Department of Animal Science Florida Agricultural
Research Report AL-1983-5 -22- Experiment Station
August, 1983 Gainesville, FL

THE EFFECT OF ENERGY DENSITY ON PERFORMANCE 1
OF STARTING PIGS FED CORN-SOY OR RYE-SOY DIETS
M. D. Harrison, M. T. Coffey, and G. E. Combs2

Previous research has indicated that the metabolizable energy (ME)
content of rye for swine was approximately 93% of corn and that the response
to antibiotic supplementation in rye-say diets was greater than that in
corn-soy diets (Harrison et al., 1979) .

This study was conducted to evaluate the effect of altering the ME level
of rye-soy and corn-soy diets for starting swine and to examine the effect of
antibiotic supplementation to rye-soy diets on pig performance.
Experimental

One hundred eight crossbred pigs (11 kg) were allotted based on weight,
sex and ancestry to six dietary treatment groups. Six pigs were allotted to
each pen with three pens per treatment. The treatments consisted of a
corn-soy starter diet (1); a diet containing Weser rye substituted for yellow
corn; (2), a rye-soy diet containing the same level of antibiotic that was
added to treatment 1 (3); a corn-soy diet in which the ME content of the diet
was lowered to equal the ME content of the rye-soy treatment by the addition
of fiber (4); a rye-soy diet to which animal fat was added (7.3%) at a level
such that the ME content of the diet was equal to the ME content of the
control (5); and a corn-soy diet that contained the same level of fat
supplementation (7.3%) as treatment 5 (6). The composition of the dietary
treatments is presented in table 1.
All pigs were housed in an enclosed nursery with elevated pens having
expanded metal floors and wire-mesh sides. Each pen contained an automatic
waterer and self feeder. Pig weight and feed consumption were measured
bi-weekly to determine average daily gain and feed efficiency. Chromic oxide
was added to the diets at a level of .5% during the last week of the trial to
serve as an indicator of nutrient digestibility. Fecal samples from each pig
were taken 48 hours after the feed containing chromic oxide was offered.

1Experiment 2778.

2Harrison, Graduate Research Assistant, Coffey, Assistant Animal Nutritionist
and Combs, Animal Nutritionist, Animal Science Department, Gainesville.

3Florida Animal Science Res. Rept. AL-1979-6.

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Results and Discussion

A summary of the growth and feed consumption data is presented in table
2, and the results of the digestion study are presented in tables 3, and 4.
Table 5 presents the digestible and metabolizable energy of all dietary
treatments.

Substitution of corn with rye (2) caused a reduction (P<.05) in both
average daily gain and feed intake. Addition of antibiotic to the rye-soy
diet (3) did not improve (P<.05) rate or efficiency of gain. There was no
reduction (P<.05) in feed intake for pigs fed rye-soy diets containing
antibiotic when compared with pigs fed the corn-soy control. Reducing the
energy density of the corn-soy diet with corn cobs (4) caused a reduction
(P<.05) in daily gain similar to that obtained when rye was substituted for
corn. Energy dilution with corn cobs did not increase feed intake relative to
the control diet. Increasing the energy density of the rye diet (5) by adding
fat improved (P<.05) daily gain to a level similar to the control pigs.
Adding fat to the corn-soy diet (6) did not improve daily gain, but feed
intake was slightly lower and feed efficiency was significantly improved
(P<.05) compared to the control.

The results of the digestibility study indicated that the dry matter and
organic matter digestibility was depressed (P<.05) by the substitution of rye
(2) for corn, and the addition of antibiotic to the rye based diet (3) did not
overcome the depression found with treatment 2. Dilution of the control diet
with corn cobs (4), an ingredient high in fiber resulted in a dry matter
digestibility that was similar to that found with rye diets and the lowest
organic matter digestiblity coefficient of all treatments. Supplementing the
rye diet with fat (5) increased (P<.05) both dry matter and organic matter
digestibility compared to the other rye-soy diets. A similar improvement was
obtained when the corn-soy diet supplemented with fat was compared (P<.05) to
the corn control.

Results were similar for crude protein and gross energy digestibility, in
that both were reduced (P<.05) by the substitution of corn with rye (2).
Adding antibiotic to the rye diet did not improve the digestibility of either
protein or energy. Crude protein and gross energy digestibility were reduced
(P<.05) by the use of corn cobs in diet 4. As was found with dry matter and
organic matter the addition of fat to the rye-soy treatment (5) improved
(P<.05) crude protein and gross energy digestiblity to a level comparable to
the control (1). Addition of fat to the corn-soy diet caused a slight but
nonsignificant increase in crude protein digestibility when compared with the
control and resulted in the highest gross energy digestibility of all
treatments (P<.05).

Substitution of corn with rye lowered (P<.05) the digestible energy
content of treatments 2 and 3 when compared with the control treatment (1).
The addition of corn cobs (4) to the control diet resulted in digestible
energy values which were similar to that of treatments 2 and 3.
Supplementation of the rye diet with fat (5) increased digestible energy to a
level higher (P<.05) than that of the control. The corn-soy diet supplemented
with fat had the highest (P<.05) digestible energy value of all dietary
treatments.

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Metabolizable energy values were calculated by the formula presented in
the 1979 NRC from the digestible energy values determined in the digestion
study. These values correspond well with the initial calculations of dietary
metabolizable energy content used to formulate the diets.

These data indicated that there was no benefit from the addition of
antibiotics to rye based diets for starting swine. Supplementing diets
containing rye with fat to provide energy content at the level of corn based
diets supported adequate performance.

Summary

A thirty-five day feeding trial was conducted to evaluate the effects of
adding antibiotics or altering dietary energy in rye based diets on the
performance of starting swine. Daily dain was reduced (P<.05) for pigs fed
rye, rye + antitiotics and for pigs fed an isocaloric corn-soy diet containing
corn cobs. Supplementing the rye diet with fat, which made the ME level equal
to the control, resulted in performance similar to pigs fed the corn-soy
control. Addition of fat to the corn-soy control did not improve average
daily gain, but pigs fed the control with added fat were the most efficient
(P<.05). Substitution of rye for corn reduced (P<.05) dry matter, organic
matter, crude protein and energy digestibility. Addition of antibiotic to the
rye diet did not improve (P<.05) digestibility of the diet. Organic matter
digestibility was lowest (P<.05) for pigs fed the corn-soy diet diluted with
corn cobs. Addition of fat to the corn-soy diet yielded the highest (P<.05)
dry matter, organic matter, and energy digestion coefficients. Pigs fed the
rye-soy diet supplemented with fat had digestion coefficients which were
greater (P<.05) than pigs fed either the rye or rye + antibiotic treatments.
Addition of fat to the rye-soy diet improved the digestibility (P<.05) of the
diet to a level equal to that of the corn-soy control.

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Table 1. Diet Composition

Treatment
Ingredient Rye Corn Rye Corn
+ + + +
Corn Rye Ab Fiber Fat Fat
1 2 3 4 5 6

Corn or rye 71.80 72.05 71.80 58.50 64.50 64.50
Soybean meal (49%) 25.00 25.00 25.00 25.00 25.00 25.00
Dynafos (MCC) 1.70 1.70 1.70 1.70 1.70 1.70
Limestone .80 .80 .80 .80 .80 .80
Iodized salt .25 .25 .25 .25 .25 .25
Trace minerals (CCC.10 .10 .10 .10 .10 .10
Vitamin premix (UF) .10 .10 .10 .10 .10 .10
Antibiotic .25 .25 .25 .25 .25
Animal faN 7.30 7.30
Corn cobs 13.30
Antioxidant .01 .01

aSupplied by Calcium Carbonate Company, Quincy, Illinois. Contained 20%
zinc, 10% iron, 5.5% manganese, 1.1% copper, 0.15% iodine, and 12% calcium.
Contained 13,200 mg riboflavin, 44,000 mg niacin, 26,400 mg pantothenic
acid, 176,000 mg choline chloride, 22,000 meg vitamin B1 5,500,000 IU
vitamin A, 880,000 ICU vitamin D3 and 22,000 IU vitamin per kilogram of
premix.
cContained 44 g chlortetracycline, 44 g sulfamethazine, 22 g penicillin
per kg of supplement.

Bedocobs, Laboratory Animal Bedding, Anderson cob Division, Delphi, IN.

eantoquin, Monsanto Company.

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Table 2. Animal Performance

Treatments
1 2 3 4 5 6

Initial wt., kg 11.1 11.0 10.9 11.0 11.0 11.0
Final wt., kg 29.8 a 27.3 b 27.3 b 27.3 b 29.4 a 30.0 a
Daily gain, kg .53 .44 .47 .47 .53 .54
Daily feed, kg 1.17a .91 b 99,b 1.10a 1.04a .98ab
Feed/gain 2.19 2.04ab 211a,b 237a 1.99a,b 180

abMeans on the same line with different superscripts differ significantly
(P<.05).

Table 3. Dry Matter and Organic Matter, Digestion Coefficients

Treatments
Dioestibilitv. % 1 2 3 4 5 6

Dry matter 82.8a 76.6b 76.1b
a h h

85.5c
di

Organic matter 85.8" 80.1" 79.9 76.9 84.5" 88.6-

abcdMeans in the same row with different superscripts significantly differ
(P<.05).

Table 4. Protein and Gross Energy, Digestion Coefficients

Treatments
Digestibility, % 1 -3 4

Crude protein 83.4ab 77.8d 78.4c'd 81.6b'c 83.0ab 85.6a

Gross energy 83.7a 74.7b 74.7b 76.2b 82.0c 87.0d

ab,cdMeans on the same row with different superscripts differ significantly
(P<.05).

--- --

75.1b
c

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Table 2. Animal Performance

Treatments
1 2 3 4 5 6

Initial wt., kg 11.1 11.0 10.9 11.0 11.0 11.0
Final wt., kg 29.8 a 27.3 b 27.3 b 27.3 b 29.4 a 30.0 a
Daily gain, kg .53 .44 .47 .47 .53 .54
Daily feed, kg 1.17a .91 b 99,b 1.10a 1.04a .98ab
Feed/gain 2.19 2.04ab 211a,b 237a 1.99a,b 180

abMeans on the same line with different superscripts differ significantly
(P<.05).

Table 3. Dry Matter and Organic Matter, Digestion Coefficients

Treatments
Dioestibilitv. % 1 2 3 4 5 6

Dry matter 82.8a 76.6b 76.1b
a h h

85.5c
di

Organic matter 85.8" 80.1" 79.9 76.9 84.5" 88.6-

abcdMeans in the same row with different superscripts significantly differ
(P<.05).

Table 4. Protein and Gross Energy, Digestion Coefficients

Treatments
Digestibility, % 1 -3 4

Crude protein 83.4ab 77.8d 78.4c'd 81.6b'c 83.0ab 85.6a

Gross energy 83.7a 74.7b 74.7b 76.2b 82.0c 87.0d

ab,cdMeans on the same row with different superscripts differ significantly
(P<.05).

--- --

75.1b
c

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Table 2. Animal Performance

Treatments
1 2 3 4 5 6

Initial wt., kg 11.1 11.0 10.9 11.0 11.0 11.0
Final wt., kg 29.8 a 27.3 b 27.3 b 27.3 b 29.4 a 30.0 a
Daily gain, kg .53 .44 .47 .47 .53 .54
Daily feed, kg 1.17a .91 b 99,b 1.10a 1.04a .98ab
Feed/gain 2.19 2.04ab 211a,b 237a 1.99a,b 180

abMeans on the same line with different superscripts differ significantly
(P<.05).

Table 3. Dry Matter and Organic Matter, Digestion Coefficients

Treatments
Dioestibilitv. % 1 2 3 4 5 6

Dry matter 82.8a 76.6b 76.1b
a h h

85.5c
di

Organic matter 85.8" 80.1" 79.9 76.9 84.5" 88.6-

abcdMeans in the same row with different superscripts significantly differ
(P<.05).

Table 4. Protein and Gross Energy, Digestion Coefficients

Treatments
Digestibility, % 1 -3 4

Crude protein 83.4ab 77.8d 78.4c'd 81.6b'c 83.0ab 85.6a

Gross energy 83.7a 74.7b 74.7b 76.2b 82.0c 87.0d

ab,cdMeans on the same row with different superscripts differ significantly
(P<.05).

--- --

75.1b
c

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Table 5. Energy Content of Dietary Treatments

Treatments
1 2 3 4 5 6

Digestible energy
kcal/gm 3.66b 3.28c 3.20c 3.30c 3.88d 4.09e

Metabolizable energy
kcal/gm 3.52b 3.15c 3.08c 3.73c 3.17 3.93e

aME=DE x (96-(0.202 x %CP/100)).
b,c,d,e Means on the same line with different superscripts differ significantly
(P<.05).