British Poultry Science
ISSN: 0007-1668 (Print) 1466-1799 (Online) Journal homepage: http://www.tandfonline.com/loi/cbps20
Requirements of the young turkey for sulphur amino acids and threonine: Comparison with other species J. P. F. D'Mello To cite this article: J. P. F. D'Mello (1976) Requirements of the young turkey for sulphur amino acids and threonine: Comparison with other species, British Poultry Science, 17:2, 157-162, DOI: 10.1080/00071667608416261 To link to this article: http://dx.doi.org/10.1080/00071667608416261
Published online: 08 Nov 2007.
Submit your article to this journal
Article views: 7
View related articles
Citing articles: 3 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=cbps20 Download by: [University of Florida]
Date: 06 November 2015, At: 20:11
Br. Poult. Set., 17: 157-162. 1976
Longman: printed in Great Britain
REQUIREMENTS OF THE YOUNG TURKEY FOR SULPHUR AMINO ACIDS AND THREONINE: COMPARISON WITH OTHER SPECIES J. P. F. D'MELLO Department of Agricultural Biochemistry, Edinburgh School of Agriculture, West Mains Road, Edinburgh EH9 3JG, Scotland Downloaded by [University of Florida] at 20:11 06 November 2015
Received for publication 1st April 1975
1. The requirements of the 3-week-old turkey for the sulphur containing amino acids and for threonine were estimated to be 0.83% and 0.94% respectively in diets containing 12.5 MJ ME/kg. 2. It is suggested that the growth responses of rats and slow-growing chicks and of fast-growing chicks and young turkeys to daily intakes of the sulphur containing amino acids and of threonine are similar. INTRODUCTION
Earlier studies on the amino acid requirements of the young turkey (D'Mello, 1975; D'Mello and Emmans, 1975), yielded data for lysine, arginine, leucine, isoleucine and valine. These studies also permitted comparisons between chicks and turkeys of the same age in their daily requirements for these amino acids. The current report provides data on the requirements of the 3-week-old poult for the sulphur containing amino acids and for threonine. Although there is considerable information on the responses of turkeys to dietary methionine supplementation (Waibel, 1959; Fitzsimmons and Waibel, 1962), the absence of appropriate analytical and food intake data preclude comparisons between chicks and turkeys with respect to their methionine requirements. MATERIALS AND METHODS
Conduct of experiments
Two experiments were conducted with male turkey poults (British United Turkeys, Triple 6). Details of the housing and management of poults are given in earlier papers (D'Mello, 1973a; D'Mello, 1975; D'Mello and Emmans, 1975). As in the earlier experiments the turkeys were allocated to treatments at 7 d of age for a period of 14 d. Experimental diets
Semi-purified diets in ground form were employed in both experiments (see Table 1). The experimental basal diets were analysed for amino acids by automatic ion-exchange chromatography. These values are listed in Table 1. In order to 157
158
J. P. F. D'MELLO TABLE 1 Composition of experimental diet.' (%) Ingredients
Maize Wheat Soyabean meal Dried whey Essential amino acid mixture and glutamic acid Mineral and vitamin mixture Maize oil
]Experiment 1
Experiment 2
45-45 •
•
i
40-00 3-00 5-57 5-98 ...
52-45 22-00 3-00 13-57 5-98 3-00
Downloaded by [University of Florida] at 20:11 06 November 2015
Amino acid content
Threonine Glycine Valine Cystine Methionine Isoleucine Leucine Tyrosine Phenylalanine Lysine Histidine Arginine Tryptophan Crude protein content Moisture content
1-10 1-17 1-42 0-33 0-30 1-23 2-35 1-12 1-39 1-54 0-72 2-00 0-27 27-11 11-4
0-74 1-07 1-01 0-30 0-60 1-10 1-52 0-76 0-99 1-57 0-51 1-69 0-21 28-14 2-6
ensure the desired limiting concentrations of methionine and threonine in the basal diets, mixtures of pure essential amino acids and glutamic acid were used to provide a proportion of the dietary crude protein. All diets were designed to be equal in nitrogen content, this being achieved by alterations in the glutamic acid additions. Energy concentrations of the diets were set at about 12*5 MJ metabolisable energy/kg of diet. A mineral and vitamin mixture which has been described before (D'Mello and Emmans, 1975) was used to supply adequate concentrations of minerals, vitamins and other additives. In the first experiment a basal diet deficient in the sulphur containing amino acids (0-63% of the diet) was used. This diet was supplemented with 0-10 and O20% DL-methionine. In experiment 2, 0*20, 0-40 and 0-60% L-threonine supplements were added to a basal diet containing 0-74% threonine. RESULTS
The responses of turkey poults to methionine additions (experiment 1) are shown in Table 2. The observed and covariance values for weight gain indicate a clear positive response (P < 0-05) to the first addition of methionine. Further supplementation with methionine increased growth further but this effect was not statistically significant. Efficiency of food conversion was similarly improved by methionine supplementation. In Table 3 are set out the results of the second experiment. Addition of 0-20% threonine to the basal diet containing 0-74% threonine increased growth rate and efficiency of food conversion significantly (P < 0-05) but higher levels failed to enhance performance any further.
METHIONINE AND THREONINE REQUIREMENTS OF TURKEYS
159
TABLE 2
Experiment 1:
Weight gain (g[d) end efficiency of food conversion (g gainjg food eaten) of turkeys fed graded levels of methionine
Values represent means of 4 replicate groups of 3 poults each: experimental period 7 to 21 d. Dietary methionine and cystine concentration (%) 0-63 0-73 0-83 SEM
Downloaded by [University of Florida] at 20:11 06 November 2015
1
Weight gain Covariance1 Observed values values 21-9 21-9 25-6 25-7 27-0 26-9 0-806 0-771 t
Efficiency of food conversion 0-564 0-615 0-640 0-0109
Values obtained from observed data by covariance analysis using the 7-d weights as covariates. TABLE 3
Experiment 2:
Weight gain (gjd) and efficiency of food conversion {g gainjgfood consumed) of turkeys fed graded levels of threonine
Weight gain Dietary threonine concentration (%) 0-74 0-94 1-14 1-34 SEM 1 2
Observed1 values 13-0 22-5 21-5 22-5 0-762
Covariance2 values 12-9 22-4 21-7 22-5 0-997
Efficiency of food conversion 0-502 0-676 0-653 0-682 0-0236
Values are means of 4 replicate groups of 3 poults each; experimental period 7 to 21 d. See footnote, Table 2.
DISCUSSION
Several estimates of the methionine and threonine requirements of the young turkey are available (Warnick and Anderson, 1968; Dunkelgod et al., 1970; Kelly, 1970; Kummero et al., 1971; Warnick and Anderson, 1973). In general, the published values for the sulphur containing amino acids exceed 1 % of the diet as against the value of 0-83 % found in experiment 1. The higher energy concentrations of the purified diets employed by the authors cited could in part account for the discrepancy. In the second experiment a requirement figure for threonine of 0-94% of the diet was obtained for the 3-week-old turkey. Again the values of Dunkelgod et al. (1970) and Warnick and Anderson (1973) are marginally higher but Kelly (1970) suggests a figure of 0-95% of the diet. It is conventional to express amino acid requirements of animals as percentages of the diet. However, it is generally acknowledged that growth increments resulting from a limiting supply of an amino acid depend upon the quantity consumed rather than upon its concentration in the diet. Thus true comparisons of published estimates are best accomplished by considering intakes of these amino acids and relating these values to weight increments achieved. Evidence published earlier (D'Mello, 1975; D'Mello and Emmans, 1975) demonstrated the advantage of
160
J. P. F. D'MELLO
adopting such an approach'in comparative studies: similarities were seen in the arginine, valine and isoleucine requirements of chicks and turkeys growing at similar rates. In this paper, such comparisons have also been made for the sulphur containing amino acids and for threonine but have been extended to include rats as well as avian species (Figs 1 and 2). Growth rates of rats, chicks and turkeys have been
Downloaded by [University of Florida] at 20:11 06 November 2015
30 r
20
-22
10
0
100
200
300
400
Methionine + cystlne intake (mg/d)
Fio. 1.—Growth responses (g/d) of growing rats ( • ) , slow-growing chicks ( • ) , fast-growing chicks (O) and young turkeys (^) in relation to methionine + cystine intake (mg/d). See text for origin of data.
plotted against intakes of methionine and cystine in Fig. 1. Data for rats have been drawn from selected values presented by Stockland et al. (1973); those for chicks growing at slow rates were taken from Boomgaardt and Baker (1973). For fastgrowing chicks data published by D'Mello (19736) were used while those in experiment 1 of the current investigation were used for young turkeys. The main criterion for selection of data from these sources was the demonstration of clear responses to methionine and cystine intake. Some papers, e.g. Fitzsimmons and Waibel (1962), were rejected due to omission of relevant data. It would appear from Fig. 1 that the growth responses of rats and slow-growing chicks to intake of sulphur containing amino acids are similar within the range of 25 to 55 mg of these amino acids per day. It is also likely that these animals utilise these amino acids with equal efficiency. A similar relationship appears to exist for the fast growing chicks used by M'Dello (19736) and the young turkeys of the present study. The slightly imperfect fit of the data for fast-growing chicks (D'Mello, 19736) could probably be attributed to the fact that the primary objective of that experiment was to study the effects of
METHIONINE AND THREONINE REQUIREMENTS OF TURKEYS
161
30r
Downloaded by [University of Florida] at 20:11 06 November 2015
20
10
0
100
200 Threonine intake (mgd)
300
400
FIG. 2.—Growth responses (g/d) of growing rats ( • ) , slow-growing chicks ( # ) , fast-growing chicks (O) and young turkeys (JL) in relation to threonine intake (mg/d). See text for origin of data.
methionine supplementation of hydrocarbon-grown yeast rather than to determine requirements. The plateaus for the various sets of results indicate the maximum growth possible in the respective experiments with the stock and diets used. A similar pattern seems to emerge from a consideration of growth responses to threonine intake. Data published by Ivan and Farrell (1975) have been selected for rats, while the results of Klain et al. (1960) and Dean and Scott (1965) have been used for the slow- and fast-growing chicks respectively. As with methionine and cystine, the responses of rats and chicks lie on the same curve. The responses taken from experiment 2 for the turkey contain an anomalous value. Clearly further work is needed to define the threonine intake-response curve more adequately. In both models illustrated in this paper displacements in the curves for individual species could arise through dietary imbalance of certain amino acids resulting in enhanced requirements (see D'Mello, 1973c). But in general factors such as energy concentration, protein level or breed should not have marked effects on the shape or position of these curves. Where the maintenance requirement for the amino acid is not small relative to the growth requirement, the curves would be displaced to the right for larger animals. The slope over the linear part of the range would still be expected to be similar in the different species. From Figs. 1 and 2 an extra 10 mg/d of amino acid intake would be expected to enhance growth rate by about 0-9 g/d for methionine and cystine and about 1-1 g/d for threonine over the linear section of the curve. 17/2—c
162
j . P. F. D'MELLO
ACKNOWLEDGEMENTS
This work was supported by a grant from the Agricultural Research Council. The author is grateful to British United Turkeys for supplying the animals and to Mr G. Emmans for helpful comments.
Downloaded by [University of Florida] at 20:11 06 November 2015
REFERENCES BOOMGAARDT, J . AND BAKER, D. H . (1973). Effect of dietary energy concentration on sulfur amino acid requirements and body composition of young chicks. J. Anim. Sci., 36: 307-311. DEAN, W. F. AND SCOTT, H . M. (1965). The development of an amino acid reference diet for the early growth of chicks. Poult. Sci., 44: 803-808. D'MELLO, J . P. F. (1973a). The use of methane-utilising bacteria as a source of protein for young chicks. Br. Poult. Sci., 14: 291-301. D'MELLO, J . P. F. (1973b). Amino acid supplementation of hydrocarbon-grown yeast in diets for young chicks. Nutr. Rep. Int., 8: 105-109. D'MELLO, J . P. F. (1973c). Amino acid interactions in poultry nutrition. 4th Europ. Poult. Conf., London, 331-336. D'MELLO, J . P. F. (1975). Amino acid requirements of the young turkey: leucine, isoleucine and valine. Br. Poult. Sci., 16: 607-615. D'MELLO, J . P. F. AND EMMANS, G. C. (1975). Amino acid requirements of the young turkey: lysine and arginine. Br. Poult. Sci., 16: 297-306. DUNKELGOD, K. E., WAIBEL, P. E., SIRNY, R. J . AND SNETSINGER, D. C. (1970). An improved free
amino acid diet for the growing turkey. Poult. Sci., 49: 261-268. Fitzsimmons, R. C. AND WAIBEL, P. E. (1962). Determination of the limiting amino acids in cornsoybean oil meal for young turkeys. Poult. Sci., 4 1 : 260-268. IVAN, M . AND FARRELL, D. J . (1975). Nutritional evaluation of wheat 2. The sequence of limiting amino acids in wheats of different protein content as determined with growing rats. Anim. Prod., 20: 77-91. KELLY, M . (1970). Amino acid requirements of young turkeys. Poult. Sci., 49: 1402. KLAIN, G. J., SCOTT H. M. AND JOHNSON B. C. (1960). The amino acid requirement of the growing chick fed a crystalline amino acid diet. Poult. Sci., 39: 39-44. KUMMERO, V. E., JONES, J . E. AND LOADHOLT, C. B. (1971). Lysine and total sulfur amino acid requirements of turkey poults, one day to three weeks. Poult. Sci., 50: 752-758. STOCKLAND, W. L., MEADE, R. J., WASS, D. F. AND SOWERS, J . E. (1973).
Influence of levels of
methionine and cystine on the total sulfur amino acid requirement of the growing rat. J. Anim. Sci., 36: 526-530. WAIBEL, P. E. (1959). Methionine and lysine in rations for turkey poults under various dietary conditions. Poult. Sci., 38: 712-721. WARNICK, R. E. AND ANDERSON, J . O. (1968). Essential amino acid levels for starting poults. Poult. Sci., 47: 1731. WARNICK, R. E. AND ANDERSON, J . O. (1973). Essential amino acid levels for starting turkey poults. Poult. Sci., 52: 445-452.
ISSN: 0007-1668 (Print) 1466-1799 (Online) Journal homepage: http://www.tandfonline.com/loi/cbps20
Requirements of the young turkey for sulphur amino acids and threonine: Comparison with other species J. P. F. D'Mello To cite this article: J. P. F. D'Mello (1976) Requirements of the young turkey for sulphur amino acids and threonine: Comparison with other species, British Poultry Science, 17:2, 157-162, DOI: 10.1080/00071667608416261 To link to this article: http://dx.doi.org/10.1080/00071667608416261
Published online: 08 Nov 2007.
Submit your article to this journal
Article views: 7
View related articles
Citing articles: 3 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=cbps20 Download by: [University of Florida]
Date: 06 November 2015, At: 20:11
Br. Poult. Set., 17: 157-162. 1976
Longman: printed in Great Britain
REQUIREMENTS OF THE YOUNG TURKEY FOR SULPHUR AMINO ACIDS AND THREONINE: COMPARISON WITH OTHER SPECIES J. P. F. D'MELLO Department of Agricultural Biochemistry, Edinburgh School of Agriculture, West Mains Road, Edinburgh EH9 3JG, Scotland Downloaded by [University of Florida] at 20:11 06 November 2015
Received for publication 1st April 1975
1. The requirements of the 3-week-old turkey for the sulphur containing amino acids and for threonine were estimated to be 0.83% and 0.94% respectively in diets containing 12.5 MJ ME/kg. 2. It is suggested that the growth responses of rats and slow-growing chicks and of fast-growing chicks and young turkeys to daily intakes of the sulphur containing amino acids and of threonine are similar. INTRODUCTION
Earlier studies on the amino acid requirements of the young turkey (D'Mello, 1975; D'Mello and Emmans, 1975), yielded data for lysine, arginine, leucine, isoleucine and valine. These studies also permitted comparisons between chicks and turkeys of the same age in their daily requirements for these amino acids. The current report provides data on the requirements of the 3-week-old poult for the sulphur containing amino acids and for threonine. Although there is considerable information on the responses of turkeys to dietary methionine supplementation (Waibel, 1959; Fitzsimmons and Waibel, 1962), the absence of appropriate analytical and food intake data preclude comparisons between chicks and turkeys with respect to their methionine requirements. MATERIALS AND METHODS
Conduct of experiments
Two experiments were conducted with male turkey poults (British United Turkeys, Triple 6). Details of the housing and management of poults are given in earlier papers (D'Mello, 1973a; D'Mello, 1975; D'Mello and Emmans, 1975). As in the earlier experiments the turkeys were allocated to treatments at 7 d of age for a period of 14 d. Experimental diets
Semi-purified diets in ground form were employed in both experiments (see Table 1). The experimental basal diets were analysed for amino acids by automatic ion-exchange chromatography. These values are listed in Table 1. In order to 157
158
J. P. F. D'MELLO TABLE 1 Composition of experimental diet.' (%) Ingredients
Maize Wheat Soyabean meal Dried whey Essential amino acid mixture and glutamic acid Mineral and vitamin mixture Maize oil
]Experiment 1
Experiment 2
45-45 •
•
i
40-00 3-00 5-57 5-98 ...
52-45 22-00 3-00 13-57 5-98 3-00
Downloaded by [University of Florida] at 20:11 06 November 2015
Amino acid content
Threonine Glycine Valine Cystine Methionine Isoleucine Leucine Tyrosine Phenylalanine Lysine Histidine Arginine Tryptophan Crude protein content Moisture content
1-10 1-17 1-42 0-33 0-30 1-23 2-35 1-12 1-39 1-54 0-72 2-00 0-27 27-11 11-4
0-74 1-07 1-01 0-30 0-60 1-10 1-52 0-76 0-99 1-57 0-51 1-69 0-21 28-14 2-6
ensure the desired limiting concentrations of methionine and threonine in the basal diets, mixtures of pure essential amino acids and glutamic acid were used to provide a proportion of the dietary crude protein. All diets were designed to be equal in nitrogen content, this being achieved by alterations in the glutamic acid additions. Energy concentrations of the diets were set at about 12*5 MJ metabolisable energy/kg of diet. A mineral and vitamin mixture which has been described before (D'Mello and Emmans, 1975) was used to supply adequate concentrations of minerals, vitamins and other additives. In the first experiment a basal diet deficient in the sulphur containing amino acids (0-63% of the diet) was used. This diet was supplemented with 0-10 and O20% DL-methionine. In experiment 2, 0*20, 0-40 and 0-60% L-threonine supplements were added to a basal diet containing 0-74% threonine. RESULTS
The responses of turkey poults to methionine additions (experiment 1) are shown in Table 2. The observed and covariance values for weight gain indicate a clear positive response (P < 0-05) to the first addition of methionine. Further supplementation with methionine increased growth further but this effect was not statistically significant. Efficiency of food conversion was similarly improved by methionine supplementation. In Table 3 are set out the results of the second experiment. Addition of 0-20% threonine to the basal diet containing 0-74% threonine increased growth rate and efficiency of food conversion significantly (P < 0-05) but higher levels failed to enhance performance any further.
METHIONINE AND THREONINE REQUIREMENTS OF TURKEYS
159
TABLE 2
Experiment 1:
Weight gain (g[d) end efficiency of food conversion (g gainjg food eaten) of turkeys fed graded levels of methionine
Values represent means of 4 replicate groups of 3 poults each: experimental period 7 to 21 d. Dietary methionine and cystine concentration (%) 0-63 0-73 0-83 SEM
Downloaded by [University of Florida] at 20:11 06 November 2015
1
Weight gain Covariance1 Observed values values 21-9 21-9 25-6 25-7 27-0 26-9 0-806 0-771 t
Efficiency of food conversion 0-564 0-615 0-640 0-0109
Values obtained from observed data by covariance analysis using the 7-d weights as covariates. TABLE 3
Experiment 2:
Weight gain (gjd) and efficiency of food conversion {g gainjgfood consumed) of turkeys fed graded levels of threonine
Weight gain Dietary threonine concentration (%) 0-74 0-94 1-14 1-34 SEM 1 2
Observed1 values 13-0 22-5 21-5 22-5 0-762
Covariance2 values 12-9 22-4 21-7 22-5 0-997
Efficiency of food conversion 0-502 0-676 0-653 0-682 0-0236
Values are means of 4 replicate groups of 3 poults each; experimental period 7 to 21 d. See footnote, Table 2.
DISCUSSION
Several estimates of the methionine and threonine requirements of the young turkey are available (Warnick and Anderson, 1968; Dunkelgod et al., 1970; Kelly, 1970; Kummero et al., 1971; Warnick and Anderson, 1973). In general, the published values for the sulphur containing amino acids exceed 1 % of the diet as against the value of 0-83 % found in experiment 1. The higher energy concentrations of the purified diets employed by the authors cited could in part account for the discrepancy. In the second experiment a requirement figure for threonine of 0-94% of the diet was obtained for the 3-week-old turkey. Again the values of Dunkelgod et al. (1970) and Warnick and Anderson (1973) are marginally higher but Kelly (1970) suggests a figure of 0-95% of the diet. It is conventional to express amino acid requirements of animals as percentages of the diet. However, it is generally acknowledged that growth increments resulting from a limiting supply of an amino acid depend upon the quantity consumed rather than upon its concentration in the diet. Thus true comparisons of published estimates are best accomplished by considering intakes of these amino acids and relating these values to weight increments achieved. Evidence published earlier (D'Mello, 1975; D'Mello and Emmans, 1975) demonstrated the advantage of
160
J. P. F. D'MELLO
adopting such an approach'in comparative studies: similarities were seen in the arginine, valine and isoleucine requirements of chicks and turkeys growing at similar rates. In this paper, such comparisons have also been made for the sulphur containing amino acids and for threonine but have been extended to include rats as well as avian species (Figs 1 and 2). Growth rates of rats, chicks and turkeys have been
Downloaded by [University of Florida] at 20:11 06 November 2015
30 r
20
-22
10
0
100
200
300
400
Methionine + cystlne intake (mg/d)
Fio. 1.—Growth responses (g/d) of growing rats ( • ) , slow-growing chicks ( • ) , fast-growing chicks (O) and young turkeys (^) in relation to methionine + cystine intake (mg/d). See text for origin of data.
plotted against intakes of methionine and cystine in Fig. 1. Data for rats have been drawn from selected values presented by Stockland et al. (1973); those for chicks growing at slow rates were taken from Boomgaardt and Baker (1973). For fastgrowing chicks data published by D'Mello (19736) were used while those in experiment 1 of the current investigation were used for young turkeys. The main criterion for selection of data from these sources was the demonstration of clear responses to methionine and cystine intake. Some papers, e.g. Fitzsimmons and Waibel (1962), were rejected due to omission of relevant data. It would appear from Fig. 1 that the growth responses of rats and slow-growing chicks to intake of sulphur containing amino acids are similar within the range of 25 to 55 mg of these amino acids per day. It is also likely that these animals utilise these amino acids with equal efficiency. A similar relationship appears to exist for the fast growing chicks used by M'Dello (19736) and the young turkeys of the present study. The slightly imperfect fit of the data for fast-growing chicks (D'Mello, 19736) could probably be attributed to the fact that the primary objective of that experiment was to study the effects of
METHIONINE AND THREONINE REQUIREMENTS OF TURKEYS
161
30r
Downloaded by [University of Florida] at 20:11 06 November 2015
20
10
0
100
200 Threonine intake (mgd)
300
400
FIG. 2.—Growth responses (g/d) of growing rats ( • ) , slow-growing chicks ( # ) , fast-growing chicks (O) and young turkeys (JL) in relation to threonine intake (mg/d). See text for origin of data.
methionine supplementation of hydrocarbon-grown yeast rather than to determine requirements. The plateaus for the various sets of results indicate the maximum growth possible in the respective experiments with the stock and diets used. A similar pattern seems to emerge from a consideration of growth responses to threonine intake. Data published by Ivan and Farrell (1975) have been selected for rats, while the results of Klain et al. (1960) and Dean and Scott (1965) have been used for the slow- and fast-growing chicks respectively. As with methionine and cystine, the responses of rats and chicks lie on the same curve. The responses taken from experiment 2 for the turkey contain an anomalous value. Clearly further work is needed to define the threonine intake-response curve more adequately. In both models illustrated in this paper displacements in the curves for individual species could arise through dietary imbalance of certain amino acids resulting in enhanced requirements (see D'Mello, 1973c). But in general factors such as energy concentration, protein level or breed should not have marked effects on the shape or position of these curves. Where the maintenance requirement for the amino acid is not small relative to the growth requirement, the curves would be displaced to the right for larger animals. The slope over the linear part of the range would still be expected to be similar in the different species. From Figs. 1 and 2 an extra 10 mg/d of amino acid intake would be expected to enhance growth rate by about 0-9 g/d for methionine and cystine and about 1-1 g/d for threonine over the linear section of the curve. 17/2—c
162
j . P. F. D'MELLO
ACKNOWLEDGEMENTS
This work was supported by a grant from the Agricultural Research Council. The author is grateful to British United Turkeys for supplying the animals and to Mr G. Emmans for helpful comments.
Downloaded by [University of Florida] at 20:11 06 November 2015
REFERENCES BOOMGAARDT, J . AND BAKER, D. H . (1973). Effect of dietary energy concentration on sulfur amino acid requirements and body composition of young chicks. J. Anim. Sci., 36: 307-311. DEAN, W. F. AND SCOTT, H . M. (1965). The development of an amino acid reference diet for the early growth of chicks. Poult. Sci., 44: 803-808. D'MELLO, J . P. F. (1973a). The use of methane-utilising bacteria as a source of protein for young chicks. Br. Poult. Sci., 14: 291-301. D'MELLO, J . P. F. (1973b). Amino acid supplementation of hydrocarbon-grown yeast in diets for young chicks. Nutr. Rep. Int., 8: 105-109. D'MELLO, J . P. F. (1973c). Amino acid interactions in poultry nutrition. 4th Europ. Poult. Conf., London, 331-336. D'MELLO, J . P. F. (1975). Amino acid requirements of the young turkey: leucine, isoleucine and valine. Br. Poult. Sci., 16: 607-615. D'MELLO, J . P. F. AND EMMANS, G. C. (1975). Amino acid requirements of the young turkey: lysine and arginine. Br. Poult. Sci., 16: 297-306. DUNKELGOD, K. E., WAIBEL, P. E., SIRNY, R. J . AND SNETSINGER, D. C. (1970). An improved free
amino acid diet for the growing turkey. Poult. Sci., 49: 261-268. Fitzsimmons, R. C. AND WAIBEL, P. E. (1962). Determination of the limiting amino acids in cornsoybean oil meal for young turkeys. Poult. Sci., 4 1 : 260-268. IVAN, M . AND FARRELL, D. J . (1975). Nutritional evaluation of wheat 2. The sequence of limiting amino acids in wheats of different protein content as determined with growing rats. Anim. Prod., 20: 77-91. KELLY, M . (1970). Amino acid requirements of young turkeys. Poult. Sci., 49: 1402. KLAIN, G. J., SCOTT H. M. AND JOHNSON B. C. (1960). The amino acid requirement of the growing chick fed a crystalline amino acid diet. Poult. Sci., 39: 39-44. KUMMERO, V. E., JONES, J . E. AND LOADHOLT, C. B. (1971). Lysine and total sulfur amino acid requirements of turkey poults, one day to three weeks. Poult. Sci., 50: 752-758. STOCKLAND, W. L., MEADE, R. J., WASS, D. F. AND SOWERS, J . E. (1973).
Influence of levels of
methionine and cystine on the total sulfur amino acid requirement of the growing rat. J. Anim. Sci., 36: 526-530. WAIBEL, P. E. (1959). Methionine and lysine in rations for turkey poults under various dietary conditions. Poult. Sci., 38: 712-721. WARNICK, R. E. AND ANDERSON, J . O. (1968). Essential amino acid levels for starting poults. Poult. Sci., 47: 1731. WARNICK, R. E. AND ANDERSON, J . O. (1973). Essential amino acid levels for starting turkey poults. Poult. Sci., 52: 445-452.
