Research Note: Effect of Soybeans Varying in Trypsin Inhibitor Content on Performance of Laying Hens Y. ZHANG and C. M. PARSONS1 Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801 T. HYMOWITZ Department of Agronomy, University of Illinois, Urbana, Illinois 61801 (Received for publication February 14, 1991)
1991 Poultry Science 70:2210-2213 INTRODUCTION
The detrimental effect of trypsin inhibitors in raw soybeans on performance of animals is well documented (Friedman et al., 1991). The Kunitz trypsin inhibitor is one of the major growth-inhibiting antinutritional factors present in raw soybeans (Friedman et al., 1991). Han et al. (1991) recently evaluated the nutritional value for chicks of a new soybean variant developed at the University of Illinois, which is isogenic to the commercially grown Williams 82 cultivar except for the lack of the Kunitz trypsin inhibitor allele (Bernard and Hymowitz, 1986). The latter study indicated that the nutritive value of raw, Kunitz trypsin inhibitor-free, full-fat soybeans (KFSB) was substantially greater than the nutritive value of raw, full-fat, conventional soybeans (CSB) but was significantly lower than the nutritive value of commercial, dehulled, solvent-extracted soybean meal (DSBM).
To whom correspondence should be sent: 322 Mumford HaU, 1301 West Gregory Drive, Urbana, IL 61801. 2 H&N Inc., Redmond, WA 98052.
The nutritional value of KFSB for laying hens has not been examined. Previous work with swine (Crenshaw and Danielson, 1985; Cook et al., 1988) suggested that the adverse effects of raw soybeans on performance of swine decrease with the pig's increasing age. Thus, the differences in nutritive value of KFSB compared with DSBM may be less for laying hens than previously observed for chicks by Han et al. (1991). Therefore, the present study evaluated the effects of varying dietary levels of raw CSB and KFSB on the performance of laying hens. MATERIALS AND METHODS
Four hundred and twenty Single Comb White Leghorn laying hens,2 35 wk of age, were used in the experiment. The hens were kept in a layer house of commercial design in raised wire cages (30 x 46 cm) with three hens per cage. Five replicate groups of 12 hens (four adjacent cages) were randomly assigned to each of seven dietary treatments. The experiment was conducted during March and April.
2210
Downloaded from http://ps.oxfordjournals.org/ at New York University on June 19, 2015
ABSTRACT A 6-wk experiment was conducted with commercial laying hens (35 wk of age) to study the effects of feeding raw, conventional, full-fat soybeans (CSB) and raw, Kunitz trypsin inhibitor-free, full-fat soybeans (KFSB) on layer performance. Dietary treatments consisted of corn and soybean meal diets formulated to contain 16% total protein with 100,72, or 48% of the soybean protein from CSB or KFSB. The remainder of the dietary soybean protein was provided as dehulled soybean meal (DSBM). Egg production, egg weight, egg yield (grams of egg per hen per day) and feed efficiency increased as the level of CSB and KFSB decreased. In general, diets containing KFSB resulted in better performance than those containing CSB. The diet containing 48% of the soybean protein from KFSB yielded performance that was not different (P>.05) than that obtained from a corn-DSBM diet. Performance from all other diets was inferior to that from the corn-DSBM diet. Pancreas weight (as a percentage of body weight) was greater for hens fed CSB compared with those fed KFSB, and both were greater than pancreas weight of hens fed the corn-DSBM diet. The dietary treatments had no consistent effect* on egg specific gravity or Haugh units. (Key words: soybeans, trypsin inhibitor, Kunitz, egg production, feed efficiency)
2211
RESEARCH NOTE TABLE 1. Ingredients and composition of diets varying in soybean source Amount and source of soybean protein Ingredients and calculated analysis
100% by CSB
72% by CSB
48% by CSB
59.37 29.63
61.84 6.37 20.79
63.78 11.36 13.86
8.7 1.8 .3 .05 .1 .05
8.7 1.8 .3 .05 .1 .05
8.7 1.8 .3 .05 .1 .05
100% by KFSB
72% by KFSB
48% by KFSB
100% by DSBM
(%) -
2,967 16 .55 .85 3.77 .45
2,913 16 .55 .85 3.77 .45
2,871 16 .55 .85 3.76 .45
58.84
61.43 6.50
63.41 11.54
67.65 21.35
30.16 8.7 1.8 .3 .05 .1 .05
21.07 8.7 1.8 .3 .05 .1 .05
14.05 8.7 1.8 .3 .05 .1 .05
8.7 1.8 .3 .05 .1 .05
2,912 16 .56 .85 3.77 .45
2,869 16 .55 .85 3.76 .45
2,803 16 .55 .84 3.77 .47
2,966 16 .56 .85 3.77 .45
*DSBM = dehulled soybean meaL analyzed CP = 48.0%; CSB = raw, conventional, full-fat soybeans, analyzed OP = 37.0%; KFSB = raw, Kunitz trypsin inhibitor-free, full-fat soybeans, analyzed CP = 36.5%. 2 Supplied the following amounts per kilogram of diet manganese, 75 mg; iron, 75 mg; zinc, 75 mg; copper, 5 mg; iodine, .75 mg; and selenium, .1 mg. Supplied the following amounts per kilogram of diet: vitamin A, 4,400 IU; cholecalciferoL 1,000 ICU; vitamin E, 11 IU; vitamin B 1 2 , .011 mg;riboflavin,4.4 mg; d-pantothenic acid, 10 mg; niacin, 22 mg; and menadione sodium bisulfite complex, 2.33 mg.
The compositions of the seven diets used in the present experiment are shown in Table 1. Diets 1 to 6 were 16% CP corn and soybean meal diets formulated to contain 100, 72, or 48% of the soybean protein from CSB or KFSB, respectively. The remainder of the dietary soybean protein was provided by DSBM. Diet 7 was a practical 16% CP cornDSBM diet. The 48 and 72% levels of protein from CSB and KFSB were equivalent to replacing 50 and 75% of the DSBM protein in Diet 7, respectively. The dietary protein levels were formulated using the analytically determined (Kjeldahl) CP values for the three soybean sources (Table 1). No attempt was made to maintain all seven diets isocaloric because the MEQ contents of CSB and KFSB for laying hens are unknown, and the primary objective of the study was to compare CSB with KFSB at different substitution levels. All diets were formulated to meet or exceed the nutrient requirements for laying hens as outlined by the National Research Council (1984). Trypsin inhibitor activities of CSB,
KFSB, and DSBM were measured using the enzymatic procedure of Friedman et al. (1991). All birds were given ad libitum access to the experimental diets during the 6-wk experimental period (35 to 41 wk). Egg production and feed consumption were recorded daily and egg weight was measured on all eggs produced for 2 consecutive days/wk. Specific gravity was determined on all eggs produced on 2 consecutive days during Weeks 38 and 41 using the flotation method with NaCl solutions varying in specific gravity from 1.056 to 1.09 in .004 increments. Haugh units were measured with a Haugh unit meter on four eggs produced on the last day of the trial from each replicate group of hens. At the end of the experiment, 10 birds were selected from the 100% CSB, 100% KFSB, and com-DSBM dietary treatments and 5 birds were selected from the other dietary treatments. These birds were killed by cervical dislocation, the pancreas removed, and its weight recorded and calculated as a percentage of the body weight. The hens were selected for this latter measurement so that their body weights were similar to
Downloaded from http://ps.oxfordjournals.org/ at New York University on June 19, 2015
Corn (8.5% CP) DSBM CSB KFSB Limestone Dicalcium phosphate Iodized salt Trace minerals2 Vitamins CholineCl (60%) Calculated analysis: ME,i, kcal/kg CP, % Met + Cys, % Lys, % Ca, % Available phosphorus, %
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ZHANG ET AL. TABLE 2. Effects of dietary soybean sources on layer performance
100% by CSB
Variable
100% by DSBM
64 d 56.8 d
82 c 57.6*
87" 58.0'ibc
80° 58.0^
87" 58.3 b
88'ab 59.2"
92 a 59.1 a
36.5 d
47.1C
50.3"
46.4°
50.6"
52.2'ab
54.4*
1.0840" 90.4°
1.0834
g 7 9 abc
116.51ab
102.6° .356° .28
a
a
.405° .27
ab
a
1.0838
g66bc
117.3'ab .429" .27'ab
1.0826 g ? 1 bc 114.1" .402° .25;bc
ab
1.0812 g 9 0 ab
b
117.4'ab .431'ab .24°
1.4 27 .83
1.0824* 1.0826 86.0° 86.8° 118.2'>ab .442'ab .24°
ab
.0007 1.04 1.61
119.9* .454a .18
SEM
a
.008 .010
"^Means within rows with no common superscripts differ (P
1991 Poultry Science 70:2210-2213 INTRODUCTION
The detrimental effect of trypsin inhibitors in raw soybeans on performance of animals is well documented (Friedman et al., 1991). The Kunitz trypsin inhibitor is one of the major growth-inhibiting antinutritional factors present in raw soybeans (Friedman et al., 1991). Han et al. (1991) recently evaluated the nutritional value for chicks of a new soybean variant developed at the University of Illinois, which is isogenic to the commercially grown Williams 82 cultivar except for the lack of the Kunitz trypsin inhibitor allele (Bernard and Hymowitz, 1986). The latter study indicated that the nutritive value of raw, Kunitz trypsin inhibitor-free, full-fat soybeans (KFSB) was substantially greater than the nutritive value of raw, full-fat, conventional soybeans (CSB) but was significantly lower than the nutritive value of commercial, dehulled, solvent-extracted soybean meal (DSBM).
To whom correspondence should be sent: 322 Mumford HaU, 1301 West Gregory Drive, Urbana, IL 61801. 2 H&N Inc., Redmond, WA 98052.
The nutritional value of KFSB for laying hens has not been examined. Previous work with swine (Crenshaw and Danielson, 1985; Cook et al., 1988) suggested that the adverse effects of raw soybeans on performance of swine decrease with the pig's increasing age. Thus, the differences in nutritive value of KFSB compared with DSBM may be less for laying hens than previously observed for chicks by Han et al. (1991). Therefore, the present study evaluated the effects of varying dietary levels of raw CSB and KFSB on the performance of laying hens. MATERIALS AND METHODS
Four hundred and twenty Single Comb White Leghorn laying hens,2 35 wk of age, were used in the experiment. The hens were kept in a layer house of commercial design in raised wire cages (30 x 46 cm) with three hens per cage. Five replicate groups of 12 hens (four adjacent cages) were randomly assigned to each of seven dietary treatments. The experiment was conducted during March and April.
2210
Downloaded from http://ps.oxfordjournals.org/ at New York University on June 19, 2015
ABSTRACT A 6-wk experiment was conducted with commercial laying hens (35 wk of age) to study the effects of feeding raw, conventional, full-fat soybeans (CSB) and raw, Kunitz trypsin inhibitor-free, full-fat soybeans (KFSB) on layer performance. Dietary treatments consisted of corn and soybean meal diets formulated to contain 16% total protein with 100,72, or 48% of the soybean protein from CSB or KFSB. The remainder of the dietary soybean protein was provided as dehulled soybean meal (DSBM). Egg production, egg weight, egg yield (grams of egg per hen per day) and feed efficiency increased as the level of CSB and KFSB decreased. In general, diets containing KFSB resulted in better performance than those containing CSB. The diet containing 48% of the soybean protein from KFSB yielded performance that was not different (P>.05) than that obtained from a corn-DSBM diet. Performance from all other diets was inferior to that from the corn-DSBM diet. Pancreas weight (as a percentage of body weight) was greater for hens fed CSB compared with those fed KFSB, and both were greater than pancreas weight of hens fed the corn-DSBM diet. The dietary treatments had no consistent effect* on egg specific gravity or Haugh units. (Key words: soybeans, trypsin inhibitor, Kunitz, egg production, feed efficiency)
2211
RESEARCH NOTE TABLE 1. Ingredients and composition of diets varying in soybean source Amount and source of soybean protein Ingredients and calculated analysis
100% by CSB
72% by CSB
48% by CSB
59.37 29.63
61.84 6.37 20.79
63.78 11.36 13.86
8.7 1.8 .3 .05 .1 .05
8.7 1.8 .3 .05 .1 .05
8.7 1.8 .3 .05 .1 .05
100% by KFSB
72% by KFSB
48% by KFSB
100% by DSBM
(%) -
2,967 16 .55 .85 3.77 .45
2,913 16 .55 .85 3.77 .45
2,871 16 .55 .85 3.76 .45
58.84
61.43 6.50
63.41 11.54
67.65 21.35
30.16 8.7 1.8 .3 .05 .1 .05
21.07 8.7 1.8 .3 .05 .1 .05
14.05 8.7 1.8 .3 .05 .1 .05
8.7 1.8 .3 .05 .1 .05
2,912 16 .56 .85 3.77 .45
2,869 16 .55 .85 3.76 .45
2,803 16 .55 .84 3.77 .47
2,966 16 .56 .85 3.77 .45
*DSBM = dehulled soybean meaL analyzed CP = 48.0%; CSB = raw, conventional, full-fat soybeans, analyzed OP = 37.0%; KFSB = raw, Kunitz trypsin inhibitor-free, full-fat soybeans, analyzed CP = 36.5%. 2 Supplied the following amounts per kilogram of diet manganese, 75 mg; iron, 75 mg; zinc, 75 mg; copper, 5 mg; iodine, .75 mg; and selenium, .1 mg. Supplied the following amounts per kilogram of diet: vitamin A, 4,400 IU; cholecalciferoL 1,000 ICU; vitamin E, 11 IU; vitamin B 1 2 , .011 mg;riboflavin,4.4 mg; d-pantothenic acid, 10 mg; niacin, 22 mg; and menadione sodium bisulfite complex, 2.33 mg.
The compositions of the seven diets used in the present experiment are shown in Table 1. Diets 1 to 6 were 16% CP corn and soybean meal diets formulated to contain 100, 72, or 48% of the soybean protein from CSB or KFSB, respectively. The remainder of the dietary soybean protein was provided by DSBM. Diet 7 was a practical 16% CP cornDSBM diet. The 48 and 72% levels of protein from CSB and KFSB were equivalent to replacing 50 and 75% of the DSBM protein in Diet 7, respectively. The dietary protein levels were formulated using the analytically determined (Kjeldahl) CP values for the three soybean sources (Table 1). No attempt was made to maintain all seven diets isocaloric because the MEQ contents of CSB and KFSB for laying hens are unknown, and the primary objective of the study was to compare CSB with KFSB at different substitution levels. All diets were formulated to meet or exceed the nutrient requirements for laying hens as outlined by the National Research Council (1984). Trypsin inhibitor activities of CSB,
KFSB, and DSBM were measured using the enzymatic procedure of Friedman et al. (1991). All birds were given ad libitum access to the experimental diets during the 6-wk experimental period (35 to 41 wk). Egg production and feed consumption were recorded daily and egg weight was measured on all eggs produced for 2 consecutive days/wk. Specific gravity was determined on all eggs produced on 2 consecutive days during Weeks 38 and 41 using the flotation method with NaCl solutions varying in specific gravity from 1.056 to 1.09 in .004 increments. Haugh units were measured with a Haugh unit meter on four eggs produced on the last day of the trial from each replicate group of hens. At the end of the experiment, 10 birds were selected from the 100% CSB, 100% KFSB, and com-DSBM dietary treatments and 5 birds were selected from the other dietary treatments. These birds were killed by cervical dislocation, the pancreas removed, and its weight recorded and calculated as a percentage of the body weight. The hens were selected for this latter measurement so that their body weights were similar to
Downloaded from http://ps.oxfordjournals.org/ at New York University on June 19, 2015
Corn (8.5% CP) DSBM CSB KFSB Limestone Dicalcium phosphate Iodized salt Trace minerals2 Vitamins CholineCl (60%) Calculated analysis: ME,i, kcal/kg CP, % Met + Cys, % Lys, % Ca, % Available phosphorus, %
2212
ZHANG ET AL. TABLE 2. Effects of dietary soybean sources on layer performance
100% by CSB
Variable
100% by DSBM
64 d 56.8 d
82 c 57.6*
87" 58.0'ibc
80° 58.0^
87" 58.3 b
88'ab 59.2"
92 a 59.1 a
36.5 d
47.1C
50.3"
46.4°
50.6"
52.2'ab
54.4*
1.0840" 90.4°
1.0834
g 7 9 abc
116.51ab
102.6° .356° .28
a
a
.405° .27
ab
a
1.0838
g66bc
117.3'ab .429" .27'ab
1.0826 g ? 1 bc 114.1" .402° .25;bc
ab
1.0812 g 9 0 ab
b
117.4'ab .431'ab .24°
1.4 27 .83
1.0824* 1.0826 86.0° 86.8° 118.2'>ab .442'ab .24°
ab
.0007 1.04 1.61
119.9* .454a .18
SEM
a
.008 .010
"^Means within rows with no common superscripts differ (P
