Department of Animal Science Florida Agricultural
Mimeograph Series Noi 62-9 Experiment Station
January, 1962 Gainesville, Florida
Effect of Dietary Enzyme Supplementation on Digestibility of
Nutrients from Dried Citrus Pulp and Dried Tomato Pulp by Lambs1/
C. B. Ammerman, L. R. Arrington, P. E. Loggins and J. T. McCall/
Studies were conducted to determine the effect of a dietary enzyme
supplement containing protease, amylase and gumase upon the digestibility of
nutrients in dried citrus pulp and dried tomato pulp.
Feeding an enzyme supplement containing anylolytic, proteolytic, and
perhaps other enzymes to fattening cattle was found to increase gains and
improve feed efficiency in rations containing low-moisture corn (Burroughs
et al., 1959). In a later publication, Burroughs et al. (1960) reported
that the same enzyme supplement increased live weight gain by an average of
9'o in 8 of 10 trials and improved efficiency of gain an average of 6% in
the 10 experiments. Increased digestibility of dry matter, crude cellulose
and crude protein by dietary enzymes was observed with lambs by Grainger and
Stroud (1960). Theurer et al. (1959), however, reported no significant
increases in nutrient digestibility or nitrogen retention with either steers
or lambs from enzyme supplementation.
Dried citrus pulp is an important carbohydrate feedstuff in the South-
east and dried tomato pulp is potentially an important feedstuff as a by-
product of the tomato industry. Both feedstuffs have been shown to possess
a low digestion coefficient for protein (Ammerman et al.., 1959 and Ammerman
et al., 1961). It was considered therefore that enzyme supplementation
might improve the nutritive value of dried citrus pulp and dried tomato pulp
by increasing the digestibility of protein and perhaps other nutrients.
The physical and nutrient composition of the rations used in this study
are shown in tables 1 and 2. The rations were mixed in a stainless steel
mixer, equally divided and 3 grams of the enzyme preparation/ per kilogram
were added to one-half of each ration. Fifty-eight percent of the protein
.2 This study was supported in part by funds from the Citrus Processors
Association, Winter Haven, Florida and by the Florida Tomato Committee,
Orlando, Florida. The enzyme preparation used in this study was
supplied by Pabst Brewing Company, Milwaukee, Wisconsin.
2/ Amerman, Assistant Animal Nutritionist; Arrington, Associate
Nutritionist; Loggins, Assistant Animal Husbandman; McCall, resent "),
address; Department of Animal Husbandry and Dairy Husban dflo
State University, Ames, Iowa. The assistance of J. E. W g J. cSung
and C. W. Burgin is gratefully acknowledged. E
/ Zymo-pabst, Pabst Brewing Company, Milwaukee, Wisconsin. arantd to
contain per pound; protease 3,405,000 PV units, amylase 5,000
units and gumase 13,620 units. Assays 6 mo. after complex oh of
tion studies indicated 50 and 75% of guaranteed protease ana las
in the tomato pulp ration came from the dried tomato pulp itself; while in the
citrus pulp ration, 29% of the protein was supplied by the dried citrus pulp.
Sufficient soybean meal was added to the citrus pulp ration in order that
protein per se would not be a factor in limiting nutrient digestibility.
Eight native wethers averaging 80 pounds in body weight were involved
in 2 conventional digestibility trials. Four lambs were used with each feed-
stuff in a single reversal design which yielded 4 individual coefficients of
digestibility for each experimental ration. Preliminary feeding periods were
21 days followed by 7-day collection periods. The lambs were fed equal amounts
twice daily and water was provided ad libitum. Average daily feed intake per
lamb was 750 grams for the citrus pulp ration and 650 grams for the tomato pulp
ration. All lambs gained weight throughout the course of the experiments.
Chemical analyses of the rations and feces were made as outlined by
A.O.A.C. (1960). All data were statistically analyzed by analysis of variance
as described by Snedecor (1956).
Table 1. Composition of Rations
Ingredients Citrus Pulp Tomato Pulp.
Bahiagrass hay1 10 20
Ground snapped cor 42
Dried citrus pulp./ 70 -
Dried tomato pulp 33
Soybean meal (50% protein) 16 -
Corn starch 1
Corn oil 2 2
Salt.3 1 1
Defluorinated phosphate 1 1
Vitamins A & D./ + +
'/ Ground through 1/2 inch screen.
2 Composite sample of four different dried citrus pulps.
The Carey Salt Company, Hutchinson, Kansas, Guaranteed minimum
analysis in percent; Mn, 0.25; Fe, 0.27; Cu, 0.033; Co, 0.01;
Zn, 0.005; I, 0.0007; and NaC1, 95.9.
4/ 2000 I. U. A and 500 I. U. D2 added per pound of ration.
- 2 -
Table 2. Average Nutrient Composition of Rations
Ether Free Energy
Ration Moisture Ash Protein Extract Fiber Extract Therms/lb.
Citrus pulp 8.7 6.5 12.7 4.4 13.8 53.9 1.72
Tomato pulp 10.3 6.3 12.6 4.2 17.4 49.2 2.01
RESULTS AND DISCUSSION
The average nutrient digestion coefficients and total digestible nutri-
ents for the experimental rations are shown in table 3. In evaluating the
effect of the enzyme supplement, it should be noted that the coefficients
obtained represent digestibility of the specific nutrient contributed by all
ingredients in the ration and not merely those from either citrus pulp or
tomato pulp. The digestibility of nitrogen-free extract in the citrus pulp
ration was significantly improved (P(0.05) by the addition of enzymes. This
difference in digestibility resulted in a slightly higher total digestible
nutrient value for this ration. This suggested improvement in nitrogen-free
extract digestibility may be an artifact, since it was not reflected in an
improvement in energy digestibility for the same ration. With approximately
54% of the citrus pulp ration being present as nitrogen-free extract (table 2),
a significant change in the utilization of this component might be expected to
produce a similar change in the energy utilization coefficients. No improve-
ment in the digestibility of nutrients in the tomato pulp ration was obtained
from the addition of enzymes.
Table 3. Average Digestion Coefficients and Total
Nutrients of Experimental Rations
Enzyme Protein Extract
* Significant at the five percent level.
- 3 -
Although the experiment was not designed to compare citrus pulp with
tomato pulp, it may be noted that all nutrients except ether extract in the
citrus pulp ration were considerably more digestible than those in the
tomato pulp ration. Average digestion coefficients obtained for the tomato
pulp ration were similar to those obtained with an Alyce clover hay.-tomato
pulp ration (70% hay, 30% tomato pulp) When fed to steers (Ammerman et al.,
Eight wether iambd were used in conventional digestibility trials to
determine the effect ot an enzyme supplement containing protease, amylase
and gumase upon the digestibility of nutrients in rations containing dried
citrus pulp or dried tomato pulp. The tationd contained either 70%S dried
citrus pulp or 33% dried tomato pulp and were supplemented with 3 grams of
the enzyme preparation per kilogram of total diet. The data from this ex-
periment indicated a significant improvement (P<0.05) in the nitrogen-free
extract digestibility of the dried citrus pulp ration but this was not
reflected in an improved energy utilization. The added enzyme yielded no
improvement in the digestibility of nutrients in the dried tomato pulp
A.O.A.C. Official Methods of Analysis. 9th Ed. 1960. Association of
Official Agricultural Chemists, Washington, D. C.
Ammerman, C. B., L. R. Arrington, J. T. McCall and G. K. Davis. 1959.
Dried Tomato Pulp-Digestibility by Steers and Chemical Composition.
Animal Husbandry and Nutrition Mimeo. Series No. 60-4.
Ammerman, C. B., L. R. Arrington, J. T. McCall, J. E. Wing and G. K. Davis.
1961. Nutritive Value of Dried Citrus Pulp for Steers. J. Ani. Sci.
Burroughs, Wise, Walter Woods, C. C. Culbertson and John Greig. 1959.
Enzyme (Agrozyme) Additions to Beef Fattening Rations Containing Low-
moisture and High-moisture Corn. Animal Husbandry Leaflet 245, Iowa
Burroughs, Wise, Walter Woods, S. A. Ewing, John Greig and Brent Theurer.
1960. Enzyme Additions to Fattening Cattle Rations. J. Ani. Sci. g9:
Grainger, R. B. and J. W. Stroud. 1960. Effect of Enzymes on Nutrient
Digestion by Wethers. J. Ani. Sci. 9:1263.
Snedecor, G. W. 1956. Statistical Methods. .5th Ed. The Iowa State
College Press, Ames, Iowa.
Theurer, Brent, John Greig, Walter Woods and Wise Burroughs. 1959. Dietary
Enzyme Supplements and Ration Digestibility in Steers and Lambs. J.
Ani. Sci. 18:1524.