibitors only depressed the availability of the intact methionine (Rao et al., 1971) However, Liener et al. 0949) had previously reported that a preparation of trypsin inhibitor was capable of inhibiting rat growth even when incorporated in diets containing either predigested protein or free amino acids. The response from adding methionine to raw soybean diets fed to rats can be influenced by ambient temperature (Yen et al., 1971). The largest increase in growth between rats fed either a heated soybean diet or a diet containing raw soybeans supplemented with methionine when compared to rats fed a raw soybean diet was obtained when the ambient temperature was 23 C compared to 7 C. The percentage of raw soybean meal in a rat diet can also alter the response of rats from adding methionine (Barnes et al., 1962). Addition of .3% methionine to diets containing 50% unheated soybean flakes increased growth of rats but no growth stimulation was obtained by the addition of methionine to a diet containing 70% unheated soybean flakes. Fat Absorption and Energy Digestibility Feeding raw soybean meal has also been shown to reduce fat absorption in young chicks; this effect was found to decrease with increasing age (Nesheim et al., 1962). Borchers (1964) fed raw soybean meal to chicks, rats, and mice and also noted depressed dietary metabolizable energy and fat absorption. However, Gar11ch and Nesheim (1966) fed chicks a crude trypsin inhibitor preparation or Kunitz trypsin inhibitor and reported that each product when added

PAGE 28

21 to a diet containing heated soybean meal depressed dietary metabolizable energy but had only a small effect on fat absorption. Providing extra calories in diets containing raw soybean meal has been reported to improve rat growth (Fisher and Shapiro, 1963) but not the gains of growing pigs (Combs et al., 1967). Feeding raw soybean meal has been observed to greatly enhance secretion of total fatty acids, phospholipids, cholesterol and bile into the duodenum when compared to feeding heated soybean meal to chicks (Sklan et al., 1972). The high secretion rate of fatty acids was counteracted by an increase in their absorption rate; yet, the overall net absorption of fatty acids was still slightly reduced compared to chicks fed heated soybean meal. The same protein fractions that cause pancreatic hypertrophy, also contract the gallbladder, accelerate bile secretion and decrease fat absorption (Sambeth et al., 1967). Serafin and Nesheim (1970) reported that undigested protein in raw soybean meal may also bind bile acids and elevate the rate of fecal excretion thereby depressing fat absorption. It had also previously been postulated that the depression in protein digestibility may also be partially responsible for the difference in metabolizable energy values between raw and toasted soybean meals fed to chicks (Nesheim and Garlich, 1966). Antibiotic Supplementation The effect of dietary antibiotics in reversing the growth depression associated with feeding raw soybeans has received considerable attention. Supplementation of diets containing raw or heated soybean meal with chlortetracycline increased the growth rate

PAGE 29

22 and feed efficiency in rats fed either diet, although the improvement was greater with rats fed the raw soybean meal diet (Hensley et al., 1953). Including aureomycin in raw and heated soybean meal diets also increased the absorption of nitrogen and the amino acids (lysine, leucine, methionine and cystine) in both diets (Carroll et al., 1953). Similar to the work of Hensley et al., the increased absorption was greater in pigs fed the raw soybean meal diet. Likewise, the inclusion of .1% procaine penicillin and .1% streptomycin sulfate in raw soybean diets increased the growth of rats equal to that obtained by feeding a heated soybean meal diet (Borchers, 1958). Braham et al. (1959) not ~ d that the inclusion of procaine penicillin, chlortetr a cycline, novabiocin, zinc bacitracin or strepton ~ cin increased chick growth in raw soybean diets by 31 to 51 % but only a 4 to 14 % improvement was measured for chicks fed the heat e d soybean diets. The raw soybean diets containing the different antibiotics did not permit equal performance when compared with the unsupplemented heat ed soybean diet. In trials with turkey poults, the beneficial effects on growth by adding antibiotics are negatively correlated with the amount of raw soybeans contained in the diet (Linerode et al., 1961). The inclusion of aureomycin in a diet containing underprocessed soybeans fed to pigs from weaning to market weight did not improve performance compared to pigs fed adequately processed soybean oil meal (Becker et al., 1953). Sheppard et al. (1967) fed weanling pigs diets containing raw or heated soybean meal and reported increased growth by including antibiotics in both diets. However, the smallest response

PAGE 30

23 was observed with antibiotic supplementation of the diet with raw soybeans. The poor growth associated with feeding raw soybeans has been suggested by Borchers (1961) to be the result of enhanced deleterious bacterial activity in the intestine. The inclusion of antibiotics in the diet may counteract this condition. Growth inhibition and increased intestinal nitrogen (protein) were observed to occur in both conventional and germ-free chicks, but Coates et al. (1970) and Hewitt and Coates (1969) reported growth inhibition in conventional chicks was significantly greater than in germ-free chicks fed raw soybean diets. However, pancreatic hypertrophy was observed in the germ-free chicks fed raw soybean meal as well as in the conventional chicks. They postulated that the intestinal microflora potentiated the anti-nutritional effects of raw soybeans by the formation of additional factors resulting from microbial action on heat-labile components in raw soybean meal. Strains of Escher1chia .Q}j_ were subsequently shown to be responsible for the adverse effects associated with the consumption of this raw soybean diet (Jayne-Williams and Hewitt, 1972). Barnes et al. (1965), working with chicks und rats, attributed the beneficial influence of antibiotics on overcoming the growth inhibiting effects of feeding raw soybean meal to the preservation of sulfur amino acids from degradation by the intestinal microflora. Trypsin contains 6.7% cystine and the increased trypsin synthesis and secreticn brought about by feeding raw soybeans can account for one-half of the cystine excreted by the rat (Barnes et al., 1965).

PAGE 31

24 Researchers using methionine labeled with 35 s isotope noted that ingested trypsin inhibitor stimulated the conversion of methionine to cystine in the pancreas since high concentrations of radioactive cystine were found in the small intestine (Barnes and Kwong, 1965). These researchers postulated that the depletion of methionine through its conversion to cystine was at least one of the mechanisms causing growth inhibition. Thus, antibiotics, possibly by reducing the bacterial degradation of cystine in the lower gut, increased the intestinal absorption of cystine sufficiently to meet the requirement for synthesis of pancreatic enzymes (Kakade et al., 1970). The microflora spectrum in the intestinal tract, which can be modified by antibiotic supplementation, will affect flatulence production (Rackis, 1966). Pazor et al. (1962) reported that oligosaccharides comprise about 15% of the air-dried weight of soybeans with sucrose, stachyose, and raffinose present in that order of abundance. Stachyose and raffinose are thought to produce large amounts of gas in the lower digestive tract. These compounds, having low molecular weights, are comprised of ci-galactosidic and ci-fructo sidic linkages. Since most animals do not have the digestive enzyme ci-galactosidase, the intact oligosaccharides enters the lower intestine where they are metabolized to such gasses as carbon dioxide, hydrogen and to a lesser extent methane (Liener, 1981). Another response observed from antibiotic supplementation was an alteraticn in pancreatic enzyme production (Goldberg and Guggenheim, 1964). One hour after feeding, the tryptic and amylolytic activities of the pancrease were much lower in rats fed raw compared to heated

PAGE 32

25 soybean flour diets. Inclusion of aureomycin or penicillin in the diet containing raw soybean flour diminished this reduction in pancreatic enzyme activity that was brought about by feeding raw soybeans. Addition of penicillin either through the diet or by subcutaneous injection improved the protein efficiency ratio and reduced the loss of proteolytic enzymes in the gut. However, the improvement was not equal to that found with rats fed diets containing heated soybean flour without antibiotic supplementation. Mineral a nd Vitamin Supp]ementat1on The supplementation of trace minerals to the diet has also been shown to improve the nutritional value of raw soybean products. The addition of raw soybeans to the diet consequently increased the dietary requirement of cyanocobalamine (vitamin s 12 >, vitamin D 3 calcium, phosphorus, zinc, iron, copper and molybdenum (Rackis, 1981). In addition, Weaver et al. (1984) found that the bioavailability of iron from defatted soyflour was relatively high and addition of vitamin C did not significantly enhance absorption of iron from raw or heat e d soyflour. Phytic acid is located in the 7S protein fraction of soybeans in the form of a soluble protein-phytate salt complex with significant amounts specifically deposited 1n the globoid inclusions of the soybean seed (Prattley and Stanley, 1982). Research has also indicated that the phytic acid content of soybeans was involved in reducing the availability of calcium, magnesium, zinc, copper and iron by the formation of complexes which are poorly absorbed (Davis et al., 1962; Liener, 1981; Ellis and Norris, 1981). However, other

PAGE 33

26 researchers have reported that the small amount of phytate present in the soybean protein does not affect the bioavailability of copper (Grace et al., 1984), iron (Welch and Van Campen, 1975) or magnesium (Lo et al., 1980). Recent evidence has indicated that heating raw soybeans can reduce their phytic acid content (Liener, 1981). The inclusion of unheated soybean meal in diets of chicks increased their susceptibility to rickets unless higher than recommended levels of vitamin o 3 were added to the diet (Carlson et al., 1964). Autoclaving the soybean meal or supplementation with calcium and phosphorus also eliminated the occurrence of rickets (Jensen and Mraz, 1966). Raw soybeans contain a heat-labile substance that increas e d the requirement for vitamin s 12 in rats (Edelstein and Guggenheim, 1970a). The metabolites associated with enzymes that require vitamin B 12 as a coenzyme are also increased (Edelstein and Guggenheim, 1970b). Supplementation of raw soybean meal diets with vitamin s 12 stimulated growth of rats (Rackis, 1981). However, Ward et al. (1986) recently reported that raw soybeans did not enhance s 12 turnover or impair B 12 absorption in chicks. Supplementing diets containing raw soybeans with other trace minerals has been shown to improve animal performance. The addition of 125 ppm copper sulfate to diets containing raw soybeans increasod average daily gain and feed efficiency of market hogs (Young et al., 1970). The researchers did not speculate whether the respon s e wa s due to the copper per se or indirectly from the bacteriostatic effect of the copper sulfate. Linerode et al. (1961) obtained no nutritional

PAGE 34

27 benefit from adding a zinc supplement in a turkey diet containing raw soybeans. Other studies utilizing iodine-deficient diets have indicated that feeding raw soybeans caused marked enlargement of the thyroid glands of rats and chicks, an effect which could be counter acted by administration of potassium iodide or partially eliminated by heat processing soybeans (Patton 0 t ul., 1939; Block et al., 1961). Other Anti-Nutritional Factors Other constituents of soybeans have been in~licated as being responsible for the reduced performance commonly associated with feeding raw soybeans. For example, hemagglutinins, a glycoprotein (Lis et al., 1966), was isolated from soybeans in 1952 (Liener and Pallensch, 1952) and later determined to comprise an estimated 1 to 3% of the protein of defatte d soybean flour (Liener and Rose, 1953). Hemagglutinins, also known a s lectins, appear to function similarly to trypsin inhibitors in the soybean plant as defensive proteins that protect the plant from insect invasion and are appropriately located on the surface of the plant cell (Lehninger, 1982). Lectins bind to certain carbohydrate groups, D-galactose and N-acetyl-D-galactosamine, on the cell surface. Soybean lectins have been shown to be readily destroyed by heat treatment and their destruction was accompanied by a marked improvement in the nutritive value of the protein when fed to chicks (Liener and Hill, 1953). However, rats fed soybean extracts, from which the l e ctins had been removed by affinity chromatography, grew just as poo r ly as those consuming the original crude soybean extract (Liener, 1981). Therefore, it appears that lectins do not play a major role in reducing the nutritional quality of soybean protein.

PAGE 35

28 Another anti-nutritional factor, saponin, which has been found in some plants to have an adverse effect on animal growth, is also a constituent of soybeans. However, feeding chicks, rats, and mice diets supplemented with three times the level of saponin found in soybean flour was not detrimental to performance (Ishaaya et al., 1969). Soybean Processing As previously discussed, heat processing inactivates several anti-nutritional factors in soybeans, such as trypsin inhibitors, hemagglutinins, goitrogens, antivitamins and phytates (Liener, 1981). However, soybeans contain other proposed anti-nutritional factors, such as saponins, estrogenic compounds, and flatulence compounds, which are heat-stable. Also, some components of raw soybeans (pyridoxine, total and free folacin) which are needed for growth are reduced when soybeans are heated (Soetrisno et al., 1982). Sugawara et al. (1985) found that the green or grassy odor of soybeans disappeared or decreased by heating but the beany odor remained even if the soybeans were heated for 8 hours. Water-extractable proteins from soybeans can be separated into four fractions with approximate sedimentation rates of 2, 7, 11 and 15S, and comprise 22, 37, 31 and 11% of the total protein in soybeans, respectively (DeMan, 1980). Trypsin inhibitors are located in the 2S fraction. The 7S fraction contains lectins, lipoxygenase (the enzyme that catalyzes the oxidation of lipids) and 7S globulin; whereas, the 11S fraction consists mainly of 11S globulin (glycinin). The 7S and 11S (glycinin) globulins are the major storage proteins of soybean

PAGE 36

29 seeds. The 7S globulin, a glycoprotein, is present as a monomer with molecular weight of 180,000 to 210,000 daltons. Glycin1n is a large molecule of 290,000 to 320,000 dalton molecular weight composed of 12 subunits having a rigid globular conformation (Kitamura et al., 1976). The 15S fraction has proteins with molecular weights approximately 600,000 daltons. The application of heat to soybean protein has been shown to alter the hydrogen and hydrophobic bonds which resulted in decreased water solubility of the proteins (DeMan, 1980). Kakade et al. (1973) suggested that native undenatured soybean protein is in itself refactory to enzymatic attack unless denatured by heat. Subsequent research indicated that glycinin in raw soybeans resists proteolytic attack (Kc:.rr,ata et al., 1979). Heating glycinin at 100 C increased the digestibility by denaturation or unfolding the conformation of the protein (form digested at a fairly high rate). However, heating glycinin at 120 C caused decreased digestibility suggesting that excess heat causes refolding of the protein in a new conformation that is more resistant to enzymatic attack. The heating of raw soybeans has been shown to increase the nutritional availability of sulphur and nitrogen in diets fed to rats (Johnson et al., 1939). The availabilities of methionine and cystine in trials with chicks increased until a temperature of 120 C was obtained; after which the availabilities then decreased (Evans and McGinnis, 1946). Carroll et al. (1953) reported that proper heat treatn,ent of soybean meal increased absorption of lysine, leucine and methionine in rats but the greatest improvement was with cystine absorption. In addition, plasma levels of threonine and trytophan in

PAGE 37

30 rats were increased markedly by heating the soybeans, indicating increased digestibility and absorption of these amino acids (Rao et al., 1971). Effects of Overheating Soybeans Overheating soybean protein impaired its nutritional quality. Evans and associates (Evans and McGinnis, 1946; Evans and McGinnis, 1948; Evans et al., 1951; Evans et al., 1962) have conducted extensive research with overheated soybean protein. They reported that with chickens, cystine was the limiting amino acid in overheated soybeans. Methionine availability was also decreased when soybean protein was autoclaved at 120 C. These workers indicated that 31% of the total cystine was destroyed and 25% became inactivated with autoclaving. The relative availabilities of cystine and methionine by chicks were increased by autoclaving raw soybeans at 100 C for 30 minutes; but autoclaving the soybeans at 130 C for 60 minutes reduced the quantity of cystine utilized to the level equivalent of feeding raw soybeans while methionine utilization was decreased. In addition, adding sucrose or glucose to soybeans increased inactivation of cystine by four fold. Subsequent research has shown that some of the soybean proteins appear to have more heat labile cystine than other soybean proteins. Iriarte and Barnes (1966) presented data which indicated that the amount of heat required to destroy the growth inhibitors also destroyed some of the cystine; such that it was the first limiting amino acid. More recent results by Crissey and Thomas (1983) further illustrated the reduced availabilities of methionine and lysine due to extreme overheating of soybeans. These researchers fed roosters commercial soybean meal (SBM) that had received additional

PAGE 38

31 autoclaving for one hour at 121 C then dried the meal for 30 minutes and reported a 38 and 22% increase in the excretion of methionine and lysine, respectively. Lysine destruction can also be used as a indicator in determining the nutritive value of overheated soybeans. Evans and Butts (1948) and Evans and McGinnis (1948) reported a greater proportion of the lysine was made inactive than was destroyed. Their results showed a greater percentage of lysine inactivated with an increase in heating temperature. The addition of sucrose or glucose further increased the binding of lysine to a form which was unavailable to enzymatic digestion. In addition to cystine, methionine and lysine, other amino acids including arginine, tryptophan, histidine and serine were partially destroyed or denatured by excessive heating of soybean meal (Liener, 1958; Skrede and Krugdehl, 1985). Kasarda and Black (1968) implied that overheating of soybean protein was a major source of ammonia evolution which could react with the available reducing sugars to form pyrazine compounds. Scott et al. (1969) noted that soybean products contain reducing carbohydrates such as glucose and these sugars can react with the free epsilon amino group of lysine in the soybean protein. This reaction is termed the "Maillard" or "browning" reaction. Heat treatment accelerates the formation of carboydrate-amino group complexes which are resistant to enzymatic hydrolysis. The result is that amino acids (especially lysine) become nutritionally unavailable. Knipfel et al. (1975) autoclaved soybean protein with different carbohydates at 121 C for 0 to 1280 minutes. Soybean protein autoclaved with sucrose, glucose,

PAGE 39

32 or fructose reduced rat growth, net protein ratio and protein digestibility more than soybean protein which was autoclaved with starch and cellulose or without the added carbohydrates. Plasma lysine was reduced more than plasma methionine when rats were fed soybean protein heated with glucose, fructose and sucrose. Supplementation of amino acids to the diets containing overheated soybeans has been studied in trials with chicks by Evans and McGinnis (1946). The addition of cystine, lysine, and methionine to the diet improved chick growth. Single addition of any of these amino acids simply did not ameliorate the depressed growth obtained from feeding overheated soybeans. Improvement of the Nutritive Value of Soybeans by Heat Processing Many factors such as heating temperature, pressure, and time are very important in obtaining the maximum nutritional value from heating soybeans. Optimum chick growth required heating soybeans 30 minutes at 107 C (Carew et al., 1961). These heating conditions confirmed earlier work of Evans and McGinnis (1946) which obtained the best chick performance when feeding soybeans that were also heated for 30 minutes at 100 to 120 C, although they found that no processing temperature above 120 C further improved protein quality for chicks. Subsequent research by Arnold (1973) indicated that heating temperatures above 120 C could produce optimum chick performance. He reported that optimum performance was obtained by heating soybeans at 149 to 160 C for 10 minutes or 171 to 194 C for 5 minutes. Feath e rston and Rogler (1966) reported improved soybean protein utilization when compared to the other treatments in chicks fed full-fat soybean flakes heated at 133 C for 20 minutes. Simovic et

PAGE 40

33 al. (1972) studied even higher temperatures and indicated that temperatures up to 158 C could be used satisfactorily but, above this temperature, the soybeans became charred. The temperatures were 95.5, 111.0, 127.0 and 158.0 C with heating durations of 3.0, 2.5, 1.5 to 2.0, or 1.0 minute, respectively. Noland et al. (1966) reported the best heating treatment for soybeans was 60 m1nutes at 115 C for pigs and 24 to 72 minutes at 115 C for rats. Feeding early weaned pigs, Lawrence (1967) obtained better heating results when soybeans were autoclaved for 24 to 36 minutes at 110 C than for longer or shorter periods of time. Subjecting raw defatted soybean flakes to live steam at atmospheric pressure (approximately 100 C) for 10 or 60 minutes permitted similar rate and efficiency of growth and feed intake when fed to weanling pigs (Clawson et al., 1981). Prior to heating, the raw soyflakes were mixed 5:1 (w/w) with water. Becker et al. (1953) reported superior growth of pigs from weaning to market when fed diets containing soybeans toasted in a French cooker for 38 to 55 minutes at 99 to 116 C compared to pigs fed diets containing soybeans toasted for 18 to 20 minutes or 33 to 37 minutes at 99 to 104 C. Hayward et al. (1936a) indicated that autoclaving soybeans for 2 one hour at 1.06 gm/cm pressure doubled the nutritive value of the protein when fed to rat s Westfall and Hauge (1948) demonstrated that soybean flour heated at 108 C for 15 to 30 minutes resulted in superior soybean protein when included in a mouse diet. Likewise, Rackis (1966) achieved maximum protein efficiency and trypsin inhibitor 1nactivation of full-fat and defatted soyflakes by steaming

PAGE 41

34 at 100 C for only 15 minutes in trials with rats. Subsequent research using higher heat processing temperatures suggested that the optimum heating period for ground whole soybeans fed to rats was 10 to 20 minutes at 120 or 132 C compared to soybeans heated at 100 C (Seerl ey et al., 1974). The oil from soybeans can be removed by various extraction processes and the heating time required to produce a nutritionally optimum soybean meal varied among the different methods (Hayward et al., 1936b). To produce optimum quality protein, expeller processed meal needed 2 to 3 minutes at 112 to 150 C, hydraulic processed meal needed 90 minutes at 105 to 124 C, and the solvent extracted meal required 15 minutes at 98 C. Ethanol extraction of raw soybeans improved performance of pigs compared to the feeding of raw unextracted soybeans, yet the improvement was still lower when compared to soybeans that were heat-treated (Hancock et al., 1985). Another method for extraction of the soybean oil, supercritical carbon dioxide at a temperature of 80 C for 8.3 hours, did not denature the trypsin inhibitor activity of raw soybeans (Pubols et al., 1985). Toasting at 109 C for 5 minutes was required to inactivate the toxic factors and permit opti~um chick growth (McFarland and Pubols, 1982). Renner and Hill (1960) also noted a variation in nutritive value between e x tracted dehulled raw soyflakes, and ground raw soybeans when fed to chicks. The extracted dehulled raw soyflakes had received optimum hea t pr-ocessing with a wide range of heating times (10 to 60 minutes) at 107 C whereas, the ground soybeans had an optimum cook of 10 minutes at 107 C. These products produced maximum metabolizable energy values and rate and efficiency of chick growth.

PAGE 42

35 The moisture content of soybeans prior to heat processing greatly influences the heating time required to produce quality soybean products (Albrecht et al. 1966). Trypsin inh1b1tors were readily destroyed by atmospheric steaming for 20 minutes provided the soybeans contained about 25% moisture before steaming, whereas soybeans containing lower inital moisture content required a longer heating time or higher processing temperatures. However, when moisture content of the soybeans was elevated to 60% by soaking overnight then only 5 minutes of atmospheric steaming was required to inactivate the trypsin inhibitors. Likewise, Waldroup et al. (1985) reported that the addition of 12% water to soybeans prior to heating decreased the time required to produce adequate protein supplements for chicks. However, Seerley et al. (1974) fed rats soybeans which had 10 or 20% moisture added prior to heating at 118 C for 40 minutes and noted no difference in their performance that could be attributed to initial moisture level. There is evidence to suggest that moist heat can reduce the damaging effects of overheating soybean protein (Renner et al., 1953). Other methods used to denature the anti-nutritional factors of soybeans and improve their nutritional value have been studied. For example, the addition of thiols such as cysteine and N-acetyl-cysteine facilitates heat inactivation in the temperature range of 25 to 85 C thereby decreasing the damage to heat sensitive amino acid residues such as cystine, methionine and lysine (Leir et al., 1981; Friedman et al., 1982). This method also increased the limited sulphur content of soybeans. It was postulated that the cations of thiols were involved

PAGE 43

36 in the formation of mixed disulfide bonds between the added thiols and enzyme inhibitors and structural proteins. The addition of cysteine prior to heating can also facilitate the heat inactivation of trypsin inhibitors in both purified soybean Kunitz inhibitor and soybean extracts, thereby indicating increased protein digestibility, protein efficiency ratio and nutritive value of soybeans (Friedman et al., 1984). Other Methods of Processing Soybeans Germination of whole raw soybeans has also been reported to imp ove their nutritional quality by increasing the protein dispersibility index (POI) and improving the odor and flavor scores as evaluated by an a-member panel test (Suberbie et al., 1981). During the early phases of germination, reserve proteins were mobilized at a steady rate, but carbohydrates were quickly depleted (McAlister and Krober, 1951). Mobilization of fat began immediately after depletion of the carbohydrate in the seed. Thus, the non-protein nitrogen content doubled (Becker et al., 1940) and the level of offending oligosaccharides were reduced markedly during germination (Pazor et al., 1962; East et al., 1972). Sprouting also reduced the energy, dry matter, total lipids, starch and concentrations of the amino acids alanine, arginine, glutamic acid, threonine, glycine, lysine, proline and serine compared to ungerminated soybeans (Peer and Leeson, 1985). These researchers further noted an increased ash, aspartic acid and leucine but no change in the concentrations of histidine, isoleucine, methionine, phenylalanine and tyrosine due to germination. Since the total protein content did not change, the percentage of individual amino acids was altered.

PAGE 44

37 The trypsin inhibitor content of soybeans during germination has been reported to change very little (Desikachar and De, 1947; Collins and Sanders, 1976). However, other researchers have noted a reduction in trypsin inhibitor as well as lipoxygenase activity during germination (Suberbie et al., 1981). Freed and Ryan (1978a) found a 13% reduction in the Kunitz trypsin inhibitor activity after seeds had been sprouting for nine days. Bates et al. (1977) obtained a 33% reduction in total trypsin inhibitor activity after only four days of sprouting and Collins and Sanders (1976) reported that up to 13% was reduced after germinating the soybeans for only three days. Likewise, Peer and Leeson (1985) reported that trypsin inhibitor activity was reduced in a cubic trend with increased sprouting time. Freed and Ryan (1978b) found that only modified forms of the Kunitz inhibitor appeared during germination. The actual benefit of germinating soybeans per se on the reduction of trypsin inhibitor activity in soybeans may be limited. Collins and Sanders (1976) found that soaking four different varieties of soybeans in water for one hour reduced their trypsin inhibitor activity between 3.4 to 10.2.%. Germination increased the nutritive value of soybeans fed to rats (Desikachar and De, 1947) but not for chicks (Mattingly and Bird, 1945). Everson et al. (1944) confirmed that sprouted soybeans had better feeding value for rats compared to the raw unsprouted soybeans. However, autoclaving both products provided additional growth responses.

PAGE 45

38 Fermentation has also been used to improve the nutritional value of soybeans (Zamora and Veum, 1979). After heating whole soybeans at 121 C for 30 minutes, they were fermented with .AsperQi]lus oryzae or Rhizopus o]1Gosporus. During fermentation, dry matter was reduced by 3% and the percentages of lysine, leucine and methionine increased slightly. Feeding pigs a diet containing soybeans fermented with Aspergil]us oryzae resulted in faster growth than pigs fed an unfermented (only heated) whole soybean diet. Feed efficiency, metabolizable energy and nitrogen utilization for pigs fed the fermented soybean diets were increased compared to pigs fed soybean meal and unfermented soybean diets. Treating raw soybean meal with formaldehyde (1% of the n~al protein content) inactivated 99, 97 and 40% of the trypsinand chymotrypsin-inhibiting and urease activities, respectively (Nitsan and Bruckental, 1977). When fed to chicks, both soybean diets (raw and heated) containing formaldehyde reduced body weight gain, feed efficiency and protein efficiency ratio compared to chicks fed either diet unsupplemented with formaldehyde. The reduction in these measured parameters due to the inclusion of formaldehyde in the diet containing heated soybeans was greater when compared to the diet containing unsupplemented raw soybeans. However, pancreatic hypertrophy and pancreatic trypsin, chymotrypsin, lipase and amylase activities were decreased by adding formaldehyde to the raw soybean diet. Also, these researchers reported that formaldehyde addition in the raw soybeans resulted in increased intestinal trypsin content but decreased amylase in both the small intestine and cecum when compared

PAGE 46

39 to feeding the unsupplemented raw soybean diet. Cecal trypsin and chymotrypsin activities did not differ significantly between these two treat m ents. Dal Borgo et al. (1967) reported that young chicks were able to utilize raw soybeans more efficiently when fed 1n combination with glucose or sucrose than when starch was provided as the source of carbohydrate. These effects were not obtained with heated soybean meal. Recent research by Pontif et al. (1986a) reported that changing the dietary carbohydrate source from corn to wheat in raw and heated soybean diets resulted in reduced average daily gain. No reduction was noticed when the carbohydrate s ource was comprised of a mixture of corn and wheat. Swine F eed i n g Tri a ls Numerous processing methods have been reported to yield quality soybean products. Among these are autoclaving (Combs et al., 1967), roasting (Baird, 1983), extrusion (Baird, 1983), and the use of microwaves (Hafez et al., 1985; Fuller and Owings, 1986). The heat generated during the process cf pelleting was not ad e quate to p r oduce a quality soybean supplement (Hanke et al., 1972; Hooks et al., 1967b). The superiority of feeding heated soybeans compared to fe e ding raw soybeans to pigs is well documented. Performance of 8-week-old pigs was improved by feeding soybeans heate d in an autoclave (Combs et al., 1967). Roasting and extrusion were also adequate heat processing methods of soybeans fed weanling pigs (Noland et al., 1976). However, Rust et al. (1972) reported that roasting (141 C) and extrusion (125 C) of whole soybeans were i nadequate heat treatments compared to SBM

PAGE 47

40 fed to pigs weaned at 21 days of age, although feed efficiency was similar between pigs fed the SBM and the two heated soybean diets. Similar adverse effects due to feeding roasted soybeans to weanling pigs were noted by Crenshaw and Danielson (1985a). Pelleting soybean meal or raw soybean diets fed to four-week-old pigs did not improve performance of pigs fed either diet (Crenshaw and Danielson, 1984a). Adams and Jensen (1985) compared the feeding value of soybeans that had been extruded or roasted for weanling pigs and reported that extrusion increased digestibilities of fat, dry matter, energy and nitrogen and metabolizable energy compared to roasting. In addition, grinding the roasted soybeans through a fine as opposed through a coarse screen did not affect their feeding value. Infra-red roasting of soybeans fed to weanling pigs provided equal growth and feed efficiency but reduced digestiblities of dry matter, ether extract and energy compared to pigs fed extruded soybeans (Faber and Zimmerman, 1973). However, the biological value of the two products was equal. Kinyamu et al. (1985) compared the performance of weanling pigs fed diets containing SBM, extruded soybeans or Jetsploded soybeans having trypsin inhibitor activities of 6.3, 8.1 and 28.0 units per milligram, respectively. The Jetsploded method requires that the soybeans be heated at a high enough ten1perature to cause the soybeans to burst. The extrusion method uses both stean1 and pressure (friction) to process the soybeans. The pigs fed the diet containing Jetsploded soybeans grew slower and were less efficient compared to pigs fed diets with soybean meal or extruded soybeans. Digestion coefficients for each diet followed a similar trend as the performance data.

PAGE 48

41 A preponderance of research on feeding soybeans to growing-finishing pigs has established that raw soybeans are an inadequate protein source and require heat processing for maximum performance of growing pigs. However, research on the necessity to heat soybeans for finishing pigs is inconclusive. Jimenez et al. (1963) found that the growth of growing-finishing pigs was improved by feeding whole soybeans which had received a heat treatment. Soybeans have been subjected to various methods of heat processing to produce adequate soybeans fed to growing-finishing pigs. Among the different processing methods are infra-red heating (Noland et al., 1970; Wahlstrom et al., 1971), dry-roasting (Hanke et al., 1972; Baird, 1983; Miller et al., 1985), extrusion (Noland et al., 1969; Hanke et al., 1972; Baird, 1983), cooking in a six-stack French cooker at 110 C for 10 minutes (Seerley et al., 1974) and cooking soybeans for six hours in a 40 gallon feed cooker mixed in a 1.0:1.7 ratio with water (Young, 1969). Chin and Diggs (1986) reported higher values for digestible and metabolizable energy, nitrogen-corrected metabolizable energy and digestible nitrogen from feeding roasted soybeans compared to raw soybeans, but the percenta ge nitrogen retained did not differ between the two protein suppl e n 1 ents. Roasting temperature is critical to produce a scybean product having optimum nutritional quality for swine (Campbell et al., 1984). These researchers reported that roasting soybeans at 110 C did not permit similar growth of growing-finishing pigs fed SBM, although a roasting temperature of 125 C produced soybeans which had equal

PAGE 49

42 nutritional value as that of commercial SBM. Likewise, extruding soybeans at 132 and 143 C provided equal growth to SBM yet improved growth compared to pigs fed soybeans extruded at 115 C (Seerley et al., 1974). Crenshaw and Danielson (1985b) substantiated earlier work which indicate that roasted soybeans were adequate protein supplements for growing-finishing pigs but also noted that barrows significantly utilized roasted soybeans more effectively than gilts. Recent research has provided additional evidence that raw soybeans are not an adequate protein supplement for growing-finishing pigs and performance was not improved when soybeans were substituted in place of SBM on a equal weight basis or when diets were reformulated to be isonitrogenous diets (Crenshaw and Danielson, 1984b). Likewise, replacing the SBM in the diet fed to growing pigs with 0, 33, 67, and 100% raw soybeans resulted in a linear decrease in average daily gain, feed efficiency, feed intake and loin-eye area (Pontif et al., 1986b). The age of the pig may influence the extent to which the anti-nutritional factors in raw soybeans affect animal performance. The beneficial effects of feeding heated soybeans to swine decreased with pig maturity (Combs and Wallace, 1969). These researchers compared effects of feeding diets containing SBM, raw and autoclaved soybeans to three-, nineand 16-week-old pigs. Performance of the threeand nine-week-old pigs was adversely affected by feeding diets containing raw soybeans. The heated soybean diet was inadequate for three-week-old pigs when compared to the SBM diet but yielded similar performance when fed to nine-week-old pigs. Sixteen week-old pigs

PAGE 50

43 were able to utilize heated and raw soybeans as effectively as properly heated SBM. Recent research indicated that feeding raw soybeans to growing-finishing pigs resulted in reduced performance regardless of initial age and weight of pigs (Crenshaw and Danielson, 1985c). Likewise, Pontif et al. (1986b) reported that the replacement of dietary SBM with raw soybeans when pigs weighed 59 kg decreased the rate and efficiency of growth and feed intake. However, the significance level on the growth data was between .OS and .10%. Jensen et al. (1970) and Hanke et al. (1972) reported also that raw soybeans were not an adequate protein supplement for finishing pigs and the heat generated during pelleting was not sufficient to improve their nutritional value. In more mature swine, gilts and sows, the data on feeding raw soybeans have been more consistent. Gestating swine were able to reproduce normally, through second and third parities, when fed diets containing raw soybeans as the only source of supplemental protein (Crenshaw and Danielson, 1983; Crenshaw and Danielson, 1985d) SBM as a protein source in gestation and lactation diets (Danielson and Crenshaw, 1984). Allee et al. (1985) confirmed that feeding raw soybeans to sows would not impair their reproductive performance but the sows fed raw soybeans lost more weight during lactation than sows fed SBM. Noland et al. (1971) reported that the whole soybean plant (pods, leaves and stems) could be pelleted to provide adequate protein supplementation for gestating swine. The plant was cut, dehydrated and pelleted when the largest pods were full grown, seeds were full size and leaves were just beginning to yellow. This soybean product,

PAGE 51

44 supplemented with ground corn, v1tam1ns and m1nerals, prov1ded satisfactory nutr1tion for gilts and sows when self-fed through the gestat1on period. Poultry Feeding Trials By comparison, the 1ncons1stencies of feed1ng raw soybeans related to swine matur1ty are s1m1lar to that of feed1ng raw soybeans to poultry. Waldroup (1982) presented an excellent review on feeding whole soybeans to poultry so the follow1ng discussion pertains only to changes in maturity. Similar to weanling pigs, the inclusion of raw soybeans to the diet of bro1ler chicks adversely affected growth compared to chicks fed heated soybeans. Ogundipe and Adams (1974) reported depressed body weight of pullets when feeding raw unextracted soybeans from 11 to 20 weeks of age, although Saxena et al. (1963) had previously reported that chicks 6 to 12 weeks of age could effectively utilize diets containing raw soybeans. Barnstein and Lipstein (1962) suggested that chicks of any age, when fed a diet containing raw soybeans, would have a reduction in growth but as chicks matured, the t1me of adaptation to raw soybeans decreased. Several researchers have indicated that raw soybeans could replace SBM 1n laying hen diets w1thout a reduction in egg production (Saxena et al., 1963; Latshaw and Clayton, 1976; Latshaw, 1974). However, other researchers have reported that raw soybeans were not en acceptable protein supplement for laying hens (Fisher et al., 1957; Rogler and Carrick, 1964; Waldroup and Hazen, 1978). Thus, raw soybeans could be processed to prov1de an acceptable protein supplement for laying hens by roasting and extrusion (Waldroup et al., 1969; Waldroup and Hazen, 1978),

PAGE 52

45 adequately supplementing the diet with methionine (Salmon and McGinnis, 1968) or including methionine and/or vitamin s 12 in the raw soybean diet (Fisher et al., 1957). In contrast, Waldroup et al. (1969) reported that adding synthetic lysine and methionine to layer diets containing raw soybeans dici not an eliorate the adverse effect on egg production. Composition of Commercial Soybean ~ea] The National Soybean Processors Association considers that SBM (48% protein) is of acceptable quality when it has less than 12% moisture, greater then 48% crude protein and less then 3.4% crude fiber (Jones, 1984). Hill and Renner (1960) reported limited variation in protein, fat, fiber, ash, and metabolizable energy content of SBM. However, a more recent study of SBM samples obtained from 18 different feed companies and five different SBM manufacturers collected during a 6-year period demonstrated that significant differences in fat and fiber content of SBM occurred among samples taken in different years (Jones, 1984). Also, moisture, protein and fiber contents were significantly different between SSM samples obtained from the different suppliers. The number of samples that did not attain the minimum acceptable quality standards increased from 39.6% in 1976 to a high of 83.3% in 1983. Upon further investigation, it was noticed that most deficiencies (40 to 60%) occurred in samples having greater then 12% moisture. Furthermore, variation has also been observed in amino acid content of SBM (Whitacre et al., 1984). The researchers found that the average content of n ; ethionine, lysine and protein in 175 SBM samples was .6, 2.6 and 46.7%, respectively.

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46 For comparison, the National Research Council (1979) considers the content of methionine, lysine, and protein to be .7, 3.2 and 48.5% respectively. Although the nutritional composition of soybeans used in the processing of various soybean meals is very important, it is necessary to subject soybeans to an adequate amount of heat processing. Longenecker et al. (1964) found marked differences in manufacturing processes for soybean concentrates and reported that in most instances heat treatment was net adequate to support maximum growth when included in diets for weanling rats. Several researchers have suggested that commercial SBM is heated for much longer periods than is required to produce optimum quality protein supplements for weanling pigs (Lawrence, 1967) and rats (Noland et al., 1966). Campbell (1974) fed weanling pigs SBM which had been processed in Arkansas and in Illinois and the rate and efficiency of growth of pigs fed the Arkansas SBM were increased compared to pigs fed the Illinois SBM. However, neither SBM equaled the performance obtained by feeding adequately processed full-fat soyflakes. Although not neccessarily confirming SBM is overheated, research by Clawson et al. (1981) demonstrated that SBM was not underheated. These researchers fed weanling pigs SBM with and without 30 minutes of additional heating with live steam at atmospheric pressure (approximately 100 C), reducing the trypsin inhibitor units from 7 to 2 per mg, and reported no difference in pig performance. Other researchers have indicated that SBM received insufficient heat processing for optimum performance of day-old chicks (McNaughton

PAGE 54

47 et al., 1981). The SBM was autoclaved at a temperature of 110 C in 5 minutes increments. Extra processing was required before the broilers could attain their genetic potential for growth. The best performance was obtained by feeding broilers SBM autoclaved an additional 10 minutes. As previously discussed, heat processing improved the nutritive value of soybeans by inactivating anti-nutritional factors. Trypsin inhibitors are considered the most important anti-nutritional factor in soybeans. However, soybeans also contain the enzyme urease which has little nutritional importance in poultry and swine diets. It is significant that the urease content is currently used by the SBM processing plants to evaluate optimum processing conditions. The analytical method developed by Caskey and Knapp (1944) monitors the urease-urea relationship in the soybean. In this method, urea is degraded by urease and the pH of the media rises due to formation of ammonia and the resultant change in pH is recorded as the urease activity CUA). This analysis is easier and quicker to conduct than determining the trypsin inhibitor content. Since the heat treatment of soybeans required to denature the urease content parallels the heat treatment necessary to inactivate trypsin inhibitors, the UA is considered a good indication of adequate heat processing (Caskey and Knapp, 1944; Albrecht et al., 1966; McNaughton and Reece, 1980). In addition, the inactivation of trypsin inhibitor and urease ~ctivities during heat processing precedes the destruction of lysine (McNaughton and Reece, 1980). However, Borchers et al. (1947) observed that urease was more sensitive to heat inactivation than trypsin inhibitors

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48 and should not be regarded as being completely accurate in determining adequacy of heat processing. These researchers along with Balloun et al. (1953) reported that the UA is of little value for detecting overheated soybean meal. The American Feed Manufacturer Association considers that SBM having UA in the range of .OS to .20 change in pH units has received adequate heat processing (Smith, 1977) which is a reduction from a UA of approximately 2.0 for raw soybeans. However, Harris (1983) reported a commercial lot of SBM with a UA of .83; thus the quality of commercial SBM being marketed does vary. Likewise, Jones (1984) assayed 1729 SBM samples taken over three years from four different suppliers for UA and reported that some SBM samples had UA higher than 1.0. There were significant differences in SBM quality manufactured by the four different suppliers, UA were .057, .074, .041 and .109, respectively. The UA value of SBM also increased according to the year it was produced, being .062, .089 and .091 for 1981, 1982 and 1983, respectively. In addition, SBM samples processed in the colder months (Oct., Nov. and Dec.) were higher in UA. Soybean meal samples (277) obtained from one source had 2.88% with UA greater than .91. In a recent study by Rudolph et al. (1983) comparing the digestibility of nitrogen and amino acids between different SBM (48.5% and 44.0%) with soybean flour, the UA of the 48.5% and 44.0% SBM was .46 and .21, respectively. Also, SBM can be overheated as indicated by Noland et al. (1976). They received SBM having a UA of .02 and reported unsatisfactory performance when fed to weanling pigs.

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49 Edwards (1983) reported a range in UA between .006 and .208 in commercial SBM from different processors. One source produced SBM having consistently higher trypsin inhibitor and UA activities which concurrently produced a higher incidence of tibial dyschondroplasia when fed to chicks. However, gains and feed efficiencies were similar in chicks fed the various SBM. Early research data indicating optimum heating times and temperatures without the UA and trypsin inhibitor activities in SBM are difficult to compare since the actual heat treatment cannot be determined. Different procedures for estimating trypsin inhibitor activity were, and are being, reported which hinders using the trypsin inhibitor activity to compare research data. The UA is a common analysis and allows more reliable comparison. Rackis (1968) stated that SBM with UA between 0.05 and 0.15 has been properly heated for maximum nutritional value. However, Lawrence (1967), feeding early weaned pigs, reported maximum pig performance when fed SBM with UA of 0.01 to 0.02 as contrasted to either greater or lesser pH change. Likewise, Noland et al. (1976) reported that autoclaved full-fat soyflakes having a UA of .03 and .05 supported higher feed intake and better gains of 8.2 kg pigs than soyflakes having UA of .01 and .11 and SBM having UA of .02. In contrast, Hansen et al. (1984a) fed SBM with and without extra heat processing having UA of .02 and .11, respectively to pigs weaned at 4 weeks of age and reported no preference to either diet when given a choice and no difference in pig performance (Hansen et al., 1984b).

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50 Nitrogen balance and gross energy digestibility were similar in growing pigs fed SBM with UA ranging between .01 and .19 {Chai-Ju et al., 1984). Also, apparent ileal nitrogen and individual amino acid digestibilities did not differ. Likewise, feeding defatted soyflakes ranging in UA between .OS and .48 to barrows ranging in weight from 25 to 45 kg resulted in no significant differences in nitrogen, amino acid and energy digestibilities and nitrogen retention between the different soyflake treatments (Vandergrift et al., 1983). Pig growth and feed efficiency were not influenced by the iffiposed dietary treatment groups. Rudolph et al. (1983) confirmed the high nutritional value of soybean products (48.5% SBM) having a high UA of .46 for 38 kg barrows. The barrows in Rudolph's and Vandergrift 1 s studies were limit-fed. One adverse effect associated with feeding low quality soy products to swine has been depressed feed intake. SeerlEy et al. (1974) fed extruded soybeans to 28.9 kg pigs having a UA of .53 and reported that the growth of these pigs did not differ from pigs fed SBM. However, the amount of feed required per unit of weight gain was increased in pigs fed the soybean product having a UA of .53. The pigs were full-fed but feed intake was not reported. The extruded soybeans having a UA of 1.83 in this study were inadequate protein supplements for growing pigs. Research on the optimum heat processing of SBM fed to chicks indicates variation sin 1 ilar to that r ep orted for pigs. McNaughton et al. (1981) fed day-old chicks commercial SBM containing a UA of .19 compared to the same SBM having additional heating to reduce the UA to .02. The best performance was obtained by feeding broilers the

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51 autoclaved SBM having a UA of .02. More recent research has indicated no difference in amino acid availability in SBM with a UA of O and .10 (Dale et al., 1986). However, SBM having a UA below .OS was previously thought to be overheated. Also, additional research has indicated that SBM with UA as high as .SO was an adequate protein supplement for broiler chicks (Waldroup et al., 1985). Likewise, Mian and Garlich (1985) found no difference in growth of turkey poults fed SBM with UA between .14 and .90. However, soybean meals with UA of .02 and 1.50 were inferior to the other treatment groups. Some differences in the UA of SBM being marketed may be attributed to the percent moisture of the soybeans before processing (McNaughton and Reece, 1980). These researchers reported that increasing the moisture content of defatted soyflakes enhances the denaturation of urease and trypsin inhibitors. Mustakes et al. (1981) report e d that the quality of SBM was influenced by heating time, jacket-steam pressure and moisture content. The moisture content of SBM prior to entering the toaster ~,as directly affected by the hexane level remaining after the oil removal process. Although the trypsin inhibitor activity of soybean meal is considered important in livestock and poultry feeds, Gillette et al. (1978) found no correlation betw e en growth and the trypsin inhibitor activity 1n commercial SBM being fed to rats. Likewise, Kakade et al. (1972) reported no correlation bet w een trypsin inhibitor activity and protein efficiency ratio in rat diets containing over 100 different varieties of soybeans.

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52 Another assay to facilitate the detern1ination of optimum soybean processing was developed by McNaughton et al. (1981). They reported that optimum heat processing could be determined by observing the change in color of the soybeans. These researchers used a Hunterlab colorimeter on the +a band to predict the trypsin inhibitor content in autoclaved SBM. However, Rudolph et al. (1983) determined color values of various soybean products using the procedure described by McNaughton and reported the +a color values did not coincide well with the trypsin inhibitor values of the different soybean products. A method which can be used to determine the protein quality of soybean meal and other protein sources fed to chicks is measuring the uric acid excretion (Miles and Featherston, 1976). Protein efficiency ratio and uric acid excretion were similar indicators of protein quality. This method is of value for studies in chicks where separation of urinary and fecal nitrogen determination is extren 1 ely diff1cult. A recent technique to more adequately evaluate the quality of soybean products has been conducted with pigs having a cannula inserted at the end of the small intestine (Vandergrift et al., 1983; Rudolph et al., 1983; Ozimek and Sauer, 1985). Therefore, a measurement of the actual uptake of nutrients can be determined. Vandergrift et al. (1983) presented data showing that a larger quantity of nutrients from raw soyflakes is digested in the cecum and large intestine by the microflora compared to adequately heated soyflakes. The range in differences in the digestibilities of nitrogen and amino acids was 14.3 to 50.6% for raw soyflakes and .5 to

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53 20.6% for soyflakes heated for 25 minutes at a maximum temperature of 100 C. Van Weerden et al. (1985) compared differences between ileal and fecal digestibilities of normal toasted, slightly undertoasted and slightly overtoasted SBM fed to growing pigs. No differences were observed in fecal digestibilities among the SBM's, whereas the ileal digestibilities of organic matter, crude protein, lysine, sulfur amino acids, threonine and tryptophan were reduced in the underand over-toasted SBM's. Ileal digestibility of the carbohydrate in the norn,al toasted meal was increased 35 to 50% compared to the underand over-toasted meals. Variation & 1 ong Soybean Varieties One factor contributing to the variability in SBM can be associated with different soybean varieties. Significant variation in both oil and protein contents of soybeans have been reported to be related to both variety and location grown (Caviness, 1973; Ologhobo and Fetuga, 1984; Gandhi et al., 1985). Other researchers have confirmed the large variation in protein and oil contents due to variety and found that the two components were negatively correlated (Hymowitz and Collins, 1974; Krivoruchco et al., 1979; Hartwig, 1979; Hafez, 1983). Also, the protein content was negatively correlated with the total sugar (Hymowitz and Collins, 1974) and the sucrose (Mwandemele, 1985) contents of soybeans but positively correlated with the stachyose content (Hymowitz and Collins, 1974). In addition, changes in the protein content of soybeans were not correlated with the pentosans, crude fiber, and ash contents and soybean seed size (Krober and Cartter, 1962).

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54 Furthermore, the protein content of soybeans was found to be not correlated with their methionine (Krober and Cartter, 1966) or the non-protein nitrogen (NPN) content (Becker et al., 1940). Krober and Gibbons (1962) confirmed the absence of a correlation between NPN and the protein content and also reported that NPN was not affected by variety or location grown but appeared to be influenced by weather conditions. However, Becker et al. (1940) indicated a wide range (2.9 to 7.8%) existed in the NPN content of the 12 varieties of soybeans studied. Several researchers have reported that the methionine content of soybeans varies having the following ranges; 1.0 to 1. 7gm/16gm N (Krober and Cartter, 1966), 1.3 to l.5gm/16gm N (Alders, 1949), and 1.3 to l.7gm/16gm N (Krober, 1956). The methionine content was influenced by location grown and planting season (Krober, 1956). In contrast to being negatively correlated with the protein content of soybeans, the oil content was positively correlated with the total sugar, sucrose, and raffinose contents of soybeans (Hymowitz and Collins, 1974). The fatty acid composition was relatively constant with different varieties grown at different locations (Collins and Sedgwick, 1959) and was influenced by temperature during the growing season (Howell and Collins, 1957). However, the linolenic and linoleic acid contents of soybeans were negatively correlated (Howell and Collins, 1957). A large variation in the raffinose and stachyose contents of soybeans exists in different varieties (Hymowitz and Collins, 1974). Likewise, Kennedy et al. (1985) compared five different soybean

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55 varieties and noted varation in sucrose (4.0 to 7.7%), stachyose (3.0 to 4.1%) and raffinose (.7 to .9%) contents. One variety had the lowest content of each of these oligosaccharides (total of all three varied between 7.6 to 12.7%). Mwandemele (1985) reported that the stachyose and raffinose contents of soybeans were positively correlated. Also, the stachyose and raffinose contents were not correlated with the protein and oil content or yield, but the sucrose content was positively correlated with yield. Other components of soybeans have been shown to vary, such as glycinin, (31.4 to 38.3% of the total protein; Hughes and Murphy, 1983), phytin phosphorus content C.51 to .73%; Averill and King, 1926), available carbohydrates and ash (Ologhobo and Fetuga, 1984), and percentage husk and cotyledons (Gandhi et al., 1984). The minerals with the most variabilities in soybeans were iron, zinc and manganese and the lowest variabilities were in calcium and phosphorus (Ologhobo and Fetuga, 1984). Birk and Waldman (1965) reported that no quantitative differences were found in UA of three s oybean varieties. However, Smith et al. (1956) found that the UA varied according to variety and location grown. Portions of the seed also vary in UA. The hull has lower UA than the hypocotyl, and the colyledons have twofold the UA of the hypocotyl. Myer and Froseth (1983) compared extruded mixtures of beans (Phaseo]us yul g eri s ) and raw soybeans. The raw soybeans in one experiment had a UA of 1.87 whereas, the raw soybeans in the second experiment contained a UA of 1.15. The soybeans with the higher UA contained 68 units more trypsin inhibitor per mg protein than the

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56 soybeans having the lower UA. A reason for the difference between the raw soybeans was not indicated by the researchers. The amount of trypsin inhibitor activity also varies between soybean varieties (Kakade et al., 1969; Hafez 1983). Likewise, Gandhi et al. (1984) compared the trypsin inhibitor content of eleven different varieties of soybeans and reported a range of 8.1 to 38.5 trypsin inhibitor units per mg sample. Two varieties having a black seed coat contained the highest trypsin inhibitor and UA values. Soybeans have also been found which do not contain the Kunitz trypsin inhibitor (Leiner and Tomlinson, 1981), with the total trypsin and chymotrypsin inhibitor activities being approximately one-half and three-fourths of that of commercial raw soyflour. Soybeans also contain nonprotein trypsin inhibitors and Hafez and Mohamed (1983) reported that a large difference occurred due to variety. Kakade et al. (1972) found a seven-fold variation in lectin content within 108 different soybean varieties evaluated. Subsequent research by Pull et al. (1978) noted the absence of lectins in five varieties of soybeans they assayed. In addition, variations in the isoflavones (compounds having estrogenic properities) and lipoxygenase (an enzyme that catalyzes the oxidation of lipids) content~ have been reported due to variety and location grown (Eldridge and Kwolak, 1983). Data on differences in feeding value between varieties of soybeans are limited. Yen et al. (1974) reported depressed performance of growing pigs fed different varieties of raw soybeans compared to SBM. However, performance of pigs fed the three varieties

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57 of raw soybeans did not differ. Bajjalieh et al. (1980) fed chicks two raw soybean varieties (one commercial and one which lacked the Kunitz inhibitor) compared the responses to chicks fed heated soybeans. The soybean variety lacking the Kunitz inhibitor permitted a greater growth response and smaller pancreatic weights of chicks than the commercial variety of soybeans, although this improvement was still below the response to chicks fed heated soybeans. Han and Parsons (1986) confirmed the greater nutritional value of raw soybeans containing a low trypsin inhibitor (Kunitz) content compared to a raw commerical variety. These researchers reported that the availabilities of lysine and methionine were similar in unheated soybeans having low trypsin inhibitor content and heated dehulled soybeans, and both had higher lysine and methionine availabilities compared to the raw commerical variety. Yen et al. (1971) fed a unheated variant soybean which had a greater nutritional value than other varieties of soybeans they studied and reported that the performance of rats remained adversely affected compared with rats fed heated soybeans. Effect of Storage on Soybeans and Soybean Products An additional factor which may alter the nutritional value of soybeans is the method and length of storage. Soybeans have been stored at 13 to 14% moisture and at 4 to 5 C for six years without deterioration (Smith and Circle, 1972). Mitchell and Beadles (1949) reported deterioration in the digestibility and biological value of soybeans which had been stored for almost three years at 25.5 C. However, pretreatment heating largely prevented this deterioration.

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58 the loss was attributed to an enzymatic factor. Nakayama and Kito (1981) stored soybeans at 13% moisture for six months and found 45% of the total phospholipids had decomposed, 72% of the total phospholipids originally extracted with the oil were lost and phosphatidylcholine and phosphatidylethanolamine were significantly decreased. Phosphatidic acid and lysophosphatidylcholine concentrations increased. In addition, the oligosaccharide content of soybeans was decreased in storage but this reduction can be stopped by heating the soybeans prior to storage which indicates changes due to enzymatic processes (Mwandemele, 1985). Saio et al. (1980) reported that bean color darkened and acid values of extracted crude oil and acidity of beans increased as deterioation progressed. Storage temperature and relative humidity are both related to overall changes during storag e but relative humidity seems to be more important. Nitrogen solubility index decreased rapidly with high temperature and relative humidity. Yao et al. (1983) reported that storage for 6 months did not affect trypsin inhibitor activity. Whole beans were rnore resistant to deterioration during storage than soybean meals (Saio et al., 1982). Also, full-fat soybean meals deteriorated more rapidly then defatted n1eals. Eff ec t of Ma turity on Co m position of Soybeans Maturity of the soybean seed can also influence soybean composition. Fehr et al. (1971) reported that fatty acids were synthesized by the soybean plant at different rates during pod filling. Linolenic acid percentage in the seeds decreased rapidly during the first 30 days and then remained constant thoughout the

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59 period of oil deposition. Immature seeds contained only 3% of the UA (Birk and Waldman, 1965) and had more available zinc (Welch and House, 1983) than mature seeds. Lipoxygenase activity, phytate content dnd the ratio of 7S and 11S protein were lower in invnature seeds compared to mature seeds (Yao et al., 1983). Fat content was found to be higher in earlier maturing varieties than later maturing varieties (Krivoruchco et al., 1979). Mwandemele (1985) reported positive correlation between concentrations of various oligosaccharides and day to maturity. Also, maturation was not related to the oil and protein contents (Yao et al., 1983). Research data on the response of soybean maturity on the trypsin inhibitor activity have been inconsistent. Collins and Sanders (1976) reported that the amount of trypsin inhibitor activity increased as the soybeans matured. However, Yao et al. (1983) found that the trypsin inhibitor activity and soybean maturity were not related. Influ e nc e of Growing Conditions on Soybean Composition As previously stated, location where soybeans are grown can affect their nutrient composition. The use of fertilizer and the various components of fertilizer can influence the resulting nutrient content of the harvested soybeans. Gaydou and Arrivets (1983) found that fertilizer containing a high level of phosphorus increased both the oil and protein contents of soybeans, while fertilizer comprised of a high level of potassium increa se d the oil content but decreased content of protein. Dolomite fertilizer which is high in both calcium and magnesium increased the oil content but did not affect protein content of soybeans. Nitrogen fertilization did not influence either

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60 oil or protein content of the soybeans. In contrast, Krober and Cartter (1966) had reported that soils low in nitrogen produced soybeans with reduced protein content. Wolf et al. (1982) grew soybeans at temperatures during the day:night of 18:13, 24:19, 27:22, 30:25 and 33:28 C and obtained a decrease in linolenic and linoleic acid, sucrose (greatly) and stachyose (slightly) with increased temperature during the growing period. Increased growing temperature also increased oleic acid, oil and protein contents. Palmitic and stearic acid, glucose, fructose and raffinose were not affected by different growing temperatures. Amino acids were generally stable except higher temperature increased methionine content. Howell and Collins (1957) had previously reported that the temper a ture in which the soybeans were grown affected the linolenic and linoleic acid contents of the soybean oil more than the variety. Krober and Collins (1948) reported that weather-damaged soybeans often had higher N PN content than undamaged soybeans.

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CHAPTER III THE EFFECT OF INCREASING THE MOISTURE CONTENT OF WHOLE SOYBEANS PRIOR TO ROASTING AT VARYING HEAT TREATMENTS ON PERFORMANCE OF WEANLING SWINE Introduction Whole "full fat'' soybeans are an excellent source of protein and energy for swine diets. Also, soybeans contain other important components, such as trypsin inhibitors (Liener, 1981) which are considered the principle heat labile anti-nutritional factors and the enzyme urease which is monitored in soybean meal processing plants as an indication of optimum heat processing (Caskey and Knapp, 1944). Subjecting soybeans to heat processing concurrently improves their nutritional value and reduces the activities of both trypsin inhibitor and urease. Previous research has been inconclusive on the feeding value of roasted soybeans as a protein supplement for weanling swine (Noland et al., 1976; Rust et al., 1972; Crenshaw and Danielson, 1984a). This could be due in part to the temperature and duration of heat processing and moisture content of soybeans prior to heating; all are important factors affecting the nutritional quality of soybeans (McNaughton and Reece, 1980). Likewise, previous research at the University of Florida (Campbell et al., 1984) indicated that roasting soybeans at 125 C permitted superior growth of finishing pigs compared 61

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62 to pigs fed soybeans roasted at 110 C. Therefore, the objectives of this study were to determine if increasing the moisture content (10% added water) of Bragg soybeans prior to roasting at 110 or 125 C would enhance the inactivation of trypsin inhibitors, decrease urease activity and increase performance when included in diets of weanling swine. Materials and Methods One-hundred eight crossbred pigs with an average initial weight of 5 kg were assigned to pens containing six pigs each by initial weight, sex and litter origin. Each treatment consisted of three replicate pens. The six dietary treatments (Table 1) were corn-based diets containing the following protein supplements: (1) soybean meal; (2) raw soybeans; (3) soybeans roasted at 110 C with no water added prior to roasting; (4) soybeans roasted at 110 C with 10% water added; (5) soybeans roasted at 125 C with no water added and (6) soybeans roasted at 125 C with 10% water added. All diets were formulated to be isonitrogenous and isocaloric. The whole soybeans used in the treatments requiring added moisture were placed into plastic containers prior to roasting and 10% Cw/w) water was added. These soybeans were then mixed periodically with the water by dumping the soybeans into other containers and then stored overnight. During the following morning, the soybeans were roasted by passing them through a Roast-A-Tron 1 gas-fired roaster. Afterwards, the soybeans were ground in a hammermill before inclusion into their respective diets. Ether extract of the raw soybeans was determined according to the procedure outlined by the AOAC (1980). Samples of raw soybeans were l Mix-Mill, Inc., Bluffton, IN.

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63 TABLE 1. PERCENTAGE COMPOSITION OF EXPERIMENTAL DIETS Ingredients Basal CD iet 1) Ground yellow corn 68.40 Soybean meal (48%) 25.40 Whole soybeans Corn oil 3.00 Dynafos 1.70 Limestone .80 Salt .25 Trace minerals cccclt .10 Vitamin premix (UF) .10 Antibioticc .25 100.00 Calculated analyses: Protein, % 18.00 Metabol izable energy Kcal/kg 3310 Soybeans (Diets 2-6) 56.90 39.90 1.70 .80 25 .10 .10 ,25 100.00 18.00 3304 a Provided by Calcium Carbonate Company, Quincy, IL. Contained 200 mg zinc, 100 mg iron, 55 mg manganese, 11 mg copper, 1.5 mg iodine, 1.0 mg cobalt and 20 mg calcium per kg complete diet. b Supplied 13.2 mg riboflavin; 44.0 mg niacin; 26.4 mg pantothenic acid; 176.0 mg choline chloride; 22.0 mg vitamin B 12 ; 5,500 IU vitamin A; 880 ICU vitamin o 3 and 22 IU vitamin E per kg of complete diet. C Provided 44 mg chlortetracycline, 44 mg sulfamethazine and 22 mg penicillin per kg of complete diet.

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64 obtained for nitrogen analysis prior to roasting. These raw soybeans were digested using a modification of the aluminum block digestion procedure of Gallaher et al. (1975). Ammonia in the digestate was measured by semiautomated colorimetry (Hambleton, 1977). Additionally, trypsin inhibitor activity (TI, Hamerstrand et al., 1981), urease activity CUA, Caskey and Knapp, 1944) and dry matter content (AOAC, 1980) were determined on both the raw and roasted soybeans and SBM. All pigs were housed during the 35-day trial in an enclosed nursery building equipped with elevated pens having expanded metal floors and wire mesh sides. Feed and water were supplied ad libitum. Pigs were individually weighed and feed consumption for each pen was determined bi-weekly. The data were subjected to analysis of variance for a randomized complete block design, with blocks representing replications. Then the basal diet (Treatment 1) and the raw soybean diet
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TABLE 2. PERFORMANCE OF WEANLING PIGS FED DIETS CONTAINING SOYBEANS ROASTED AT 110 OR 125 C WITH AND WITHOUT 10% \1ATER ADDED PRIOR TO ROASTING .s..fil1 l:2RAGG SOY8E8t:iS Temperature, C Raw llO llO 125 Added Moisture, % 0 0 0 10 0 Avg. initial weight, kg 5.04 5.03 5.02 5.03 5.03 Avg. final weight, kg 16.80 7.87f 7.56f 9.75 11.03 Avg. daily gain, kg a re .13~ e ., .08d .06d .17d Avg. daily feed, kg .59C .33 .32 .4ld .39 Avg. feed/gain l.76e 4_45C,d 5.23c 3.09 ,e 2.33e a Least squares means for daily gain and treatment means for feed values. b Standard error of the mean. c,d,e,f Means in same row with different superscripts are different (P<.05). 125 10 5.03 13. 71 d .25 .SSC 2.2le .s.E_Mb .02 .02 .41

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66 (unheated) soybeans or soybeans roasted at 110 C with no water added prior to roasting were adversely (P<.05) affected. Weight gains of pigs fed the diet containing soybeans which had 10% water added prior to roasting at 110 C were augmented (P<.05) compared to pigs fed a diet with soybeans roasted at 110 C without added water and equal (P>.05) to pigs fed soybeans roasted at 125 C. Likewise, addition of 10% water prior to roasting soybeans at 125 C permitted an additional increase (P<.05) in pig growth. The decreased performance of pigs fed raw soybeans was expected and these data agree with previous research evaluating raw soybeans fed to starting, growing and finishing pigs (Jimenez et al., 1963; Combs et al., 1967; Hanke et al., 1972; Yen et al., 1974). Also, the depressed growth of weanling pigs fed roasted soybeans is consistent with the findings of Rust et al. (1972) and Crenshaw and Danielson (1985a) but is in contrast with the work of Noland et al. 0976). Feed consumption by pigs fed the diets containing soybean meal or soybeans having 10% water added prior to being roasted at 125 C were equal (P>.05). However, feed consumption by pigs fed these two diets was greater (P<.05) when compared to the feed consumed by pigs fed the other treatment groups. Roasting soybeans at 110 C with or without added water and at 125 C without inclusion of water did not (P>.05) increase the quantity consumed when compared to pigs fed the raw soybean diet. Similarly, feed-to-gain ratios of pigs fed the diets containing soybean meal or soybeans roasted at 125 C with or without additional water exceeded (P<.05) the efficiency of pigs fed diets containing raw soybeans or soybeans roasted at 110 C without water

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67 being added. Rust et al. (1972) reported that the growth of pigs fed roasted soybeans were depressed but the efficiency of growth was similar to pigs fed soybean meal. Noland et al. (1976) also reported similar feed efficiency when weanling pigs were fed either roasted soybeans or SBM. In contrast, Crenshaw and Danielson (1985a) obtained depressed feed efficiency when weanling pigs were fed diets containing roasted soybeans compared to SBM. The main effects of roasting temperature and water addition are shown in Table 3. Pigs fed diets containing Bragg soybeans roasted at 125 C consumed more (P<.05) feed, grew faster (P<.05) and were more (P<.10) efficient in utilization of feed than pigs fed diets containing soybeans roasted at 110 C. Similarly, adding 10% water prior to roasting the soybeans improved (P<.05) feed intake and average daily growth of pigs compared to pigs fed roasted soybeans without added water prior to roasting. Although the feed-to-gain ratios between treatments containing O or 10% added water had a large numerical difference, these ratios were not different (P>.05). The urease CUA) and trypsin inhibitor CTI) activities, indices used to assess soybean quality, of the different soybean products are presented in Table 4. None of the heat treatments was effective in lowering the UA of the full-fat soybeans to less than .2. Soybean meal with a UA range between .OS to .2 is considered to have received optimum heat processing by commercial soybean processing plants (Smith, 1977). Roasting soybeans at 110 C without added water reduced the TI and UA by 25.9 and 7.6%, respectively. Adding 10% water prior to roasting at 110 C or roasting at 125 C without added water resulted

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68 TABLE 3. MAIN EFFECT PERFORMANCE MEANS OF WEANLING PIGS FED DIETS CONTAINING SOYBEANS ROASTED AT 110 OR 125 C WITH AND WITHOUT 10% WATER ADDED PRIOR TO ROASTING Tem12era:ty ce Added Maj ~:tu ce a .s.B:1 llOC 125 C 0% 10% Avg. initial weight, kg 5.02 5.02 5.02 5.02 Avg. final weight, kg 8.69b 12.41 9.35b 11.78 Avg. daily gain, kg .lOb .2lc .12b .19c .04 Avg. daily feed, kg .37 d .47c .35 .48c 03 Avg. feed/gain 4.16 2.27e 3.78 2.65 .79 a Standard error of the mean. b,cCl "th ff t "thd"ff t t o umn means w1 1n main e ec s w1 1 eren superscr1p s are different (P<.05). d,e Column means within main effects with different superscripts are different (P<.10).

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69 TABLE 4. UREASE AND TRYPSIN INHIBITOR ACTIVITIES OF THE DIFFERENT SOYBEAN PRODUCTS Product Unheated soybeans Roasted 110 C; 0% water Roasted 110 C; 10% water Roasted 125 C; 0% water Roasted 125 C; 10% water Soybean meal (48%) Trypsin Inhibitor mg/gm defatted sample 53.95a 40.00 24.00 22.88 9.18 3.11 Urease Activity pH change 1.97 1.82 1.30 0.55 0.25 0.10 a Larger values are indicative of less heat processing.

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70 in similar reductions in TI. The inclusion of 10% water prior to roasting at 125 C resulted in the largest reductions in TI and UA (83.0 and 87.3%, respectively) yet the product still contained between twoand three-fold the TI and UA of soybean meal. Pig performance data reflect the difference in heat processing and indicate that soybean products having a UA of .25 or higher are not adequate protein supplements for weanling pigs. These results concur with the work of Albrecht et al. (1966), McNaughton and Reece (1980), and Waldroup (1985) which suggest that increasing the moisture content of soybeans prior to heating increased the inactivation of TI and UA. These data also agree with the findings of Campbell et al. (1984) in that soybeans roasted at 125 Chad a higher nutritional value when compared to soybeans roasted at 110 C. In addition, the depressed performance of weanling pigs fed soybeans having a UA higher than .2 is in agreement with the optimum range of UA used by the American Feed Manufacturer Association to indicate soybean products that have received adequate heat processing (Smith, 1977). The Bragg variety of soybeans roasted in this study had remained in the field for a longer period of time (1-2 months) than normal before being harvested. The moisture content of these soybeans was 10.33% and with the addition of 10% water was analyzed to be 20.45% prior to roasting. Roasting the soybeans at 110 C with and without added water reduced the moisture content to 13.1 and 9.0%, respectively. Further evaluation of the soybeans noted lower protein (32.7%) and higher fat (23.9%) contents than that published by the NRC (1979; 37.0 and 18.0%, respectively). However, the actual values and

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71 not the NRC (1979) values were used to calculate the experimental diets. Therefore, the protein content of the experimental diets was isonitrogenous.

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CHAPTER IV FEEDING VALUE AND CO~POSITIONAL VARIATION AND RELATIONSHIPS ASSOCIATED WITH DIFFERENT VARIETIES OF SOYBEANS Introduction Full-fat soybeans can be utilized as an excellent source of both energy and protein in swine diets. However, soybeans also contain several anti-nutritional factors which require inactivation before yielding a product having the highest nutritional value. Trypsin inhibitors are considered the most important anti-nutritional factor in soybeans and subjecting soybeans to heat processing has been used satisfactorily to reduce the trypsin inhibitor activity (Liener, 1981). Heat processing has been shown to be required when soybeans are added to diets fed to young pigs and becomes less critical when soybeans are fed to finishing pigs (Combs and Wallace, 1969). Although previous research has been inconclusive on the feeding value of raw soybeans for growing-finishing swine (Combs and Wallace, 1969; Jensen et al., 1970; Crenshaw and Danielson, 1985c; and Pontif et al., 1986), raw soybeans have been found to be adequate protein supplements for gilts and sows (Crenshaw and Danielson, 1984d). Another technique that can be used to reduce the trypsin inhibitor activity of soybeans is germination (Bates et al., 1977; Suberbie et al., 1981). Collins and Sanders (1976) reported that soybeans which had been rinsed twice 72

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73 daily and allowed to germinate for three days lost up to 13.2% of their trypsin inhibitor activity. Numerous new varieties of soybeans are released annually which have improved agronomic advantages over existing varieties. However, the nutritional value of these new soybean varieties has often been a minor selection criterion. Significant variations in both oil and protein contents and urease activity (UA) of soybeans have been reported to be related to both variety and location grown (Smith et al., 1956; Caviness, 1973; Ologhobo and Fetuga, 1984; Gandhi et al., 1984). Likewise, the trypsin inhibitor activity (TI) also varies among different soybean varieties (Kakade et al., 1969; Hafez, 1983). Besides the varietal differences in the constituents of soybeans, relationships among the various components do exist. Several researchers (Hymowitz and Collins, 1974; Krivoruchco et al., 1979; Hartwig, 1979; Hafez, 1983) have reported that the protein and fat components of soybeans were negatively correlated. These varietal differences would indicate that the heat processing required to destroy the heat labile anti-nutritional factors could vary between the different varieties of soybeans. Data on differences in feeding value among different varieties of soybeans are limited. Yen et al. (1974) reported no difference in performance of growing pigs fed either of three different varieties of raw soybeans. However, the growth of pigs fed a commercial soybean meal was superior to the pigs fed the diets containing different varieties of raw soybeans.

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74 The objectives of these studies were: (1) to determine the relationships of various nutritional components and evaluate their variability in different varieties of soybeans, (2) to determine variability of similar varieties of soybeans grown at different locations, (3) to evaluate the trypsin inhibitor and urease activities of soybeans which were germinated or heated in an autoclave at 110 C for 7.5 or 15.0 minutes, and (4) to evaluate the performance of growing-finishing pigs fed diets containing either Bragg (unheated and heated at 110 or 125 C) or Davis (unheated and heated at 110 C) variety of soybeans. M at e rials and Me thods Trial 1 Fifteen commerical varieties and three experimental strains of soybeans were obtained from the University of Florida Agronomy Department and the protein and fat contents, urease activity CUA) and trypsin inhibitor activity (TI) were determined using procedures described below. The effect of heat processing was assessed by placing approximately 25 g of whole soybeans in aluminum drying pans having a 6 cm diameter. Three replicate drying pans per soybean variety were randomly placed on a 30 X 60 cm stainless steel tray and autoclaved for 7.5 or 15.0 minutes at 110 C and 422 g m/cm 2 pressure. The soybeans from the three replicate drying pans were combined after cooling and ground prior to determination of the TI and UA. The effect of germination on TI and UA was determined by germinating the different varieties of soybeans for 7 days and then only the soybeans which had sprouted were removed, dried and ground.

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75 Trial 2 Four commercial varieties and thirty-four experimental strains of soybeans were obtained from the same source as soybeans used in Trial 1 and analyzed for protein and fat contents and TI and UA. These soybeans were grown during the growing season subsequent to those soybeans used in Trial 1. There is a large variation in the size of soybean seeds being marketed, and the correlation of this variable with the measured parameters was determined. Soybean size was quantitated with micrometer calipers from measurements taken on the long axis directly between the cotyledons of the soybeans. Trial 3 To evaluate the effect of the varietal differences in soybeans on their feeding value, the following trial was conducted. One-hundred and eight crossbred pigs with an average weight of 40 kg were allotted on the basis of initial weight, sex and litter origin to six dietary treatment groups. Six pigs were assigned to each pen with three replicate pens per treatment. The dietary treatments (Table 5) consisted of the following protein supplements: (1) commercial soybean meal; (2) unheated Bragg soybeans; (3) Bragg soybeans roasted at 110 C; (4) Bragg soybeans roasted at 125 C; (5) unheated Davis soybeans and (6) Davis soybeans roasted at 110 C. Roasting consisted of passing whole soybeans through a Roast-A-Tron 1 gas-fired roaster. Afterwards, the roasted and unheated soybeans were ground in a hammermill before inclusion into their respective diets. The two varieties of soybeans were obtained locally from different suppliers. l Mix-Mill, Inc., Bluffton, IN.

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76 TABLE 5. PERCENTAGE COMPOSITION OF EXPERIMENTAL DIETS (;i[ol'ler Die:ts Ejoj~ber: Dj~ts Ingredients Control Soybeans Control Soybeans Ground ye 11 ow corn 76.80 70.30 82.65 77.35 Soybean meal 20.00 14.40 \/hole soybeans 26.50 19.70 Dicalcium phosphate 1.70 1. 70 1.70 1. 70 Limestone 0.80 0.80 0.80 0.80 Iodized salt 0.25 0.25 0.25 0.25 Trace minerals (CCC~a 0.10 0.10 0.10 0.10 Vitamin premix (UF) 0.10 0.10 0.10 0.10 Antibiotic premixc 0.2s o. 25 100.00 100.00 100.00 100.00 Calculated analyses: Protein, % 16.00 16.00 14.00 14.00 Metabolizable energy Kcal/kg 3250 3250 3250 3250 a Provided by Calcium Carbonate Company, Quincy, IL. Contained 200 mg zinc, 100 mg iron, 55 mg manganese, 11 mg copper, 1.5 mg iodine, 1.0 mg cobalt and 20 mg calcium per kg complete diet. b Supplied 13.2 mg riboflavin; 44.0 mg niacin; 26.4 mg pantothenic acid, 176 mg choline chloride; 22 mg vitamin B 12 ; 5,500 IU vitamin A; 880 ICU vitamin D 3 and 22 IU vitamin E per kg of complete diet. c Provided 110 mg chlortetracycline, 110 mg sulfamethazine and 55 mg penicillin per gm complete grower diet.

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77 The Bragg soybeans were harvested after remaining in the field approximately one to two months longer than normal. The Davis soybeans were harvested after a normal period of time. The grower diets were fed for 28 days and then the pigs were fed their respective finishing diet. All pigs were housed in a semi-enclosed concrete barn with partially slotted floors. Feed and water were supplied ad libitum. Pig weights and feed consumptions were determined bi-weekly. In all trials, the protein and fat contents (A0AC, 1980) and UA (Caskey and Knapp, 1944) of the soybeans were conducted on air dry samples. Samples for nitrogen analysis were digested using a modification of the alumimum block digestion procedure of Gallaher et al. (1975). Ammonia in the digestate was determined by semi-automatical colorimetry (Hambleton, 1977). Trypsin inhibitor activity (Hamerstrand et al., 1981) was determined on defatted soybean samples. Urease activity and Tl of germinated seeds were determined on samples which had both the fat and moisture removed. All analyses were conducted in duplicate. In Trials 1 and 2, the individual variety means were used to calculate the gross correlations among the various components. Correlations were considered significant if the probability level was .05 or less. In Trial 3, the growth data were analyzed by least squares analysis of variance with initial weight as a covariate. Feed intake and feed efficiency data were subjected to analysis of variance for a randomized complete block design. Duncan's multiple range test was used to determine treatment differences. All statistical analyses were conducted following the procedures developed by SAS (1979).

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TABLE 6. CO M POSITION OF THE DIFFERENT VARIETIES OF SOYBEANS (TRIAL 1) U8 i t;;_ Rtl TI z r ng L g G e rr ii j n i: r t ed Protein Fat H ea t Pro ces singz ~ jnyt e ~ ~t 110 C U A TI rn 2 rn 2 Q.Q 7. 5 lS Q 0 0 7. 5 1 5 Q { D. ~ t i 2 { n 1c: l'.'. < 1 ifi 2 CQ111t 1if-! t:~ j i:l ] ~-;;i r j e t "i e s a A sg row 7372 3 8 .42 20.21 1.44 .095 02 45.18 8.62 4.46 1. 72 35.70 B ra x ton 39.55 19.21 1.36 0 9 0 .01 35.79 9.46 3.99 1.66 31.49 Cok e r 237 38. 68 20.78 1.04 .155 .00 28.25 9.14 2.63 1.51 25.26 C oke r 3 68 3 8 50 20.73 1.17 .0 4 0 .oo 25. 00 7.44 3.13 1. 72 21. 05 Cok e r 4 8 8 36.44 21.13 1.37 .125 .02 2 8 .79 10.09 3.99 1.44 24.30 Cobb 37.51 19. 6 0 1.57 .175 00 2 9 .82 8.65 3.59 1.96 26.00 C e nt e nnial 41. 0 8 19.40 1. 26 0 9 5 02 34.47 9.70 3.57 1.38 31. 84 Fost e r 3 8 .37 19.13 1.34 070 03 38.16 9.23 3.81 1. 8 6 25. 96 GaSoy-17 36. 60 20.11 1.27 0 8 5 04 31. 73 8.31 3. 43 1.57 26.75 --.J co Hutton 39.5 8 18. 8 0 1.14 0 9 5 .02 35.65 10.41 3.37 F'-.A 60 4 41.50 19. 44 1.54 050 02 35.26 10.99 4.01 1.62 33.51 RA 8 01 3 8 .1 8 1 9 .71 1.33 1 4 0 03 32.35 8.63 3.95 1.63 28.33 I / ri g ht 3 8 2 2 19.4 8 1.25 .100 .0 8 32.10 12. 63 5.05 1.33 29.21 G r 01rn a t d if fe c rnt l ccaiions Bra gg N o. 1 37. 86 2 0.24 1.4 6 .135 09 40.53 14.28 5.32 1.82 33.60 Bra gg No. 2 3 2 .7 4 23. 92 1.81 .1 4 0 05 53.95 11.80 3.11 K irby No. 1 3 6 94 19. 85 1.6 9 .1 6 5 04 40. 2 6 12.95 3. 03 Kir by N o. 2 39.24 19.03 1.35 .110 02 35 .39 11.67 4.07 E xge rj h c nta l st c a j n s a F806 717 3 8 3 8 20.90 1.71 .170 06 40.53 8.49 4.30 2.04 35.09 F806 950 37.35 20.69 1. 76 .370 05 46.05 11. 87 3.64 2.03 33.60 FU l920 2 3 iJ H l 20 81 11 :z o 345 1 08 6 1. 84 1 6 8 7 4. 94 2 .01 49 ,7 ~ Me an 3 8 .17 20.1 6 1. 43 .137 03 37.55 10.56 3. 87 1. 70 30. 70 S.E. M .41 25 .05 02 .01 1.99 .52 .16 06 1. 65 C V 1.:Z 6 5, 6 1 1 5 4 8 61 33 :Z t\ 6 9 23 ,7 5 22 20 18 0~ 13. 7 6 2 1.5 2 a UA-U reas e A c tivity; TI-Try p sin Inhibi t or A c tivity; RA-Ring Around; F-Florida.

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79 Results and Discussion Trial 1 A summary of the protein, fat, and trypsin inhibitor (TI) and urease activities (UA) of the soybeans is shown in Table 6. The percentage of protein and fat in the various soybean varieties studied ranged between 32.74 to 41.50% and 18.80 to 21.13% with an average of 38.17 and 20.16%, respectively. The UA, used in commercial soybean meal processing plants to indicate adequacy of heat processing, averaged 1.43 in the unheated soybeans. After heat processing the soybeans at 110 C for 7.5 and 15.0 minutes, the average UA was reduced to .14 and .03, respectively. The American Feed Manufacturers Association considers that soybeans have received adequate heat processing if the UA is between .05 and .2 (Smith, 1977). Therefore, heating the different varieties of soybeans for 7.5 minutes at 110 C was adequate for all varieties except for two of the experimental strains (F80-6950 and F81-9202). A wide variation among the different varieties of soybeans (approximately 2.5 fold) was observed in the TI values, ranging from 25.00 to 61.84 mg/gm of sample with a coefficient of variation of 23.75%. Autoclaving the soybeans for 7.5 or 15.0 minutes reduced the average TI activity to 10.56 and 3.87 mg/gm of defatted soybean sample, respectively. These data are in agreement with previous research reporting a wide range in oil and protein concentrations (Caviness, 1973; Ologhobo and Fetuga, 1984; Ghandhi et al., 1984), TI (Kakade et al.,1968; Hafez, 1983; Ghandi et al., 1984) and UA (Smith et al., 1956). The wide range in UA is in contrast with

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80 Waldman (1965). However, these researchers only compared a limited number (3) of soybean varieties. Germinating the seeds for seven days reduced the average TI activity to 30.70 mg/gm of defatted soybean sample. The largest reductions in TI activity were with the soybean varieties initially having the highest TI activity. Two varieties (Bragg and Kirby) were grown in different areas which permitted an evaluation of the effects of location on the compositional variablity of soybeans. Variation in most of the constituents was observed in the same variety grown in different locations. Several factors other than variety such as growing temperature (Wolf et al., 1982), type of fertilizer applied to the soil (Gaydor and Arrivets, 1983) and plant maturity (Fehr et al., 1950; Birk and Waldman, 1965; Yao et al., 1983) have been reported to alter soybean composition. The experimental strains of soybean used in this study were classified as being of the vegetable type of soybeans. This type of soybean is noted for having a bland flavor and large seeds (Hinson, 1986). All soybeans had a yellow seed coat except for the F80-6717 strain which had a black seed coat. Ghandi et al. (1984) compared the TI of eleven different varieties of soybeans of which only two varieties had black seed coats. The soybeans with the black seed coats had the highest TI contents. The F80-6717 strain (black seed coat) studied in this trial had a increased TI activity compared to the average of all varieties but was not the strain with the highest TI activity. The percentage reduction in TI and UA in the different

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81 varieties of soybeans by heat processing or germination are presented in Table 7. Heating the soybeans at 110 C for 7.5 or 15.0 minutes reduced their TI activity by 71.36 and 89.34%, respectively. Whereas, the UA activity was reduced 90.62 and 97.73% by heat processing the soybeans for 7.5 and 15.0 minutes, respectively. The increased 1nactivation of UA compared to TI concur with data of Borchers et al. (1947) and McNaughton and Reece (1980). Germinating the soybean seeds for seven days only lowered the TI content by 15.44%. Previous research has been inconsistent on the reduction of TI by germinating soybeans. Desikachar and De (1947) and Collins and Sanders (1978) reported little change in TI by germinating soybeans. However, Bates (1977) found a 33 % reduction in TI by sprouting soybeans for 4 days. Similarly, Collins and Sanders (1976) obtained up to 13.2 % reduction in TI after germinating seeds for only 3 days. Gross correlations associating protein and fat with UA and TI activities are shown in Table 8. The initial TI activity of the soybeans (unheated) was positively correlated with the percent inactivation of TI by heating the soybeans for 7.5 (P<.046) or 15.0 minutes (P<.001). The UA prior to heating the soybeans was also positively correlated with the percentage TI inactivation by heating the soybeans for 15.0 minutes (P<.027). However, the initial UA (prior to heating the soybeans) was not correlated (P>.05) with the percent reduction of their UA by heating for either 7.5 or 15.0 minutes. Furthermore, the protein and fat concentrations of the soybeans were not correlated (P>.05) with the percent reduction of TI or UA.

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82 TABLE 7. PERCENT REDUCTION OF TRYPSIN INHIBITOR AND UREASE ACTIVITIES BY HEAT PROCESSING AND GERMINATION (TRIAL 1) Trypsin inhibitor Urease activity Germination Heat Processing, minutes at 110 C Varietya (7.5) (15.0) (7.5) (15.0) Commercial varieties Asgrow 7372 80.9 90.l 93.4 98.6 Braxton 73.6 88.9 93.4 99.3 Coker 237 67.7 90.7 85.1 100.0 Coker 368 70.2 87.5 96.6 100.0 Coker 488 65.0 86.1 90.9 98.5 Cobb 71. 0 88.0 88.9 100.0 Centennial 71.9 89.8 92.5 98.4 Foster 75.8 90.0 94.8 97.8 GaSoy-17 73,8 89.2 93.3 96.9 Hutton 70.8 90.6 91. 7 98.3 RA 604 68.8 88.6 96.8 98.7 RA 801 73.3 87.8 89.5 97.7 \'/right 60.7 84.3 92.0 94.0 Gr01m at diff e rent )cc a ticns Bragg No. 1 64.8 86.9 90.8 93.8 Bragg No. 2 78.1 94.2 92.3 97.2 Kirby No, 1 67.8 92.5 90.2 97,6 Kirby No, 2 67.0 88.5 91. 9 98.5 E x ri er i r:, e nta l str a ins F80-6717 79.1 89.4 90.l 96.8 F80-6950 74.2 92.1 79.0 97.2 F80-9202 72.7 92,0 79.7 95.3 Mean 71.4 89.3 90,6 97.7 a RA-Ring around; F-Florida, 21. 0 12.0 10.6 15.8 15. 6 12.8 7.6 32.0 15.7 5,0 12.4 9.0 17.1 13. 4 27.0 20.0 15.4

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8 3 TABLE 8. GROSS CORRELATIONS OF PROTEIN AND FAT CONTENTS WITH TRYPSIN INHIBITOR AND UREASE ACTIVITIES (TRIAL 1) Protein, % Fat,% -. 776 P<.001 Protein, % UA, o.o min UA, 7.5 min UA, 15.0 min TI, 0.0 min TI, 7 .5 min Urease actiyitya Trypsin inhibitora o.o .475 P<.034 -.441 P<.051 Heat Processing, minutes 7,5 15,0 0,0 7,5 15 I 0 .295 .244 P<.207 P<.299 -.264 -.295 P<.261 P<.160 .461 .724 P<.006 P<.041 .440 P<. 0522 .438 P<.054 -.328 P<.157 .446 P<.0003 .135 P<.570 -.132 P<.578 .186 P<.049 -.181 P<.444 -.176 P<.458 .186 P<.432 .615 .547 .143 P<.004 P<.013 P<.546 .608 .738 .669 P<.004 P<.0002 P<.001 .667 .320 P<.001 P<.169 .489 P<.029 a Urease activity (UA, t::. pH); Trypsin inhibitor activity (TI, mg/gm).

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84 The protein concentration was negatively correlated with the fat concentration (P<.0001) and UA of the unheated soybeans (P<.052) but was not correlated (P>.05) with the UA after heat processing or the TI prior or after heat processing. The negative correlation in the protein and fat concentrations of soybeans has previously been well documented (Hymowitz and Collins, 1974; Krivoruchco et al., 1979; Hartwig, 1979; Hafez, 1983). The fat concentration was positively correlated with the UA (P<.034) and TI (P<.054) activity prior to heat processing; whereas after heat processing, there was no correlation (P>.05) between these components. The TI was positively correlated (P<.0003) with the UA of the unheated soybeans. Both the TI and UA of the unheated soybeans were positively correlated (P<.05) with the UA of the soybeans which had received heat processing for 7.5 or 15.0 minutes and the TI activity of soybeans heated for 7.5 minutes. The TI and UA of the unheated soybeans were not correlated (P>.05) with the TI activity of the soybeans heated for 15.0 minutes. Several researchers (Caskey and Knapp, 1944; Albrecht et al., 1966; McNaughton and Reece, 1980) have reported that the UA is a good indicator of adequately heat processed soybeans. The positive correlation in the pres e nt study between TI and UA would confirm these data. The UA was correlated with the TI of the unheated soybeans or soybeans heated for 7.5 minutes but was not correlated to the TI of soybeans heated for 15.0 minutes. A reason for the lack of correlation of UA with TI of soybeans heated for 15.0 minutes may be because these soybeans would be considered overheated (UA less than .OS) by the American Feed Manufacturer Association (Smith, 1977).

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85 Ba 11 oun et a 1. 0953) reported that the UA is of 1 ittl e va 1 ue for detecting overheated soybean meal. Trial 2 The seed size, protein, fat, UA and TI analyses are presented in Table 9. The average size of the soybean seeds studied was 7.15 mm with a range between 5.68 and 10.32 mm. The percentages of protein and fat in the various soybean varieties ranged between 37.09 to 43.62% and 17.19 to 22.81% with averages of 39.39 and 20.46%, respectively. The averages of the UA and TI activity (1.52 and 37.24 mg/gm, respectively) are similar to the values obtained in Trial 1. However, the range in UA (.56-2.05) was greater whereas the range in TI (23.06-60.05 mg/gm) was similar to what was observed in Trial 1. The majority of the soybean varieties utilized in this study were used to confirm trends noticed in Trial 1. The Late Giant variety is the parent stock for some vegetable types of soybeans. The F83 experimental strains of -7895, -7923, -7959 and -7962 are closely related to the F81-9202 of Trial 1 which had an extremely high activity of TI (61.84 mg/gm sample). Likewise, these strains also contained a hi g h activity of TI with one strain (F83-7923) containing 60.05 mg TI/gm. The isolines are strains which have similar genetic material except for only one trait and in niost cases the composition was similar. In addition, there are sev e ral different trypsin inhibitors present in soyb e ans. The first trypsin inhibitor isolated from soybeans has been referred to as the Kunitz inhibitor. The two L81 strains are from genetic lines noted for the absence of the Kunitz inhibitor but their overall TI activity was not reduced compared to

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86 TABLE 9. COMPOSITION OF THE DIFFERENT VARIETIES OF SOYBEANS CTRIAL 2) ~ariet~a Sjzei mm S~ed Qoa:t Fsrti~ a U8 1Al2tl a II i mgLg Commercia] yarie:tj es Bragg 7.40 y 39.37 20.93 1.64 36.75 Kan rich 7.85 y 36. 73 21.23 1.81 37.54 Kirby 6.93 y 40.19 21.46 1.59 38.95 Late Giant 10.00 B 40.40 19.87 1.88 37.89 E~12e c j m~n:ta] s:tcaios BR6 6.96 y 38.36 20.75 1.61 42.65 D82-3332 ( IR) 6.82 y 37.86 22.37 1.53 36.84 F85-11346 (VT) 10.17 y 37.09 21.11 1.80 47.10 F85-11349 ( VT> 10.32 B 35.48 21.31 1.83 57.00 F80-6692 (VT) 7.85 y 40.83 22.81 1.85 38.53 F83-7895 (VT) 7.58 y 42.16 19. 76 1.92 42.89 F83-7923 (VT) 8.02 y 37.84 22.30 1.88 60.05 F83-7959 (VT) 8.18 y 42.88 21.30 2.00 58.42 F83-8177 (VT) 9.61 B 37.73 20.19 1.63 35.17 F85-494 (IL-1) 6.01 y 40.76 20.96 1. 81 33.85 F85-495 (IL-1) 6.29 y 39.53 19.86 1. 78 33.54 F85-606 (IL-2) 6.54 y 41.41 21.14 1.67 23.14 F85-604 CIL-2) 6.18 y 37.69 20.32 1.87 27 .04 F85-2297 (LM) 6.69 y 39.93 20.53 1.13 23.06 F85-2773 ( IR) 6.29 y 40.85 19.64 1.41 39.21 F85-2757 ( IR) 6.37 y 39.23 19.07 0.56 33.51 F85-2853 ( IR) 5.68 y 38. 76 17.19 0.95 38.60 F85-2892 ( IR) 5.92 y 38.54 19.15 0.99 30.68 F85-2927 ( IR) 5.68 y 39.74 18.06 0.79 29.72 F85-2983 ( IR) 6.95 y 40.45 21.12 1.38 41.67 F85-3093 ( IR) 6.66 y 39.21 20.17 1.00 37.72 F85-3182 ( IR) 5.92 y 39.85 20.41 0.91 32.74 F85-3208 ( IR) 6.18 y 37.88 22.42 0.88 32.30 F85-3229 ( IR) 6.43 y 43.62 18.68 1.70 43.07 F85-3981 (HS) 6.08 y 39.79 19.26 0.77 32.69 F85-7356 (HS) 7.29 y 38.86 20.04 1.61 37.98 F85-7433 (HS) 6.64 y 37.61 20.55 1.92 34.82 L81-4387 (AK) 6.23 y 34.52 21.80 1.13 39.25 L81-4590 (AK) 7.09 y 38. 01 22.54 1.67 33.95 UFV-1 (LM) 6.53 y 39.89 20.08 1.83 31.14 GCQ~n a:t Qjffecen:t ]oca::l;jQns F85-994 CIL-G) 7.73 y 39.91 19.63 1.66 30.42 F85-994 (IL-PR) 7. 08 y 42.52 18.13 1.87 33.85 F85-998 ( I L-G) 7.04 y 41.50 19.80 1.65 38.33 F65-998 OL-PR~ 8 1 09 y 40.65 20.16 l. 32.62 Means 7.15 39.39 20.46 1.52 37.24 S. E. M. .19 .30 .20 06 1.28 c. ~16,59 4.81 5,62 26, 9l 21.74 a IR-insect resistant; VT-vegetable type; LM-late maturing; IL-isolines; HS-hard seed coat; AK-absence of the Kunitz inhibitor; G-grown in Gainesville, Florida; PR-grown in Puerto Rico; Y-yellow; B-black; UA-urease activity; TI-trypsin inhibitor activity.

PAGE 94

87 the average TI activity. These results are in contrast with those of Leiner and Tomlinson (1981) who reported a 50% reduction in the TI activity of soybeans in which the Kunitz TI was absent. Coefficients and probability levels of gross correlations are given in Table 10. Size of the soybeans was not significantly correlated with the protein (P>.336) and fat (P>.119) concentrations but was positively correlated with the UA (P<.0002) and TI (P<.0005). The lack of a significant correlation between the size of the seeds and their protein concentration is in agreement with the findings of Krober and Cartter (1962). Similar to Trial 1, the fat concentration was negatively correlated with the protein content (P<.014) and positively correlated with the UA (P<.054) of the unheated soybeans. Likewise, the TI activity was not correlated with the protein concentration (P<.232) but was positively correlated with the UA (P<.015). However, inconsistent with Trial 1, the protein concentration was not correlated with the UA (P<.372) and the fat concentration was not correlated with the TI activity (P<.130). Tri a l 3 Grower period. Av e r ag e daily g ain and f eed e ffici e ncy of pi g s fed unheated Bragg soybeans were depressed (P<.05) and growth of pigs fed soybean meal was superior (P<.05) when compared to pigs fed the other dietary treatments (Table 11). The Bragg soybeans required roasting at 110 C to permit growth and feed efficiency similar (P>.05) to that of pigs which received the unheated Davis soybeans. Similarly, to equal the growth of pigs fed Davis soybeans roasted at 110 C, the Bragg soybeans had to be roasted at 125 C. Roasting either variety of soybeans at 110 C improved (P<.05) pig growth and feed

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88 TABLE 10. GROSS CORRELATIONS OF PROTEIN AND FAT WITH TRYPSIN INHIBITOR AND UREASE ACTIVITIES (TRIAL 2) Prot e in, % Fat,% UAa, 6. pH ua. mg/gm Size, mm Protein, % Fat,% -.156 P<.336 Urease activity, 6. pH .2503 P< .119 -.387 P<.014 .559 .523 P<.0002 P<.0005 .145 -.193 P<.372 P<. 232 .306 .244 P<.054 P< .130 .383 P<.015 a Urease activity CUA, 6.pH); Trypsin inhibitor activity (TI, mg/gm).

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TABLE 11. PERFORMANCE OF GROWING-FINISHING PIGS FED DIETS CONTAINING SOYBEAN MEAL OR DIFFERENT VARIETIES OF SOYBEANS (UNHEATED OR HEATED) So~beao ~2cjetjes Bc a gg Dayjs Control Unheated llOC 125 C Unheated llOC .{i[ o 1 ve r _P e riod Avg. initial weight, kg 40.03 39.95f 40.00 4o.og 39.98 39.98d Avg. daily gain, kg .86~ 47 C .56e 77 f .5~ 76 f Avg. feed/gain 2.88 4. 43d 3.60d,e 3.2f 3. 84 3 .27e' Avg. daily feed intake, kg 2.48c 2.10 2.oi 2.47c 2.20c,d 2.48c Finish e r P e rjod Avg. initial weight, kg 64 .3lc 53.19d 55. 74c d 61.5\ 56.09c 61.16c Avg. daily gain, kg .69J .56c .63d' .68d 65d .68d Avg. feed/gain 3.84 5.20 4.10 4.04 4.35 3.96 Avg. daily feed intake, kg 2.83 2.70 2.47 2.85 2. 71 2.81 Oyer a l] Avg. initial weight, kg 40.03 39.95 40.00 40.00 39.98 39.98 Avg. final weight, kg 114.86c 88.43e 96.73d 109. 72c 98.52d 109 .57 C Avg. daily gain, kg 77e .Slc .59d .73d .6ld 72d e Avg. feed/gain 3.53 4.99 3. 96 ,e 3. 78 ,e 4.21 3 .81 Avg. daily feed intake, kg 2.73 2.52 2.34 2.74 2.56 2.76 a Standard error of the mean. b Least squares means for daily gain and treatment means for feed values. c,d,e,f Means in same row with different superscripts are different (P<.05). SEMa 04 .11 08 --O'.) '-Cl .04 .11 09 .04 .11 09

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90 efficiency when compared to pigs fed the unheated soybeans. Increasing the roasting temperature of the Bragg soybeans from 110 C to 125 C permitted an additional increase (P<.05) in pig growth but feed-to-gain ratio was not improved (P>.05). Feed intake of the diets containing Bragg soybeans (unheated or roasted at 110 C) was depressed (P<.05) compared to the consumption of the diets containing either soybean meal, Bragg soybeans roasted at 125 C, or Davis soybeans roasted at 110 C. Daily intake of the diets containing the unheated soybeans did not differ (P>.05). Finisher period. The average daily gain data were adjust e d for the large difference in initial weight due to simultaneously switching each treatment group to their respective finisher diet. Pigs fed the diets containing unheated Bragg soybeans continued to have inadequate growth and feed efficiency. However, growth and feed-to-gain ratio of pigs fed the diet containing unheated Davis soybeans were equal (P>.05) to pigs fed diets containing soybean meal or roasted soybeans of either variety. Roasting the Bragg soybeans at 110 C improved (P<.05) their utilization but did not provide (P>.05) an additional increase in growth compared to pigs fed the unheated Bragg soybeans. Increasing the roasting temperature of Bragg soybeans from 110 to 125 C did not improve (P > .05) th e ir feeding value. There were no differences (P>.05) in feed intake b e tween the dietary treatments during the finisher period. Overall. Pi gs f e d unh ea t ed B r agg s oybe a ns d urin g both th e g row e r and finisher periods had poorer gain (P<.05) and were less (P<.05) efficient than any other treatment group. Average daily gain of pigs

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91 was improved (P<.05) by feeding either variety of soybeans roasted at 110 C when compared to pigs fed the unheated soybeans. Feed-to-gain ratio was improved (P<.05) by roasting the Bragg soybeans at 110 C but feed efficiency of pigs fed Davis soybeans roasted at 110 C did not improve (P>.05) compared to pigs fed unheated soybeans. Roasting the Bragg soybeans at 125 C permitted an additional increase (P<.05) in pig growth but feed efficiency (F/G) was similar to pigs fed Bragg soybeans roasted at 110 C. Feed intake during the entire growing-finishing period did not differ (P>.05) between the different treatment groups. The TI and UA of the different soybean products are presented in Table 12. None of the heat treatments was sufficient to lower the UA of either variety of soybeans to less than .2 which is considered by commercial soybean processing plants as indicative of optimum heat processing (Smith, 1977). The UA is an indication of the anti-nutritional factors contained in soybean products (Caskey and Knapp, 1944; Albrecht et al., 1966; McNaughton and Reece, 1980). The unheated Davis soybeans had lower UA and TI activities compared to the Bragg soybeans (unheated or roasted at 110 C). Similarly, the Davis soybeans roasted at 110 C contained lower UA and TI activities then the Bragg soybeans roasted 110 C. The Davis soybeans roasted at 110 C also had a lower TI activity compared to the Bragg soybeans roasted at 125 C. Pig performance data reflect this varietal difference in UA and indicate that soybean products having a UA higher than .2 can be adequate protein supplements for growing-finishing swine diets. These results agree with Vandergrift et al. (1983), Rudolph et al. (1983)

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92 TABLE 12. UREASE INDEX AND TRYPSIN INHIBITOR CONTENT OF THE DIFFERENT SOYBEAN PRODUCTS Soybean product Bragg soybeans, unheated Bragg soybeans roasted at 110 C Bragg soybeans roasted at 125 C Davis soybeans, unheated Davis soybeans roasted at 110 C Urease indexa 6. pH 1.97 1. 80 .52 1.47 .84 Trypsin inhibitor, mg/gm sample 53.95 44.08 15.10 36. 97 11. 42 a Index used by commercial soybean processing plants to monitor quality of heat processing of soybeans. An index less than .20 is associated with soybeans that have received adequate heat processing.

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93 and Seerley et al. (1974) that soybean products having UA higher than .2 can still be satisfactory protein supplements for growing-finishing swine. These data indicated that the extent of heat treatment required to destroy the heat labile anti-nutritional factors found in raw soybeans can differ among varieties of soybeans. These varietal differences could account for contrasting data reported for the feeding value of unheated or roasted soybeans obtained in previous studies. Similar performance of finishing pigs fed unheated Davis soybeans or soybean meal is in agreement with data of Combs and Wallace (1969) who reported that finishing pigs could efficiently utilize raw soybeans; whereas the reduced performance of pigs fed unheated Bragg soybeans in the present study is consistent with data indicating that feeding raw soybeans would reduce pig performance regardless of initial age or weight of pigs (Crenshaw and Danielson, 1985c; Pontif et al., 1986). However, Combs and Wallace (1969) along with Jimenez et al. (1963), Hanke et al. (1972) and Yen et al. (1974) have noted that raw soybeans are not a satisfactory protein supplement for growing pigs. The results of the present study are in agreement with these findings. As previously stated, the Bragg soybeans remained in the field for one to two months longer than the Davis soybeans before being harvested. The influence of this additional variable on the results of this study cannot b e determined but requires further assessment.

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CHAPTER V OPTIMUM HEAT PROCESSING OF DEFATTED SOYFLAKES FOR CHICKS AND STARTING, GROWING AND FINISHING SWINE Introduction Improvement in the nutritional value of raw soybeans by subjecting them to heat processing has been recognized for almost seventy years (Osborne and Mendel, 1917). Adequacy of the heat processing of soybean meal is estimated by monitoring the quantity of the urease enzyme present in the soybean product. The American Feed Manufacturer Association considers that soybean meal (SBM) having a urease activity (UA) in the range of .05 to .2 (quantified in changes in pH units) has received adequate heat processing; this is a reduction from a UA of approximately 2.0 for raw (uncooked) soybeans (Smith, 1977). However, variability in the quality (heat processing) of SBM being marketed does exist. Jones (1984) assayed 1729 samples of SBM produced from four different suppliers during a three year period and found several samples having UA greater than 1.0. Furthermore, the UA of the SBM samples varied among suppliers, increased between 1981 to 1983 and was highest in samples processed in the colder months (Oct., Nov. and Dec.). Soybean meal with UA in the range of .05 to .2 is currently considered adequately processed for all animal species regardless of age. Therefore, it is reasonable to suggest that this range in UA 94

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95 should also apply to whole soybeans. However, previous research (Combs and Wallace, 1969) indicated that the required amount of heat processing of soybeans to produce adequate protein supplements decreased with increased maturity (age) in swine. These researchers reported that 16-week-old pigs were able to utilize raw soybeans as effectively as SBM. More recent research data have indicated that feeding raw soybeans to growing-finishing pigs would reduce performance regardless of initial age and weight of pigs (Crenshaw and Danielson, 1985c). In addition, Jensen et al. (1970) and Pontif et al. (1986b) reported that feeding diets containing raw soybeans would reduce performance of finishing pigs from 55 kg to market weight. Contrasting results with raw and heated soybeans indicate the possibility that older pigs may utilize SBM exposed to less than adequate heat processing. Comparison of previous r e search on soybean quality fed to different species and starting, growing and finishing pigs is difficult because different soybean products and heat processing conditions were used. Therefore, these studies were conducted using the same soybean products and identical heat processing methods throughout. The objectives of these studies were to determine (1) if day-old chicks and weanling pigs required equal heat processing of SBM for maximum performance, (2) if heat processing of SBM could be reduced and still permit the SBM to be used as an adequate protein supplement for older swine and (3) amino acid absorption in soyflakes heated for different lengths of time fed to pigs fitted with a ileo-cecal cannula.

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96 Materials and Methods Six trials were conducted utilizing crossbred pigs and one trial involved day-old chicks. Defatted soybean flakes 1 were obtained that had undergone minimal heat processing which still contained similar trypsin inhibitor and urease activities as raw soybeans. The soyflakes were autoclaved at 110 C (422 gm/cm 2 pressure) for varying lengths of time in 30 x 60 mm stainless steel trays at a thickness of 2.5 mm. Thereafter, the heated flakes were placed on the floor in thin layers to cool. The cooking times for each trial are presented in Table 13. To limit the variation among the small batches, the quantity of soybean flakes required for all trials was processed before mixing any diet. Trial l; Chic k Trial Two hundred forty one-day-old Cobb-feather sexed chicks were used. Chicks were allocated to the five dietary treatments (Table 13) on the basis of initial weight and sex. Three males and three females were assigned to each pen with eight replicate pens per treatment. Diet composition is presented in Table 14. Chicks were maintained on a 24-hour constant light schedule in thermostatically controlled electrically heated Petersime battery brooders with raised wire floors. Experimental diets and tap water were offered ad libitum throughout the 21-day experimental period. At the end of the study, chicks were weighed and 16 chicks per treatment were randomly selected and killed by cervical dislocation. Each pancreas was removed and weighed. 1 Nutrisoy obtained from Archer Daniels Midland, Decatur, IL.

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97 TABLE 13. DIETARY TREATMENTS USED IN CHICKS AND Sl'IINE TRIALS Study 0 Chick Swine Starter Grower X X Finisher X X Heating Time, minutes at 110 C 6 12 X X 16 X X X X 18 20 X X X X a This was a commercial soybean meal (48%). 22 X X X X X X

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98 TABLE 14. PERCENTAGE COMPOSITION OF EXPERIME~~AL DIETS Chick Diets Swine Diets Ingredients Starter Grower Finisher Ground yellow corn 56.94 71. 80 82.90 85.85 Soybean product 35. 71 25.00 14.00 11.20 Corn oil 3.50 Dicalcium phosphate 1.60 1. 70 1. 70 1. 70 Ground limestone 1.20 .80 80 .80 Salt .40 25 .25 .25 DL-methionine .15 Trace minerals (CCC)a .10 .10 .10 Vitamin premix (UF) 0 10 .10 .10 Micro ingr8di e ntsc .so Antibiotic I ?5 I 15 100.00 100.00 100.00 100.00 Calculated analy ses : a b C d Protein, % 23. 00 18.00 14.00 13. 00 Metabolizable e n e r gy Kcal/kg 3394 3258 3244 3244 Provided by Calciu m Carbonate Company, Quincy, Il. Contained 200 mg zinc, 100 mg iron, 55 mg manganese, 11 mg copper, 1.5 mg iodine, 1.0 mg cobalt and 2 0 mg calciu rn per kg complete diet. Supplied 13.2 mg riboflavin; 44.0 mg niacin; 26.4 mg pantoth e nic acid; 176.0 mg choline chloride; 22.0 m cg s 12 ; 5,500 IU vitamin A; 880 ICU vitamin D 3 and 22 IU vitamin E per kg of complete di et. Ingredients supplied per kilogram of d iet: vitamin A palmitate, 6600 IU; vitamin D, 22 00 ICU; me nadione dirnethylpyrimidinol bisulfite, 2.2 mg ; ribofl a vin, 4.4 mg ; pantothenic ac id, 13.2 mg ; niacin, 39.6 mg; cholin e chloride, 499.4 mg ; vitamin B 12 .022 mg; ethoxyquin, .0125 % ; m an ga n ese 60 mg; iron, 50 mg; copper, 6 mg; zinc, 3 6 mg Provided 110 mg chlort et rac y clin e 110 mg sulfamethazine and 55 mg pencillin per kg of co mp let e st art e r diet and 66 mg chlortetracyc line and 66 mg sulfamethazin e and 33 mg penicillin per kg of complete grower di e t.

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99 Trial 2: Starter Period Sixty pigs averaging 5.25 kg were assigned to the five dietary treatments (Table 13) on the basis of initial weight, sex and litter origin. Diet compositions are presented in Table 14. The 35-day feeding period involved two replicate pens of six pigs each per treatment. Pigs were housed in an enclosed building equipped with elevated pens having expanded metal floors and wire mesh sides. Pig weights and feed consumption were determined weekly. Feed and water were offered free choice. Trial 3: Grower Period Sixty crossbred pigs weighing approximately 34 kg were allotted to the five dietary treatments (Table 13) on the basis of initial weight, sex and litter origin. The trial consisted of a 25-day feeding period utilizing two replicate pens of six pigs each per treatment. Diet compositions are presented in Table 14. Pigs were housed in a semi-enclosed concrete barn with partially slotted floors. Pig weights and feed consumption were determined bi-weekly. Trial 4: Finisher Pericd Sixty crossbred pigs, the majority of which were used in the grower period (Trial 3), with an average weight of 70 kg, were distributed to the five dietary treatments (Table 13) on the basis of initial weight, sex, litter origin and previous grower treatment. Each treatment consisted of two replicate pens of six pigs each. Diet compositions are presented in Table 14. Between the initiation of the 20-day finishing phase and completion of the growing phase, all pigs were fed a standard growing-finishing diet. Pigs were housed in a

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100 semi-enclosed concrete growing-finishing barn with solid floors. Pigs were weighed and feed consumption was determined bi-weekly. Feed and water were supplied ad libitum in Trials 1-4. Trials 5, 6 and 7; Dig es tibility Trials Eight crossbred barrows initially weighing approximately 6.8 (Trial 5), 34.0 (Trial 6) and 68.0 kg (Trial 7) were used in a replicated 4 X 4 latin square design to obtain the digestion coefficients for four of the five diets (four with the longest heating times) fed in Trials 2, 3 and 4, respectively (Table 14). Chromic oxide (0.25 % ) was added as a marker to determine protein and amino acid digestibilities. The pigs were surgically fitted with a T-cannula approximately 15 cm proximal to the ileocecal junction. Pigs recovered rapidly from the surgery and after 14 days were placed directly into stainless steel metabolism cages. The trial was initiated appro x imately ten days post-surgery. Each of the four experimental periods consisted of a 3-day adjustment phase and a 4-day ileal digesta collecting period. Pigs were limit fed twice daily at 12-hour intervals (700 and 1900 hours). The amount fed was determined by the pig eating the least during the 3-day adjustment phase. Immediately after pigs were fed, a sample of the digesta (approximately 150 ml twice daily) was collected in plastic bags and frozen for later analyses. The digesta samples were later freezed-dried and the eight samples collected per pig for each collection period were combined and ground for analysis. Samples of digesta and feed were analyzed for chromic oxide (Christian and Coup, 1954) protein and amino acids. Samples for

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101 protein (N x 6.25) determination were digested using a modification of the aluminum block digestion procedure of Gallaher et al. (1975). Ammonia in the digestate was determined by semiautomated colorimetry (Hambleton, 1977). Samples were hydrolyzed for amino acid analysis by a modified procedure of Davies and Thomas (1973). Amino acid content 1 was determined with high pressure liquid chromatography by the method of Jones et al. (1981). Trypsin inhibitor (Hamerstrand et al., 1981) and urease activities (Caskey and Knapp, 1944) were determined on the defatted soyflakes. The data from all Trials 1 through 4 were subjected to analysis of variance for a randomized block design and the data from Trials 5 through 7 were subjected to an analysis of variance procedure for a 4 X 4 Latin Square design (SAS, 1979). Duncan's multiple range test was used to determine treatment differences since the break point and not trends was of interest. Results and Discussion Trypsin inhibitor and UA of the soy products are shown in Table 15. Heating the raw soybean flakes for 6 minutes reduced the TI and UA by 53 and 11%, respectively. To produce a soybean product similar to SBM required heating the soybean flakes for 22 minutes at 110 C. Trial 1: Chic k Trial Chicks fed the diet containing SBM had increased (P<.05) gains during the 21-day study compared to chicks fed diets containing defatted soyflakes cooked for 16, 18 or 22 minutes (Table 16). All 1 Perkin-Elmer Series 4 Liquid Chromatography, Norwalk, CT.

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10 2 TABLE 15. TRYPSIN INHIBITOR AND UREASE ACTIVITIES OF THE DIFFERENT SOYBEAN PRODUCTS a Product Defatted soyflakes Unheated (raw flakes) Heated for 6 min. Heated for 12 min. Heated for 16 min. Heated for 18 min. Heated for 20 min. Heated for 22 min. Soybean meal Trypsin Inhibitor mg/gm defatted sample 37.8 17.8 8.4 6.4 5.6 5.3 3.8 3.1 a 2 Cooked at 110 C and 422 gm/cm pressure. Urease Activity pH change 1.95 1. 73 1.65 .42 .26 .18 .07 .04

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TABLE 16. PERFOP.MANCE OF CHICKS FED DIETS CONTAINING DIFFERENT SOYBEAN PRODUCTS HEAT PROCESSED AT VARYING LENGTHS OF TIME Heating Time, minutes at llOC Item 16 18 20 22 SBM Initial weight, gm 45.40 45.64 44.96 44.56b 45.43 Total gain, gm 514. oob 522.oob 534.oob,c 523. 00 543. ooc 21.54 Avg. daily feed, gm 38. 70 39.80 40.40 39.60 40.60 75 Avg. feed/gain 1.59 1.60 1.59 1.59 1.57 02 Pancreas wei g ht, 485.6b 402.4c 384.6c 380.6c 381. 7C mg/100 gm body wt 24.82 a Standard error of the mean. b,c Means with differ e nt superscripts are different (P<.05). ...... 0 w

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104 diets containing the defatted soyflakes (16, 18, 20 and 22 minutes) as the protein source permitted similar (P>.05) ch1ck growth. Feed consumption and efficiency were not influenced by the imposed experimental factors. Feeding soybean products having elevated trypsin inhibitor (low heat processing) to chicks resulted in an enlargement of the pancreas (Alumot and Nitsan, 1961; Nesheim and Garlich, 1962). Likewise, in agreement with the previous data, the chicks fed soybean flakes cooked for 16 minutes had larger (P<.05) pancreas weight when compared to chicks fed the other dietary treatments. Pancreas weight of chicks fed the diet containing SBM or soybean flakes cooked for 18, 20 and 22 minutes was similar (P>.05). The performance of chicks in this study was not reduced by feeding soyflakes having a UA of .42 which is 2-fold higher than the UA considered by the American Feed Manufacturer Association as receiving optimum heat processing. These data concur with the work of Waldroup et al. (1985) which indicated that soybean meal with UA of .5 were adequate protein supplements for broiler chicks. Similarly, Main and Garlick (1985) found no difference in growth of turkey poults fed soybean meal with UA between .14 and .9. Trials 2-4: Swine Trials Summaries of the performance data for the three swine studies are presented in Tables 17 and 18. Starter period. Average daily gain of pigs fed diets containing SBM or soybean flakes heated for 22 minutes was similar and both dietary treatments were superior (P<.05) to pigs fed soybean flakes heated for 16 minutes. Growth of pigs fed soybean flakes heated for

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TABLE 17. PERFORMANCE OF STARTING PIGS FED DIETS CONTAINING DIFFERENT SOYBEAN PRODUCTS HEAT PROCESSED FOR VARIOUS LENGTHS OF TIME Heating Time, minutes at 110 C Item 16 18 20 22 SBM SEMa St a rt e r Pe rio d Avg. initial weight, kg 5.24 5.26 5.24 5.26 5. 25 Avg. final weight, kg 15.89 17. 23b 17.3\ 18. 31 18.37 Avg. daily gain, kg C .34 'C .35 ,c .37b .37b .04 .30d Avg. daily fe e d, kg .57 .6oc,d .63b,c .6sb,c 69b 03 Avg. feed/gain 1.87 1. 75 1.81 1. 75 1.83 .06 a Standard error of the mean. b,c,d Means with different superscripts are different ( P<. 05). 1--' 0 U1

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TABLE 18. PERFORMANCE OF GRO\'/ING-FINISHING PIGS FED DIETS CONTAINING DEFATTED SOYFLAKES HEAT PROCESSED FOR VARIOUS LENGTHS OF TI M E H e ating Time, minutes at 110 C SE M a 0 6 12 16 22 G r ov, e r P e riod Avg. initial weight, k g 34.73 34. 73 34.69 34.69 34.65 Avg. final weight, kg 45.17 so. 64d 52.75 54.56 56. 83 Avg. daily gain, kg .4oe 63 .74C .79c .88b 03 Av g d aily f eed kg 1.78d 2.09c 2.osc 2.17b,c 2.34b 01 Avg. f eed / g ain 4.40c 3.3oc 2.s1b 2.73b 2.68b 02 ...... 0 en Fi ni s h e r Pericd Avg. in itia l weight, kg 70.48 70.41 70.29 70.41 70.37 Avg. final we i ght kg 79.45 83 .16 84.82 82.54 85.05 Avg. daily ga in, kg .45C .64b .73b .72b .73b 07 Avg. d aily f eed kg 2.08 2.43b 2.56b 2.56b 2.56b .11 Avg. feed/gain 4.64c 3.81 3.52 3.53 3.46 09 a Standard e rror of the mea n. b,c,d,e Mea ns with diff e ren t superscript s ar e different (P<.05).

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107 16, 18 or 20 minutes did not differ (P>.05). Feed consumption of pigs fed soybean flakes heated for 16 minutes was less (P<.05) when compared to pigs fed SBM and soybean flakes heated for 20 and 22 minutes. Feed intake of pigs fed soybean flakes heated for 16 and 18 minutes was similar (P>.05). Feed-to-gain ratio was not influenced by the experimental factors. Grower period. Rate of gain of pigs fed the unheated soybean flakes was adversely affected (P<.05) and pigs fed soyflakes heated for 22 minutes were superior (P<.05) compared to all other treatment groups. Growth of pigs fed soybean flakes heated for 12 and 16 minutes did not differ (P>.05) and was increased (P<.05) compared to pigs fed soybean flakes heated for only 6 minutes. Feed intake of pigs fed soybean flakes heated for 22 minutes was increased (P<.05) compared to pigs fed soybean flakes heated for 0, 6 and 12 minutes. Pigs fed soybean flakes heated for 16 and 22 minutes consumed similar (P>.05) quantities of feed. Feed intake and feed efficiency of pigs fed unheated soybean flakes were adversely affected compared to the other dietary treatment groups. Finisher period. As was obs0rved in the grower period, feeding unheated soybean flakes continued to be an inadequate protein supplement for finishing pigs. However, growth and feed-to-gain ratio of pigs fed soybean flakes heated for 6, 12, 16 and 22 minutes did not differ (P>.05). Likewise, average daily intake was not affected by the imposed dietary treatments. These studies were designed to determine the most optimal rations that could include underprocessed SBM without adversely affecting

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108 animal performance. Practical type rations for both chicks and pigs were fed and comparisons between species were made even though the protein level used in the studies differed and as pigs matured the quantity of SBM in the diets was reduced. Therefore, these data indicate that compared to starting pigs, chicks can withstand soybean products with higher UA (less heat processing) without adversely affecting growth. This is based upon the observation that soybean flakes containing a UA of .42 reduced the growth of starting pigs but not chicks when compared to feeding soybean flakes cooked for 22 minutes (UA of .07). Similarly, feeding soybean flakes having a UA of .42 to growing pigs resulted in a growth depression; whereas, finishing pigs can adequately utilize soybean flakes receiving less heat processing (higher UA) compared to starting and growing pigs. These data are in agreement with the research of Combs and Wallace (1969) in that older pigs (heavier body weight) can efficiently utilize soybean products having reduced heat processing. However, in this study unheated defatted soybean flakes were inadequate protein supplements for finishing pigs. Several researchers (Jensen et al., 1970; Crenshaw and Danielson, 1985c; Pontif et al., 1986b) have reported that raw soybeans are not adequate protein supplements for finishing pigs. In contrast, Combs and Wallace (1969) obtained equal performance of sixteen-week-old pigs fed diets containing soybean meal or raw soybeans. Vandergrift et al. (1983) fed raw defatted soyflakes to barrows weighing approximately 34 kg and noted a depression in pig performance compared to feeding heated soyflakes having a UA between .05 and .48. Rudolph et al. (1974) confirmed the high nutritional value of soy

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109 products (48.5% SBM) having a high UA of .46 for 38 kg barrows. However, in these two studies, the barrows were limited fed. Therefore, feed intake which is reduced when low quality soybean products are fed did not vary. From the results of the present study, a numerical reduction in feed intake as well as a significant depression in growth was obtained for pigs weighing 35 kg fed soyflakes having UA between .07 to .42. Trials s, 6 and 7; Digestibility Trials Summaries of the performance data for the three digestion studies are presented in Tables 19-21. Starter period. The nitrogen and amino acid digestibilities (except methionine and serine) deter~ined at the end of the small intestine of 6.8 kg pigs were similar (P>.05) among the diets containing soyflakes heated for 16, 18, 20 or 22 minutes (Table 19). The digestibility of methionine in diets containing soyflakes heated for 16 minutes was reduced (P<.05) compared to diets containing soyflakes heated for either 20 or 22 minutes; whereas, the serine digestibility of diets containing soyflakes heated for 22 minutes were superior (P<.05) to the diets containing soyflakes heated for 16 or 18 minutes. Grower period. E x cept for histidine, Glycine, threonine, lysine, and nitrogen, the digestibilities of diets fed to 34 kg pigs containing soyflakes heated for 6 minutes were depressed (P<.05) compared to diets containing soyflakes heated for 12, 16 or 22 minutes (Table 20). The digestibilities of these amino acids did not differ in the diets containing soyflakes heated for 12, 16 or 22 minutes.

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110 TABLE 19. AMINO ACID AND NITROGEN DIGESTIBILITIES DETERMINED AT THE END OF THE SMALL INTESTINE OF STARTI N G PIGS (6. 8 KG B\'/) FED DIETS CONTAINING SOYFLAKES HEATED VARYING LENGTHS OF TI M ES (TRIAL 5) tiea:tjog Ilffii i:rt llQ C SE M a 16 18 20 22 Nitrogen, % 62.97 67. 70 67.59 71.39 Amino acids, % Essential Arginine 86.59 90.37 88.88 89.70 1.39 Histidine 79.92 82.78 80.79 84.97 2.48 Isoleucine 71. 76 76.17 75.90 75.90 .58 Leucine 77 .39 77.30 76. 65 76.14 .67 Lysine 8 2 .18 86.88 80.66b 87.2\ 2.86 Methionine 75 .13 C 78.49b,c 83.3 8 85.00 3.34 Phenylalanine 72.04 78. 71 77. 9 1 78.26 2.82 Threonine 65. 24 72.33 66.08 68.47 3. 77 Valine 66.41 71.19 70.38 70.98 2.84 Nonessential Alanine 64. 8 7 70. 72 68.46 70.54 3.47 Aspartic acid 69.53 70.7 4 72.73 74.23 3.45 Cystine 66.20 63.17 62. 85 71.30 5.24 Glutarnic acid 76.7 6 78.64 79.88 80.97 4.16 Glycine 58.92 59.04c 61.75 65.50b 5.92 Serine 63. 94 C 67.55 72. 8 3b ,c 78.76 4.31 Tyrosine 76.63 79.14 75.02 77. 75 2.74 a Standard error of th e m ean. b,c M eans with diff e r e nt sup e rscripts are different (P<.05).

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111 TABLE 20. AMINO ACID AND NITROGEN DIGESTIBILITIES DETERMINED AT THE END OF THE SMALL INTESTINE OF GROWING PIGS (34 KG BW) FED DIETS CONTAINING SOYFLAKES HEATED VARYING LENGTHS OF TI M ES (TRIAL 6) Hea:tj ng Iic ri e2 mjou:te~ gj; UQC SE li a 6 12 16 22 Nitrogen, % 59.12 62.08 65. 89 63.39 Amino acids, % Essential 82.99b 81.16b 81. 77b Arginine 77. 25 C 1. 72 Histidine 72.09 72.89b 67.70b 74.46b 3.14 Isoleucine 67.66c 75.52b 73. 73 b 74.53 b 3 .11 Leucine 64.28c 73.58 71.17 72.48 0.82 Lysine 66.89 71.51b 70. 66 b 73. 02b 4.07 Me thionine 72. 74 C 79.91b 76. 65 b 78. 60b 3.32 Phenylalanine 67. 71 C 75. 94b 73. 30 C 74. 65 b 3.05 Threonine 58.67c 66.54b 57. 89 b 59.22b 2.69 Valine 66. 07 C 73.84 70.94 72.12 3.61 Nonessential b b b Alanine 65. 40 C 73. 87 b 70. 45 b 72 .14 b 3.47 Aspartic acid 68. 08 C 76.34b 74. 71 b 74.11 b 2.80 Cystine 43.11 C 60. 94 b 64. 80 b 56. 71 b 4.25 Glutamic acid 73. 24 C 78.46 77.84 78.31 3.23 Glycine 53.49 62.30 b 59.89b 58. 4 0b 4.31 Serine 68. 24 C 74.54b 74. 66 b 75. 80 b 2.86 Tyrosine 66. 81 C 74.48 71. 88 73. 04 3. 25 a Standard error of the mean. b,c Me ans with different superscripts a re different (P<.05).

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112 Finisher period. Trends in amino acid digestibilities in this study (68 kg pigs) are not as noticeable as in the previous two studies (Table 21). Digestibilities of ten of the amino acids were not (P>.05) influenced by the imposed dietary treatments. However, the digestibilities of nitrogen and six of the amino acids (aspartic acid, arginine, alanine, tyrosine, glycine and threonine) were improved (P<.05) in diets containing soyflakes heated for 22 minutes. Comparison of these three trials, shows that as the animals increased in age, the amino acid digestibilities were reduced. Explanation of these results is not readily apparent. Comparison with previous research is difficult since different diets were fed, animals of varying genetic backgrounds were utilized and various methods were used to determine amino acid digestibility; whereas, in the present studies the same soybean product was used at the three different stages of growth. Vandergrift et al. (1983) reported that the nitrogen and amino acid digestibilities determined at the end of the small intestine did not differ when 25 to 45 kg barrows were fed diets containing defatted soyflakes with UA between .05 and .48. In the grower study, the similar digestibilities of nitrogen and amino acids of diets containing soyflakes heated from 12 to 22 minutes CUA between 1.65 and .07) are in agreement, but also indicate that soyflakes having much higher UA than .42 can be equally utilized. Several researchers (Vandergrift et al., 1983; Rudolph et al., 1983; Ozimek and Sauer, 1985; Van Veerden et al., 1985) have reported that nitrogen and amino acid digestibilities determined at the end of

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113 TABLE 21. AMINO ACID AND NITROGEN DIGESTIBILITIES DETERMINED AT THE END OF THE S M ALL INTESTINE OF FINISHING PIGS (68 KG BW) FED DIETS CONTAINING SOYFLAKES HEATED VARYING LENGTHS OF TI M ES (TRIAL 7) t]eatj ng Tjmei mjou:tes a:t llQ C SE M a 6 12 16 22 Nitrogen, % 43.71c 48.56c 58.34 b 55.94b Amino acids, % Essential 80.59b Arginine 76.76c 74.60c 77. 26c 1.12 Histidine 67.65 63.30 71. 79 70.59 3.99 Isoleucine 60.41 57.83 63. 01 65.33 1.62 Leucine 60.35 59.56 64.9 4 66.45 2.41 Lysine 57. 73 60.06 62.40 63.56 3.00 M ethionine 65.44 60.65 63.20 68.73 1.91 Phenylalanine 64.42 62.82d 67.32 69.31b 1.88 Threonine 50. 99C 42.77 49.31 C 58.28 2.7 4 Valine 54.50 52.82 57.89 62.13 1.91 Nonessenti a l 5 4 83 b ,c b b Alanine 49.61c 59.62b 59 .13 b 0.34 Aspartic a cid 61. 6 0b 5 4. 16c 63.31 63. 98 1.81 Cystine 62.88 59.96 69.81 64.12 3.75 Glutamic acid 6 7.49 63 .59 d 67 .33 C 69. 07 b 1.54 Glycine 4 8. 93 C 39.73 45.97 59. 71 3.25 Serine 67.76 62.83 65. 95 b 68. 27 b 2.18 Tyrosine 60.7o b ,c 57.57c 64.60 67.21 2.02 a Standard error of the mean. b,c,d M "th d"ff t eans w1 1 e r e n superscripts ar e different (P<.05).

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114 the small intestine are better evaluations of the nutritional value of soybean products than digestion coefficient determined over the total digestive tract. The inadequately heat processed soybean products in those studies had larger differences between the digestibilities determined at the end of the small intestine and total tract. Therefore, the digestibilities determined through the total digestive tract would over estimate the nutritional value of inadequate heat processed soybean products. Just et al. (1981) reported that the nitrogen absorbed from the large intestine is not retained by the pig, but excreted in the urine. Thus suggesting that amino acids disappearing from the large intestine have minimal nutritional values for the pig. Rudolph et al. (1983) and Vandergrift et al. (1983) indicated that tryptophan and threonine are two amino acids in soybean products that are degraded to the largest extent in the large intestine. Similarly, the lower digestibility of threonine compared to the other amino acids in this study suggests that a larger amount of threonine would be available for degradation in the large intestine. The University of Florida research farm receives approximately four shipments of SBM annually. Samples of the SBM during the last 5 years (two different suppliers) were obtained and analyzed for UA and the data are presented in Table 22. All samples had UA less then .2 which is considered by the American Feed Manufacturer Association to be indicative of adequately processed soybean meal. The highest UA was .14 and the lowest was one sample with no detectable UA. Thus, all soybean meal samples could be considered adequately heat processed. These results are in contrast with the large variability reported by Smith (1977).

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11 5 TABLE 22. UREASE ACTIVITY OF SOYBEAN MEAL UTILIZED AT THE UF SWINE RESEARCH FARM DURING THE LAST FIVE YEARS 1982 12fil .070 045 .135 .140 .065 .060 .ass Average .082 .081 Year of purchase UAa, .c,.pH 19 8 4 .030 .030 .050 .115 .056 .010 .055 .045 .110 055 .ooo .020 .010 a Urease activity measured as change in pH according to the method of Caskey and Knapp.

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CHAPTER VI CONCLUSIONS Eleven experiments were conducted to evaluate several factors that could influence the nutritional quality of soybean products fed to swine and chicks. Trial 1 was conducted to (1) evaluate the performance of weanling pigs (108 crossbred pigs weighing 5 kg initially) fed di e ts containing soybean meal or "full-fat" soybeans (unheat ed or roa s ted at 110 or 125 C 1dth O or 10 ;~ water added prior to roastin g ), (2) to determine if these roasting conditions would enhance d e naturation of the trypsin inhibitor and urease activities of the soybeans. Growth of pigs fed the diet containing soybean ~eal was superior (P<.05) co mp ared to the other treatr. 1 ent groups (whol e soybeans). Incr e asin g tho roasting temperature from 110 to 125 C or addin g 10 ;; 1 11 oisture prior to roastin g soybeans augn,ented (P.<.05) feed intake and weight g ains of weanling pi g s. Fe e d efficiency was improved (P<.05) in pi g s fed soybeans roasted at 125 C compared to foeding soybeans roast ed at 110 C. Altliough not significant (P>.05), a large numerical diff e r ence in f e ed-to-gain ratio was noted between pigs fed soybeans roast ed with and w ithout 10 % wat e r added prior to roastin g The adverse pe rfor ma nce of pigs fed diets containing the various protein su~ple rne nt s cont ai nin g who le so ybeans compar e d to soybean meal reflects the high trypsin inhibitor and urease activities of the whole soybeans. The inclusion of 10% water prior to roastin g 116

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117 at 110 C or roasting soybeans at 125 C without added water equally enhanced the denaturation of trypsin inhibitor. Two trials were also conduct e d using seventeen corr~ercial varieties and thirty-seven experimental strains of soybeans to evaluate the variability and relationships in their fat and protein contents and urease and trypsin inhibitor activities (Trials 2 and 3). Reduction in the TI and UA of the different varieties of soybeans by germinating or heating in an autoclave at 110 C for 7.5 and 15.0 minutes was also d e t erm in ed Variations in the fat and protein contents and TI and UA were observed in the different varieties of soybeans. Heating the different v a rieties of soybeans (Trial 2) for 7.5 an d 15.0 m inut e s r ed uced the TI and UA an average of 71.4 and 90.6 and 8 9.3 an d 97.8%, resp e ctively. Germinating th e seeds for seven days reduced the TI activity by 15.4 In both trials, the fat concentration ~as n esa tively corr e lat ed (P<.05) w ith the pro te in concentration and positively correlated ( P< .05) with the UA of the unheated soybeans. The TI activity was positively correlated (P<.05) with the UA b ut was not correlat e d (P>.05) with the prot e in concentration. The size of the soybeans was positively correlated (P<.05) with the TI and UA. N o r e lationship (P>.05) was obtained between the s iz e of the soybeans a n d thei r pro t e in or fat concentrations. In trial 4, 10 8 crossbred pi g s were utilized to e valuat e the performance of ~row in g -fini s hing swine (40 kg initially) fed diets containing so ybe an ~ 1eal or di ffer e nt vc.rieties of whole soybeans (Bragg vs. Davis) that were e ith e r unh ea t e d or roast ed at varying temperatur es During the grol'!er periocJ, pis;s f e d the re!~/ or roasted

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118 soybean diets gained weight more slowly (P<.05) than those fed soybean meal Growth of p i gs was increased (P<.05) by roasting either variety of soybeans at 110 C. Roasting the Bragg soybeans at 125 C supported additional improve me nt in pig growth compared to pigs fed Bragg soybeans roasted at 110 C. Feed efficiency of pigs fed soybean mea l, Bragg soybeans roasted at 125 C or Davis soybeans roasted at 110 C were superior (P<.05) compared to pigs fed unheated soybeans of either variety. During the finisher period, utilization of roasted soybeans of either variety and raw Davis soybeans permitted pig growth and feed efficiency equal (P>.05) to pigs fed soybean m eal Raw soybeans (Bragg) continue d to be an ina de quate prot e in supplement. Feed intake amoung the dietary treatments did no t differ (P>.05) during the finisher period. Average daily gain and feed efficiency we re depressed (P<.05) in pigs f e d rav Bragg soybeans throughout the entire growin g -finishin g period co,nr;ared to p igs fed the other dietary tr e at me nts. F eedi n g either variety of soy bea ns roasted at 110 C resulted in irr:proved (P<.CS) pi g gro11th compar e d to pigs fed unheated soybeans. R oastin g at 110 C i mp roved (P<.05) feed-to-gain ratio of the Bragg soybeans but d id not improv e (P>.05) utilization of the Davis variety. T he t w o vari e ti e s of soybeans studied (Bragg vs. Davis) haci different ur ease ind exe s and r eq uire d diff e rent amounts of heat processin g to produce protein s u pp l e r r. e nts adequate fer growin g -f inishing swin8 Additional expe ri n.e nt s six trials involving crossbr e d pigs and one 21-day trial usin~ day-old chic ks were conducted to eval ua te the utilization of defatted soybean flak e s which haci been subjected to

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119 inadequate heat processing (und erprocessed) as affected by diffe r ent species (chicks and weanling pigs) and maturity (a ge) of swine. Also, twenty-four barrov1s (eight per starter, growe r and finisher study) fitted with a T-cannula near the terminal end of the il eum were used to determine amino acid digestibilities. Total gain, feed intake and feed efficiency of chicks were not influenc ed (P>.05) by feeding defatted soybean flakes heated for 16, 1 8, 20 or 22 minutes CUA between .42 and .07); whereas, growth rate and feed intake of weanling pigs and average daily ga in of srowin g pigs f ed defatted soybean flakes heat ed f or 16 minutes were adversely affected (P<.05) when compared to pi gs fed de fatted soybean fl akcs heated for 22 ri1i nutes. Heating the defatt ed soybean flakes betv,een 1 6 and 22 r:iinutes did not affect (P>.05) daily feed consumption by weilnlin g piss Amino acid digestibilities, except for n eth ionine and serine, wer e not influ enced when wea nlin g pigs were f ed diets cont aining defatted soyflakes heated for 1 6 18, 20 or 22 minutes Dur"ing the grmer pericd f eed intake and efficiency were r e duced (P<.05) co m pared to pigs fed defatteo soybean fla kes heated for 22 minutes by feedin g defatted soybean flakes heated for 12 and 6 ninutes, respectiv e ly. Likewise, a majority of the c mino acid digestibil ities was sir. ilar bet1-1een diets containin g defa tted soyfla ke s heated for 12, 1 6 or 22 minutes Howe v er i n r. 1 ost cases ( ex c e r:;t for lysin e gly cine and histidine) ari : ino acid d isestibiliti es were r ed uc ed (P<.05) 11h e r. g r0v1ing pigs were fed scyfla:<:e s heated for 6 r. 1 inutes cor.1p2.red to the diets cont a ining soyflakes h e ated for 12, 16, or 22 minutes. Hm1ever, finishing pigs fed defatted soybean flak es heated for 6, 12, 16 or 22 rninutes

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120 grew at a similar (P>.05) rate and required equal (P>.05) amounts of feed per body weight gain. The feeding of defatted soybean flakes heated for 0, 6, 12, 16 or 22 minutes to finishing pigs did not influence (P>.05) feed intake. The amino acid digestibilities cf the finisher diets were not consistently influenced by the different heat processin g times. Digestibilities of histidine, isoleucine, leucine, lysine, methionine, phrnylalanine, valine, cystine, glutamic acid and serine were not influenced (P>.05) and arginine, threonine, alanine, aspartic acid, glycine and tyrosine were aff e ct ed (P<.05) by feeding diets containing soyfla kes heated for varying lensths of tinE (6 to 22 minutes). In conclusion, these data indicat ed that th e r.;ci sture content of soybeans prior to heatin g th e temperature and length of heating ti m e to which the soybeans are s ubj ected the species and age of ani ma l f ed and the variety of soybe an s f eo are all i mpo rtant factors to be consider e d 1hen detern iining their nutritional value.

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APPENDIX A STATISTICAL ANALYSIS TABLES

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Table 23. MEANS FOR CHAPTER III EXPERIMENT C289C) SBM-Control N Mean SD SE M ~ar c~ Avg. Initial Wt., kg 18 5.04 1.14 0.27 1.301 22.61 Avg. Final Wt., kg 17 16.80 2.43 0.59 5.894 14.45 Avg. Daily Gain, kg 17 0.33 0.06 0.01 0.0003 16.88 Avg. Daily Feed, kg 3 0.59 0.03 0.02 0.0008 4.89 Avg, Feed/Gain 3 1. 76 0.01 0,01 0,0002 0,84 Raw Avg. Initial \1t., kg 18 5. 03 0.84 0.20 0.705 16.68 Avg. Final \~t., kg 15 7.87 2.41 0.62 5.791 30.58 Avg. Daily Gain, kg 15 0.09 0.06 0.01 0.003 73.90 Avg. Daily Feed, kg 3 0.33 0.04 0.02 0.001 11.09 Aye, Fe ed /Gain 3 4,45 0,81 0 ,47 0,664 18.33 llOC-no water Avg. Initial Wt ., kg 18 5.02 0.66 0.16 0.442 13 .24 Avg. Final Wt., kg 16 7 .56 2.47 0.62 6.127 32. 73 Avg. Daily Gain, kg 16 0.07 0.06 0.02 0.004 91.63 Avg. Daily Feed, kg 3 0.32 0.06 0.03 0.004 18.86 Ayo, Feed/Gain 3 5, 23 2.41 1.39 5, 8 16 46 11 llOC-10% water Avg. Initial Wt. kg 18 5.03 0.72 0.17 0.523 14.37 Avg. Final ~It., kg 17 9.75 2.07 0.50 4.293 21.26 Avg. Daily Gain, kg 17 0.13 0.05 0.01 0.003 38.97 Avg. Daily Feed, kg 3 0.41 0.05 0.03 0.003 12.93 Avg, F eed /Gain -, 3,06 0,37 0,21 0.138 12.05 ;> 125C-no water Avg. Initial \'It., kg 18 5. 03 0.70 0.16 0.486 13.86 Avg. Final vlt. kg 17 11.03 2.23 0.54 4.960 20.19 Avg. Daily Gain, kg 17 0.17 0.05 0.01 0.003 32.23 Avg. Daily Feed, kg 3 0.39 0.08 0.04 0.006 19.92 Av e; Feed/Gain 3 2 .33 Q,10 0,06 0,010 4,21 1 22

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123 Table 23-continued. 125C-10% water Meao SD SE~ 1 ~gr c~ Avg. Initial Wt., kg 18 5.02 0.58 0.14 0.339 11.60 Avg. Final Wt., kg 18 13. 71 2.98 0.70 8.91 21. 78 Avg. Daily Gain, kg 18 0.25 0.07 0.02 0.005 29.66 Avg. Daily Feed, kg 3 0.55 0.12 0.07 0.013 21. 05 8Y.g. EeedLGgjn 2,21 Q, ll Q.lQ Q.Q3Q z.a2

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124 Table 24. STATISTICAL ANALYSIS FOR CHAPTER III EXPERIMENT (289C). Dependent Variable: Average Daily Gain, kg Mean MSE Root MSE R-Square .176 004 .061 80 AOV Table SQl.![C~ DF ss F-~alue Model 35 .980 7.56 Trt 5 .809 43. 65 Sex 1 .002 .54 Rep 2 .016 2.11 Trt*Sex 5 .020 1.06 Trt*Rep 10 020 .53 Sex*Rep 2 003 45 Trt*Rep*Sex 9 014 41 Int Wt Cov 1 .012 3.26 E 0 64 237 Dependent Variable: Feed Intake, Kg Mean .434 MSE .002 Root MSE R-Square Coefficient of Variation Source Model Trt Rep Ercoc DF 7 5 2 10 Dependent Variable: .049 .904 11.28 ss .224 .192 033 024 Feed/Gain F-Va]ue 13. 41 16.05 6.82 Mean MSE Root MSE R-square Coefficient of 3.18 1.019 1.01 .76 31.76 Source DF ss F-va]ue Model 7 31.57 4.43 Trt 5 28.44 5.58 Rep 2 3.13 1.54 EccQC lQ 10.12 PR>F .0002 .0002 .0136 Variation PR>E 0173 0103 .2621 CV 34.50 PB>E .0001 .0001 .4666 .1294 .3906 .8624 .6379 9251 .0756

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125 Table 25. MEANS FOR CHAPTER III EXPERIMENT (289C) Heat=llOC SD SE~'I ~at c~ Avg. Initial Wt., kg 36 5.03 0.68 0.11 0.469 13.62 Avg. Final Wt., kg 33 8.69 2.50 0.43 6.249 28.77 Avg. Daily Gain, kg 33 0.10 0.06 0.01 0.004 63.87 Avg. Daily Feed, kg 6 0.37 0.07 o. 03 0.005 19.68 Avg. Feed/Gain 6 4,16 1,94 0,79 3,761 46.65 Heat=l25C Avg. Initial Wt., kg 36 5.03 0.63 0.10 0.401 12.60 Avg. Final Wt., kg 35 12.41 2.94 a.so 8.635 23.68 Avg. Daily Gain, kg 35 0.21 0.08 0.01 0.006 36.00 Avg. Daily Feed, kg 6 0.47 0.12 0.05 0.016 26.56 Ayo, Feed/Gain 6 2,27 0,14 0,06 0,020 6.27 No water Avg. Initial \'It., kg 36 5.03 0.67 0.11 o. 451 13.36 Avg. Final Wt., kg 33 9.35 2.91 0.51 8.449 31.09 Avg. Daily Gain, kg 33 0.12 0.08 0.01 0.006 63.41 Avg. Daily Feed, kg 6 0.35 0.07 0.03 0.005 20.61 Ayo, Fe e d/Gain 6 3,78 2,20 0,90 4.849 58.24 10% water Avg. Initial \'It. kg 36 5.03 0.65 0.11 0.419 12.87 Avg. Final Wt., kg 35 11. 78 3.24 0.55 10.510 27 .51 Avg. Daily Gain, kg 35 0.19 0.09 0.01 0.007 44.41 Avg. Daily Feed, kg 6 0.48 0.11 0.04 0.012 23. 01 Ay o Fe e d/Gain 6 2,65 Q,54 0,22 0,296 20.53

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126 Table 26. STATISTICAL ANALYSIS FOR CHAPTER III EXPERIMENT ( 289C). Dependent Variable: Average Daily Gain, kg Mean MSE Root MSE R-Square CV .158 004 .061 70 38.03 AOV Table SQ!J[C!il DE ss F-Va]ue PB>E Model 24 .370 4.25 .0001 Heat l .189 52.14 .0001 Moisture l .086 23.66 .0001 Sex l 009 2.47 .1235 Rep 2 .017 2.30 .1128 N*H 1 .001 .36 .5533 H*S 1 .011 3.14 .0834 H*R 2 .003 .47 .6303 M*S 1 .ooo 03 .8588 M*R 2 .000 .01 .9941 S*R 2 005 .73 .4858 M*H*R 2 .007 .92 .4075 H*R*S 2 .000 07 .9323 M*S*R 2 .002 .28 .7604 M*H*S*R 2 .001 .12 .8914 Int Wt Cov 1 018 4.88 0325 Error 43 .156 Dependent Variable: Feed Intake, Kg Mean MSE Root MSE R-Square Coefficient of Variation .419 002 .043 .973 10.29 Source OF ss F-~a]ye PB>E Model 9 .647 7.98 .1163 Moisture 1 .236 26.23 .0361 Heat 1 .159 17.67 .0522 Rep 2 .204 11.30 .0813 M*H 1 .017 1.90 .3024 M*R 2 002 .10 .9121 H*R 2 029 1.62 .3816 Ercoc 2 Ql8

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127 Table 26-continued. Dependent Variable: Feed/Gain Mean MSE Root MSE R-square Coefficient of Variation 3.21 1.238 1.11 .92 34.61 SQyrce OF ss F-value PB>E Model 9 27.09 2.43 .3254 Moisture 1 3.84 3.10 .2202 Heat 1 10.66 8.61 0992 Rep 2 3.88 1.57 .3896 M*H 1 3.08 2.48 .2557 M*R 2 1. 73 .70 .5882 H*R 2 3.90 1.58 .3883 Error 2 2 48

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128 Table 27. MEANS FOR CHAPTER IV EXPERIMENT CS-1). Soybeans-1 N Mean SD SE~ c~ Protein,% 20 38.17 1.82 0.41 3.304 4.76 Fat,% 20 20.16 1.13 0.25 1. 282 5.61 Urease Activity 20 1.43 0.22 0.05 0.049 15.48 Trypsin I (Raw) 20 37.55 8.92 1.99 79.585 23. 75 Trypsin I (7.5 M) 20 10.56 2.34 0.52 5.499 22.20 Trypsin I (15 M) 20 3.87 0.70 0.16 0.490 18.08 TI Reduction (7.5 M) 20 71.36 5.10 1.14 25. 977 7.14 TI Reduction (15 M) 20 89.34 2.34 0.52 5.484 2.62 Urease A (7. 5 M) 20 0.14 0.08 0.02 0.007 61.33 Urease A (15 M) 20 0.03 0.03 0.01 0.0007 78.69 Germination UA 16 1. 70 0.23 0.06 0.055 13. 76 Germination TI 16 30. 70 6.61 1.65 43.660 21.52 UA Remained (7.5 M) 20 0.09 0.05 0.01 0.002 49.77 UA Remained (15 M) 20 0.02 0.02 o.oo 0.0003 77.49 TI Remained (G) 16 84,56 0,07 0.02 0,005 8.25 Soybeans-2 t::l SQ SEM ~Q[ c~ Protein, % 40 39.39 1.90 0.30 3.596 4.81 Fat,% 40 22.46 1.26 0.20 1.595 5.62 Urease Activity 40 1.52 0.41 0.06 0.168 26.91 Trypsin I (Raw) 40 37.24 8.10 1.28 65 576 21.74 Sj ze i mrn 40 7,l5 1,19 0, 19 1,407 16,59 Table 28. MEANS FOR CHAPTER IV (GROWER & FINISHER) EXPERIMENT (289A) SBM-Control t::l Mea n SD SEM ~2r c~ Avg. Initial Wt., kg 18 40.03 3.59 0.85 12.906 8.97 Avg. Interim Wt., kg 17 64.31 4.71 1.14 22. 233 7.33 Avg. Final Wt., kg 17 114.86 9.06 2.20 82.008 7.88 ADG, kg (grower) 17 0.86 0.08 0.02 0.006 9.07 ADG, kg (finisher) 17 0.74 0.11 0.03 0.012 14.60 ADG, kg (overall) 17 0.78 0.08 0.02 0.007 10.95 ADF, kg Cg rower) 3 2.48 0.13 0.08 0.017 5.31 ADF, kg (finisher) 3 2.83 0.09 0.05 0.007 3.06 ADF, kg (overall) 3 3.73 0.07 0.04 0.004 2.40 AFG (grower) 3 2.88 0.09 0.05 0.007 2.99 AFG (finisher) 3 3.84 0.21 0.12 0.043 5.39 8EG (Q~ ~ c 2 lJ) 3 J,53 0.13 o.o:z Q.Ql6 3.59

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129 Table 28-continued. Bragg-125C Mean SD SEt li Yar CY Avg. Initial Wt., kg 18 40.00 4.09 0.96 16.753 10.23 Avg. Interim Wt., kg 18 61.54 5.99 1.41 35.942 9.74 Avg. Final Wt., kg 18 109.72 13.80 3.25 190.378 12.58 ADG, kg Cg rower) 18 0.77 0.10 0.02 0.011 13.55 ADG, kg (finisher) 18 0.71 0.15 0.04 0.023 21.58 ADG, kg (overall) 18 0.73 0.13 0.03 0.016 17.50 ADF, kg (grower) 3 2.47 0.11 0.06 0.011 4.27 ADF, kg (finisher) 3 2.85 0.20 0.11 0.040 6.99 ADF, kg (overall) 3 2.74 0.14 0.08 0.020 5.17 AFG Cg rower) 3 3.22 0.17 0.10 0.028 5.21 AFG (finisher) 3 4.04 0.29 0.17 0.084 7.17 AFG (overall) 3 3,78 0,20 0,12 0,041 5,33 Raw-Davis [':l ~~90 SD SE~ , Y2r CY Avg. In it i al \Vt. kg 18 39.98 3.31 0.78 10.948 8.28 Avg. Interim Wt., kg 18 56.09 5.39 1.27 29.007 9.60 Avg. Final Wt., kg 18 98.52 11.34 2.67 128.592 11.51 ADG, kg Cg rower) 18 0.58 0.10 0.02 0.010 17 .so ADG, kg (finisher) 18 0.62 0.11 0.03 0.012 17.75 ADG, kg ( ove ra 11 ) 18 0.61 0.10 0.02 0.010 16.14 ADF, kg Cg rower) 3 2.20 0.04 0.03 0.002 2.06 ADF, kg (finisher) 3 2. 71 0.18 0.10 0.031 6.50 ADF, kg (overall) 3 2.56 0.11 0.06 0.012 4.36 AFG Cg rower) 3 3.84 0.46 0.26 0.210 11.91 AFG (finisher) 3 4.35 0.05 0.03 0.003 1.20 AFG (over al l) 3 4,21 0, 11 0,07 0, 013 2,72 Davis-llOC tJ SD SEM Y2r CY Avg. Initial Wt., kg 18 39.98 4.13 0.97 17.083 10.34 Avg. Interim Wt., kg 18 61.16 6.42 1.51 41.194 10.49 Avg. Fin al \Vt. kg 17 109.57 13.22 3.21 174.759 12.06 ADG, kg Cg rower) 18 0.76 0.12 0.02 0.014 15.92 ADG, kg (finisher) 17 0.71 0.12 0.03 0.014 17.04 ADG, kg (overall) 17 0.72 0.12 0.03 0.013 16.06 ADF, kg (grower) 3 2.48 0.28 0.16 o. 078 11. 25 ADF, kg (finisher) 3 2.81 0.37 0.21 0.138 13.22 ADF, kg Coverall) 3 2.76 0.43 0.25 0.189 15. 71 AFG (grower) 3 3.27 0.27 0.16 0.075 8.35 AFG (finisher) 3 3.96 0.42 0.24 0.177 10.64 AEG (oyer a ]]) 3 3,~l 0,47 Q,27 Q,225 l2d~

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130 Table 29. STATISTICAL ANALYSIS FOR CHAPTER IV (GROWER & FINISHER) EXPERIMENT (289A) Dependent Variable: Average Daily Gain, kg (grower) Mean MSE Root MSE R-Square CV .664 .008 091 .82 13. 72 AOV Table SQ!.! DE ss F-~a]ue P8>E Model 36 2.605 8. 72 .0001 Trt 5 1.967 47.39 .0001 Sex 1 .096 11.63 .OOll Rep 2 007 .41 .6674 Trt*Sex 5 .060 1.44 .2207 Trt*Rep 10 085 1.02 .4326 Sex*Rep 2 .006 .37 .6887 Trt*Rep*Sex 10 .156 1.88 .0619 Int Wt Cov 1 .183 22.06 .0001 Error 70 .581 Dependent Variable: Average Daily Gain, kg (finisher) Mean MSE Root MSE R-Square CV .649 010 099 .68 15.33 AOV Table SQl.!cc e DE ss E-Y'.g]ye EG>F Model 36 1.449 4.07 .0001 Trt 5 .137 2. 77 .0243 Sex 1 .076 7.73 .0070 Rep 2 033 1.68 .1939 Trt*Sex 5 .087 1. 76 .1315 Trt*Rep 10 .163 1.64 .1130 Sex*Rep 2 .001 .06 .9412 Trt*Rep*Sex 10 .095 .96 .4896 Int Wt Cov 1 .201 20.32 .0001 Error 69 683

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131 Table 29-continued. Dependent Variable: Average Daily Gain, kg (overall) Mean MSE Root MSE R-Square .653 .009 094 71 AOV Table SQ!.!C~~ DF ss F-Va]ue Model 36 1.523 4.79 Trt 5 .912 20.65 Sex 1 .127 13.35 Rep 2 031 1.73 Trt*Sex 5 .080 1.81 Trt*Rep 10 .085 .97 Sex*Rep 2 .003 .17 Trt*Rep*Sex 10 .127 1.44 Int Wt Cov 1 .097 10.96 Error 69 .610 Dependent Variable: Feed Intake, Kg (grower) Mean 2.291 MSE Root MSE R-Square Coefficient of Variation Source Model Trt Rep Error 034 OF 7 5 2 10 .185 .668 8.08 ss .690 .669 .020 ,343 F-Va)ue 2.87 3.90 .30 PB>E .0639 .0320 .7490 Dependent Variable: Feed Intake, Kg (finisher) Mean 2. 729 Source Model Trt Rep Error MSE 053 OF 7 5 2 10 Root MSE R-Square Coefficient of Variation .231 .421 8.45 ss .387 .290 096 .532 F-V a) ue 1.04 1.09 .91 PR>E .4626 .4220 .4350 CV 14.38 PB>E .0001 .0001 .0003 .1847 .1209 .4812 .8401 .1820 .0015

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132 Table 29-continued. Dependent Variable: Feed Intake, Kg (overall) Mean MSE Root MSE R-Square Coefficient of Variation 2.611 051 .225 .495 8.62 SQucce OF ss F-~alue PB>F Model 7 497 1.40 .3030 Trt 5 409 1.62 .2423 Rep 2 .088 .87 .4490 Ercor 10 ,506 Dependent Variable: Feed/Gain Cg rower) Mean MSE Root MSE R-square Coefficient of Variation 3.54 .071 267 .86 7.55 SQU[C~ OF ss F-ya]u e Pf3>E Model 7 4.508 9.01 .0013 Trt 5 4.481 12.53 0005 Rep 2 .027 .19 8311 Eccoc lQ .:21s Dependent Variable: Feed/Gain ( finisher) Mean MSE Root MSE R-square Coefficient of Variation 4.25 .072 269 .84 6.32 SQucce D F ss F-value PB>E Model 7 3. 728 7 .38 .0027 Trt 5 3. 710 10.29 .0011 Rep 2 .018 .12 .8840 Ercoc 10 I 721 Dependent Variable: Feed/Gain (overall) Mean MSE Root MSE R-square Coefficient of Variation 4.05 .068 261 85 6.46 SQ!.![C~ DF ss F-y a ]ue EB>E Model 7 3.978 8.32 .0017 Trt 5 3.972 11.63 0007 Rep 2 .006 .04 .9570 ECCQC lQ 6e3

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133 Tab le 30. MEANS FOR CHAPTER V (CHICK TRIAL) (290 chicks) Soybean Meal Me~rn SD SEM ~ar c~ Avg. Initial Wt., gm 45 45.43 2.01 0.30 4.033 4.42 Avg. Total Gain, gm 45 543.00 60.02 8.66 3602.450 11.04 Pancreas Wt., gm 16 381. 74 61.05 15.26 3726.676 15.99 Avg. Daily Feed, gm 8 40.60 1.42 0.50 2.010 3. 49 Ayo, Fe ed /Gain 8 1.57 0.05 0,02 0, 003 3.47 16 minute Avg. In it i al lvt. gm 47 45.40 0.87 0.13 0.753 1.91 Avg. Total Gain., gm 47 514.00 65. 83 9.50 4334.099 12.82 Pancreas Wt., gm 16 485.63 64.47 16.12 4156.431 13.27 Avg. Daily Feed, gm 8 38. 70 1.66 0.59 2.751 4.28 Ay o Feed/Gain 8 1.59 0.08 0,03 0,006 4,89 18 minute Avg. Initial lvt., gm 46 45.84 1.43 0.21 2.038 3.13 Avg. Total Gain, gm 46 522.00 57.29 8.27 3281.915 10. 71 Pancreas Wt., gm 16 402.40 65.15 16.29 4244.675 16.19 Avg. Daily Feed, gm 8 39.80 2.12 0.75 4.498 5.33 Ay o Fe ed /Gain 8 1,60 0.05 0,02 0,003 3 I 23 20 minute Avg. Initial vlt. gm 46 44.96 1. 76 0.26 3.109 3.92 Avg. Total Gain, gm 46 534.00 49.75 7.18 2475.241 9.52 Pancreas Wt., gm 16 384.61 53.16 13.29 2826.108 13. 82 Avg. Daily Feed, gm 8 40.40 2.44 0.86 5.969 6.05 Ay o Fe ed /Gain 8 1. 59 0.06 0.02 0.004 3,96 22 minute Avg. In it i al vit. gm 47 44.56 1. 70 0.25 2.909 3. 83 Avg. Total Gain, gm 47 523.00 58.53 8.45 3425. 375 11.19 Pancreas Wt., gm 16 380.58 50.86 12.71 2586.454 13.36 Avg. Daily Feed, gm 8 39.60 1.44 o. 51 2.065 3.62 Ayo, F eed /Gain 1. 59 O.Q5 Q.02 0.003 3.20

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134 Tab le 31. STATISTICAL ANALYSIS FOR CHAPTER V (CHICK TRIAL) (290 chicks) Dependent Variable: Average Total Gain, gm Mean MSE Root MSE R-Square CV 527.42 2320. 51 48.17 55 9.13 AOV Table SQ!.! [C~ DE ss F-Yalue PR>E Model 79 459597.8 2.51 .0001 Trt 4 26283.06 2.83 0264 Sex 1 158158. 00 68.26 .0001 Rep 7 71858.53 4.42 0002 Trt*Sex 4 4469.14 .48 7493 Trt*Rep 28 97916.74 1.51 0610 Sex*Rep 7 42778.76 2.67 .0134 Trt*Rep*Sex 28 58133.59 89 .6216 Error 160 371282.0 Dependent Variable: Feed Intake, gm Mean MSE Root MSE R-Square Coefficient of Variation 39. 83 2.80 1.67 433 4.20 Source DF ss F-Ya]u~ PB>F Model 11 59.94 1.94 0764 Trt 4 17 .39 1.55 2149 Rep 7 42.54 2.17 0687 EttQt 28 7 8 ,Sl Dependent Variable: Feed/Gain Mean MSE Root MSE R-square Coefficient of Variation 1.59 .002 .044 585 2.78 Sou r:c e DF ss F-va 1 u e PB>E Model 11 .077 3.58 0031 Trt 4 .004 48 .7497 Rep 7 073 5.36 .0006 Er:rnr: 28 ,05 4 Dependent Variable: Pancreas Wt., gm Mean MSE Root MSE R-square Coefficient of Variation 406.99 3079. 53 55.49 465 13.63 Source DF ss F-va]y~ PB>E Model 11 182372.194 5.38 .0001 Trt 4 128675.342 10.45 .0001 Rep 7 53696.851 2.49 .0244 Error 68 209408,312

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135 Tab le 32. MEANS FOR CHAPTER V (STARTER PERIOD) (290A) SBM-Control SD SEt:1 ~Q[ c~ Avg. Initial Wt., kg 18 5.25 0.79 0.18 0.619 14. 97 Avg. Final Wt., kg 17 18.37 3.47 0.48 12.029 18.88 Avg. Daily Gain, kg 17 0.37 0.09 0.02 0.008 23.36 Avg. Daily Feed, kg 3 0.69 0.07 0.04 0.006 11.01 Avg. Feed/Gain 3 1. 83 0.02 0.01 0.0006 1.32 16 minute Avg. Initial Wt., kg 18 5.25 0.76 0.18 0.573 14. 43 Avg. Final Wt., kg 18 15.89 3.62 0.85 13 .100 22.78 Avg. Daily Gain, kg 18 0.30 0.09 0.02 0.008 29.82 Avg. Daily Feed, kg 3 0.57 0.05 0.03 0.002 8.26 Ayg, Feed/Gain 3 1.87 0.08 0.05 o. 007 4. 52 18 minute Avg. Initial ~Jt., kg 18 5.26 0.66 0.15 0.435 12.54 Avg. Final Wt., kg 18 17. 23 3.11 0.73 9.662 18.04 Avg. Daily Gain, kg 18 0.34 0.07 0.02 0.006 21.91 Avg. Daily Feed, kg 3 0.60 0.08 0.05 0.006 13. 41 Ayo. Fe ed /Gain 3 1. 75 0.02 0.02 0, 0005 1. 29 20 minute Avg. Initial Wt., kg 18 5.24 0.67 0.16 0.446 12.74 Avg. Final Wt., kg 18 17.38 2.87 0.68 8.258 16.54 Avg. Daily Gain, kg 18 0.35 0.07 0.02 0.005 20.72 Avg. Daily Feed, kg 3 0.63 0.03 0.02 0.0008 4.66 Avg. Feed/Gain 3 1.81 0.07 0.04 o. 005 3,84 22 minute Avg. Initial Wt., kg 18 5.26 o. 70 0.16 0.486 13.25 Avg. Final \Vt., kg 18 18.31 3 .15 0.74 9.948 17.22 Avg. Daily Gain, kg 18 0.37 0.08 0.02 0.006 21.28 Avg. Daily Feed, kg 3 0.65 0.04 0.02 0.002 6.63 Avg. Fe ed /Gain 3 1. 75 0,02 O,Ql 0.0004 1,16

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136 Table 33. STATISTICAL ANALYSIS FOR CHAPTER V (STARTER PERIOD) (290A) Dependent Variable: Average Daily Gain, kg Mean MSE Root MSE R-Square .348 .006 .077 43 AOV Table SQ!.! r~e DE ss F-Va]ue Model 30 265 1.48 Trt 4 .059 2.47 Sex 1 015 2.60 Rep 2 008 65 Trt*Sex 4 005 .20 Trt*Rep 8 .013 27 Sex*Rep 2 .018 1.52 Trt*Rep*Sex 8 .012 25 Int Wt Cov 1 069 11.53 Error 58 .346 Dependent Variable: Feed Intake, Kg Mean .626 MSE .0009 Root MSE R-Square Coefficient of Variation .031 .87 4.89 Source Model Trt Rep E OF 6 4 2 8 ss .053 026 .027 007 Dependent Variable: Feed/Gain Mean 1.80 Source Model Trt Rep Error MSE 002 OF 6 4 2 e Root MSE .047 F-V a )u e 9.36 6.94 14.20 PR>F .0029 0103 0023 R-square Coefficient of Variation 68 2. 63 ss .039 030 .009 018 F-va l ue 2.91 3.37 1.98 PR>E .0824 .0674 .2002 CV 22.21 PB>E 0997 0542 .1125 .5245 9366 9746 .2275 .9781 .0012

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137 Tab le 34. MEANS FOR CHAPTER V (GRO\'IER PERIOD) (290) Raw Soy flakes t:l SD SE~1 ~[ c~ Avg. Initial Wt., kg 12 34. 73 4.22 1.22 17.782 12.14 Avg. Final Wt., kg 11 45.17 5.90 1.78 34.782 13.06 Avg. Daily Gain, kg 11 0.40 0.10 0.03 0.010 24.95 Avg. Daily Feed, kg 2 1. 78 0.11 0.08 0.012 6.17 Avo. Feed/Gain 2 4.40 0.28 0.02 0.0008 0.64 6 minute Avg. Initial Wt., kg 12 34. 73 4.31 1.24 18.569 12.41 Avg. Final Wt., kg 11 50.64 5.71 1.72 32.664 11.29 Avg. Daily Gain, kg 11 0.63 0.09 0.03 0.007 13. 75 Avg. Daily Feed, kg 2 2.09 0.02 0.01 0.0003 0.80 Ayo. Feed/Gain 2 3.30 0.11 0,08 0.012 3.31 12 minute Avg. Initial Wt., kg 12 34.69 3.96 1.14 15. 682 11.41 Avg. Final Wt., kg 11 52. 75 6.26 1.89 39.196 11. 87 Avg. Daily Gain, kg 11 0.74 0.14 0.04 0.020 19.21 Avg. Daily Feed, kg 2 2.05 0.01 0.01 0.0002 0.67 Ayg, Feed/Gain 2 2,81 0.16 0.11 0,024 5.58 16 minute Avg. Initial vlt. kg 12 34.69 3.25 0.94 10.548 9.36 Avg. Final Wt., kg 12 54.56 4.06 1.17 16.520 7.45 Avg. Daily Gain, kg 12 0.79 0.09 0.03 0.008 11.24 Avg. Daily Feed, kg 2 2.71 0.07 a.as 0.006 3.45 Avg. 2 2 .73 0.00 0,00 0.000 0,05 22 minute Avg. In it i a 1 vlt. kg 12 34. 65 2.63 0.76 6.908 7.58 Avg. Final vlt. kg 11 56. 83 4.42 1.33 19.573 7.78 Avg. Daily Gain, kg 11 0.88 0.11 0.03 0.012 12.61 Avg. Daily Feed, kg 2 2.34 0.08 a.as 0.006 3.31 Avg. 2 2,68 Q,20 O,H Q,038 :Z. 3 l

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13 8 Tab le 35. STATISTICAL ANALYSIS FOR CHAPTER V (GROWER PERIOD) (290) Dependent Variable: Average Daily Gain, kg Mean MSE Root MSE R-Square .691 .088 .097 84 AOV Table SQU[~~ DE ss F-Va]ye Model 20 1. 755 9.24 Trt 4 1.416 37.29 Sex 1 .000 .01 Rep 1 009 96 Trt*Sex 4 .045 1.19 Trt*Rep 4 057 1.51 Sex*Rep 1 037 3.92 Trt*Rep*Sex 4 047 1.24 Error 35 .332 Dependent Variable: Feed Intake, Kg Mean 2.09 MSE .006 Root M SE R-Square Coefficient of Variation Source M odel Trt Rep Error D F 5 4 1 4 .078 .932 3.72 ss .330 .330 .000 024 F-V a ) u e 10.93 13. 67 .oo Dependent Variable: Feed/Gain Mean MSE Root MSE R-square Coefficient of 3.18 .018 .135 .98 4.23 Source O F ss F-v a )u e Model 5 4.164 45. 83 Trt 4 4.161 57. 25 Rep 1 .003 .16 E 4 7 P B > F .0190 0133 9483 Variation PB>E .0013 .0009 .7061 CV 14.10 PB>E .0001 0001 .9284 .3345 .3331 2191 0556 .3119

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139 Tab le 36. MEANS FOR CHAPTER V (FINISHER PERIOD) (290B) Raw Soy flakes Mean SD SE~1 Yac CY Avg. Initial Wt., kg 12 70.48 5.99 1. 73 35. 831 8.49 Avg. Final Wt., kg 12 79.45 8.10 2.34 65.695 10.20 Avg. Daily Gain, kg 12 0.45 0.17 0.05 0.029 38.08 Avg. Daily Feed, kg 2 2.08 0.17 0.12 0.028 8.11 Ayo, Feed/Gain 2 4,64 0,51 0,63 0,265 11. 08 6 minute Avg. Initial Wt., kg 12 70.41 5.80 1.67 33. 633 8.24 Avg. Final Wt., kg 12 83.16 6.26 1.81 39.231 7.53 Avg. Daily Gain, kg 12 0.64 0.10 0.03 0.009 15. 07 Avg. Daily Feed, kg 2 2.43 0.12 0.08 0.014 4.96 Ayo, Feed/Gain 2 3.81 0.02 0.01 0,0004 0.50 12 minute Avg. Initial Wt., kg 12 70.29 6.86 1.98 47.063 9.56 Avg. Final Wt., kg 12 84.82 9.29 2.68 86.263 10.95 Avg. Daily Gain, kg 12 0.73 0.18 0.05 0.033 24.96 Avg. Daily Feed, kg 2 2.56 0.24 0.17 0.059 9.51 Av a Fe e d/Gain 2 3.52 0,15 0.11 0.024 4.37 16 minute Avg. Initial Wt., kg 12 70.41 9.18 3.65 84.225 13.03 Avg. Final Wt., kg 10 82.54 9.00 2.84 80.926 10.90 Avg. Daily Gain, kg 10 0.72 0.12 0.04 0.014 16.56 Avg. Daily Feed, kg 2 2.58 0.12 0.08 0.014 4.62 Ava. Feed/Gain 2 3.57 0.12 0.09 0,016 3.51 22 minute Avg. Initial Wt., kg 12 7.37 7.02 2.03 49.355 9.98 Avg. Final Wt., kg 12 85. 05 5.97 1.92 35.689 7.02 Avg. Daily Gain, kg 12 0.73 0.20 0.06 0.041 27. 74 Avg. Daily Feed, kg 2 2.56 0.59 0.42 0.353 23.22 Ay o F e ed/Gain 2 3,'1 6 0.33 0.23 o.10~ 9.52

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140 Tab le 37. STATISTICAL ANALYSIS FOR CHAPTER V (FINISHER PERIOD) (290B) Dependent Variable: Average Daily Gain, kg Mean MSE Root MSE R-Square 651 .024 .154 .57 AOV Table SQ!.! [C~ DE ss F-Value Model 20 1.183 2.49 Trt 4 703 7.41 Sex 1 059 2.51 Rep 1 .014 .60 Trt*Sex 4 090 .95 Trt*Rep 4 .067 .70 Sex*Rep 1 .001 03 Trt*Rep*Sex 4 231 2.43 Int Wt Cov 1 018 75 Error 37 878 Dependent Variable: Feed Intake, Kg Mean 2.440 MSE .067 Root MSE R-Square Coefficient of Variation Sou cc e Model Trt Rep E DF 5 4 1 4 .258 .68 10.59 ss .557 .355 .202 6 7 F-Valu e 1.67 1.33 3.02 P R> F .3204 .3949 .1572 Dependent Variable: Feed/Gain Mean M SE Root M SE R-square Coefficient of Variation 3.802 038 .195 93 5.13 Source OF ss F-l'. a 1 y e PR > E Model 5 2.175 11. 43 .0175 Trt 4 1.915 12.58 .0155 Rep 1 .261 6.86 .0589 E 4 52 CV 23.67 PR>F .0079 .0002 .1219 4448 .4475 .5958 8662 0645 .3910

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141 Tab le 38. MEANS FOR CHAPTER V DIGESTIBILITY TRIALS (STARTER PERIOD-290C) 16 minutes I:t~D 1 z tJ Mean SD SEt':1 ~Q[ c~ Dig Asp 7 .6781 0.12 0.05 0.016 18.50 Dig Glu 7 .7591 0.09 0.03 0.008 11.45 Dig His 7 .7902 0.12 0.04 0.014 14.77 Dig Ser 6 .6570 0.19 0.08 0.035 28.38 Dig Arg 7 8600 0.08 0.03 0.006 8.86 Dig Gly 6 .5953 0.21 0.08 0.042 34. 59 Dig Thr 7 6413 0.17 0.06 0.027 25.82 Dig Ala 7 .6403 0.13 0.05 0.016 19.98 Dig Tyr 7 .7598 0.08 0.03 0.006 10.27 Dig Met 7 .7466 0.11 0.04 0.012 14.93 Dig Val 7 .6559 0.11 0.04 0.013 17.51 Dig Phe 7 7148 0.10 0.04 0.010 13. 69 Dig Ile 7 7118 0.10 0.04 0.010 13. 77 Dig Leu 7 7701 0.11 0.04 0.012 14.41 Dig Lys 7 .8065 0.16 0.06 0.024 19.35 Dig Cys 7 ,6416 0.13 0.05 0,018 21. 00 18 minutes I:teff1 I N SD SEM c~ Dig Asp 7 6897 0.10 0.04 0.011 15.28 Dig Glu 7 7750 0.07 0.03 0.006 9. 71 Dig His 7 .8196 0.10 0.04 0.010 12.43 Dig Ser 7 .6556 0.19 0.07 0.035 28.35 Dig Arg 7 .8966 0.05 0.02 0.003 5. 65 Dig Gly 7 .5742 0.18 0.07 0.032 31.32 Dig Thr 7 7085 0.09 0.04 0.009 13.34 Dig Ala 7 .6945 0.08 0.03 0.007 11.69 Dig Tyr 7 7790 0.06 0.02 0.003 7.23 Dig Met 7 7771 0.10 0.04 0.009 12.48 Dig Val 7 .6996 0.08 0.03 0.007 12.10 Dig Phe 7 7787 0.06 0.02 0.003 7.20 Dig Ile 7 7513 0.07 0.03 0.005 9.14 Dig Leu 7 .7659 0.05 0.02 0.003 7.19 Dig Lys 7 8529 0.11 0.04 0.011 12.54 Dig Cys 7 6058 Cl,15 0,06 0.022 24. l2

PAGE 149

142 Table 38-continued. 20 minutes I:te!l11 7o N Mea n SD SEM ~ar c~ Dig Asp 8 7273 0.12 0.04 0.016 17.20 Dig Glu 8 .7988 0.07 0.03 0.005 9.09 Dig His 8 8079 0.08 0.03 0.006 9.42 Dig Ser 8 7283 0.14 0.05 0.019 19.12 Dig Arg 8 .8888 0.05 0.02 0.003 6.06 Dig Gly 8 .6175 0.12 0.04 0.016 20.22 Dig Thr 8 .6608 0.12 0.04 0.015 18.69 Dig Ala 8 .6846 0.09 0.03 0.009 13.57 Dig Tyr 8 7502 0.10 0.03 0.010 13.30 Dig Met 8 .8338 0.05 0.02 0.002 5.82 Dig Val 8 .7038 0.10 0.03 0.010 13.98 Dig Phe 8 7791 0.05 0.02 0.003 7.09 Dig Ile 8 .7590 0.08 0.03 0.006 10.33 Dig Leu 8 7665 0.05 0.02 0.003 6.70 Dig Lys 8 8066 0.15 0.05 0.024 19.08 Dig Cys 8 ,6285 0.19 0.07 0,036 30.35 22 minutes l:t~ffl I N Mea o SD SE~1 ~g[ c~ Dig Asp 8 7423 0.12 0.04 0.014 16.07 Dig Glu 8 .8071 0.05 0.02 0.002 5.95 Dig His 8 .8497 0.04 0.02 0.002 5.17 Dig Ser 8 .7876 0.07 0.02 0.004 8.56 Dig Arg 8 .8970 0.03 0.01 0.0009 3.28 Dig Gly 8 6550 0.07 0.02 0.005 10.48 Dig Thr 8 6847 0.06 0.02 0.004 9.44 Dig Ala 8 .7054 0.05 0.02 0.002 6.86 Dig Tyr 8 7775 0.04 0.01 0.002 5.30 Dig Met 8 8500 0.02 0.01 0.0003 2. 23 Dig Val 8 .7098 0.05 0.02 0.002 6.85 Dig Phe 8 .7826 0.03 0.01 0.001 4.21 Dig Ile 8 .7590 0.04 0.01 0.001 4.91 Dig Leu 8 .7614 0.04 0.01 0.002 5.19 Dig Lys 8 8729 0.09 0.03 0.008 10.38 Dig Cys 8 7130 0,09 Q,03 0,009 13,11

PAGE 150

143 TABLE 39. STATISTICAL ANALYSIS FOR CHAPTER V DIGESTIBILITY TRIALS (STARTER PERIOD-290C) Dependent Variable: Dig Asp Mean MSE Root MSE R-square Coefficient of Variation 7110 .005 069 73 9.74 SQ!.!t~~ DF ss E-ya]ue PB>E Model 7 .285 8.51 .0001 Trt 3 010 .67 .5801 Week 3 265 18.41 .0001 Rep 1 .ooo .02 .8899 Eccoc 22 .105 Dependent Variable: Dig Glu Mean MSE Root MSE R-square Coefficient of Variation .7862 .04 047 .66 5.94 SQYCC~ DE ss F-va]ue PR>F Model 7 095 6.24 .0004 Trt 3 .0ll 1.93 .2240 Week 3 081 12.44 .0001 Rep 1 003 1.39 .2513 Eccor 22 ,048 Dependent Variable: Dig His Mean MSE Root MSE R-square Coefficient of Variation .8177 .002 049 .75 6.05 SQYCC~ DF ss F-ya]ue PR>E Model 7 .158 9.24 .0001 Trt 3 .0ll 1.57 .2249 Week 3 .144 19.58 .0001 Rep 1 .ooo .10 7540 Error 22 054 Dependent Variable: Dig Arg Mean MSE Root MSE R-square Coefficient of Variation .8861 .0008 .028 .79 3.16 SQYCs;;~ OF ss F-va]ue PR>F Model 7 .066 12.05 0001 Trt 3 006 2.43 .0924 Week 3 .059 25.11 .0001 Rep 1 000 .59 .4490 Ero 22 017

PAGE 151

144 Table 39-continued. Dependent Variable: Dig Thr Mean MSE Root MSE R-square Coefficient of Variation .6737 .006 .075 .66 11.18 SQ!..! rce DF ss F-va 1 ue PB>F Model 7 .247 6.22 .0004 Trt 3 .021 1.25 .3147 Week 3 .224 13.17 .0001 Rep 1 005 85 .3674 E ror 22 125 Dependent Variable: Dig Ala Mean MSE Root MSE R-square Coefficient of Variation .6821 058 .069 .54 10.16 SQ!..! rce DF ss F-va] ue PB>E Model 7 .126 3.76 0079 Trt 3 .016 1.09 .3741 Week 3 .102 7.08 .0017 Rep 1 007 1. 40 .2500 Error 22 ,106 Dependent Variable: Dig Tyr Mean MSE Root MSE R-square Coefficient of Variation .7664 003 .055 53 7.17 SQ!J r~e DF ss E-~a] ue P8>F Model 7 075 3.56 .0104 Trt 3 .007 75 .5327 Week 3 058 6.38 .0028 Rep 1 .013 4.30 .0499 Error 22 .066 Dependent Variable: Dig Met Mean MSE Root MSE R-square Coefficient of Variation .8045 004 .067 .51 8.31 Source DF ss F-va]ue P8>E Model 7 .104 3.32 .0145 Trt 3 045 3.35 .0374 Week 3 .048 3.59 .0300 Rep 1 .003 79 .3824 Errgr 22 ,098

PAGE 152

145 Table 39-continued. Dependent Variable: Dig Val Mean MSE Root MSE R-square Coefficient of Variation .6933 .003 .057 68 8.21 SQU cce OF ss F-va]ue PR>E Model 7 .148 6.55 .0003 Trt 3 .011 1.10 .3705 Week 3 .129 13.30 .0001 Rep 1 006 1. 92 .1795 Error 22 071 Dependent Variable: Dig Phe Mean MSE Root MSE R-square Coefficient of Variation .7649 003 .057 45 7.40 Source DF ss F-vg] u~ PB>E Model 7 058 2.58 .0421 Trt 3 .021 2.17 .1209 Week 3 032 3.35 .0376 Rep 1 003 83 .3735 Error 22 .070 Dependent Variable: Dig Ile Mean MSE Root MSE R-square Coefficient of Variation 7462 .003 .051 62 6.77 SQU[C~ DF ss E-v.]!Je PB>E Model 7 .094 5. 23 .0013 Trt 3 .009 1.24 .3202 Week 3 075 9.73 .0003 Rep 1 .008 3.10 .0923 Error 22 I 003 Dependent Variable: Dig Leu Mean MSE Root MSE R-square Coefficient of Variation .7658 .004 065 .51 8.55 SQurce OF ss F-~a] ue PB>E Model 7 .027 92 .5111 Trt 3 .0008 06 .9802 \teek 3 .023 1.81 .1743 Rep 1 .004 92 .3469 Error 22 .004

PAGE 153

146 Table 39-continued. Dependent Variable: Dig Lys Mean MSE Root MSE R-square Coefficient of Variation 8351 003 057 84 6.85 SQ!.! cce DF ss F-v a lue PB>F Model 7 .392 17.09 .0001 Trt 3 .026 2.60 .0780 Week 3 .366 37. 23 .0001 Rep 1 .0002 05 .8214 Error 2 2 072 Dependent Variable: Dig Cys Mean MSE Root MSE R-square Coefficient of Variation 6488 .011 .105 .60 16.17 Sol.! rce D F ss Fva ]I.! ~ P B> E Model 7 .367 4.77 .0022 Trt 3 036 1.09 .3750 ~/eek 3 .306 9.28 .0004 Rep 1 .011 1.03 .3223 Ecror 22 242 Dependent Variable: Dig Ser Mean M SE Root M SE R-square Coefficient of Variation 7124 .007 .086 75 12.10 SQ!J [C~ D E ss F-v a ] l.! e PB > E Model 7 .481 9.24 .0001 Trt 3 .087 3.90 0233 Week 3 .387 17.37 .0001 Rep 1 .013 1. 72 .2039 Error 2 1 ,1 56 Dependent Variable: Dig Gly Mean MSE Root MSE R-square Coefficient of Variation .6128 .014 .118 49 19.31 Soucc e D F s s F-Y'. a ] u e PB > E Model 7 .281 2.86 .0290 Trt 3 021 49 .6899 Week 3 254 6.04 .0039 Rep 1 .001 .11 .7453 E 2 1 29 4

PAGE 154

147 Table 40. MEANS FOR CHAPTER V DIGESTIBILITY TRIALS (GROWER PERIOD-290E) 6 minutes l:t~l! l 1 tl Mean SD SEM YQC c~ Dig Asp 8 6808 0.42 0.01 0.001 5. 71 Dig Glu 8 7324 0.04 0.01 0.002 5.50 Dig His 8 .7209 0.07 0.02 0.005 9.92 Dig Ser 8 .6824 0.07 0.02 0.005 10.42 Dig Arg 8 7725 0.04 0.01 0.001 4.76 Dig Gly 8 .5349 0.12 0.04 0.013 21. 77 Dig Thr 8 .5867 0.09 0.03 0.008 15.18 Dig Ala 8 .6540 0.06 0.02 0.003 9.10 Dig Tyr 8 .6681 0.06 0.02 0.003 8.31 Dig Met 8 .7274 0.07 0.03 0.005 10.02 Dig Val 8 .6607 0.05 0.02 0.003 7.67 Dig Phe 8 .6771 0.05 0.02 0.003 7.64 Dig Ile 8 .6766 0.04 0.02 0.002 6.52 Dig Leu 8 .6428 0.08 0.03 0.006 12.06 Dig Lys 8 .6689 0.09 0.03 0.008 13.42 Dig Cys 8 4394 0.11 0.04 0,012 24.60 12 minutes I:t ern z tl Megn SD SE~ Yar c~ Dig Asp 7 .7640 0.06 0.02 0.003 7.44 Dig Glu 7 .7869 0.05 0.02 0.003 6.59 Dig His 7 7200 0.14 0.05 0.002 19.16 Dig Ser 7 .7424 0.07 0.03 0.005 9.53 Dig Arg 7 8309 0.04 0.01 0.001 4.67 Dig Gly 7 .6282 0.09 0.03 0.008 14.71 Dig Thr 7 .6653 0.08 0.03 0.006 11.40 Dig Ala 7 7397 0.06 0.02 0.003 8.02 Dig Tyr 7 .7465 0.06 0.02 0.003 7.47 Dig Met 7 8043 0.04 0.02 0.002 5. 65 Dig Val 7 7406 0.05 0.02 o. 003 7 .31 Dig Phe 7 .7612 0.05 0.02 0.003 6.76 Dig Ile 7 7578 0.05 0.02 0.002 6.53 Dig Leu 7 .7372 0.05 0.02 0.003 7.45 Dig Lys 7 7278 0.09 0.03 0.007 11.84 Dig C'lS 7 I 6037 o.o:z 0.03 0.005 1 2 ,21

PAGE 155

148 Table 40-continued. 16 minutes l:ts.!ll l t Mean SD SEM Ygr CY Dig Asp 8 7471 0.04 0.01 0.001 5.01 Dig Glu 8 7784 0.03 0.01 0.0008 3.55 Dig His 8 .6770 0.11 0.04 0.013 16.70 Dig Ser 8 .7466 0.05 0.02 0.002 6.50 Dig Arg 8 .8116 0.03 0.01 0.001 4.01 Dig Gly 8 .5989 0.10 0.03 0.010 16.68 Dig Thr 8 .5789 0.08 0.03 0.006 13. 93 Dig Ala 8 7045 0.05 0.02 0.003 7.37 Dig Tyr 8 7188 0.05 0.02 0.002 6.41 Dig Met 8 7665 0.05 0.02 0.002 6.49 Dig Val 8 .7094 0.05 0.02 0.003 7.34 Dig Phe 8 .7330 0.05 0.02 0.002 6.49 Dig Ile 8 7373 0.05 0.02 0.002 6.20 Dig Leu 8 7117 0.06 0.02 0.003 7.87 Dig Lys 8 .7066 0.05 0.02 0.002 6. 73 Dig C ys 8 6400 0.11 0.04 0.013 17.92 22 minutes I:t eo 1 ~l Mea o SD SEM '{a[ CY Dig Asp 7 7486 0.04 0.02 0.002 5.55 Dig Glu 7 .7897 0.03 0.01 0.001 4.42 Dig His 7 7431 0.05 0.02 0.003 6.82 Dig Ser 7 .7661 0.06 0.02 0.004 8.50 Dig Arg 7 .8241 0.03 0.01 0.0007 3. 23 Dig Gly 7 .6027 0.10 0.04 0.010 16.84 Dig Thr 7 6065 0.20 0.04 0,009 15.84 Dig Ala 7 7305 0.03 0.01 0.001 4.67 Dig Tyr 7 .7379 0.04 0.01 0.001 5.07 Dig Met 7 7917 0.05 0.02 0.002 6.04 Dig Val 7 7303 0.04 0.01 0.002 5. 43 Dig Phe 7 7546 0.03 0.01 0.001 4.33 Dig Ile 7 7536 0.03 0.01 0,001 4.56 Dig Leu 7 7346 0.04 0.01 0.002 5. 43 Dig Lys 7 7370 0.06 0.02 0.003 8.07 Dig Cys 6 ,59 42 0 ,10 0.04 Q,009 l6.4Q

PAGE 156

149 Table 41. STATISTICAL ANALYSIS FOR CHAPTER V DIGESTIBILITY TRIALS (GROWER PERIOD-290E) Dependent Variable: Dig Asp Mean MSE Root MSE R-square Coefficient of Variation .6087 003 056 43 9.22 Source DF ss F-va l ue PB>F Model 7 .052 2.36 .0587 Trt 3 .042 4.48 .0134 Week 3 .0ll 1.12 .3621 Rep 1 .008 2.47 .1306 Error 22 ,069 Dependent Variable: Dig Glu Mean MSE Root MSE R-square Coefficient of Variation .6694 .004 .065 26 9.66 SQ!.! rce DF ss F-va] !,,!e PB>E Model 7 .032 1.09 .4039 Trt 3 .0ll .88 .4661 ~/eek 3 .016 1.31 .2958 Rep 1 .011 2.57 .1232 Error 22 ,092 Dependent Variable: Dig His Mean MSE Root MSE R-square Coefficient of Variation .6857 004 063 .41 9.19 SQ!.!rce DF ss F-va] ue PB>E Model 7 .062 2.22 .0727 Trt 3 031 2.57 .0804 Week 3 .021 1. 73 .1899 Rep 1 .013 3.28 .0838 Error 22 ,087 Dependent Variable: Dig Arg Mean MSE Root MSE R-square Coefficient of Variation 7732 .001 .034 43 4.46 SQ!.! rce DF ss E-y9Jye EB>E Model 7 .020 2.40 .0552 Trt 3 .012 3.51 .0323 Week 3 .009 2.50 .0864 Rep 1 .002 1.56 .2253 Errnr 22 ,026

PAGE 157

150 Table 41-continued. Dependent Variable: Dig Thr Mean MSE Root MSE R-square Coefficient of Variation .5061 003 054 66 10.65 SQ!J rce DF ss F-vc1 lue PR>F Model 7 .113 5.55 .0012 Trt 3 .082 9. 43 .0004 Week 3 .039 4.44 0151 Rep 1 .014 4.66 0431 Error 20 ,05 8 Dependent Variable: Dig Ala Mean MSE Root MSE R-square Coefficient of Variation .5594 005 .070 41 12.44 Sgu rce DF ss F-yc1] 1,Je P8>F Model 7 075 2.20 .0740 Trt 3 .046 3.11 .0448 Week 3 .020 1.37 .2769 Rep 1 .018 3.70 .0673 Error 22 ,1 06 Dependent Variable: Dig Tyr Mean MSE Root M SE R-square Coefficient of Variation .6257 .004 065 .42 10.37 SQyrce DF ss Fva]ue PB>E Model 7 .068 2.30 .0644 Trt 3 .038 2.98 0537 Week 3 .028 2.22 .1142 Rep 1 .013 3.19 .0877 Error 22 I 093 Dependent Variable: Dig Me t Mean M SE Root M SE R-square Coefficient of Variation .6460 .004 .066 .31 10.30 Sour ce D F ss Fva lu e PB>E Model 7 .044 1.43 .2419 Trt 3 .024 1. 82 .1723 Week 3 .021 1.56 .2269 Rep 1 005 1.08 .3099 Error 22 097

PAGE 158

151 Table 41-continued. Dependent Variable: Dig Val Mean MSE Root MSE R-square Coefficient of Variation 5685 005 .072 .36 12.71 SQurce DF ss F-va l ue PR>F Model 7 065 1. 79 .1411 Trt 3 035 2.24 .1119 Week 3 .029 1.88 .1617 Rep 1 .011 2.05 .1660 Erro 22 ll5 Dependent Variable: Dig Phe Mean MSE Root MSE R-square Coefficient of Variation .6602 .004 .061 .32 9.23 Soy rce DF ss F-ya]ue PB>E Model 7 .039 1.49 .2236 Trt 3 018 1.59 .2213 Week 3 .019 1. 71 .1935 Rep 1 .008 2.04 .1675 Error 22 ,082 Dependent Variable: Dig Ile Mean MSE Root MSE R-square Coefficient of Variation .6171 004 .062 .32 10.05 SQIJ rce OF ss F-va]ue PB>E Model 7 039 1.46 .2341 Trt 3 .022 1.89 .1606 Week 3 015 1.35 .2847 Rep 1 009 2.27 .1458 Error 22 .085 Dependent Variable: Dig Leu Mean MSE Root MSE R-square Coefficient of Variation .6294 006 075 .30 11.97 SQu rce OF ss F-va] ue PB>E Model 7 053 1.34 .2771 Trt 3 025 1. 44 .2569 Week 3 .021 1.25 .3166 Rep 1 .010 1.69 .2071 Errnr 22 .006

PAGE 159

15 2 Table 41-continued. Dependent Variable: Dig Lys Mean MSE Root MSE R-square Coefficient of Variation .6087 .007 .081 .42 13.39 SQY cce OF ss F-yalue PB>F Model 7 .105 2.25 .0691 Trt 3 .015 76 .5306 Week 3 .048 2.42 .0932 Rep 1 .052 7.85 .0104 Error 22 ,146 Dependent Variable: Dig Cys Mean MSE Root MSE R-square Coefficient of Variation 6427 .007 .085 46 13.23 Source OF ss F-yg]ye PB>E Model 7 .136 2.68 .0346 Trt 3 039 1. 79 .1783 Week 3 .100 4.60 .0120 Rep 1 .004 61 .4442 Erroc 22 159 Dependent Variable: Dig Ser Mean MSE Root MSE R-square Coefficient of Variation .6629 003 .057 .33 8.62 SQucce OF ss F-ya] ue P8>E Model 7 035 1.55 .2016 Trt 3 .013 1.29 .3040 Week 3 .023 2.37 .0979 Rep 1 .005 1.67 .2097 Error 22 ,072 Dependent Variable: Dig Gly Mean MSE Root MSE R-square Coefficient of Variation 4914 007 .086 .54 17.57 SQY cce OF ss F-va]ye EB>F Model 7 .157 3.02 .0278 Trt 3 .130 5.81 0058 Week 3 023 1.04 .3978 Rep 1 .020 2.65 .1208 Erroc rn ,134

PAGE 160

153 Tab le 42. MEANS FOR CHAPTER V DIGESTIBILITY TRIALS (FINISHER PERIOD-290F) 6 minutes Itemt % N Mean SD SE M Yat CY Dig Asp 7 .6334 0.03 0.01 0.00007 4.08 Dig Glu 7 .6847 0.04 0.02 0.002 6.28 Dig His 7 .7064 0.04 0.02 0.002 5.88 Dig Ser 7 .6774 0.06 0.02 0.004 9.51 Dig Arg 7 8026 0.03 0.01 0.00009 3.82 Dig Gly 7 .5880 0.08 0.03 0.007 13. 88 Dig Thr 7 .5730 0.06 0.02 0.003 10.24 Dig Ala 7 .5860 0.06 0.02 0.004 10.27 Dig Tyr 7 .6653 0.05 0.02 0.002 7.21 Dig Met 7 .6847 0.06 0.02 0.003 8.67 Dig Val 7 .6152 0.05 0.02 0.002 7.81 Dig Phe 7 .6887 0.05 0.02 0.002 6.81 Dig Ile 7 .6486 0.05 0.02 0.002 7.02 Dig Leu 7 .6644 0.04 0.02 0.002 6.80 Dig Lys 7 .6234 0.11 0.04 0.013 18. 51 Dig Cys 7 .6262 0.05 0.02 0.003 8,20 12 minutes l:tS1ffil N ~ ,le an SD SE~ 1 l'.'.2[ CY Dig Asp 8 6331 0.07 0.02 0.005 11. 07 Dig Glu 8 6733 0.08 0.03 0.007 12.21 Dig His 8 7179 0.07 0.02 0.005 9.95 Dig Ser 8 6595 0.08 0.03 0.006 11.84 Dig Arg 8 .7726 0.05 0.02 0.003 6.61 Dig Gly 8 4727 0.12 0.05 0.015 25. 83 Dig Thr 7 .4989 0.10 0.04 0.011 20.62 Dig Ala 8 .5962 0.09 0.03 0.008 15.40 Dig Tyr 8 .6460 0.10 0.03 0.010 15.13 Dig Met 8 6320 0.08 0.03 0.006 12.71 Dig Val 8 .5789 0.10 0.04 0.011 18.18 Dig Phe 8 6732 0.08 0.03 0.007 12.63 Dig Ile 8 6301 0.08 0.03 0.007 13.22 Dig Leu 8 .6494 0.09 0.03 o. 009 14.56 Dig Lys 8 .6240 0.08 0.03 0.006 12.77 Qig Cys 8 62 8 1 0.11 Q,Q1 Q.QU lQ,45

PAGE 161

1 5 4 Table 42-continued. 16 minutes l:t~ll l i tl Me an so SEM Ygt: CY Dig Asp 7 .5478 0.08 0.03 0.006 14.44 Dig Glu 7 .6432 0.08 0.03 0.007 12.74 Dig His 7 .6386 0.08 0.03 0.007 13.25 Dig Ser 7 .6356 0.03 0.01 0.0008 4.41 Dig Arg 7 7508 0.03 0.01 0.0009 3.94 Dig Gly 6 .3995 0.08 0.03 o. 007 21.37 Dig Thr 7 .4399 0.05 0.02 0.002 11.45 Dig Ala 7 .5034 0.07 0.03 0.005 14.58 Dig Tyr 7 .5844 0.06 0.02 0.004 10.92 Dig Met 7 .6136 0.07 0.03 o. 005 11. 19 Dig Val 7 .5369 0.06 0.02 0.004 11. 87 Dig Phe 7 .6350 0.06 0.02 0.003 9.02 Dig Ile 7 .sass 0.06 0.02 0.004 10.24 Dig Leu 7 6013 0.07 0.03 0.005 12.28 Dig Lys 7 .6124 0.09 0.03 0.008 15.06 Dig Cvs 7 611 8 o. 11 0,04 0.01 2 17. 8 7 22 minutes I:t en1 1 tl Mea o SD SE M Yar CY Dig Asp 8 .6160 0.04 0.01 0.001 6.10 Dig Glu 8 .6749 0.05 0.02 0.003 7.56 Dig His 8 .6765 0.07 0.02 0.005 10.06 Dig Ser 8 .6776 0.06 0.02 0.004 9.09 Dig Arg 8 .7676 0.03 0.01 0.001 4.14 Dig Gly 7 .4896 0.06 0.02 0.004 12.55 Dig Thr 7 .5127 0.04 0.01 0.001 7.57 Dig Ala 8 .5483 0.06 0.02 0.004 11.82 Dig Tyr 8 .6770 0.06 0.02 0.004 10.06 Dig Met 8 .6544 0.06 0.02 0.004 9.52 Dig Val 8 .5450 0.07 0.03 0.005 13.31 Dig Phe 8 .6442 0.06 0.02 0.003 8.95 Dig Ile 8 .6041 0.06 0.02 o. 003 9.80 Dig Leu 8 .6035 0.08 0.03 0.007 13. 72 Dig Lys 8 .5774 0.10 0.03 0.009 16.59 D j g C::ts 8 6288 o. 11 0,0 4 O.Qll 17,0 2

PAGE 162

155 Tab le 43. STATISTICAL ANALYSIS FOR CHAPTER V DIGESTIBILITY TRIALS (FINISHER PERIOD-290F) Dependent Variable: Dig Asp Mean MSE Root MSE R-square Coefficient of Variation .7337 001 036 64 4.97 SQ!.J cce OF ss F-va]ue PR>E Model 7 .053 5.65 .6427 Trt 3 030 7.54 .0012 Week 3 .017 4.27 .0162 Rep 1 005 3.52 .0740 Erroc 22 .029 Dependent Variable: Dig Glu Mean MSE Root MSE R-square Coefficient of Variation 7707 .001 031 63 4.00 Source OF ss F-va] ue P8>E Model 7 036 5.38 .OOll Trt 3 .014 5. 07 .0080 Week 3 .015 5.15 .0075 Rep 1 .006 5.80 .0249 Eccoc 22 .021 Dependent Variable: Dig His Mean MSE Root MSE R-square Coefficient of Variation 7142 .006 .080 .49 11.17 SQ!.J[C~ DF ss F-ya] ue PB>F Model 7 .132 2.97 .0238 Trt 3 .019 1.00 .4110 Week 3 .112 5.88 .0042 Rep 1 .0009 15 .7043 Eccoc 22 .140 Dependent Variable: Dig Arg Mean MSE Root MSE R-square Coefficient of Variation .8086 .0005 .022 .76 2.76 Sou cce OF ss F-va] ue PB>E Model 7 035 9.96 .0001 Trt 3 .014 9.40 .0003 Week 3 .017 11.09 .0001 Rep 1 003 6.45 .0186 Erroc 22 .on

PAGE 163

156 Table 43-continued. Dependent Variable: Dig Thr Mean MSE Root MSE R-square Coefficient of Variation .6076 003 .055 .70 9.05 SQIJ [Ce OF ss F-va]ue PB>F Model 7 .158 7.46 .0001 Trt 3 .034 3.78 .0252 Week 3 .102 11. 25 .0001 Rep 1 .025 8.30 .0087 E[ror 22 ,066 Dependent Variable: Dig Ala Mean MSE Root MSE R-square Coefficient of Variation 7053 .001 .038 .70 5.40 Source OF ss F-ya]ue PB>E Model 7 .073 7.25 .0001 Trt 3 .030 6.96 .0018 Week 3 .035 8.10 .0008 Rep 1 006 4.06 .0563 E 0 22 001 Dependent Variable: Dig Tyr Mean MSE Root MSE R-square Coefficient of Variation .7162 .002 .041 61 5.66 SQU t!;;~ DE ss F-yg]Ue PEs>E Model 7 .056 4.83 .0020 Trt 3 .025 5.15 0076 Week 3 023 4.62 .0119 Rep 1 .006 3.37 .0798 Error 22 ,036 Dependent Variable: Dig Met Mean MSE Root MSE R-square Coefficient of Variation 7708 .001 .038 .70 4.96 SQU re~ OF ss F-ya]ue PEs>E Model 7 075 7 .31 .0001 Trt 3 .022 5.04 .0083 Week 3 .046 10.61 .0002 Rep 1 003 2.22 .1505 Error 22 ,032

PAGE 164

157 Table 43-continued. Dependent Variable: Dig Val Mean MSE Root MSE R-square Coefficient of Variation .7086 .001 .038 65 5.41 SQ!.! cce OF ss F-ya l ue PB>F Model 7 .061 5.90 .0006 Trt 3 .025 5.75 .0046 Week 3 .025 5.61 .0052 Rep 1 009 5.89 .0238 E or 22 032 Dependent Variable: Dig Phe Mean MSE Root MSE R-square Coefficient of Variation 7297 .001 037 .66 5.12 SQu rce OF ss F-yu] ye PB>F Model 7 .060 6.09 .0005 Trt 3 030 7 .15 .0016 Week 3 .019 4.60 .0121 Rep 1 .008 5.81 .0248 Error 22 ,031 Dependent Variable: Dig Ile Mean MSE Root MSE R-square Coefficient of Variation 7297 001 .032 .72 4.45 SQu c~!i.l DE ss E-ya]ue PB>E Model 7 059 8.03 .0001 Trt 3 .029 9.14 .0004 Week 3 .020 6.36 .0029 Rep 1 008 7. 74 .0109 E rot' 22 o z ~ Dependent Variable: Dig Leu Mean MSE Root MSE R-square Coefficient of Variation .7046 .002 .048 .62 6.82 SQurc~ O F ss F-v a ]ue PB>E Model 7 085 5.29 .0012 Trt 3 .040 5.80 .0045 Week 3 030 4.34 0152 Rep 1 .012 5.35 0305 Error 22 ,051

PAGE 165

158 Table 43-continued. Dependent Variable: Dig Lys Mean MSE Root MSE R-square Coefficient of Variation .7074 004 .060 49 8.49 SQU [C~ OF ss F-value PB>F Model 7 .078 3.08 .0203 Trt 3 015 1.43 .2606 ~Jeek 3 056 5.17 .0075 Rep l 004 1.08 .3097 E or 22 079 Dependent Variable: Dig Cys Mean MSE Root MSE R-square Coefficient of Variation .5782 .006 .081 68 13.98 Sou cce OF ss F-vu]ue PB>F Model 7 .269 5.89 .0010 Trt 3 .171 8.71 .0008 Week 3 .071 3.61 .0322 Rep 1 .024 3.71 .0691 Euoc 22 .124 Dependent Variable: Dig Ser Mean MSE Root MSE R-square Coefficient of Vari at ion .7330 .002 .004 69 5.97 SQ!.! [C~ DE ss F-yg]Ue EB>E Model 7 .095 7 .13 .0002 Trt 3 027 4.74 .0106 Week 3 .065 11.28 .0001 Rep 1 .001 41 .5300 E or 22 042 Dependent Variable: Dig Gly Mean MSE Root MSE R-square Coefficient of Variation .5895 .004 065 .70 11. 05 SQ!.! cce OF ss F-va] ue PB>E Model 7 .221 7.43 .0001 Trt 3 .031 2.47 .0884 Week 3 .157 12.34 .0001 Rep 1 034 8.13 .0093 E[[O[ 23 I Q23

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APPENDIX B TRYPSIN INHIBITOR ASSAY PROCEDURE

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PROCEDURE FOR TRYPSIN INHIBITOR ACTIVITY ANALYSIS (Hamerstrand et al., 1980. Cereal Chemistry 58:42) Materials Tris-buffer Dissolve tris(hydroxymethyl) aminomethane (1.21 g) and CaC1 2 H 2 0 (0.59 g) in 180 ml dH 2 0. Adjust pH to 8.2 with lN HCl and make up to 200 ml with dR 7 0. Prewarm to 37 C prior to BAPA formulation. This solution is stable up to 8 hours. BAPA (benzoyl-DL-arginine-p-nitroanalide hydrochlcride) Dissolve BAPA (0.080 g) in 2 ml of dimethyl sulfoxide and dilute to 200 ml with tris buffer. This solution is stable up to 4 hours. Trypsin Solution Weigh out trypsin (0.004 g) into a 200-ml volumetric flask and dilute to 200 ml with O.OOlN HCl. The trypsin solution is stable up to a month. Sarnp l e E x trc1ct 1. Weigh out 1 g defatted soy sample and place in beaker with 500 ml of O.OlN NaOH (pH adjusted to 8.4-10). Stir to keep sample suspended for 3 hours. 2. Dilute* the supsension so that 1 ml of the sample and 1 ml of dH 2 o will inhibit 40-60% of the trypsin used as a standard in the analysis. Note: To get the proper dilution requires trial and error with repetition if necessary. For example, 3 ml of the suspension placed into 50 ml H 2 o may provide the appropriate dilution to achieve the 40-60% inhibition of trypsin when 1 ml of the diluted sample and 1 ml of dH 2 0 are combined. However, 3:50 will not always be the appropriate dilution to yield the required results. Pr oced ure 1. To each of four test tubes, add 1 ml of the diluted sample plus 1 ml dH 2 0. Prepare a fifth tube for the trypsin standard by adding only 2 ml dH 2 0. 2. Add 2 ml of the trypsin solution to three of the four tubes containing the sample extract and the tube containing the dH 2 o. Place the tubes in a constant temperature bath (37 C) for 10 min. 160

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161 3. Add 5 ml of prewarmed BAPA solution rapidly into each tube. Vortex each tube and replace into the water bath immediately. 4. Terminate the reaction at exactly 10 min later by adding l ml of 30% acetic acid and immediately vortexing. 5. The fourth tube containing sample extract Cl ml) and dH 0 Cl ml) serves as a sample blank. It is prepared by the same proce~ure except that the trypsin solution was added sf:tfil the reaction was terminated by the addition of acetic acid. 6. Determine the absorbance of each solution at 410 nm against the sample blank. Subtract the values obtained from each of the three sample extracts from the trypsin standard and average these values. 7. Calculate the trypsin inhibitor content utilizing the following: A std-Asam TI, mg/g of sample= 19 x dilution factor where: TI=trypsin inhitor content Astd=absorbance of the standard Asam=absorbance of the sample Dilution factor for the example described under the extraction step (3:50) would be 1667.

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LITERATURE CITED Adams, K. L. and A. H. Jensen. 1985. Effect of processing on the utilization by young pigs of the fat in soyabeans and sunflower seeds. Anim. Feed Sci. Tech. 12:241. Albrecht, W. J., G. C. Mustakas and J. E. McGhee. 1966. Rate studies on atmospheric steaming and immersion cooking of soybeans. Cereal Chem. 43: 400. Alders, O. H. 1949. The study of 20 varieties of soybeans with respect to quantity and quality of oil, isolated protein and nutritional value of the meal. J. Amer. Oil Chem. Soc. 26:126. Allee, G. L., D. F. Li and J. Nelssen. 1985. Use of raw soybeans in sow diets. Kansas State Univ. Rep. of Progress 486:58. Almquist, H. J., E. Mecchi, F. H. Kratzer and C. R. Grau. 1942. Soybean protein as a source of amino acids for the chick. J. Nutr. 24:385. Alumot, E. and Z. Nitsan. 1961. The influence of soybean antitrypsin on the intestinal proteolysis of the chick. J. Nutr. 73:71. AOAC. 1973. Official Methods of Analysis (12th Ed.). Association of Official Analytical Chemists. Washington, D.C. Arnold, J. B. 1973. Nutritional value of heat treated whole soybeans. Can. J. An im. Sci. 51 :57. Averill, H. P. and C. G. King. 1926. Phosphorus content of soybeans. J. Amer. Chem. Soc. 49:724. Baintner, K. 1981. Trypsin-inhibitor and chymotrypsin-inhibitor studies with soybean e x tracts. J. Agr. Food Chem. 31:376. Baird, D. M. 1983. Feedin g and energy value of extruded and full fat soybeans for hogs. J. Anim. Sci. 57 (Suppl. 1):276. Bajjalieh, N., J. H. Orf, T. Hymowitz and A. H. Jensen. 1980. Response of youn g chicks to raw defatted, Kunitz trypsin inhibitor variant soybeans as sources of dietary protein. Poul. Sci. 59 :328. 162

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163 Balloun, S. L., E. L. Johnson and L. K. Arnold. 1953. Laboratory estimation of the nutritive value of soybean oil meals. Poul. Sci. 3 2: 517. Barnes, R. H., G. Fiala and E. Kwong. 1962. Methionine supplementation of processed soybeans in the rat. J. Nutr. 77:278. Barnes, R. H. and E. Kwong. 1965. Effect of soybean trypsin inhibitor and penicillin on cystine biosynthesis in the pancreas and its transport as exocrine protein secretion in the intestinal tract of the rat. J. Nutr. 86:245. Barnes, R. H., E. Kwong and G. Fiala. 1965. Effect of penicillin added to an unheated soybean diet on cystine excretion in feces of the rat. J. Nutr. 85:123. Barnstein, S. and B. Lipstein. 1962. The influence of age of chick on their sensitivity to raw soybean oil meal. Poul. Sci. 42:61. Bates, R. P., F. W. Knapp and P. E. Araujo. 1977. green-mature, dry mature and sprouted soybeans. 42: 271. Protein quality of J. Food Sci. Becker, D. E., C. R. Adams, S. W. Terrill and R. G. Meade. 1953. The influence of heat treatment and solvent upon the nutritive value of soybean oil meal for swine. J. Anim. Sci. 12:107. Becker, H. C., R. T. Milner and R. A. Nagel. 1940. A method for determination of nonprotein nitrogen in soybean meal. Cereal Chem. 17:447. Bielorai, R., Z. Harduf and E. Alumot. 1972. The free amino acid pattern of the intestinal contents of chicks fed raw and heated soybean meal. J. Nutr. 102:1377. Bielorai, R., M. Tamin, E. Alumot, A. Bar and S. Hurwitz. 1973. Digestive absorption of proteins in the intestinal segments of chicks fed raw and heated soybean meal. J. Nutr. 103:1291. Birk, Y., A. Gertler and S. Khalef. 1963. A pure trypsin inhibitor from soybeans. Biochem. J. 87:281. Birk, Y. and M. Waldman. 19 6 5. Amylolytic-, trypsin-inhibiting, and urease activity in three varieties of soybeans and in soybean plant. Qualitas Plant Mater. Vegetabl e s 12:199. Block, R. J., R.H. Mandl, H. W. Howard, C. D. Bauer and D. \/. Anderson. 1961. The curative action of iodine on soybean goiter and the changes in the distribution of iodoamino acids in the serum and in thyroid gland digests. Arch. Biochem. Biophys. 93:15.

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164 Booth, A. N., D. J. Robbins, W. E. Ribelin, F. De Eds, A. K. Smith and J. J. Rackis. 1964. Prolonged pancreatic hypertrophy and reversibility in rats fed raw soybean meal. Proc. Soc. Exp. Biol. Med. 116:1067. Borchers, R. 1958. Effect of dietary level of raw soybean oil meal on the growth of weanling rats. J. Nutr. 66:229. Borchers, R. 1961. Counteraction of the growth depression of raw soybean oil meal by amino acid supplements in weanling rats. J. Nutr. 75:330. Borchers, R. activity. 1964. Raw soybean feeding decreases transamidinase Proc. Soc. Exp. Biol. Med. 115:893. Borchers, R. and C. W. Ackerson. 1951. Nutritive value of legumes seeds. XI. Counteracting the growth inhibitor of raw soybeans. Proc. Soc. Exp. Biol. Med. 78: 81. Borchers, R. A., C. W. Ackerson, F. E. Mussehl and A. Moehl. 1948. Trypsin inhibitor. VIII. Growth inhibiting properties of a soybean trypsin inhibitor. Arch. Biochem. Biophys. 19:317. Borchers, R., C. W. Ackerson and R. M. Sandstedt. 1947. Trypsin inhibitor. III. Determination and heat destruction of the trypsin inhibitor of soybeans. Arch. Biochem. 12:367. Bowman, D. E. 1944. Fractions derived from soybeans and navy beans which retard the tryptic digestion of casein. Proc. Soc. Exp. Biol. Med. 57:139. Braham, J.E., H. R. Bird and C. A. Baumann. 1959. Effect of antibiotics on the weight of chicks and rats fed raw or autoclaved soybean meal. J. Nutr. 67:149. Brambila, S., M. C. Nesheim and F. W. Hill. 1961. Effect of trypsin supplementation on the utilization by the chick of diets containing raw soybean oil meal. J. Nutr. 75:13. Campbell, D. R. 1974. diet of young pigs. Fayetteville. Improved energy and protein sources in the M.S. Thesis, Univ. of Arkansas, Campbell, D. R., M. T. Coffey and G. E. Combs. 1984. Performance of growing-finishing swine fed diets containing soybean meal or soybeans with varying heat treatments. Univ. Florida Res. Rep. AL-84-6. Carew, L. B., Jr., F. W. Hill and M. C. Nesheim. 1961. The comparative value of ground unextracted soybeans and heated dehulled soybean flakes as a source of soybean oil and energy for the chick. J. Amer. Oil Chem. Soc. 38:249.

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165 Carlson, C. W., H. C. Saxena, L. S. Jensen and J. McGinnis. 1964. Rachitogenic activity of soybean fractions. J. Nutr. 82:507. Carroll, R. W., G. W. Hensley, C. L. Sitter, E. L. Wilcox and W. R. Graham, Jr. 1953. Absorption of nitrogen and amino acids from soybean meal as affected by heat treatment or supplementation with aureomycin and methionine. Arch. Biochem. Biophys. 45:260. Caskey, C. D., Jr. and F. C. Knapp. 1944. inadequately heated soybean oil meal. 16:640. Method of detecting Ind. Eng. Chem. Anal. Ed. Caviness, C. E. 1973. Influence of variety and location on oil and protein content of soybean seed. Arkansas Farm. Res. Nov.-Dec., pp 3. Chai-Ju, C., T. D. Tanksley, D. A. Knabe, T. Zebrowska and E. J. Gregg. 1984. Effect of different heat treatments during processing on nutrient digestibilities of soybean meal by growing swine. J. Anim. Sci. 59 (Suppl. 1):268. Chin, S. F. and R. G. Diggs. 1986. Energy values and nitrogen digestibility for roasted soybeans, unprocessed soybeans and milo in swine rations. J. Anim. Sci. 63 (Suppl. 1):37. Christian, K. R. and M. R. Coup. 1954. Measurement of feed intake by grazing cattle. New Zealand J. Sci. Tech. 36:328. Clawson, A. J., H. A. Ramsey and W. D. Armstrong. 1981. heat treatment on the trypsin inhibitor concentration meal and on performance of pigs to which it was fed. Sci. 53:50 (Suppl. 1). Effect of in soybean J. An i rn. Coates, M. E., D. Hewitt and P. Golob. 1970. A comparsion of the effects of raw and heated soybean meal in diets for germ-free and conventional chicks. Brit. J. Nutr. 24:213. Co ll i n s F I. and V E S ed g w i ck several varieties of soybeans. 1959. Fatty acid composition of J. Amer. Oil Chem. Soc. 36:641. Coll ins, J. L. and G. G. Sanders. 1976. Changes in trypsin inhibitory activity in some soybean varieties during maturation and germination. J. Food Sci. 41:168. Combs, G. E., R. G. Conness, T. H. Berry and H. D. Wallace. 1967. Effect of raw and heated soybeans on gain, nutrient digestibility, plasma amino acids and other blood constituents of growing swine. J. Anim. Sci. 26:1067. Combs, G. E. and H. D. Wallace. 1969. young growing and finishing swine. AN-70-2. Raw and heated soybeans for Univ. Florida Res. Rep.

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166 Corring, T., A. M. Gueugneau and J. A. Chayvialle. 1985. Short-term effects of raw soybean diet ingestion upon the exocrine pancreatic secretion in the pig. Beretning fra Statens Husdyrbrugsforsog 580:109. Crenshaw, M. A. and D. M. Danielson. 1983. Raw soybeans as a protein source for brood sows. J. Anim. Sci. 57 (Suppl. 1):93. Crenshaw, M. A. and D. M. Danielson. 1984a. Performance of pigs fed pelleted and non-pelleted pig starter diets supplemented with soybean meal or raw soybeans. J. Anim. Sci. 59:277. Crenshaw, M. A. and D. M. Danielson. 1984b. Evaluating raw soybeans as a supplemental protein for growing-finishing pig diets. J. Anim. Sci. 59 (Suppl. 1):98. Crenshaw, M. A. and D. M. Danielson. 1985a. Roasted soybeans in weanling pig diets. J. Anim. Sci. 61 (Suppl. 1):101. Crenshaw, M. A. and D. M. Danielson. 1985b. Value of feeding roasted soybeans to growing-finishing pigs as influenced by sex of pigs. J. Anim. Sci. 61 (Suppl. 1):101. Crenshaw, M. A. and D. M. Danielson. 1985c. Raw soybeans for growing-finishing pigs. J. Anim. Sci. 60:725. Crenshaw, M. A. and D. M. Danielson. 1985d. Raw soybeans for gestating swine. J. Anim. Sci. 60:163. Crissey, S. D. and O. P. Thomas. 1983. The amount of fecal amino acids from roosters fasted, fed non-protein diets, soybean meal or autoclaved soybean meal. Poul. Sci. 62 (Suppl. 1):1406. Dada, S. 1983. Energy conservation in solvent extraction. J. Amer. Oil Chem. Soc. 60:409. Dal Borgo, G., M. H. Pubols and J. McGinnis. 1967. Effect of using sugar or starch in the diet on biological response in the chick to autoclaving hexane-extracted soybean meal. Poul. Sci. 46:885. Dale, N., O. W. Charles and S. Duke. 1986. Reliability of urease activity as an indicator of overprocessing of soybean meal. Poul. Sci. 65 (Suppl. 1):164. Danielson, D. M. and M. Crenshaw. 1984. Utilizing raw soybeans in gestation-lactating diets. J. Anim. Sci. 59 (Suppl. 1):98. Davies, M. G. and A. J. Thomas. 1973. An investigation of hydrolytic techniques for the ammino acid analysis of foodstuffs. J. Sci. Food. Agr. 24:1525.

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167 Davis, P. N., L. C. Norris and F. H. Kratzer. 1962. Interference of soybean proteins with the utilization of trace minerals. J. Nutr. 77:217. DeMan, J. M. 1980. Principles of Food Chemistry. The AVI Publishing Company Inc., Westport, CT. Desikachar, H. S. R. and S.S. De. 1947. Role of inhibitors in soybean. Science 106:421. East, J. W., T. 0. M. Nakayama and S. B. Parkman. 1972. Changes in stachyose, raffinose, sucrose, and monosaccharides during germination of soybeans. Crop Sci. 12:7. Edelstein, S. and K. Guggenheim. 1970a. Causes of the increased requirement for vitamin B12 in rats subsisting on an unheated soybean flour diet. J. Nutr. 100:1377. Edelstein, S. and K. Guggenheim. 1970b. Changes in the metabolism of vi~amin B 12 and methionine in rats fed unheated soyabean flour. Brit. J. l'lutr. 24: 735. Edwards, H. M., Jr. 1983. Effects of different soybean meals on the incidence of tibial dyschondroplasia in the chicken. J. Nutr. 115: 1005. Eldridge, A. C. and W. F. Kwolek. 1983. Soybean isoflavones: Effect of environment and variety on composition. J. Agr. Food Chem. 31 :394. Ellis, R. and E. R. Norris. 1981. Relation between phytic acid and trace metals in wheat bran and soybean. Cereal Chem. 58:367. Evans, R. J., S. L. Bandermer and D. H. Bauer. 1962. Effect of heating soybean proteins in the autoclave on the liberation of cystine and methionine by several digestion procedures. J. Agr. Food Chem. 10:416. Evans, R. J. and H. A. Butts. lysine in soybean oil meal. 1948. Studies on heat inactivation of J. Biol. Chem. 175:15. Evans, R. J., A. C. Groschke and H. A. Butts. 1951. heat inactivation of cystine in soybean oil meal. 30:414. Studies of the Arch. B iochem. Evans, R. J. and J. McGinnis. 1946. The influence of autoclaving soybean oil meal on the availability of cystine and methionine for chicks. J. Nutr. 31:449. Evans, R. J. and J. McGinnis. 1948. Cystine and methionine metabolism by chicks receiving raw or autoclaved soybean oil me a l J Nut r. 3 5 : 4 77

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168 Everson, G., H. Steenbock, D. C. Cederquist and H. T. Parsons. 1944. The effect of germination, the stage of maturity, and the variety upon the nutritive value of soybean protein. J. Nutr. 27:225. Faber, J. L. and D. R. Zimmerman. 1973. Evaluation of infared-roasted and extruder-processed soybeans in baby pig diet. J. Anim. Sci. 36:902. Featherston, W. R. and J. C. Regler. 1966. A comparison of processing conditions of unextracted soybeans for utilization by the chick. Poul. Sci. 45:330. Fehr, W. R., J. C. Thorne and E. G. Hammond. 1971. Relationship of fatty acid formation and chlorophyll content in soybean seeds. Crop Sci. 11:211. Fisher, H. and D. Johnson, Jr. 1958. The effectiveness of essential amino acid supplementation in overcoming the growth depression of unheated soybean meal. Arch. Biochem. Biophys. 77:124. Fisher, H., D. Johnson, Jr. and S. Ferdo. 1957. The utilization of raw soybean meal protein for egg production in the chicken. J. Nutr. 61:611. Fisher, H. and R. Shapiro. 1963. Counteracting the growth retardation of raw soybean m eal with extra protein and calories. J. Nutr. 80:425. Freed, R. C. and D. S. Ryan. 1978a. Changes in the Kunitz inhibitor during germination of soybeans: An immunoelectrophoresis assay system. J. Food Sci. 43:317. Freed, R. C. and D. S. Ryan. 1978b. Note on modification of the Kunitz soybean trypsin inhibitor during seed germination. Cereal Chem. 55:534. Friedman, M., 0-K. K. Grosjean and J. C. Zahnley. 1982. Cooperative effects of heat and thiols in inactivating trypsin inhibitors from legumes in solution and in the solid state. Nutr. Rep. Int. 25: 743. Friedman, M., M. R. Gunbmann and 0-K. K. Grosjean. 1984. Nutritional improvement of soy flour. J. Nutr. 114:2241. Fuller, J.C., Jr. and W. J. Owings. 1986. soybeans as a feedstuff in broiler diets. (Suppl. 1). Microwave treated whole Poul. Sci. 65:46 Fushiki, T., S-i. Fukuoka and K. Iwai. 1984. Stimulation of rat pancreatic enzyme secretion by diet components. Agr. Biol. Chem. 48:1867.

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169 Gallaher, R. N., C. O. Weldon and J. G. Futral. block digester for plant and soil analysis. Proc. 39:803. 1975. An aluminum Soil Sci. Soc. Amer. Gandhi, A. P., M. M. Nenwani and N. Ali. 1984. Investigations on the trypsin inhibitor, urease and cooking behavior of soybean Glycine max. Merr. Food Chem. 15:215. Gandhi, A. P., M. M. Nenwani and N. Ali. 1985. characteristics of soybean Glycin max. Merr. Some physico-chemical Food Chem. 17:71. Garlich, J. D. and M. C. Nesheim. 1966. Relationship of fraction of soybeans and a crystalline trypsin inhibitor to the effects of feeding unheated soybean meal to chicks. J. Nutr. 88:100. Gaydou, E. M. and J. Arrivets. 1983. Effects of phosphorus, potassium, dolomite, and nitrogen fertilization on the quality of soybean yields, proteins and lipids. J. Agr. Food Chem. 31:765. Gertler, A. and Z. Nitsan. 1970. The effect of trypsin inhibitors on pancreato-peptidase E, trypsin, chymotrypsin, and amylase in the pancreas and intestinal tract of chicks receiving raw and heated soya-beans diet. Brit. J. Nutr. 24:893. Gillette, M. H., B. M. Schoenborne, B. O. Schneeman, L. J. Koong and N. L. Canolty. 1978. Nutritional quality of four commercially processed soybean products. J. Food Sci. 43:1729. Goldberg, A. and K. Guggenheim. 1964. Effect of antibiotics in pancreatic enzymes of rats fed soybean flour. Arch. Biochem. Biophys. 108:250. Gorrill, A. D. L. and J. vi. Thomas. 1967. Body weight changes, pancreatic size and enzyme activity, and proteolytic activity and protein digestion in intestinal contents from calves fed soybean and milk protein diets. J. Nutr. 92:215. Grace, S., S. L. Settle and F. H. Steinke. 1984. Bioavailability of copper in isolated soybean protein using the rat as an experimental model. J. Nutr. 114:332. Green, G. M., B. A. Olds, G. Mathews and R. L. Lyman. 1977. Protein as a regulator of pancreatic enzyme sercretion in the rat. Proc. Soc. Exp. Biol. Med. 142:1162. Gustafson, M.A., Jr., C. J. Flegal and P. J. Schaible. 1971. The effects of microwave heating on the properties of raw unextracted soybeans for utilization by the chick. Poul. Sci. 50:358. Hafez, Y. S. 1983. Nutrient composition of different varieties and strains of soybean. Nutr. Rep. Int. 28:1197. Hafez, Y. S. and A. I. Mohamed. 1983. inhibitor in soy and winged beans. Presence of nonprotein trypsin J. Food Sci. 48:75.

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170 Hafez, Y. S., A. I. Mohamed, F. M. Hewedy and G. Singh. 1985. Effects of microwave heating on solubility, digestibility and metabolism of soy protein. J. Food Sci. 50:415. Haines, P. C. and R. L. Lyman. 1961. Relationship of pancreatic enzyme secretion to growth inhibition in rats fed soybean trypsin inhibitor. J. Nutr. 74:445. Ham, W. E. and R. M. Sandstedt. 1944. A proteolytic inhibiting substance in the extract from unheated soybean meal. J. Biol. Chem. 154:505. Hambleton, L. G. 1977. Semiautomated method for simultaneous determination of phosphorus, calcium and crude protein in animal feeds. J. Assoc. Official Anal. Chem. 60:845. Hamerstrand, G. E., L. T. Black and J. D. Glover. 1981. Trypsin inhibitors in soy products: Modification of the standard analytical procedure. Cereal Chem. 58:42. Han, Y. and C. M. Parsons. 1986. varying in trypsin inhibitor. Nutritional evaluation of soybean Poul. Sci. 65 (Suppl. 1):54. Hancock, J. D., E. R. Peo, Jr., A. J. Lewis and J. D. Crenshaw. 1985. Effects of ethanol extraction and heat treatment on utilization of soybean flakes by weanling pigs. J. Anim. Sci. 61 (Suppl. 1):310. Hanke, H. E., J. W. Rust, R. J. Meade and L. E. Hanson. 1972. Influence of source of soybean protein, and of pelleting, on rate of gain and gain/feed of growing swine. J. Anim. Sci. 35:958. Hansen, B. C., E. R. Flores, T. D. Tanksley, Jr. and D. A. Knabe. 1984a. Effect of different heat treatments during processing of soybean meal on performance of pigs weaned at four weeks of age. J. Anim. Sci. 59 (Suppl. l>:269. Hansen, B. C., D. A. Knabe and T. D. Tanksley, Jr. 1984b. different heat treatments during processing of soybean diet preference of pigs weaned at four weeks of age. Sci. 59 (Suppl. 1) :269. Effect of meal on J. Anim. Harris, J. R. 1983. broil er growth. High urease content in soybean meal affects (As cited in Poultry Digest, June, 1983, p. 306). Hartwig, E. E. 1979. Breeding productive soybeans with a higher percentage of protein. In: Seed Protein Improvement in Cereals and Legumes. pp 59. IAEA, Vienna, Austria. Hasdai, A. and I. E. Liener. 1983. Growth, digestibility and enzymatic activities in the pancreas and intestines of hamsters fed raw and heated soy flour. J. Nutr. 113:662.

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183 Yao, J. J., L. S. Wei and M. R. Steinberg. 1983. Effect of maturity on chemical composition and storage stability of soybeans. J. Amer. Oil Chem. Soc. 60:1245. Yen, J. T., T. Hymowitz and A. H. Jensen. 1971. Utilization by rats of protein from a trypsin-inhibitor variant soybean. J. Anim. Sci. 33:1012. Yen, J. T., T. Hymowitz and A. H. Jensen. 1974. Effects of soybeans of different trypsin-inhibitor activities on performance of growing swine. J. Anim. Sci. 38:304. Yen, J. T., A.H. Jensen and J. Simon. 1977. Effect of dietary raw soybean and soybean trypsin inhibitor on trypsin and chymotrypsin activities in the pancreas and in the small intestinal juice of growing swine. J. Nutr. 107:156. Young, L. G. 1969. Moist heating of soybeans for swine. J. Anim. Sci. 29:150 (Abstr.). Young, L. G., R. G. Brown, G. C. Ashton and G. E. S m ith. 1970. Effect of copper on the utilization of raw soybeans by mark e t pigs. Can. J. Anim. Sci. 50:717. Zamora, R. G. and T. L. Veum. 1979. \'/hole soybeans fermented with Aspergillus oryzae and Rhizopus oli g osporus for g rowing pigs. J. Anim. Sci. 48:63. Zebrowska, T., T. D. Tanksley, Jr., and D. A. K nab e 19 8 5, The influence of diff e rently proc e ss e d soy bea n mea l s on t he ex ocrine pancr e atic secretion of growing pigs. Be r e tnin g fra Statens Husdyrbrugsforsog 580:149.

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BIOGRAPHICAL SKETCH Donnie Ray Campbell was born June 17, 1949, in Harrison, Arkansas. He graduated from Green Forest High School in 1967. He then attended Arkansas Tech in Russellville, Arkansas, from the fall of 1967 until he transferred to the University of Arkansas in the fall of 1969. The author was awarded a Bachelor of Science degree in animal nutrition in December, 1971. Upon college gracuaticn, he became assistant manager of a 500-sow swine operation. He returned to school in the fall of 1972 and received a Master of Science degree in animal nutrition in the spring of 1974. Until 1981, he continued to work at the University of Arkansas as a research assistant. At this time, the author begin working for Farmland Industries in Kansas City for two years. In order to obtain a doctoral degree in anirr.al science (swine nutrition) and to continue the quest for the elusive bass, he returned to school at the University of Florida in 1983. The author is currently employed by Manna Pro Feed Corporation in Kansas City, Kansas. 184

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I certify that I have read this study and that in my op1n1on it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. \\ ~&6,.,~XQ. Calvin E. White, Chairman Associate Professor of Animal Science I certify that I have read this study and that in my op1n1on it conforw.s to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. George E~ombs, Coch airman Professor of Animal Science Richard D. Miles Professor of Poultry Science I certify that I have read this study and that in my oprn1cn it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. / / I I / ,,. ...__, Robert O. My er 1 Associate Professor of Animal Science I certify that I have read this study and that in my op1n1on it conforr. 1 s to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Doctor of Philosophy. / Rachel M Shireman -= Associate Professor of Food Science and Hurnan Nutrition

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This dissertation was submitted to the Graduate Faculty of the College of Agriculture and to the Graduate School and was accepted as partial fulfillment of the requirements for the degree of Doctor of Philosophy. December, 1986 Dean, Col Dean, Graduate School

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UNIVE R S IT Y OF FLORIDA 111111111111111111111 1 111111111111111111111111111111111111111111 3 1262 08553 4609


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