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Influence of pericarp and endosperm colour and type on digestibility of grain sorghum by pigs
Animal Feed Science and Technology, 2 (1977) 219--224 219 © Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands
INFLUENCE OF PERICARP AND ENDOSPERM COLOUR AND TYPE ON DIGESTIBILITY OF GRAIN SORGHUM BY PIGS*
P.R. NOLAND, D.R. CAMPBELL, R.N. SHARP and Z.B. JOHNSON
Department of Animal Sciences, University of Arkansas, Fayetteville, Ark .72701 (U.S.A.) (Received 28 September 1976)
ABSTRACT
Noland, P.R., Campbell, D.R., Sharp, R.N. and Johnson, Z.B., 1977. Influence of pericarp and endosperm colour and type on digestibility of grain sorghum by pigs. Anita. Feed Sci. Technol., 2: 219--224. Twenty-five grain sorghum cultivars were used to study differences in digestible energy, digestible protein and apparent nitrogen retention. Eight pigs were used to evaluate each cultivar. Results indicated that cultivars with a yellow seed coat are significantly superior in digestibility to cultivars with brown seed coats. Cultivars having a yellow endosperm had greater digestibility of energy and protein and more of the absorbed nitrogen was retained than with those cultivars having either white, white corneous or yellow corneous endosperm.
INTRODUCTION
Previous research with grain sorghum has indicated that there are significant differences in the performance of pigs fed on various cultivars (Peo and Hudman, 1958; Hillier et al., 1959). Tanksley (1974) has reported that the digestibility of protein is consistently lower for sorghum than for maize and that the metabolizable energy content of yellow, non-yellow and heteroyellow sorghum is significantly less than that of maize. May and Nelson (1973) reported that the metabolizable energy c o n t e n t of sorghum cultivars with brown seed coat is less than for those with yellow seed coats. The correlation between metabolizable energy and tannin c o n t e n t was 0.39. Noland et al. {1966) reported that pigs fed on a ration containing sorghum with a brown seed coat gained 6--7% more slowly and required 15--22% more feed per unit gain than those fed on a maize diet. The object of the present research was to determine if the digestibility of *Published with the approval of the Director of the Arkansas Agricultural Experiment Station.
220
the energy and protein in sorghum is influenced by the type of seed coat. MATERIALS AND METHODS
Castrate, crossbred male pigs weighing 10 kg initially were used to evaluate the digestibility of the energy and protein in 27 sorghum cultivars. The final pig weights were approximately 20 kg. Each pig was fed on the experimental diet for a 2-day preliminary period and a 5-day complete collection period. In order to use a minimum number of pigs to evaluate the cultivars and thereby reduce variation due to pigs, the preliminary and collection periods were kept short. Pig weight significantly influenced digestibility of energy and protein and apparent nitrogen retention. Therefore it was imperative that the pigs be used only in a relatively narrow weight range (10--20 kg) for the evaluation of nutrient digestibility. Each pig was used to evaluate four cultivars and each diet was given to eight pigs in two metabolism trials of 4 X 4 Latin square design. The experimental grains were produced in varietal trials at the University of Arkansas, Fayetteville, during the years 1972, 1973 and 1974. The fertilizer levels and cultural practices were the same in each year. The protein (N X 6.25) c o n t e n t of the cultivars ranged from 7.7 to 12.2%. The grain sorghums were ground in a hammermill with a 2.5 mm screen and mixed with the other diet components to produce 14% total protein. The diets were composed of the following ingredients: 79.24--90.24% grain sorghum, 6--17% dehulled soya bean meal, 2.5% dicalcium phosphate, and 0.5% iodized salt. Vitamins, antibiotics, and zinc were added at the following levels per kilogram of diet: 4818 I.U. vitamin A; 264 I.U. vitamin D; 4.4 mg riboflavin; 26 mg calcium pantothenate; 11 mg niacin; 110 mg choline; 22 pg vitamin B~2; 110 mg chlortetracycline; 110 mg sulfamethazine; 55 mg penicillin; and 100 mg zinc as oxide. Three of the 27 cultivars were represented in two different years and one was used in each of three years. There were seven cultivars with yellow seed coat and yellow endosperm; one cultivar with yellow seed coat and white endosperm; one cultivar with brown seed coat and yellow corneous endosperm; five cultivars with brown seed coat and white corneous endosperm; seven cultivars with brown seed coat and white endosperm; and six cultivars with brown seed coat and yellow endosperm. Association of Official Agricultural Chemists (1965) methods were used to determine dry matter and total nitrogen. A bomb calorimeter was used to determine gross energy (Parr Instrument Co., 1960}. All analyses were conducted in triplicate. The digestion coefficients were analyzed by least-squares procedures as outlined by Harvey (1960). Average weight of the pigs during the week of each digestion trial was treated as an independent variable in the analysis. A discrepancy exists in some of the least-squares means presented in Tables I and II owing to slight changes in the number of observations when the
221
yellow corneous and white corneous data were removed from the model. In addition to the true error, the residual term in the least-squares analysis also contains variability attributable to within and between trials which is n o t associated with the main effects of the model. RESULTS AND DISCUSSION
The least square means for digestibility of energy and protein and apparent nitrogen retention are summarized in Table I. Analysis of variance indicated that diets containing sorghum with brown seed coat had significantly lower digestibility coefficients for energy and protein than those containing sorghum with yellow seed coat. Type of seed coat did n o t significantly affect N retention. Endosperm type had a significant effect on digestibility of energy and protein and on N retention. Diets containing cultivars with yellow endosperm were more completely digested than those containing the other types of endosperm. The energy in diets containing sorghum with a yellow corneous or white corneous type of endosperm was digested least efficiently. The white endosperm diets were intermediate between the two extremes in digestible energy. Endosperm type also had a significant effect on protein digestibility and N retention, the yellow being superior to the other endosperm types. Pig weight significantly influenced digestibility and N retention. Since both seed coat colours were n o t represented in all endosperm types, a second analysis of the data was made using only cultivars with two seed coat colours (brown and yellow) and two endosperm types (white and yellow). This analysis (Table II) was made to determine if there was a significant seed coat colour X endosperm type interaction. Endosperm t y p e (white vs. yellow) did n o t significantly affect energy digestibility, b u t the diets containing yellow endosperm sorghum had protein significantly more digestible than those containing the sorghum with white endosperm. Nitrogen retention was significantly less from the diets containing sorghum with white endopserm than from those with yellow endosperm. There was n o t a significant interaction between endosperm type and seed coat colour. The results of these digestion trials indicate that the gross energy and protein in sorghum cultivars with yellow seed coat were more digestible than those in cultivars with a brown seed coat. The depressed digestibility of the brown seed coat cultivars is probably associated with the high tannin content of the seed. Although tannin was n o t determined on all cultivars, the average tannin content of 10 brown seed coat cultivars was 0.67% while five of the non-brown seed coat cultivars contained 0.22% tannin. For these cultivars the correlation between tannin content and digestibility of energy was - 0 . 6 8 . The correlation between tannin content and digestibility of protein was - 0 . 5 8 . This negative relationship between tannin c o n t e n t and nutrient digestibility is in agreement with values
176 80
120 16 72 48
Seed coat colour Brown Yellow
Endosperm type Yellow Yellow corneous White White corneous
* P < 0.05 ** P < 0.01 *** P < 0.001
Analysis of variance (F values) Total (255) Seed coat colour (1) Endosperm type (3) Weight of pig (1) Residual (249)
256
All samples
Frequency (or d.f.)
15 2 9 6
22 10
32
No. of cultivars
24.86*** 2.71" 41.28"**
80.6±0.7 77.7±1.0 79.2±0.6 78.0±0.6
76.3±0.5 81.4±0.5
78.9±0.6
(%)
Digestibility of energy
65.4±1.0
Digestibility of protein (%)
10.50"** 6.15"* 28.31"**
69.5±1.1 65.3±1.6 64.7±1.1 62.3±1.1
62.620.9 68.3±0.9
Least square means of digestion coefficients of grain sorghum cult±vats
TABLE I
0.18 2.79* 18.53"**
33.9±1.5 32.5±2.0 28.1±1.4 29.0±1.4
30.4±1.1 31.3±1.1
30.9±1.3
(%)
Apparent nitrogen retention
10.0±0.2 10.0±0.1 10.9±0.2 10.8±0.2
Total protein (%)
t~ b~
223
T A B L E II Least square m e a n s o f digestion c o e f f i c i e n t s o f d i f f e r e n t grain s o r g h u m cultivars Frequency (or d.f.)
Digestibility o f energy (%)
Digestibility of protein (%)
Apparent nitrogen retention
(%)
All s a m p l e s
192
79.9 -+ 0.5
67.1 ± 0.8
31.0 -+ 1.1
Seed c o a t c o l o u r Brown Yellow
112 80
77.4 ± 0.5 82.4 ± 0.5
64.4 ± 0.8 69.8 ± 0.8
30.6 +- 1.1 34.5 ± 1.1
Endosperm Yellow White
120 72
80.6 ± 0.5 79.2 ± 0.5
69.5 ± 0.8 64.7 +- 0.8
37.1 +- 1.1 31.2 +- 1.1
29.19"**
11.46"**
2.34 0.04 28.40***
9.84** 0.59 29.74***
0.16 7.78** 1.89 13.17"**
Analysis o f variance (F values) Total 191 Seed c o a t c o l o u r 1 Endosperm type 1 Coat x e n d o s p e r m 1 Weight o f pig 1 Residual 187 ** P < 0.01 * * * P < 0.001
previously reported by Nelson et al. (1975) with the chick. It is possible that the tannin complexes with the amino acids and the glucose resulting from starch digestion, and interferes with absorption. An alternative explanation is that the tannin interferes with the actual enzymatic degradation of the protein and starch. Diets containing cultivars with yellow endosperm were superior to those containing other endosperm types with respect to energy and protein digestibility and N retention. There was no seed coat colour X endosperm type interaction. Differences in digestibility were of sufficient magnitude to explain the inferior performance obtained with brown seed coat sorghum (Noland et al., 1966). Pig weight (10--20 kg range) had a significant effect on digestibility and N retention. It has been previously reported that digestive enzymes continue to develop from birth until a pig weighs 20 kg.
224
REFERENCES Association of Official Agricultural Chemists, 1965. Official Methods of Analysis (10th ed.) Assoc. Official Agric. Chemists, Washington, D.C., 957 pp. Harvey, W.R., 1960. Least-squares analysis of data with unequal subclass frequencies. U.S. Dept. Agric., Agric. Res. Serv., ARS 20-8, 157 pp. Hillier, J.D., Martin, J.J. and Waller, G.R., 1959. The relative value of six varieties of milo for growing and finishing swine. Okla. Agric. Exp. Sta., Misc. Publ., No. 55, pp. 41--46. May, M.A. and Nelson, T.S., 1973. Digestible and metabolizable energy content of varieties of milo for rats. J. Anim. Sci., 36: 874--876. Nelson, T.S., Stephenson, E.L., Burgos, A., Floyd, J. and York, J.O., 1975. Effect of tannin content and dry matter digestion on energy utilization and average amino acid availability of hybrid sorghum grains. Poult. Sci., 54: 1620--1623. Noland, P.R., Baugus, C.A. and Scott, K.W., 1966. The use of various types of grain sorghum for growing and finishing swine. Proc. 2nd Annual Arkansas Anita. Sci. Res. Conf., Dept. Anita. Sci., Univ. Ark., Fayetteville, pp. 20--22. Parr Instrument Co., 1960. Oxygen bom b calorimetry and combustion methods. Manual, Parr Instrument Co., Moline, Ill., 56 pp. Peo, E.R., Jr. and Hudman, D.B., 1958. Grain sorghum for growing-finishing swine. J. Anita. Sci., 17: 813--818. Tanksley, T.D., 1974. Sorghum vs. corn for growing-finishing swine. Proc. 1974 Texas Nutr. Conf., Texas Agric. Exp. Sta., Texas A. and M. Univ., Bryan, pp. 214--221.
INFLUENCE OF PERICARP AND ENDOSPERM COLOUR AND TYPE ON DIGESTIBILITY OF GRAIN SORGHUM BY PIGS*
P.R. NOLAND, D.R. CAMPBELL, R.N. SHARP and Z.B. JOHNSON
Department of Animal Sciences, University of Arkansas, Fayetteville, Ark .72701 (U.S.A.) (Received 28 September 1976)
ABSTRACT
Noland, P.R., Campbell, D.R., Sharp, R.N. and Johnson, Z.B., 1977. Influence of pericarp and endosperm colour and type on digestibility of grain sorghum by pigs. Anita. Feed Sci. Technol., 2: 219--224. Twenty-five grain sorghum cultivars were used to study differences in digestible energy, digestible protein and apparent nitrogen retention. Eight pigs were used to evaluate each cultivar. Results indicated that cultivars with a yellow seed coat are significantly superior in digestibility to cultivars with brown seed coats. Cultivars having a yellow endosperm had greater digestibility of energy and protein and more of the absorbed nitrogen was retained than with those cultivars having either white, white corneous or yellow corneous endosperm.
INTRODUCTION
Previous research with grain sorghum has indicated that there are significant differences in the performance of pigs fed on various cultivars (Peo and Hudman, 1958; Hillier et al., 1959). Tanksley (1974) has reported that the digestibility of protein is consistently lower for sorghum than for maize and that the metabolizable energy content of yellow, non-yellow and heteroyellow sorghum is significantly less than that of maize. May and Nelson (1973) reported that the metabolizable energy c o n t e n t of sorghum cultivars with brown seed coat is less than for those with yellow seed coats. The correlation between metabolizable energy and tannin c o n t e n t was 0.39. Noland et al. {1966) reported that pigs fed on a ration containing sorghum with a brown seed coat gained 6--7% more slowly and required 15--22% more feed per unit gain than those fed on a maize diet. The object of the present research was to determine if the digestibility of *Published with the approval of the Director of the Arkansas Agricultural Experiment Station.
220
the energy and protein in sorghum is influenced by the type of seed coat. MATERIALS AND METHODS
Castrate, crossbred male pigs weighing 10 kg initially were used to evaluate the digestibility of the energy and protein in 27 sorghum cultivars. The final pig weights were approximately 20 kg. Each pig was fed on the experimental diet for a 2-day preliminary period and a 5-day complete collection period. In order to use a minimum number of pigs to evaluate the cultivars and thereby reduce variation due to pigs, the preliminary and collection periods were kept short. Pig weight significantly influenced digestibility of energy and protein and apparent nitrogen retention. Therefore it was imperative that the pigs be used only in a relatively narrow weight range (10--20 kg) for the evaluation of nutrient digestibility. Each pig was used to evaluate four cultivars and each diet was given to eight pigs in two metabolism trials of 4 X 4 Latin square design. The experimental grains were produced in varietal trials at the University of Arkansas, Fayetteville, during the years 1972, 1973 and 1974. The fertilizer levels and cultural practices were the same in each year. The protein (N X 6.25) c o n t e n t of the cultivars ranged from 7.7 to 12.2%. The grain sorghums were ground in a hammermill with a 2.5 mm screen and mixed with the other diet components to produce 14% total protein. The diets were composed of the following ingredients: 79.24--90.24% grain sorghum, 6--17% dehulled soya bean meal, 2.5% dicalcium phosphate, and 0.5% iodized salt. Vitamins, antibiotics, and zinc were added at the following levels per kilogram of diet: 4818 I.U. vitamin A; 264 I.U. vitamin D; 4.4 mg riboflavin; 26 mg calcium pantothenate; 11 mg niacin; 110 mg choline; 22 pg vitamin B~2; 110 mg chlortetracycline; 110 mg sulfamethazine; 55 mg penicillin; and 100 mg zinc as oxide. Three of the 27 cultivars were represented in two different years and one was used in each of three years. There were seven cultivars with yellow seed coat and yellow endosperm; one cultivar with yellow seed coat and white endosperm; one cultivar with brown seed coat and yellow corneous endosperm; five cultivars with brown seed coat and white corneous endosperm; seven cultivars with brown seed coat and white endosperm; and six cultivars with brown seed coat and yellow endosperm. Association of Official Agricultural Chemists (1965) methods were used to determine dry matter and total nitrogen. A bomb calorimeter was used to determine gross energy (Parr Instrument Co., 1960}. All analyses were conducted in triplicate. The digestion coefficients were analyzed by least-squares procedures as outlined by Harvey (1960). Average weight of the pigs during the week of each digestion trial was treated as an independent variable in the analysis. A discrepancy exists in some of the least-squares means presented in Tables I and II owing to slight changes in the number of observations when the
221
yellow corneous and white corneous data were removed from the model. In addition to the true error, the residual term in the least-squares analysis also contains variability attributable to within and between trials which is n o t associated with the main effects of the model. RESULTS AND DISCUSSION
The least square means for digestibility of energy and protein and apparent nitrogen retention are summarized in Table I. Analysis of variance indicated that diets containing sorghum with brown seed coat had significantly lower digestibility coefficients for energy and protein than those containing sorghum with yellow seed coat. Type of seed coat did n o t significantly affect N retention. Endosperm type had a significant effect on digestibility of energy and protein and on N retention. Diets containing cultivars with yellow endosperm were more completely digested than those containing the other types of endosperm. The energy in diets containing sorghum with a yellow corneous or white corneous type of endosperm was digested least efficiently. The white endosperm diets were intermediate between the two extremes in digestible energy. Endosperm type also had a significant effect on protein digestibility and N retention, the yellow being superior to the other endosperm types. Pig weight significantly influenced digestibility and N retention. Since both seed coat colours were n o t represented in all endosperm types, a second analysis of the data was made using only cultivars with two seed coat colours (brown and yellow) and two endosperm types (white and yellow). This analysis (Table II) was made to determine if there was a significant seed coat colour X endosperm type interaction. Endosperm t y p e (white vs. yellow) did n o t significantly affect energy digestibility, b u t the diets containing yellow endosperm sorghum had protein significantly more digestible than those containing the sorghum with white endosperm. Nitrogen retention was significantly less from the diets containing sorghum with white endopserm than from those with yellow endosperm. There was n o t a significant interaction between endosperm type and seed coat colour. The results of these digestion trials indicate that the gross energy and protein in sorghum cultivars with yellow seed coat were more digestible than those in cultivars with a brown seed coat. The depressed digestibility of the brown seed coat cultivars is probably associated with the high tannin content of the seed. Although tannin was n o t determined on all cultivars, the average tannin content of 10 brown seed coat cultivars was 0.67% while five of the non-brown seed coat cultivars contained 0.22% tannin. For these cultivars the correlation between tannin content and digestibility of energy was - 0 . 6 8 . The correlation between tannin content and digestibility of protein was - 0 . 5 8 . This negative relationship between tannin c o n t e n t and nutrient digestibility is in agreement with values
176 80
120 16 72 48
Seed coat colour Brown Yellow
Endosperm type Yellow Yellow corneous White White corneous
* P < 0.05 ** P < 0.01 *** P < 0.001
Analysis of variance (F values) Total (255) Seed coat colour (1) Endosperm type (3) Weight of pig (1) Residual (249)
256
All samples
Frequency (or d.f.)
15 2 9 6
22 10
32
No. of cultivars
24.86*** 2.71" 41.28"**
80.6±0.7 77.7±1.0 79.2±0.6 78.0±0.6
76.3±0.5 81.4±0.5
78.9±0.6
(%)
Digestibility of energy
65.4±1.0
Digestibility of protein (%)
10.50"** 6.15"* 28.31"**
69.5±1.1 65.3±1.6 64.7±1.1 62.3±1.1
62.620.9 68.3±0.9
Least square means of digestion coefficients of grain sorghum cult±vats
TABLE I
0.18 2.79* 18.53"**
33.9±1.5 32.5±2.0 28.1±1.4 29.0±1.4
30.4±1.1 31.3±1.1
30.9±1.3
(%)
Apparent nitrogen retention
10.0±0.2 10.0±0.1 10.9±0.2 10.8±0.2
Total protein (%)
t~ b~
223
T A B L E II Least square m e a n s o f digestion c o e f f i c i e n t s o f d i f f e r e n t grain s o r g h u m cultivars Frequency (or d.f.)
Digestibility o f energy (%)
Digestibility of protein (%)
Apparent nitrogen retention
(%)
All s a m p l e s
192
79.9 -+ 0.5
67.1 ± 0.8
31.0 -+ 1.1
Seed c o a t c o l o u r Brown Yellow
112 80
77.4 ± 0.5 82.4 ± 0.5
64.4 ± 0.8 69.8 ± 0.8
30.6 +- 1.1 34.5 ± 1.1
Endosperm Yellow White
120 72
80.6 ± 0.5 79.2 ± 0.5
69.5 ± 0.8 64.7 +- 0.8
37.1 +- 1.1 31.2 +- 1.1
29.19"**
11.46"**
2.34 0.04 28.40***
9.84** 0.59 29.74***
0.16 7.78** 1.89 13.17"**
Analysis o f variance (F values) Total 191 Seed c o a t c o l o u r 1 Endosperm type 1 Coat x e n d o s p e r m 1 Weight o f pig 1 Residual 187 ** P < 0.01 * * * P < 0.001
previously reported by Nelson et al. (1975) with the chick. It is possible that the tannin complexes with the amino acids and the glucose resulting from starch digestion, and interferes with absorption. An alternative explanation is that the tannin interferes with the actual enzymatic degradation of the protein and starch. Diets containing cultivars with yellow endosperm were superior to those containing other endosperm types with respect to energy and protein digestibility and N retention. There was no seed coat colour X endosperm type interaction. Differences in digestibility were of sufficient magnitude to explain the inferior performance obtained with brown seed coat sorghum (Noland et al., 1966). Pig weight (10--20 kg range) had a significant effect on digestibility and N retention. It has been previously reported that digestive enzymes continue to develop from birth until a pig weighs 20 kg.
224
REFERENCES Association of Official Agricultural Chemists, 1965. Official Methods of Analysis (10th ed.) Assoc. Official Agric. Chemists, Washington, D.C., 957 pp. Harvey, W.R., 1960. Least-squares analysis of data with unequal subclass frequencies. U.S. Dept. Agric., Agric. Res. Serv., ARS 20-8, 157 pp. Hillier, J.D., Martin, J.J. and Waller, G.R., 1959. The relative value of six varieties of milo for growing and finishing swine. Okla. Agric. Exp. Sta., Misc. Publ., No. 55, pp. 41--46. May, M.A. and Nelson, T.S., 1973. Digestible and metabolizable energy content of varieties of milo for rats. J. Anim. Sci., 36: 874--876. Nelson, T.S., Stephenson, E.L., Burgos, A., Floyd, J. and York, J.O., 1975. Effect of tannin content and dry matter digestion on energy utilization and average amino acid availability of hybrid sorghum grains. Poult. Sci., 54: 1620--1623. Noland, P.R., Baugus, C.A. and Scott, K.W., 1966. The use of various types of grain sorghum for growing and finishing swine. Proc. 2nd Annual Arkansas Anita. Sci. Res. Conf., Dept. Anita. Sci., Univ. Ark., Fayetteville, pp. 20--22. Parr Instrument Co., 1960. Oxygen bom b calorimetry and combustion methods. Manual, Parr Instrument Co., Moline, Ill., 56 pp. Peo, E.R., Jr. and Hudman, D.B., 1958. Grain sorghum for growing-finishing swine. J. Anita. Sci., 17: 813--818. Tanksley, T.D., 1974. Sorghum vs. corn for growing-finishing swine. Proc. 1974 Texas Nutr. Conf., Texas Agric. Exp. Sta., Texas A. and M. Univ., Bryan, pp. 214--221.