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The Availability of Amino Acids From Palm Kernel, Soybean, Cottonseed and Rapeseed Meal for the Growing Chick
The Availability of Amino Acids From Palm Kernel, Soybean, Cottonseed and Rapeseed Meal for the Growing Chick E . N . NWOKOLO, D. B . BRAGG AND W . D . KITTS
Department of Poultry Science, University of British Columbia, Vancouver, B.C. V6T IW5, Canada (Received for publication March 5, 1976)
POULTRY SCIENCE 55: 2300-2304, 1976
INTRODUCTION
E
ARLY attempts to estimate the biological availability of amino acids from feeds include "in vitro" enzymic digestion using pancreatin (Riesen et al., 1947) or pepsin plus pancreatin (Sheffner et al., 1956). Ford and Salter (1966) coupled the enzymic digestion procedure with gel filtration and microbiological assay of free amino acids. Carpenter (1960) and Rao et al. (1963) estimated lysine availability by chemical methods while Stott and Smith (1966) used Tetrahymena pyriformis W. for measuring availability of lysine, methionine, arginine and histidine. Price et al. (1953) employed chick carcass analysis to evaluate dietary amino acids and proteins. De Muelenaere et al. (1967) estimated lysine availability of cereal products by fecal and growth analysis. Miner and Watts (1961) determined amino acid availability in cottonseed and soybean meals by the balance method while Sarwar et al. (1975) evaluated the availability of amino acids in processed and unprocessed soybean and rapeseed meal by a combination of the balance method and carcass analysis.
In addition to considerable expenditure of time, labour and material, many studies were limited to the utilization of only one amino acid while others were limited to a few amino acids. Also, the low values observed in some of these studies, indicated that availability might have been underestimated. Bragg et al. (1969) reported a method that measured the actual disappearance of amino acids from the gut and provided an accurate assessment for the availability of sixteen dietary amino acids simultaneously, as indicated by its application (Ivy et al., 1971; Stephenson et al., 1971; Rostagno et al., 1973; Sarwar et al., 1975, Sarwar and Bowland, 1975). Due to limited comparative studies on amino acid availability of dietary protein sources, this study was designed to compare amino acid content and availability of palm kernel meal (PKM), Soybean meal (SBM), cottonseed meal (CSM) and rapeseed meal (RSM) by the growing chick. EXPERIMENTAL Commercial samples of PKM, SBM, CSM and RSM were used throughout this study. PKM was imported from Nigeria, SBM and
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ABSTRACT Amino acid composition was determined for palm kernel meal (PKM), soybean meal (SBM), cottonseed meal (CSM), and rapeseed meal (RSM). These protein sources were fed to broiler chicks to determine the availability of amino acids. The concentrations of amino acids were closely related to protein content with a few exceptions (e.g. arginine was high in PKM and glutamic acid was high in CSM). Amino acid availability varied among protein sources. Average amino acid availability (16 amino acids) was 84.5, 97.3, 92.5 and 91.9% from PKM, SBM, CSM and RSM respectively. Significant differences in availability of each individual amino acid were observed among feedstuffs tested. Also, considerable variation was observed for availability among amino acids within feedstuffs. Glycine and arginine were low in PKM whereas lysine was lowest in CSM and methionine was lowest in RSM. SBM showed high amino acid availability for all amino acids tested.
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AMINO ACID AVAILABILITY
% Amino acid availability
TABLE 1.—Proximate analyses of PKM, SBM,
CSM and RSM (dry matter basis) Ingredient
% D.M.
% Protein
% Fibre
Ash
% Ether extract
PKM SBM CSM RSM
92.0 91.1 92.4 90.5
21.3 48.0 41.0 38.0
17.5 6.5 13.6 12.0
5.0 6.0 7.0 7.2
7.8 0.6 2.0 1.5
%
TABLE 2.—Amino acid composition of PKM, SBM CSM and RSM (dry matter basis)
Amino acids Lysine Histidine Arginine Aspartic acid Threonine Serine Glutamic acid Proline Glycine Alanine Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine
PKM 0.69 0.41 2.68 1.69 0.66 0.90 3.62 0.50 0.91 0.81 0.43 0.47 0.60 1.23 0.58 0.82
Protein source (%) SBM CSM RSM 2.95 1.23 3.45 5.64 1.88 2.48 9.01 1.21 2.16 2.16 1.02 0.75 1.92 3.71 1.84 2.44
2.19 1.37 5.60 4.74 1.51 2.15 10.32 1.58 2.31 2.04 1.68 0.70 1.22 2.85 1.45 2.48
2.08 0.98 1.93 2.38 1.48 1.48 6.22 2.16 1.79 1.58 0.75 0.84 1.30 2.57 1.09 1.49
= Total A. A. consumed - (Total A.A. Protein feces
CSM and RSM were between 21.3 and 48.0%. PKM was highest in crude fibre and ether — Total A. A. Non-protein feces) extract. x 100 -H Total A.A. consumed A comparison of each amino acid level in PKM to SBM (Table 2) showed that lysine Amino acid availability represented the perwas lowest (23% of SBM) and arginine was centage of amino acids actually utilized by the chick after correction of endogenous highest (77% of SBM). PKM is deficient in amino acids measured on excreta from the the essential amino acids especially lysine, amino acid free diet. All results were ex- threonine and methionine. PKM can be sucpressed on a dry matter basis. Data were cessfully utilized as a protein source in the statistically tested according to Snedecor chick diet, provided that it is adequately sup(1956) and differences between treatments plemented with other protein sources. were determined by multiple range analysis The amino acid composition of SBM, CSM (Duncan, 1955). and RSM agree well with values in the literature (N.A.S.—N.R.C., 1969). Rapeseed meal is lower than SBM and CSM in histidine, RESULTS AND DISCUSSION arginine, serine and valine, but slightly higher The proximate analysis of PKM, SBM, in methionine. Considering the fact that the CSM and RSM are presented in Table 1. protein content is lower than in SBM and Differences in protein content of PKM, SBM, CSM, RSM has a good amino acid pattern
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RSM were obtained in Canada and CSM was purchased from the U.S.A. The experimental arrangement was a completely randomized design involving four experimental diets with each diet fed to four replicate groups of four chicks each. The feeding trial and analysis were carried out according to the procedure of Bragg et al. (1969). This method includes analysis of endogenous amino acids excreted by the chick. The amount of endogenous amino acids is significant and corrections for this factor are necessary in availability calculations to clearly distinguish availability from digestibility. Dry matter consumption and fecal dry matter output during the experiment were recorded. Amino acids in PKM, SBM, CSM, RSM and feces collected for each diet were determined by amino acid analysis (Piez and Morris, 1960) following hydrolysis with 3NHC1 for 15 hours at 121° C. Amino acid availability was calculated by the equation presented by Bragg et al. (1969).
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E. N. NWOKOLO, D. B. BRAGG AND W. D. KITTS
TABLE 3.—Amino acid availability in PKM, SBM, CSM and RSM fed to chicks
Amino acid
SBM
Protein source (%) CSM
90.0a 90.1a 93.2a 87.6a 86.5a 88.7a 90.1a 68.0a 63.3a 85.5a 68.4a 91.4a 86.1a 88.5a 85.0a 90.5a 84.5
99.0c 98.8c 98.8b 98.3c 97.9c 98.1c 98.9c 93.0b 92.9b 97.4d 92.9b 98.7b 97.7c 98.4d 98.0c 98.6c 97.3
89.0a 93.8b 95.7a 93.6b 89.8b 93.0b 96.3b 90.9b 91.7b 89.2b 91.1b 93.3b 91.3b 92.4b 94.2bc 95.2b 92.5
RSM
Average
94.4b 94.2b 95.8a 91.7b 90.8b 91.4ab 94.9b 91.2b 89.4b 94.2c 90.9b 78.4a 91.6b 94.0c 92.8b 94.8b
93.1 94.2 95.9 92.8 91.2 92.8 94.3 85.5 84.1 91.6 85.6 90.4 91.7 93.3 92.5 94.8
91.9
—
Means with different letters among protein sources are significantly different (P < 0.01). and can be utilized efficiently in poultry rations as a major supplier of amino acids. Commerical rape seed meal appears to have a greater potential for providing more dietary amino acids than is presently utilized (approximately 5% in layer diets and 15% in broiler diets). The amino acid availability of the protein concentrates (Table 3) showed some variation between the feed ingredients. It was evident that SBM had the greatest amino acid availability while PKM had the lowest (P < 0.01). CSM and RSM were intermediate in amino acid availability between PKM and SBM. The availability of amino acids in PKM averaged 84.5% (range of 63.3% to 93.2%). Availability of the essential amino acids for the chick showed that glycine (63.3%) and valine (68.4%) were exceptionally low. Availability figures for lysine (90.0%), threonine (86.5%) and methionine (91.4%) indicated effective utilization of these amino acids. The low availability of glycine and valine coupled with the relatively low levels of these amino acids in PKM necessitates amino acid supplementation or the use of considerable amounts of other protein sources, when PKM is incorporated into chick rations. Nesheim (1965)
suggested that factors responsible for lowered amino acid availability from certain feed ingredients could include protein-sugar interactions in feedstuffs with low levels of protein, protein-fat interactions involving carbonyl products reacting with free amino groups, inhibitors of plant origin and heat treatment during processing. Dammers (1965) and Flipot et al. (1971) implicated crude fibre as a factor depressing availability of amino acids. However, it is difficult to evaluate the reason for low glycine and valine availability from PKM. The ingredient has a high fibre content although this may not be the major influencing factor on amino acid utilization due to the fact that all amino acids were not affected as severely as glycine and valine. The combination of low protein (21.3%), high ether extract (7.8%), high levels of acid detergent fibre and acid detergent lignin may influence the availability of glycine and valine. Furthermore, the product undergoes extensive heat treatment during processing of the meal. Since no inhibitors of plant origin have been observed in PKM, it is assumed that none are present. The percentage availability of amino acids in SBM shown in Table 3 averaged 97.3%
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Lysine Histidine Arginine Aspartic acid Threonine Serine Glutamic acid Proline Glycine Alanine Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine Average
PKM
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AMINO ACID AVAILABILITY
Information on the availability of amino acids in RSM is limited and only a few studies have been reported. The availability of amino acids from RSM (Table 3) varied from 78.4% to 95.9% with an average of 91.9%. With the exception of methionine which was 78.4% available, the essential amino acids showed
relatively high availability although most were significantly lower than in SBM. These results were considerably higher than amino acid digestibility reported by Cho and Bayley (1970) and by Tao et al. (1971) for RSM but agreed closely with the results of Sarwar et al. (1975). Cho and Bayley (1970) employing pig fecal analysis had reported a range of 74% to 86% for RSM amino acid digestibility. Tao et al. (1971) using colostomized broiler chicks showed that true digestibility coefficients for 16 amino acids of RSM varied from 63% to 80%. However, Bragg et al. (1969) showed that normal chicks provided higher values with greater reproduceability than colostomized chicks. Sarwar et al. (1975) used balance trials to show amino acid availability of 83 to 92% for RSM. The lower digestibility coefficients for amino acids observed by Cho and Bayley (1970) appears to be the result of procedure utilized. Digestibility trials do not include a method for measuring endogenous amino acids. Therefore, an endogenous correction is not utilized in calculating the apparent digestibility, thus a lower value results from this procedure compared to the availability procedure. Successful methods of detoxification of RSM have been developed and the product provides a good source of essential amino acids and a relatively high level of availability, therefore RSM can be incorportaed as a major protein source in the diet of growing animals. ACKNOWLEDGEMENT The authors wish to express their appreciation to the National Research Council of Canada for providing the support that made this study possible. Also, appreciation is gratefully acknowledged for the supply of cottonseed meal provided by Mayflower Farms of Portland, Oregon.
REFERENCES Bragg, D. B., C. A. Ivy and E. L. Stephenson, 1969.
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(with a range of 92.0% to 99.0%). This is in agreement with results reported by Flipot et al. (1971) and by Ivy et al. (1970) for SBM, but higher than those reported by Cho and Bayley (1970) using pig fecal analysis. This would be expected due to the absence of a correction for endogenous amino acids in the latter study. The results of this study were also slightly higher than values reported by Eggum (1968) but agreed closely with those by Sarwar et al. (1975) for SBM fed to rats. Amino acid availability of CSM (Table 3) averaged 92.5% with a range of 89.0% to 96.3%. Lysine (89.0%) was lower than shown for SBM and RSM while methionine (93.3%) was higher than values for PKM and RSM. Most amino acids were approximately 5.0% lower in availability for CSM than was observed for SBM. Miner and Watts (1961) using a balance method reported appreciable differences between total and available amino acids in cottonseed meal. Kuiken and Lyman (1948) reported the availability of essential amino acids from hydraulic type CSM to vary from 63.6% (lysine) to 93.7% (arginine) while solvent extracted CSM gave availability results above 90% (Kuiken, 1951). Thyong (1967) reported lysine availability in cottonseed cake and CSM as 67.3% and 72.5% respectively. It is of considerable interest to note that CSM has a high level of essential amino acids which are well utilized. In many developing countries of the world where cotton is produced and processed, CSM can effectively replace the more expensive SBM in the diet of growing monogastric animals. Gossypol content will affect use in poultry diets due to the adverse effect on egg yolk quality.
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E . N . NWOKOLO, D. B . BRAGG AND W . D .
Nesheim, M. C , 1965. Amino acid availability in processed proteins. Cornell Nutrition Conference for Feed Manufacturers. Piez, K. A., and L. Morris, 1960. Amodified procedure for the automatic analysis of amino acids. Anal. Biochem. 1: 187-201. Price, W. A. (Jr.), M. W. Taylor and W. C. Russell, 1953. The retention of essential amino acids by the growing chick. J. Nutrition, 51: 413-422. Rao, S. R., F. L. Carter and V. L. Frampton. 1963. Determination of available lysine in oilseed meal proteins. Anal. Chem. 35: 1927-1930. Riesen, W. H., D. R. Clandinin, C. A. Elvehjem and W. W. Cravens, 1947. Liberation of essential amino acids from raw, properly heated, and over heated soybean oil meal. J. Biol. Chem. 167: 143-150. Rostagno, H. S., J. C. Ragler and W. R. Featherson, 1973. Studies on the nutritional value of sorghum grains with varying tannin content for chicks. 2. Amino acid digestibility studies. Poultry Sci. 52: 772-778. Sarwar, G., and J. P. Bowland, 1975. Availability of amino acids in wheat cultivars used in diets for weanling rats. Can. J. Anim. Sci. 55: 579-586. Sarwar, G., D. W. F. Shannon and J. P. Bowland, 1965. Effects of processing conditions on the availability of amino acids in soybean and rapeseed proteins when fed to rats. Can. Inst. Food Sci. Technol. J. 8: 137-141. Sheffner, A. L., R. Adachi and H. Spector, 1956. Measurement of the net utilization of heat-processed proteins by means of the pepsin digest-residue (PDR) amino acid index. J. Nutrition, 60: 507-516. Snedecor, G. W. 1956. Statistical Methods. The Iowa State University Press. Ames, Iowa. Stephenson, E. L., J. O. York, D. B. Bragg and C. A. Ivy, 1971. The amino acid content and availability of different strains of grain sorghum to the chick. Poultry Sci. 50: 581-584. Stott, J. A., and H. Smith, 1966. Microbiological assay of protein quality with Tetrahymena pyriformis W. 4: Measurement of available lysine, methionine, arginine and histidine. Br. J. Nutr. 20: 663-673. Tao, R., R. J. Belzile and G. J. Brisson, 1971. Amino acid digestibility of rapeseed meal fed to chickens; effects of fat and lysine supplementation. Can. J. Anim. Sci. 51:705-709. Thyong, N. V., 1967. Availability and digestibility of lysine in oil meal and oil cakes. Nutr. Abstr. Rev. 37: 37-38.
MARCH 2-4, 1977. MIDWEST POULTRY FEDERATION CONVENTION, RADISSON DOWNTOWN HOTEL, MINNEAPOLIS, MINNESOTA
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Methods for determining amino acid availability of feeds. Poultry Sci. 48: 2135-2137. Carpenter, K. J., 1960. Estimation of the available lysine in animal-protein foods. Biochem. J. 77: 604-610. Cho, C. Y., and H. S. Bayley, 1970. Evaluation of rapeseed and soybean meals as protein sources for swine: apparent digestibilities of amino acids. Can. J. Anim. Sci. 50: 521-528. Dammers, J., 1965. Digestibility in the pig. Factors influencing the digestion of the components of the feed and the digestibility of the amino acids. Nutr. Abstr. Rev. 35: 1169. De Muelenaere, H. J. H., M. L. Chen and A. E. Harper, 1967. Assessment of factors influencing estimation of availability of threonine, isoleucine and valine in cereal products. J. Agr. Food Chem. 15: 318-323. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42. Eggum, B. C. 1968. Nutritional evaluation of proteins by laboratory animals. In: Evaluation of Novel Protein Products. Bender, A. I., R. Kihlberg, B. Lofquist, and L. Munck, Ed. Proc. of International Biological programme (IBP) and Wenner-Gren Centre Symposium. Stockholm, Sweden. Pergamon Press, New York. Flipot, P., R. J. Belzile and G. J. Brisson, 1971. Availability of the amino acids in casein, fishmeal, soy protein and zein as measured in the chick. Can. J. Anim. Sci. 51:801-802. Ford, J. E., and D. N. Salter, 1966. Analysis of enzymically digested food proteins by sephadex-gel filtration. Br. J. Nutr. 20: 843-860. Ivy, C. A., D. B. Bragg and E. L. Stephenson, 1971. The availability of amino acids from soybean meal for the growing chick. Poultry Sci. 50: 408-410. Kuiken, K. A., 1951. Availability of amino acids in cottonseed products. Federation Proc. 10: 211-212. Kuiken, K. A., and C. M. Lyman, 1948. Availability of amino acids in some foods. J. Nutrition, 36: 359-368. Miner, J. J., and A. B. Watts, 1961. Biological evaluation of soybean oil meal versus cottonseed meal by amino acid digestibility and protein efficiency ratio studies. Poultry Sci. 51: 1431. National Academy of Sciences—National Research Council, 1969. United States—Canadian Tables of Feed Composition. Publication 1684, National Academy of Sciences, Washington, D.C.
KITTS
Department of Poultry Science, University of British Columbia, Vancouver, B.C. V6T IW5, Canada (Received for publication March 5, 1976)
POULTRY SCIENCE 55: 2300-2304, 1976
INTRODUCTION
E
ARLY attempts to estimate the biological availability of amino acids from feeds include "in vitro" enzymic digestion using pancreatin (Riesen et al., 1947) or pepsin plus pancreatin (Sheffner et al., 1956). Ford and Salter (1966) coupled the enzymic digestion procedure with gel filtration and microbiological assay of free amino acids. Carpenter (1960) and Rao et al. (1963) estimated lysine availability by chemical methods while Stott and Smith (1966) used Tetrahymena pyriformis W. for measuring availability of lysine, methionine, arginine and histidine. Price et al. (1953) employed chick carcass analysis to evaluate dietary amino acids and proteins. De Muelenaere et al. (1967) estimated lysine availability of cereal products by fecal and growth analysis. Miner and Watts (1961) determined amino acid availability in cottonseed and soybean meals by the balance method while Sarwar et al. (1975) evaluated the availability of amino acids in processed and unprocessed soybean and rapeseed meal by a combination of the balance method and carcass analysis.
In addition to considerable expenditure of time, labour and material, many studies were limited to the utilization of only one amino acid while others were limited to a few amino acids. Also, the low values observed in some of these studies, indicated that availability might have been underestimated. Bragg et al. (1969) reported a method that measured the actual disappearance of amino acids from the gut and provided an accurate assessment for the availability of sixteen dietary amino acids simultaneously, as indicated by its application (Ivy et al., 1971; Stephenson et al., 1971; Rostagno et al., 1973; Sarwar et al., 1975, Sarwar and Bowland, 1975). Due to limited comparative studies on amino acid availability of dietary protein sources, this study was designed to compare amino acid content and availability of palm kernel meal (PKM), Soybean meal (SBM), cottonseed meal (CSM) and rapeseed meal (RSM) by the growing chick. EXPERIMENTAL Commercial samples of PKM, SBM, CSM and RSM were used throughout this study. PKM was imported from Nigeria, SBM and
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ABSTRACT Amino acid composition was determined for palm kernel meal (PKM), soybean meal (SBM), cottonseed meal (CSM), and rapeseed meal (RSM). These protein sources were fed to broiler chicks to determine the availability of amino acids. The concentrations of amino acids were closely related to protein content with a few exceptions (e.g. arginine was high in PKM and glutamic acid was high in CSM). Amino acid availability varied among protein sources. Average amino acid availability (16 amino acids) was 84.5, 97.3, 92.5 and 91.9% from PKM, SBM, CSM and RSM respectively. Significant differences in availability of each individual amino acid were observed among feedstuffs tested. Also, considerable variation was observed for availability among amino acids within feedstuffs. Glycine and arginine were low in PKM whereas lysine was lowest in CSM and methionine was lowest in RSM. SBM showed high amino acid availability for all amino acids tested.
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AMINO ACID AVAILABILITY
% Amino acid availability
TABLE 1.—Proximate analyses of PKM, SBM,
CSM and RSM (dry matter basis) Ingredient
% D.M.
% Protein
% Fibre
Ash
% Ether extract
PKM SBM CSM RSM
92.0 91.1 92.4 90.5
21.3 48.0 41.0 38.0
17.5 6.5 13.6 12.0
5.0 6.0 7.0 7.2
7.8 0.6 2.0 1.5
%
TABLE 2.—Amino acid composition of PKM, SBM CSM and RSM (dry matter basis)
Amino acids Lysine Histidine Arginine Aspartic acid Threonine Serine Glutamic acid Proline Glycine Alanine Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine
PKM 0.69 0.41 2.68 1.69 0.66 0.90 3.62 0.50 0.91 0.81 0.43 0.47 0.60 1.23 0.58 0.82
Protein source (%) SBM CSM RSM 2.95 1.23 3.45 5.64 1.88 2.48 9.01 1.21 2.16 2.16 1.02 0.75 1.92 3.71 1.84 2.44
2.19 1.37 5.60 4.74 1.51 2.15 10.32 1.58 2.31 2.04 1.68 0.70 1.22 2.85 1.45 2.48
2.08 0.98 1.93 2.38 1.48 1.48 6.22 2.16 1.79 1.58 0.75 0.84 1.30 2.57 1.09 1.49
= Total A. A. consumed - (Total A.A. Protein feces
CSM and RSM were between 21.3 and 48.0%. PKM was highest in crude fibre and ether — Total A. A. Non-protein feces) extract. x 100 -H Total A.A. consumed A comparison of each amino acid level in PKM to SBM (Table 2) showed that lysine Amino acid availability represented the perwas lowest (23% of SBM) and arginine was centage of amino acids actually utilized by the chick after correction of endogenous highest (77% of SBM). PKM is deficient in amino acids measured on excreta from the the essential amino acids especially lysine, amino acid free diet. All results were ex- threonine and methionine. PKM can be sucpressed on a dry matter basis. Data were cessfully utilized as a protein source in the statistically tested according to Snedecor chick diet, provided that it is adequately sup(1956) and differences between treatments plemented with other protein sources. were determined by multiple range analysis The amino acid composition of SBM, CSM (Duncan, 1955). and RSM agree well with values in the literature (N.A.S.—N.R.C., 1969). Rapeseed meal is lower than SBM and CSM in histidine, RESULTS AND DISCUSSION arginine, serine and valine, but slightly higher The proximate analysis of PKM, SBM, in methionine. Considering the fact that the CSM and RSM are presented in Table 1. protein content is lower than in SBM and Differences in protein content of PKM, SBM, CSM, RSM has a good amino acid pattern
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RSM were obtained in Canada and CSM was purchased from the U.S.A. The experimental arrangement was a completely randomized design involving four experimental diets with each diet fed to four replicate groups of four chicks each. The feeding trial and analysis were carried out according to the procedure of Bragg et al. (1969). This method includes analysis of endogenous amino acids excreted by the chick. The amount of endogenous amino acids is significant and corrections for this factor are necessary in availability calculations to clearly distinguish availability from digestibility. Dry matter consumption and fecal dry matter output during the experiment were recorded. Amino acids in PKM, SBM, CSM, RSM and feces collected for each diet were determined by amino acid analysis (Piez and Morris, 1960) following hydrolysis with 3NHC1 for 15 hours at 121° C. Amino acid availability was calculated by the equation presented by Bragg et al. (1969).
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E. N. NWOKOLO, D. B. BRAGG AND W. D. KITTS
TABLE 3.—Amino acid availability in PKM, SBM, CSM and RSM fed to chicks
Amino acid
SBM
Protein source (%) CSM
90.0a 90.1a 93.2a 87.6a 86.5a 88.7a 90.1a 68.0a 63.3a 85.5a 68.4a 91.4a 86.1a 88.5a 85.0a 90.5a 84.5
99.0c 98.8c 98.8b 98.3c 97.9c 98.1c 98.9c 93.0b 92.9b 97.4d 92.9b 98.7b 97.7c 98.4d 98.0c 98.6c 97.3
89.0a 93.8b 95.7a 93.6b 89.8b 93.0b 96.3b 90.9b 91.7b 89.2b 91.1b 93.3b 91.3b 92.4b 94.2bc 95.2b 92.5
RSM
Average
94.4b 94.2b 95.8a 91.7b 90.8b 91.4ab 94.9b 91.2b 89.4b 94.2c 90.9b 78.4a 91.6b 94.0c 92.8b 94.8b
93.1 94.2 95.9 92.8 91.2 92.8 94.3 85.5 84.1 91.6 85.6 90.4 91.7 93.3 92.5 94.8
91.9
—
Means with different letters among protein sources are significantly different (P < 0.01). and can be utilized efficiently in poultry rations as a major supplier of amino acids. Commerical rape seed meal appears to have a greater potential for providing more dietary amino acids than is presently utilized (approximately 5% in layer diets and 15% in broiler diets). The amino acid availability of the protein concentrates (Table 3) showed some variation between the feed ingredients. It was evident that SBM had the greatest amino acid availability while PKM had the lowest (P < 0.01). CSM and RSM were intermediate in amino acid availability between PKM and SBM. The availability of amino acids in PKM averaged 84.5% (range of 63.3% to 93.2%). Availability of the essential amino acids for the chick showed that glycine (63.3%) and valine (68.4%) were exceptionally low. Availability figures for lysine (90.0%), threonine (86.5%) and methionine (91.4%) indicated effective utilization of these amino acids. The low availability of glycine and valine coupled with the relatively low levels of these amino acids in PKM necessitates amino acid supplementation or the use of considerable amounts of other protein sources, when PKM is incorporated into chick rations. Nesheim (1965)
suggested that factors responsible for lowered amino acid availability from certain feed ingredients could include protein-sugar interactions in feedstuffs with low levels of protein, protein-fat interactions involving carbonyl products reacting with free amino groups, inhibitors of plant origin and heat treatment during processing. Dammers (1965) and Flipot et al. (1971) implicated crude fibre as a factor depressing availability of amino acids. However, it is difficult to evaluate the reason for low glycine and valine availability from PKM. The ingredient has a high fibre content although this may not be the major influencing factor on amino acid utilization due to the fact that all amino acids were not affected as severely as glycine and valine. The combination of low protein (21.3%), high ether extract (7.8%), high levels of acid detergent fibre and acid detergent lignin may influence the availability of glycine and valine. Furthermore, the product undergoes extensive heat treatment during processing of the meal. Since no inhibitors of plant origin have been observed in PKM, it is assumed that none are present. The percentage availability of amino acids in SBM shown in Table 3 averaged 97.3%
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Lysine Histidine Arginine Aspartic acid Threonine Serine Glutamic acid Proline Glycine Alanine Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine Average
PKM
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AMINO ACID AVAILABILITY
Information on the availability of amino acids in RSM is limited and only a few studies have been reported. The availability of amino acids from RSM (Table 3) varied from 78.4% to 95.9% with an average of 91.9%. With the exception of methionine which was 78.4% available, the essential amino acids showed
relatively high availability although most were significantly lower than in SBM. These results were considerably higher than amino acid digestibility reported by Cho and Bayley (1970) and by Tao et al. (1971) for RSM but agreed closely with the results of Sarwar et al. (1975). Cho and Bayley (1970) employing pig fecal analysis had reported a range of 74% to 86% for RSM amino acid digestibility. Tao et al. (1971) using colostomized broiler chicks showed that true digestibility coefficients for 16 amino acids of RSM varied from 63% to 80%. However, Bragg et al. (1969) showed that normal chicks provided higher values with greater reproduceability than colostomized chicks. Sarwar et al. (1975) used balance trials to show amino acid availability of 83 to 92% for RSM. The lower digestibility coefficients for amino acids observed by Cho and Bayley (1970) appears to be the result of procedure utilized. Digestibility trials do not include a method for measuring endogenous amino acids. Therefore, an endogenous correction is not utilized in calculating the apparent digestibility, thus a lower value results from this procedure compared to the availability procedure. Successful methods of detoxification of RSM have been developed and the product provides a good source of essential amino acids and a relatively high level of availability, therefore RSM can be incorportaed as a major protein source in the diet of growing animals. ACKNOWLEDGEMENT The authors wish to express their appreciation to the National Research Council of Canada for providing the support that made this study possible. Also, appreciation is gratefully acknowledged for the supply of cottonseed meal provided by Mayflower Farms of Portland, Oregon.
REFERENCES Bragg, D. B., C. A. Ivy and E. L. Stephenson, 1969.
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(with a range of 92.0% to 99.0%). This is in agreement with results reported by Flipot et al. (1971) and by Ivy et al. (1970) for SBM, but higher than those reported by Cho and Bayley (1970) using pig fecal analysis. This would be expected due to the absence of a correction for endogenous amino acids in the latter study. The results of this study were also slightly higher than values reported by Eggum (1968) but agreed closely with those by Sarwar et al. (1975) for SBM fed to rats. Amino acid availability of CSM (Table 3) averaged 92.5% with a range of 89.0% to 96.3%. Lysine (89.0%) was lower than shown for SBM and RSM while methionine (93.3%) was higher than values for PKM and RSM. Most amino acids were approximately 5.0% lower in availability for CSM than was observed for SBM. Miner and Watts (1961) using a balance method reported appreciable differences between total and available amino acids in cottonseed meal. Kuiken and Lyman (1948) reported the availability of essential amino acids from hydraulic type CSM to vary from 63.6% (lysine) to 93.7% (arginine) while solvent extracted CSM gave availability results above 90% (Kuiken, 1951). Thyong (1967) reported lysine availability in cottonseed cake and CSM as 67.3% and 72.5% respectively. It is of considerable interest to note that CSM has a high level of essential amino acids which are well utilized. In many developing countries of the world where cotton is produced and processed, CSM can effectively replace the more expensive SBM in the diet of growing monogastric animals. Gossypol content will affect use in poultry diets due to the adverse effect on egg yolk quality.
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