Deficient Amino Acids in a 22% Protein Corn-Soybean Meal Diet for Young Turkeys

Deficient Amino Acids in a 22% Protein Corn-Soybean Meal Diet for Young Turkeys R. J. STAS 1 ' 2 and L. M. POTTER Department of Poultry Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (Received for publication September 25, 1981)

1982 Poultry Science61:933-938

INTRODUCTION Earlier studies (Baldini et al., 1 9 5 4 ; Fisher et al, 1 9 5 6 ; Waibel, 1959) have shown m e t h i o n i n e and lysine t o be the t w o m o s t limiting a m i n o acids in corn-soybean meal diets for y o u n g t u r k e y s . In r e c e n t years, supplement a t i o n of m e t h i o n i n e and, t o a lesser e x t e n t , lysine, t o commercial p o u l t r y diets has improved p r o d u c t i o n considerably. When t h e deficiency of t h e m o s t limiting a m i n o acid is corrected b y s u p p l e m e n t a t i o n in low p r o t e i n diets, a n o t h e r a m i n o acid is likely t o b e c o m e limiting. Berry et al. ( 1 9 6 2 ) a t t e m p t e d t o d e t e r m i n e t h e m o s t limiting a m i n o acids in s o y b e a n protein for weanling pigs and albino rats. Their results clearly indicated t h a t m e t h i o n i n e was t h e first limiting a m i n o acid, t h r e o n i n e t h e second, and lysine t h e third. Warnick and A n d e r s o n ( 1 9 6 8 ) used semi-purified diets containing 14% p r o t e i n from soybean meal and 4% p r o t e i n from an a m i n o acid m i x t u r e t o deter-

'This paper was prepared from a portion of a thesis submitted by the senior author in partial fulfillment of the requirements for the M.S. degree. 2 Present address: School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104.

mine t h e sequence of limiting essential a m i n o acids for t h e growing chick. E x p e r i m e n t a l diets were f o r m u l a t e d b y omitting at least one of t h e essential a m i n o acids from t h e m i x a d d e d t o t h e 18% p r o t e i n basal diet. T h e results of their s t u d y indicated t h a t t h r e o n i n e , valine, and lysine are t h e n e x t m o s t limiting a m i n o acids in soybean p r o t e i n if m e t h i o n i n e and cystine are adequate. It is desirable t o d e t e r m i n e deficient a m i n o acids in c o m m o n l y used diets r a t h e r t h a n in specific feed ingredients. Therefore, this s t u d y was c o n d u c t e d t o d e t e r m i n e t h e m o s t deficient a m i n o acids in a m e t h i o n i n e - s u p p l e m e n t e d 2 2 % p r o t e i n diet for y o u n g turkeys c o m p o s e d primarily of g r o u n d yellow corn a n d dehulled soybean meal. MATERIALS AND METHODS T h r e e similar experiments were c o n d u c t e d utilizing a t o t a l of 1,440 p o u l t s divided i n t o 12 dietary t r e a t m e n t s per e x p e r i m e n t . In t h e first e x p e r i m e n t , p o u l t s of a medium-size variety were o b t a i n e d from t h e University h a t c h e r y . T h e poults used in t h e second a n d t h i r d experim e n t s were Large White t u r k e y s o b t a i n e d from a commercial h a t c h e r y . All t u r k e y s were sexed a t 1 day of age a n d raised t o 8 d a y s of age o n a practical-type diet formulated t o m e e t all National Research Council ( N R C , 1 9 7 7 ) r e q u i r e -

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ABSTRACT Three similar poult experiments were conducted to determine which amino acids are most deficient in a 22% protein corn-soybean meal diet supplemented with .3% DL-methionine. Diets were formulated to contain 1) 30% protein, 2) 22% protein, and 3) 22% protein plus all essential amino acids. Nine additional diets consisted of the latter diet excluding at least one added essential amino acid. All diets were fed to poults from 8 to 18 or 20 days of age. Removing either valine, lysine, threonine, or isoleucine from the amino acid mixture significantly reduced (P<.05) body weight gain by 9.3, 870T6.0, and 4.1%, respectively. These reductions, however, were not as great as the 13.9% reduction obtained by feeding the unsupplemented 22% protein diet. Results indicate that the 22% protein corn-soybean meal diet may be more deficient in nitrogen for nonessential amino acid production than in any one essential amino acid. (Key words: deficient amino acids, corn-soybean diets, lysine, valine, threonine, arginine, turkeys, poults)

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STAS AND POTTER

TABLE 1. Basal diet (22% protein)*

Ingredients Ground yellow corn Glucose monohydrate Stabilized fat Dehulled soybean meal Defluorinated phosphate Iodized salt Trace mineral mix D DL-Methionine Vitamin and feed additives 0

Amount (g/kg) 463.4 55 60 370 37.5 4 1 3 6.1

From Kjeldahl analyses, the basal diets contained 22.1, 20.5, and 20.5% protein for Experiments 1, 2, and 3, respectively. By adding 20.15% dehulled soybean meal in place of an equal amount of ground yellow corn, the analyses were 29.4, 28.9, and 29.8% protein for Experiments 1, 2, and 3, respectively. By calculation, the basal diet should contain 22.3% protein and 3,176 kcal metabolizable energy per kilogram diet. Supplied per kilogram of diet: 150 mg manganese, 100 mg zinc, 70 mg iron, 10 mg copper, 2.2 mg iodine, and .8 mg cobalt from manganese oxide, zinc oxide, ferrous sulfate, copper oxide, calcium iodate, and cobalt carbonate, respectively, with calcium carbonate as a diluent. c Supplied per kilogram of diet: 14,300 IU vitamin A, 7,150 ICU vitamin D 3 , 55 IU vitamin E, 11 mg menadione dimethylpyrimidol bisulfite (50% pure), 3.3 mg thiamine HC1, 11 mg riboflavin, 22 mg Dcalcium pantothenate, 110 mg niacin, 4,400 mg choline chloride (50% pure), 15.4 Mg vitamin B 1 2 , 2.2 mg folic acid, .22 mg biotin, 5.5 mg pyridoxine HC1, 125 mg ethoxyquin, .2 mg selenium, and 55 mg erythromycin thiocyanate.

22% protein diets was calculated using values given by NRC (1977). The difference in amounts of amino acids between the two diets was used as the amount of essential amino acids supplemented to the 22% protein basal diet (Table 2). Therefore, the 30% protein diet and the 22% protein diet supplemented with amino acids contained equal amounts of the essential amino acids. The remaining nine experimental diets were formulated by adding all essential amino acids to the 22% protein basal diet, except at least one of the test amino acids. All of the test amino acids were removed singly, except glycine, phenylalanine, and tyrosine, which were removed together. The diets formed in this manner required the poults to depend solely on the 22% protein diet to supply the specific amino acid under test. All amino acids were added in the L-form, except DL-methionine. Three amino acids, L-lysine, L-arginine, and L-histidine, were added as the hydrochloride to supply the required level of these amino acids on an equimolar basis. In the first experiment, each of the 12 diets was fed to two pens of males and two pens of females with 10 poults per pen. In the second and third experiments, the poults were divided into 60 pens of 8 poults each. Each diet was fed to two pens of males and two pens of females, except the three control diets which were fed to four pens of each sex. The poults were weighed in groups at 8, 14, and 20 days of age, except in Experiment 3, which was terminated 2 days early due to an insufficient amount of feed resulting from greater than expected feed consumption. The poults were reared in thermostatically controlled Petersime starter batteries. Average feed consumption of the poults in each pen, corrected for mortality, was determined at each weigh period. Feed and water were provided ad libitum. The data of each experiment were subjected to analysis of variance and the least significant difference between the control and experimental groups determined. Similar, statistical analyses were also conducted on the combined data of the three experiments. RESULTS The results of the combined data are presented in Table 3, and the analyses of variance of these data are presented in Table 4. The average body weight gain of the poults fed the unsupplemented 22% protein diet was signifi-

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ments. At that time, poults were allotted to experimental groups on the basis of body weight to assure similar average group weights at the start of an experiment. The composition of the 22% protein basal diet used in this study is presented in Table 1. All protein and amino acids were supplied by ground yellow corn, dehulled soybean meal, and methionine. This diet was fortified with sufficient amounts of minerals and vitamins to exceed the NRC (1977) requirements of young turkeys. By adding 20.15% dehulled soybean meal to the basal diet in the place of an equal amount of ground yellow corn, a diet containing 30% protein was formed and served as a positive control. The amino acid content of both the 30% and

DEFICIENT AMINO ACIDS IN A CORN-SOYBEAN DIET

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TABLE 2. Protein and amino acid composition of the control diets ("/a)3Differ-

22% Protein

30% Protein

enrpt)

Protein Arginine Glycine Serine Histidine Isoleucine Leucine Lysine Methionine Cystine Phenylalanine Tyrosine Threonine Tryptophan Valine

22.33 1.59 1.02 1.25 .58 1.12 1.92 1.29 .66 .34 1.00 .95 .89 .30 1.25

30.33 2.23 1.41 1.76 .81 1.57 2.46 1.89 .76 .46 1.33 1.26 1.20 .42 1.69

8.00 .64 .39 .50 .23 .44 .54 .60 .10 .12 .33 .31 .31 .12 .44

Calculated from values given by NRC (1977). Amounts of amino acids added as a mixture to the diet containing 22% protein supplemented with amino acids.

TABLE 3. Average body weights at 18 or 20 days of age and body weight gains, feed consumptions, and feed efficiencies from 8 to 18 or 20 days of age (Experiments 1, 2, and 5 ) a

Diet

Body weight

Body weight gain

30% protein 22% protein 22% protein + all amino acids — Arginine c — Gly, Phe, Tyr — Histidine — Isoleucine — Leucine — Lysine — Threonine — Tryptophan — Valine Difference required for significance"

328.1 300.6*** 330.9 323.5 331.8 330.4 321.6* 329.9 312.9*** 317.2*** 327.1 310.3*** 7.9

215.9 188.2*** 218.5 211.1 219.7 217.9 209.6* 217.7 201.0*** 205.5** 214.9 198.2*** 7.8

Feed consumption

Feed efficiency"

321.7 314.4 323.8 320.9 335.2 327.9 327.8 323.3 319.4 320.4 323.5 311.6 13.0

.6659 .5924*** .6727 .6523 .6552 .6614 .6364** .6681 .6282*** .6359** .6625 .6322*** .0231

{%>

a Each value represents the average of 12 pens of poults or 104 poults per average, except the first three diets which represent the average of 20 pens of poults or 168 poults per average.

Body weight gain divided by feed consumption. c

Minus arginine means the 22% protein diet plus all amino acids except arginine; the next eight diets are presented in a similar manner. Significantly different from values for the diet containing 22% protein plus all added amino acids. *P<.05. **P<.01. ***P<.001.

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Ingredient

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STAS AND POTTER TABLE 4. Analysis of variance of body weights at 18 or 20 days of age and body weight gains, feed consumptions, and feed efficiencies from 8 to 18 or 20 days of age of turkeys (Experiments 1, 2, and 3) Mean square

df

Experiment Diets Sex Replicate Experiment X diets Experiment X sex Experiment X replicate Replicate X sex Experiment X sex X replicate Error

2 11 1 1 22 2 2 1 2 123

Body weight 226,892*'* 1,131*** 74,433*** 27 196 1,307*** 188 9 103 120

90,282*** 1,118*** 47,942*** 55 187 755** 185 30 93 115

Feed consumption 134,033*** 437 70,031*** 1,326 176 1,489* 452 293 178 324

Feed efficiency (X 10 6 ) 48,674*** 6,000*** 23,772*** 7,231** 1,514 9,860*** 4,620* 138 40 1,017

*P<.05. **P<.01. ***P<.001.

candy lower (P<.001), approximately 13.9% or 30.3 g, when compared with the diet containing all added essential amino acids. Body weight gains for the diet containing 22% protein plus all essential amino acids and for the diet containing 30% protein were similar. Therefore, by increasing only the protein level of the diet from 22 to 30% through the addition of dehulled soybean meal to the diet, body weight gain was significantly (P<.001) increased. By removing either valine, lysine, or threonine from the amino acid mixture, body weight gains were reduced by 20.3, 17.5 (P<.001), and 13.0 g (P<.01) or by 9.3, 8.0, and 6.0%, respectively. By removing isoleucine from the amino acid mixture, body weight gain was reduced (P<.05) only by 8.9 g or by 4.1%. These reductions, however, were not as great as that observed by feeding the 22% protein diet alone. Average body weight gains obtained from poults fed any of the remaining diets were not significantly different from that of the fully supplemented 22% protein control diet but were sigificantly greater than that of the unsupplemented 22% protein basal diet. The feed consumption of the poults fed the diet containing 22% protein plus all essential amino acids was not significantly different from that of any other diet. The greatest feed efficiency was obtained from poults fed the diet

containing 22% protein plus the essential amino acid mixture. The 22% protein diet without added amino acids produced a feed efficiency approximately 12% less (P<.001) than that of the fully supplemented amino acid diet. Diets lacking either lysine, valine, threonine, or isoleucine resulted in a significantly lower (P<.01) feed efficiency when compared with the 22% protein diet plus all essential amino acids. These diets also produced feed efficiencies significantly greater (P<.01) than that of the 22% protein diet. The feed efficiencies from the remaining diets were not significantly different than that from the positive control diet but were significantly greater than that from the 22% protein basal diet.

DISCUSSION The poults fed the unsupplemented 22% protein diet had significantly reduced body weight gains and feed efficiencies in contrast to those fed the 30% protein diet. These reductions were expected, as this diet was obviously deficient in total protein, lysine, and threonine (Table 5). The minimum protein requirement for turkeys 0 to 4 weeks of age is 28% (NRC, 1977). The reduced growth rate from feeding the 22% protein basal diet was apparently not a result of a severe imbalance of

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Source of variation

Body weight gain

DEFICIENT AMINO ACIDS IN A CORN-SOYBEAN DIET

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TABLE 5. Comparison of the NRC requirements and the amino acid composition of a 22% protein diet expressed as percent of diet

Amino acid

NRC (1977) amino acid requirements (0 to 4 wks of age)

Amino acid composition of the 22% protein diet a

Arginine Glycine + serine Histidine Isoleucine Leucine Lysine Methionine + cystine Methionine Phenylalanine + tyrosine Phenylalanine Threonine Tryptophan Valine

1.6 1.0 .58 1.1 1.9 1.7 1.05 .53 1.8 1.0 1.0 .26 1.2

1.59 2.27 .58 1.12 1.92 1.29 1.00 .66 1.95 1.00 .89 .30 1.25

Percentage of requirement

(/a)

T"he corn-soybean meal diet supplemented with .3% DL-methionine.

amino acids, since feed consumption was not significantly reduced. Feed consumptions were greatly reduced from feeding diets with a severe imbalance of amino acids in experiments conducted by other researchers (Lewis and D'Mello, 1967; Sugahara etal, 1969; Harper
tion of the 22% protein basal diet used in this study indicates which amino acids may be expected to be deficient (Table 5). Most of the essential amino acids were adequately supplied by the 22% protein diet; however, only 76 and 89% of the required amounts of lysine and threonine, respectively, were supplied by this diet. By supplementing all of the essential amino acids to this diet, increases in growth were observed as expected. When either valine, lysine, threonine, or isoleucine was removed from the supplemented amino acid mixture, growth rate and feed efficiency were significantly reduced. These results indicate that valine, lysine, threonine, and isoleucine are deficient in a 22% protein diet supplemented with .3% DL-methionine. However, from the data presented in Table 5, isoleucine and valine appeared to be adequately supplied by the 22% protein diet. Therefore, these data indicate that the requirements for valine and isoleucine were underestimated by the NRC (1977) or that the amounts of these amino acids in the basal diets were overestimated by our calculations. Several studies have indicated that lysine is a limiting amino acid in addition to metiiionine in low protein corn-soybean meal diets (Baldini et al., 1954; Waibel, 1959; Fitzsimmons and Waibel, 1962; Anderson and Warnick, 1970). Results of the present study confirm these reports. The present study also indicates that

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99 227 100 102 101 76 95 125 108 100 89 115 104

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In the present study, it appears that the synthesis of nonessential amino acids from excess essential amino acids caused a significant increase in body weight gain until either valine, lysine, threonine, or isoleucine became more limiting than protein per se for nonessential amino acid formation. In general, it is postulated that when protein is not the limiting factor for nonessential amino acid synthesis, valine, lysine, threonine, and isoleucine are deficient amino acids in a 22% protein cornsoybean meal diet for young turkeys. ACKNOWLEDGMENTS Turkeys for two of the experiments con-

ducted in this study were supplied by Wampler Foods, Inc., Harrisonburg, VA. Vitamins were supplied by Agricultural Processing Corporation, Salem, VA and by Hoffmann-LaRoche, Inc., Nutley, NJ.

REFERENCES Anderson, J. O., and R. E. Warnick, 1970. Effect of replacing part of die soybean meal in turkey poult rations with amino acid and carbohydrate mixtures. Poultry Sci. 49:459—467. Baldini, J. T., H. R. Rosenberg, and J. Waddell, 1954. The protein requirement of the turkey poult. Poultry Sci. 33:539-543. Berry, T. H., D. E. Becker, O. G. Rasmussen, A. H. Jensen, and H. W. Norton, 1962. The limiting amino acids in soybean protein. J. Anim. Sci. 21: 558-561. Blair, R., D.W.F. Shannon, J. M. McNab, and D.J.W. Lee, 1972. Effects on chick growth of adding glycine, proline, glutamic acid or diammonium citrate to diets containing crystalline essential amino acids. Br. Poultry Sci. 13:215-228. Fisher, H., J. Dowling, Jr., and K. H. Maddy, 1956. Low protein diets for turkeys raised under practical conditions. Poultry Sci. 35:239—241. Fitzsimmons, R. C , and P. E. Waibel, 1962. Determination of the limiting amino acids in cornsoybean oil meal diets for young turkeys. Poultry Sci. 41:260-268. Harper, A. E., N. J. Benevenga, and R. M. Wohlhueter, 1970. Effects of ingestion of disproportionate amounts of amino acids. Physiol. Rev. 50:428— 558. Lewis, D., and J.P.F. D'Mello, 1968. Growth and dietary amino acid balance. Pages 345—366 in Growth and Development of Mammals. G. A. Lodge and G. E. Lamming, ed. Plenum Press, New York, NY. National Research Council, 1977. Nutrient Requirements of Poultry. Natl. Acad. Sci., Washington, DC. Sugahara, M., D. H. Baker, and H. M. Scott, 1969. Effect of different patterns of excess amino acids on performance of chicks fed amino aciddeficient diets. J. Nutr. 97:29-32. Velu, J. G., D. H. Baker, and H. M. Scott, 1970. Amino acid balance and body composition changes in die young chick. Poultry Sci. 49: 1448. Waibel, P. E., 1959. Methionine and lysine in rations for turkey poults under various dietary conditions. Poultry Sci. 38:712-721. Warnick, R. E., and J. O. Anderson, 1968. Limiting essential amino acids in soybean meal for growing chickens and the effects of heat upon availability of the essential amino acids. Poultry Sci. 47:281-287.

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threonine, valine, and lysine are deficient in a 22% protein corn-soybean meal diet for young turkeys. Previous researchers have found these amino acids to be limiting in practical diets for species other than turkeys (Berry et al, 1962; Warnick and Anderson, 1968). To synthesize body proteins, the poult requires all essential amino acids of those proteins to be present in adequate amounts from a particular diet. When a deficient amino acid diet is fed, protein synthesis continues until the limiting amino acid is no longer available and growth is arrested. In the present study, one would expect that by removing the most limiting amino acids from the amino acid mixture, weight gain would be reduced to the level of the basal diet. However, comparison of the weight gain achieved by feeding the 22% protein basal diet with the gains from feeding diets in which when either valine, lysine, threonine, or isoleucine was removed from the supplemented amino acid mixture, the reduction was not as great as that observed in poults fed the 22% protein basal diet. Therefore, the 22% protein basal diet appears to be primarily deficient in nonessential amino acid nitrogen rather than in a specific essential amino acid. Supplementing the 22% protein basal diet with the essential amino acids may have provided a source of nitrogen to be used to synthesize nonessential amino acids. Blair et al. (1972) obtained increased rates of growth of chicks from adding a source of nitrogen, preferably glutamic acid, to diets containing required levels of essential amino acids from crystalline sources.