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Threonine Requirement of Broiler Males from 42 to 56 Days in a Summer Environment
2000 Poultry Science Association, Inc.
THREONINE REQUIREMENT OF BROILER MALES FROM 42 TO 56 DAYS IN A SUMMER ENVIRONMENT W. A. DOZIER, III,1 and E. T. MORAN, JR. Poultry Science Department and Alabama Agricultural Research Station Auburn University, AL 36849-5416 e-mail: [email protected] M. T. KIDD2 Nutri-Quest, Inc. 1400 Elbridge Payne Road Suite 110 Chesterfield, MO 63017
SUMMARY Amino acid requirements of broilers may be altered during extreme environmental conditions. Threonine is a limiting amino acid for broilers, particularly at finishing when a hot environment would decrease feed intake. The dietary threonine requirement was examined with male broilers from 42 to 56 days of age during summer production. Birds were given a common feeding regimen until 6 wk of age, then six experimental diets consisting of progressive increments of threonine that ranged from 0.50 to 0.80% were fed from 42 to 56 days of age. Feed conversion was optimized at a total dietary threonine concentration approximating 0.67% of the diet; however, growth rate and feed consumption were not significantly affected by dietary threonine. Increasing dietary threonine did not alter carcass yield nor the proportions of abdominal fat and Grade A carcasses, but, breast fillet weight and its relative yield was maximized at 0.62% dietary threonine. Threonine need for male broilers is less for optimum breast meat recovery than feed conversion ratio during hot temperature conditions. Key words: Amino acid, breast fillet, broiler, threonine 2000 J. Appl. Poultry Res. 9:496–500
DESCRIPTION OF PROBLEM Threonine is considered to be the third limiting amino acid for the chick fed low protein corn-soybean meal diets [1]. Threonine requirements for broilers have been evaluated from 0 to 6 wk of age [2, 3, 4, 5, 6, 7, 8], but data are limited beyond 6 wk of age. NRC [9] estimates that the total dietary threonine requirement for 1
broilers is 0.68% of the diet from 6 to 8 wk of age based on computer modeling. Kidd et al. [10] reported that the dietary threonine requirement for maximum live performance and breast meat yield occurred at 0.67% of the diet for male broilers during 42 to 56 days of age in a thermoneutral environment. Conversely, Webel et al. [3] estimated the dietary threonine requirement of male broilers to be 0.60% for optimum live perfor-
To whom correspondence should be addressed. Present address: University of Georgia, Department of Poultry Science, Rural Development Center, P.O. Box 1209 Tifton, GA 31793 2 Present address: Mississippi State University, Department of Poultry Science, Box 9665 Mississippi State, MS 39762
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Primary Audience: Complex Managers, Feed Manufacturers, Nutritionists
DOZIER ET AL.: THREONINE NEED OF BROILERS mance from 42 to 56 days of age, but the carcass was not evaluated. Lysine and methionine requirements of broilers have been reported to be less at high ambient temperatures than at thermoneutral conditions [11, 12]. Reduction of amino acid needs in a hot environment probably relates to decreased growth rate and muscle accretion [13, 14, 15, 16]. This study evaluated the threonine requirement of male broilers reared from 42 to 56 days of age under summer production. Measurements extended beyond live performance to include carcass quality and meat yield.
The study used 750 Ross么 × Ross乆 308 [17] male broilers randomly distributed to 30 pens (25 birds/pen; 0.09 m2/bird) in an open-sided house having thermostatically controlled curtains and cross-ventilation. Each pen had fresh pine shavings and was equipped with one bell waterer and one tube feeder. Birds were vaccinated for MarTABLE 1. Common diets fed from placement until 6 wk of age, percentages “as is” INGREDIENT Corn Soybean mean (48% CP) Corn gluten meal (60% CP) Poultry oil DL-methionine L-lysineⴢHCl L-glutamic acid Dicalcium phosphate Limestone Sodium chloride Vitamin premixA Trace-mineralB CoccidiostatC CALCULATED ANALYSES % CP Kcal ME/kg % Lysine % TSAA % Threonine A
STARTER
GROWER
55.33 27.00 4.15 5.00 0.20 0.28 3.75 1.85 1.40 0.46
63.72 22.89 4.00 4.37 0.08 0.23 1.09 1.26 1.46 0.32 0.25 0.25 0.08
23.0 3,200 1.25 0.95 0.84
20.0 3,200 1.10 0.76 0.78
Supplied per kg of diet: vitamin A, 7,356 IU; vitamin D3, 2,205 IU; vitamin E, 8 IU; vitamin B12, 0.02 mg; riboflavin, 5.5 mg; niacin, 36 mg; d-pantothenic acid, 13.0 mg; choline, 501 mg; menadione, 2.2 mg; folic acid, 0.5 mg; pyridoxine, 2 mg; thiamine, 1 mg. B Supplied mg per kg of diet: manganese, 65; zinc, 55; iron, 6; copper, 6; iodine, 1; selenium, 0.2. C Coban 60, Elanco Products Inc., Indianapolis, IN 46285.
TABLE 2. Composition of threonine deficient basal diet fed from 6 to 8 wk of ageA INGREDIENT Corn Peanut meal (42% CP) Corn gluten meal (60% CP) Poultry oil Dicalcium phosphate Limestone Potassium sulfate Sodium chloride Vitamin premixB Trace-mineral premixC CoccidiostatD L-lysineⴢHCl DL-methionine L-valine L-isoleucine L-tryptophan L-glutamic acid Sand AMINO ACID ANALYSESE Threonine Lysine Methionine Cystine Tryptophan Isoleucine Valine Arginine
PERCENTAGE 67.08 20.05 3.96 3.58 1.25 1.27 0.31 0.24 0.25 0.25 0.08 0.59 0.10 0.07 0.12 0.03 0.45 0.32 0.49 0.92 0.36 0.30 0.17 0.66 0.78 1.24
A Diet was formulated to contain 0.50% threonine, 0.95% lysine, 18% crude protein, 3,200 kcal ME/kg, 0.80% calcium, and 0.30% available phosphorus. B Supplied per kg of diet: vitamin A, 7,356 IU; vitamin D3, 2,205 IU; vitamin E, 8 IU; vitamin B12, 0.02 mg; riboflavin, 5.5 mg; niacin, 36.1 mg; d-pantothenic acid, 13 mg; choline, 501 mg; menadione, 2.2 mg; folic acid, 0.5 mg; pyridoxine, 2 mg; thiamine, 1 mg. C Supplied mg per kg of diet: manganese, 65; zinc, 55; iron, 6; iodine, 1; copper, 6; selenium, 0.2. D Coban 60, Elanco Products, Inc., Indianapolis, IN 46285. E Representative sample was analyzed by a commercial laboratory (Experiment Station Chemical Laboratories, University of Missouri-Columbia).
ek’s disease, Newcastle disease, and infectious bronchitis at the hatchery; immunization for infectious bursal disease followed 14 days later. From placement until 41 days of age birds were fed common starter and grower feeds that satisfied NRC [9] nutrient recommendations (Table 1). At 42 days, birds were weighed and allocated to pens so that each pen had a similar bird number (23 birds/pen; 1.0 m2/bird) and average body weight (2,137 g). Experimental treatments consisted of six concentrations of total threonine using diets that ranged from 0.50 to 0.80% in
Downloaded from http://japr.oxfordjournals.org/ by guest on March 21, 2016
MATERIALS AND METHODS
497
JAPR: Research Report
498
RESULTS AND DISCUSSION Body weight at 6 wk of age was depressed by existing summer conditions prior to the start
of experimentation (Table 3). Amino acid analyses of the basal diet confirmed that threonine was low while the concentrations of other nondispensable amino acids exceeded the requirements outlined by NRC [9] (Table 2). Supplementing L-threonine to the basal diet led to improved feed conversion but did not significantly alter either body weight gain or feed consumption from 42 to 56 days of age (Table 4). Optimum feed conversion occurred when total dietary threonine approximated 0.67% based on the associated regression equation (Table 5). This dietary concentration of threonine for optimum feed conversion ratio is consistent with previous estimates [9, 10] but is greater than that reported by Webel et al. [3]. The absence of a statistically significant response for growth rate to threonine is partially attributable to additional variance associated with measurements during summer conditions. Furthermore, mortality was extensive, but L-threonine supplementation did not alter its incidence (grand means ± SEM: 12.2 ± 4.59% total; 0.8 ± 0.85% SDS; 0.8 ± 1.01% ascites; 10.0 ± 4.67% heat stress; 0.5 ± 0.68% leg problems). Increasing dietary threonine in the final feed also did not influence chilled carcass weight nor its relative yield (grand means ± SEM: 2210 ± 66.2 g carcass weight; 71.8 ± 1.00% carcass yield) and abdominal fat removed from the body cavity was similar (grand means ± SEM: 67 ± 2.6 g fat weight; 3.02 ± 0.064% fat yield). Previous reports have shown that threonine adequacy does not alter carcass fatness [4, 8, 10, 19]. Proportions of Grade A carcasses (grand mean ± SEM: 36.3 ± 6.30%) and the incidence of associated defects were not altered by the progressive addition of dietary threonine as well (grand means: 13.2% wings dislocated, 3.3% wings broken, 34.5% wings bruised, 6.8% drumsticks broken, 5.4%
TABLE 3. Live performance and mortality of male broilers prior to initiation of experimentation at 42 days of age under summer conditionsA
AGE, days C
0 to 21 22 to 41D 0 to 41 A
MORTALITY, %
BW, g
BW Gain, g
F/GB
Total
SDS
Ascites
Legs
713 2137 —
674 1424 2097
1.45 1.84 1.72
8.35 8.87 17.22
— 6.30 —
— 0.13 —
— 0.67 —
Values are grand means involving 30 pens each having 25 chicks at placement. Feed/gain values were corrected for mortality. C Average temperature and relative humidity with their standard deviations were 30 ± 2.9 °C and 71 ± 10.4%, respectively. D Average temperature and relative humidity were 29 ± 3.1 °C and 78 ± 11.1%, respectively. B
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progressive increments of 0.06%. The basal diet was formulated to contain 0.50% threonine, 0.95% lysine, 18% crude protein, and 3,200 kcal ME/kg (Table 2). Other nondispensable amino acids were at least 105% of NRC [9] recommendations. Peanut meal (analyzed aflatoxin concentration of 18 ppb) was used as the primary protein source to create the low threonine basal diet. Lthreonine was added to the basal diet in progressive increments of 0.06% at the expense of sand. Mortality that occurred during experimentation was gross necropsied; cause was classified as sudden death syndrome (SDS), ascites, leg problems, or other reasons. Feed conversions were corrected for mortality. At 56 days of age, birds were placed in transportation coops and held for approximately 14 hr before processing. All birds were processed in an automated pilot plant at Auburn University that involved a 9-min kill line followed by a 7-min evisceration line. Carcasses were placed in slush ice for 4 hr, then abdominal fat was removed, and defects influencing carcass quality were evaluated by type and location. Carcasses were deboned on stationary cones the following day by experienced commercial personnel. Data were statistically evaluated by the analysis of variance procedure of SAS [18] involving a randomized complete block design. Blocks were considered areas of the house used for live production. The mean separation procedure employed orthogonal polynomials. Threonine requirement was estimated at 95% of the upper asymptote by regression analysis when a quadratic response was observed (p < 0.05).
DOZIER ET AL.: THREONINE NEED OF BROILERS
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TABLE 4. Live performance of male broilers given progressive dietary increases of L-threonine from 42 to 56 days of age under summer conditionsA F/GB
BIRD/DAY Final BW, g
BW gain, g
Feed intake, g
THR intake, g
42 to 56 days
0 to 56 days
0.50 0.56 0.62 0.68 0.74 0.80 SEM (20 df)
3028 2993 3268 3164 2946 3089 116.5
59 60 77 74 63 66 5.9
167 170 190 167 155 163 8.1
0.83 0.95 1.18 1.15 1.15 1.30 0.052
2.82 2.85 2.48 2.34 2.49 2.50 0.105
1.95 1.99 1.95 1.92 2.04 1.91 0.034
*** NS 0.73
** * 0.51
NS NS 0.50
Orthogonal Polynomials Linear Quadratic R2
NS NS 0.23
NS 0.08 0.32
NS NS 0.43
A Values are least-square means of 5 pens each having 23 birds at 42 days. Average temperature and relative humidity with their standard deviations were 27 ± 2.8 °C and 78 ± 8.7%, respectively. B Feed/gain values corrected for mortality. NS, p > 0.10; *p < 0.05; **p < 0.01; ***p < 0.001.
TABLE 5. Regression equations of statistically significant measurements with male broilers given progressive dietary L-threonine from 42 to 56 days of age under summer conditions RESPONSE CRITERIA
EQUATIONA
R2 B
CVC
Feed/Gain 7.61 − 14.45 (THR) + 10.08 (THR*THR) 0.36 Fillet weight, g −383 + 2588 (THR) − 2004 (THR*THR) 0.17 Fillet yield, % 0.91 + 58.08 (THR) − 44.25 (THR*THR) 0.18
8.92 9.90 4.65
LINEAR QUADRATIC REQUIREMENTD ** NS NS
* * *
0.67 0.62 0.62
A
Prediction equation based on total dietary threonine. R = Multiple coefficient of determination. CV = Coefficient of variation. D Total dietary threonine requirement estimate at 95% of upper asymptote. NS, p > 0.05; *p < 0.05; **p < 0.01. B 2 C
TABLE 6. Yield of cone-deboned parts from carcasses of male broilers given progressive dietary increases of L-threonine from 42 to 56 days of age under summer conditionsA WINGS
DRUMSTICKS
THIGHS
FILLETS
TENDERS
CAGE
THR, %
Wt, g
%
Wt, g
%
Wt, g
%
Wt, g
%
Wt, g
%
Wt, g
%
0.50 0.56 0.62 0.68 0.74 0.80 SEM (20 df)
241 239 257 251 241 242 5.9
11.1 11.0 11.0 11.1 11.3 11.2 0.11
305 298 325 313 302 304 8.2
14.0 13.7 13.9 13.8 14.2 14.0 0.19
353 358 386 368 352 358 9.6
16.2 16.5 16.5 16.2 16.5 16.6 0.21
416 416 477 455 413 415 19.6
19.0 19.1 20.4 20.0 19.4 19.2 0.39
95 94 105 103 95 96 4.1
4.3 4.3 4.5 4.5 4.5 4.4 0.08
709 711 766 743 703 713 19.5
32.5 32.7 32.8 32.8 33.1 32.9 0.46
Orthogonal Polynomials Linear NS Quadratic NS R2 0.31
0.08 NS 0.44
NS NS 0.30
NS NS 0.34
NS 0.07 0.36
NS NS 0.21
NS * 0.35
A Values are least-square means of 5 pens each providing about 21 carcasses. NS, p > 0.10; *p < 0.05.
NS * 0.44
NS 0.08 0.30
NS NS 0.35
NS 0.08 0.37
NS NS 0.17
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THR, %
JAPR: Research Report
500 drumsticks bruised, 3.7% breast bruised, 0.6% breast blister, 26.2% back and thigh bruised, 3.2% back and thigh torn skin, and 6.6% back and thigh scratched skin). Supplemental threonine that progressed from a deficient concentration to adequacy led to increasing amounts of breast fillets deboned from the carcass but alterations with other carcass parts were not statistically significant (Table 6). Dietary threonine approximating 0.62% of the diet was necessary for 95% of maximum breast fillet weight and relative yield based on the associated
regression equations (Table 5). Kidd and Kerr [19] conducted a threonine titration study with broilers in a hot environment, and they reported that no advantage occurred in either live performance or breast meat yield to increasing dietary threonine. Heat stress conditions probably necessitate a decrease in growth to enable survival; thus, threonine need for breast meat is altered accordingly. High ambient temperatures are known to result in reduced feed consumption and meat yield [13, 14, 15, 16], which would reduce heat production in its own right.
1. Dietary threonine needed by male broilers in a heat stress environment was estimated to be 0.67% of the diet between 42 to 56 days of age in order to optimize feed conversion. 2. The amounts of chilled carcass and associated abdominal fat, as well as proportions of Grade A carcasses, were not affected by threonine concentrations between 0.50 and 0.80% total. 3. Breast fillets deboned from the carcass were the only carcass part improved by threonine, and a total of 0.62% was necessary for maximum yield.
REFERENCES AND NOTES 1. Fernandez, S.R., S. Aoyagi, Y. Han, C.M. Parsons, and D.H. Baker, 1994. Limiting order of amino acids in corn and soybean meal for growth of the chick. Poultry Sci. 73:1887–1896. 2. Smith, N.K., Jr., and P.W. Waldroup, 1988. Investigation of threonine requirements of broiler chicks fed diets based on grain sorghum and soybean meal. Poultry Sci. 67:108–112. 3. Webel, D.M., S.R. Fernandez, C.M. Parsons, and D.H. Baker, 1996. Digestible threonine requirement of broiler chickens during the period three to six and six to eight weeks posthatching. Poultry Sci. 75:1253–1257. 4. Kidd, M.T., and B.J. Kerr, 1997. Threonine responses in commercial broilers at 30 to 42 days. J. Appl. Poultry Res. 6:362–367. 5. Thomas, O.P., M. Farran, C.B. Tamplin, and A.I. Zuckerman, 1987. Broiler starter studies. I. The threonine requirements of male and female broiler chicks. II. The body composition of males fed varying levels of protein and energy. Pages 38–42 in: Proc. Maryland Nutr. Conf., Baltimore, MD. 6. Uzu, G., 1986. Threonine requirement for broilers. AEC information Poultry 252, Rhoˆ ne-Poulenc, 03600 Commentry, France. 7. Robbins, K.R., 1987. Threonine requirement of the broiler chick as affected by protein level and source. Poultry Sci. 66:1531– 1534.
of growth, carcass, and economic responses. J. Appl. Poultry Res. 8:160–169. 11. Balnave, D., and A. Oliva, 1990. Responses of finishing broilers at high temperatures to dietary methionine source and supplementation levels. Australian J. Agric. Res. 41:557–564. 12. McNaughton, J.L., J.D. May, F.N. Reece, and J.W. Deaton, 1977. Lysine requirements of broilers as influenced by environmental temperatures. Poultry Sci. 56:1354–1355. 13. Leeson, S., 1986. Nutritional considerations of poultry during heat stress. World’s Poultry Sci. J. 42:69–81. 14. Teeter, R.G., M.O. Smith, F.N. Owens, S.C. Arp, S. Sangiah, and J.E. Breazile, 1985. Chronic heat stress and respiratory alkalosis: Occurrence and treatment in broiler chicks. Poultry Sci. 61:1060–1064. 15. Smith, M.O., 1993. Parts yield of broilers reared under cycling high temperatures. Poultry Sci. 73:1146–1150. 16. Cahaner, A., Y. Pinchasov, I. Nir, and Z. Nitsan, 1995. Effects of dietary protein under high ambient temperature on body weight, breast meat yield, and abdominal fat deposition of broiler stocks differing in growth rate and fatness. Poultry Sci. 74:968–975. 17. Ross Breeders, Inc., Huntsville, AL 35805.
8. Penz, A.M., Jr., G.L. Colnago, and L.S. Jensen, 1997. Threonine supplementation of practical diets for 3 to 6 wk old broilers. J. Appl. Poultry Res. 6:355–361.
18. SAS Institute, 1988. SAS/STAT User’s Guide. Release 6.03 Edition. SAS Institute, Inc., Cary, NC. The percentages of carcass defects and grade were analyzed as arc sine √%.
9. National Research Council, 1994. Nutrient Requirements of Poultry. 9th Rev. Edition. Natl. Acad. Press, Washington, DC.
19. Kidd, M.T., and B.J. Kerr, 1999. Repuesta del pollo de engorda a aminoa´cidos limitantes dietarios durante las etapas de crecimiento y finalizacio´ n. Pages 1–30 in: Decimo Primer Ciclo de Conferencias Sobre Aminoa´cidos Sinteticos, Mexico City, Mexico.
10. Kidd, M.T, S.P. Lerner, J.P. Allard, S.K. Rao, and J.T. Halley, 1999. Threonine needs of finishing broilers: An evaluation
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CONCLUSIONS AND APPLICATIONS
THREONINE REQUIREMENT OF BROILER MALES FROM 42 TO 56 DAYS IN A SUMMER ENVIRONMENT W. A. DOZIER, III,1 and E. T. MORAN, JR. Poultry Science Department and Alabama Agricultural Research Station Auburn University, AL 36849-5416 e-mail: [email protected] M. T. KIDD2 Nutri-Quest, Inc. 1400 Elbridge Payne Road Suite 110 Chesterfield, MO 63017
SUMMARY Amino acid requirements of broilers may be altered during extreme environmental conditions. Threonine is a limiting amino acid for broilers, particularly at finishing when a hot environment would decrease feed intake. The dietary threonine requirement was examined with male broilers from 42 to 56 days of age during summer production. Birds were given a common feeding regimen until 6 wk of age, then six experimental diets consisting of progressive increments of threonine that ranged from 0.50 to 0.80% were fed from 42 to 56 days of age. Feed conversion was optimized at a total dietary threonine concentration approximating 0.67% of the diet; however, growth rate and feed consumption were not significantly affected by dietary threonine. Increasing dietary threonine did not alter carcass yield nor the proportions of abdominal fat and Grade A carcasses, but, breast fillet weight and its relative yield was maximized at 0.62% dietary threonine. Threonine need for male broilers is less for optimum breast meat recovery than feed conversion ratio during hot temperature conditions. Key words: Amino acid, breast fillet, broiler, threonine 2000 J. Appl. Poultry Res. 9:496–500
DESCRIPTION OF PROBLEM Threonine is considered to be the third limiting amino acid for the chick fed low protein corn-soybean meal diets [1]. Threonine requirements for broilers have been evaluated from 0 to 6 wk of age [2, 3, 4, 5, 6, 7, 8], but data are limited beyond 6 wk of age. NRC [9] estimates that the total dietary threonine requirement for 1
broilers is 0.68% of the diet from 6 to 8 wk of age based on computer modeling. Kidd et al. [10] reported that the dietary threonine requirement for maximum live performance and breast meat yield occurred at 0.67% of the diet for male broilers during 42 to 56 days of age in a thermoneutral environment. Conversely, Webel et al. [3] estimated the dietary threonine requirement of male broilers to be 0.60% for optimum live perfor-
To whom correspondence should be addressed. Present address: University of Georgia, Department of Poultry Science, Rural Development Center, P.O. Box 1209 Tifton, GA 31793 2 Present address: Mississippi State University, Department of Poultry Science, Box 9665 Mississippi State, MS 39762
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Primary Audience: Complex Managers, Feed Manufacturers, Nutritionists
DOZIER ET AL.: THREONINE NEED OF BROILERS mance from 42 to 56 days of age, but the carcass was not evaluated. Lysine and methionine requirements of broilers have been reported to be less at high ambient temperatures than at thermoneutral conditions [11, 12]. Reduction of amino acid needs in a hot environment probably relates to decreased growth rate and muscle accretion [13, 14, 15, 16]. This study evaluated the threonine requirement of male broilers reared from 42 to 56 days of age under summer production. Measurements extended beyond live performance to include carcass quality and meat yield.
The study used 750 Ross么 × Ross乆 308 [17] male broilers randomly distributed to 30 pens (25 birds/pen; 0.09 m2/bird) in an open-sided house having thermostatically controlled curtains and cross-ventilation. Each pen had fresh pine shavings and was equipped with one bell waterer and one tube feeder. Birds were vaccinated for MarTABLE 1. Common diets fed from placement until 6 wk of age, percentages “as is” INGREDIENT Corn Soybean mean (48% CP) Corn gluten meal (60% CP) Poultry oil DL-methionine L-lysineⴢHCl L-glutamic acid Dicalcium phosphate Limestone Sodium chloride Vitamin premixA Trace-mineralB CoccidiostatC CALCULATED ANALYSES % CP Kcal ME/kg % Lysine % TSAA % Threonine A
STARTER
GROWER
55.33 27.00 4.15 5.00 0.20 0.28 3.75 1.85 1.40 0.46
63.72 22.89 4.00 4.37 0.08 0.23 1.09 1.26 1.46 0.32 0.25 0.25 0.08
23.0 3,200 1.25 0.95 0.84
20.0 3,200 1.10 0.76 0.78
Supplied per kg of diet: vitamin A, 7,356 IU; vitamin D3, 2,205 IU; vitamin E, 8 IU; vitamin B12, 0.02 mg; riboflavin, 5.5 mg; niacin, 36 mg; d-pantothenic acid, 13.0 mg; choline, 501 mg; menadione, 2.2 mg; folic acid, 0.5 mg; pyridoxine, 2 mg; thiamine, 1 mg. B Supplied mg per kg of diet: manganese, 65; zinc, 55; iron, 6; copper, 6; iodine, 1; selenium, 0.2. C Coban 60, Elanco Products Inc., Indianapolis, IN 46285.
TABLE 2. Composition of threonine deficient basal diet fed from 6 to 8 wk of ageA INGREDIENT Corn Peanut meal (42% CP) Corn gluten meal (60% CP) Poultry oil Dicalcium phosphate Limestone Potassium sulfate Sodium chloride Vitamin premixB Trace-mineral premixC CoccidiostatD L-lysineⴢHCl DL-methionine L-valine L-isoleucine L-tryptophan L-glutamic acid Sand AMINO ACID ANALYSESE Threonine Lysine Methionine Cystine Tryptophan Isoleucine Valine Arginine
PERCENTAGE 67.08 20.05 3.96 3.58 1.25 1.27 0.31 0.24 0.25 0.25 0.08 0.59 0.10 0.07 0.12 0.03 0.45 0.32 0.49 0.92 0.36 0.30 0.17 0.66 0.78 1.24
A Diet was formulated to contain 0.50% threonine, 0.95% lysine, 18% crude protein, 3,200 kcal ME/kg, 0.80% calcium, and 0.30% available phosphorus. B Supplied per kg of diet: vitamin A, 7,356 IU; vitamin D3, 2,205 IU; vitamin E, 8 IU; vitamin B12, 0.02 mg; riboflavin, 5.5 mg; niacin, 36.1 mg; d-pantothenic acid, 13 mg; choline, 501 mg; menadione, 2.2 mg; folic acid, 0.5 mg; pyridoxine, 2 mg; thiamine, 1 mg. C Supplied mg per kg of diet: manganese, 65; zinc, 55; iron, 6; iodine, 1; copper, 6; selenium, 0.2. D Coban 60, Elanco Products, Inc., Indianapolis, IN 46285. E Representative sample was analyzed by a commercial laboratory (Experiment Station Chemical Laboratories, University of Missouri-Columbia).
ek’s disease, Newcastle disease, and infectious bronchitis at the hatchery; immunization for infectious bursal disease followed 14 days later. From placement until 41 days of age birds were fed common starter and grower feeds that satisfied NRC [9] nutrient recommendations (Table 1). At 42 days, birds were weighed and allocated to pens so that each pen had a similar bird number (23 birds/pen; 1.0 m2/bird) and average body weight (2,137 g). Experimental treatments consisted of six concentrations of total threonine using diets that ranged from 0.50 to 0.80% in
Downloaded from http://japr.oxfordjournals.org/ by guest on March 21, 2016
MATERIALS AND METHODS
497
JAPR: Research Report
498
RESULTS AND DISCUSSION Body weight at 6 wk of age was depressed by existing summer conditions prior to the start
of experimentation (Table 3). Amino acid analyses of the basal diet confirmed that threonine was low while the concentrations of other nondispensable amino acids exceeded the requirements outlined by NRC [9] (Table 2). Supplementing L-threonine to the basal diet led to improved feed conversion but did not significantly alter either body weight gain or feed consumption from 42 to 56 days of age (Table 4). Optimum feed conversion occurred when total dietary threonine approximated 0.67% based on the associated regression equation (Table 5). This dietary concentration of threonine for optimum feed conversion ratio is consistent with previous estimates [9, 10] but is greater than that reported by Webel et al. [3]. The absence of a statistically significant response for growth rate to threonine is partially attributable to additional variance associated with measurements during summer conditions. Furthermore, mortality was extensive, but L-threonine supplementation did not alter its incidence (grand means ± SEM: 12.2 ± 4.59% total; 0.8 ± 0.85% SDS; 0.8 ± 1.01% ascites; 10.0 ± 4.67% heat stress; 0.5 ± 0.68% leg problems). Increasing dietary threonine in the final feed also did not influence chilled carcass weight nor its relative yield (grand means ± SEM: 2210 ± 66.2 g carcass weight; 71.8 ± 1.00% carcass yield) and abdominal fat removed from the body cavity was similar (grand means ± SEM: 67 ± 2.6 g fat weight; 3.02 ± 0.064% fat yield). Previous reports have shown that threonine adequacy does not alter carcass fatness [4, 8, 10, 19]. Proportions of Grade A carcasses (grand mean ± SEM: 36.3 ± 6.30%) and the incidence of associated defects were not altered by the progressive addition of dietary threonine as well (grand means: 13.2% wings dislocated, 3.3% wings broken, 34.5% wings bruised, 6.8% drumsticks broken, 5.4%
TABLE 3. Live performance and mortality of male broilers prior to initiation of experimentation at 42 days of age under summer conditionsA
AGE, days C
0 to 21 22 to 41D 0 to 41 A
MORTALITY, %
BW, g
BW Gain, g
F/GB
Total
SDS
Ascites
Legs
713 2137 —
674 1424 2097
1.45 1.84 1.72
8.35 8.87 17.22
— 6.30 —
— 0.13 —
— 0.67 —
Values are grand means involving 30 pens each having 25 chicks at placement. Feed/gain values were corrected for mortality. C Average temperature and relative humidity with their standard deviations were 30 ± 2.9 °C and 71 ± 10.4%, respectively. D Average temperature and relative humidity were 29 ± 3.1 °C and 78 ± 11.1%, respectively. B
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progressive increments of 0.06%. The basal diet was formulated to contain 0.50% threonine, 0.95% lysine, 18% crude protein, and 3,200 kcal ME/kg (Table 2). Other nondispensable amino acids were at least 105% of NRC [9] recommendations. Peanut meal (analyzed aflatoxin concentration of 18 ppb) was used as the primary protein source to create the low threonine basal diet. Lthreonine was added to the basal diet in progressive increments of 0.06% at the expense of sand. Mortality that occurred during experimentation was gross necropsied; cause was classified as sudden death syndrome (SDS), ascites, leg problems, or other reasons. Feed conversions were corrected for mortality. At 56 days of age, birds were placed in transportation coops and held for approximately 14 hr before processing. All birds were processed in an automated pilot plant at Auburn University that involved a 9-min kill line followed by a 7-min evisceration line. Carcasses were placed in slush ice for 4 hr, then abdominal fat was removed, and defects influencing carcass quality were evaluated by type and location. Carcasses were deboned on stationary cones the following day by experienced commercial personnel. Data were statistically evaluated by the analysis of variance procedure of SAS [18] involving a randomized complete block design. Blocks were considered areas of the house used for live production. The mean separation procedure employed orthogonal polynomials. Threonine requirement was estimated at 95% of the upper asymptote by regression analysis when a quadratic response was observed (p < 0.05).
DOZIER ET AL.: THREONINE NEED OF BROILERS
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TABLE 4. Live performance of male broilers given progressive dietary increases of L-threonine from 42 to 56 days of age under summer conditionsA F/GB
BIRD/DAY Final BW, g
BW gain, g
Feed intake, g
THR intake, g
42 to 56 days
0 to 56 days
0.50 0.56 0.62 0.68 0.74 0.80 SEM (20 df)
3028 2993 3268 3164 2946 3089 116.5
59 60 77 74 63 66 5.9
167 170 190 167 155 163 8.1
0.83 0.95 1.18 1.15 1.15 1.30 0.052
2.82 2.85 2.48 2.34 2.49 2.50 0.105
1.95 1.99 1.95 1.92 2.04 1.91 0.034
*** NS 0.73
** * 0.51
NS NS 0.50
Orthogonal Polynomials Linear Quadratic R2
NS NS 0.23
NS 0.08 0.32
NS NS 0.43
A Values are least-square means of 5 pens each having 23 birds at 42 days. Average temperature and relative humidity with their standard deviations were 27 ± 2.8 °C and 78 ± 8.7%, respectively. B Feed/gain values corrected for mortality. NS, p > 0.10; *p < 0.05; **p < 0.01; ***p < 0.001.
TABLE 5. Regression equations of statistically significant measurements with male broilers given progressive dietary L-threonine from 42 to 56 days of age under summer conditions RESPONSE CRITERIA
EQUATIONA
R2 B
CVC
Feed/Gain 7.61 − 14.45 (THR) + 10.08 (THR*THR) 0.36 Fillet weight, g −383 + 2588 (THR) − 2004 (THR*THR) 0.17 Fillet yield, % 0.91 + 58.08 (THR) − 44.25 (THR*THR) 0.18
8.92 9.90 4.65
LINEAR QUADRATIC REQUIREMENTD ** NS NS
* * *
0.67 0.62 0.62
A
Prediction equation based on total dietary threonine. R = Multiple coefficient of determination. CV = Coefficient of variation. D Total dietary threonine requirement estimate at 95% of upper asymptote. NS, p > 0.05; *p < 0.05; **p < 0.01. B 2 C
TABLE 6. Yield of cone-deboned parts from carcasses of male broilers given progressive dietary increases of L-threonine from 42 to 56 days of age under summer conditionsA WINGS
DRUMSTICKS
THIGHS
FILLETS
TENDERS
CAGE
THR, %
Wt, g
%
Wt, g
%
Wt, g
%
Wt, g
%
Wt, g
%
Wt, g
%
0.50 0.56 0.62 0.68 0.74 0.80 SEM (20 df)
241 239 257 251 241 242 5.9
11.1 11.0 11.0 11.1 11.3 11.2 0.11
305 298 325 313 302 304 8.2
14.0 13.7 13.9 13.8 14.2 14.0 0.19
353 358 386 368 352 358 9.6
16.2 16.5 16.5 16.2 16.5 16.6 0.21
416 416 477 455 413 415 19.6
19.0 19.1 20.4 20.0 19.4 19.2 0.39
95 94 105 103 95 96 4.1
4.3 4.3 4.5 4.5 4.5 4.4 0.08
709 711 766 743 703 713 19.5
32.5 32.7 32.8 32.8 33.1 32.9 0.46
Orthogonal Polynomials Linear NS Quadratic NS R2 0.31
0.08 NS 0.44
NS NS 0.30
NS NS 0.34
NS 0.07 0.36
NS NS 0.21
NS * 0.35
A Values are least-square means of 5 pens each providing about 21 carcasses. NS, p > 0.10; *p < 0.05.
NS * 0.44
NS 0.08 0.30
NS NS 0.35
NS 0.08 0.37
NS NS 0.17
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THR, %
JAPR: Research Report
500 drumsticks bruised, 3.7% breast bruised, 0.6% breast blister, 26.2% back and thigh bruised, 3.2% back and thigh torn skin, and 6.6% back and thigh scratched skin). Supplemental threonine that progressed from a deficient concentration to adequacy led to increasing amounts of breast fillets deboned from the carcass but alterations with other carcass parts were not statistically significant (Table 6). Dietary threonine approximating 0.62% of the diet was necessary for 95% of maximum breast fillet weight and relative yield based on the associated
regression equations (Table 5). Kidd and Kerr [19] conducted a threonine titration study with broilers in a hot environment, and they reported that no advantage occurred in either live performance or breast meat yield to increasing dietary threonine. Heat stress conditions probably necessitate a decrease in growth to enable survival; thus, threonine need for breast meat is altered accordingly. High ambient temperatures are known to result in reduced feed consumption and meat yield [13, 14, 15, 16], which would reduce heat production in its own right.
1. Dietary threonine needed by male broilers in a heat stress environment was estimated to be 0.67% of the diet between 42 to 56 days of age in order to optimize feed conversion. 2. The amounts of chilled carcass and associated abdominal fat, as well as proportions of Grade A carcasses, were not affected by threonine concentrations between 0.50 and 0.80% total. 3. Breast fillets deboned from the carcass were the only carcass part improved by threonine, and a total of 0.62% was necessary for maximum yield.
REFERENCES AND NOTES 1. Fernandez, S.R., S. Aoyagi, Y. Han, C.M. Parsons, and D.H. Baker, 1994. Limiting order of amino acids in corn and soybean meal for growth of the chick. Poultry Sci. 73:1887–1896. 2. Smith, N.K., Jr., and P.W. Waldroup, 1988. Investigation of threonine requirements of broiler chicks fed diets based on grain sorghum and soybean meal. Poultry Sci. 67:108–112. 3. Webel, D.M., S.R. Fernandez, C.M. Parsons, and D.H. Baker, 1996. Digestible threonine requirement of broiler chickens during the period three to six and six to eight weeks posthatching. Poultry Sci. 75:1253–1257. 4. Kidd, M.T., and B.J. Kerr, 1997. Threonine responses in commercial broilers at 30 to 42 days. J. Appl. Poultry Res. 6:362–367. 5. Thomas, O.P., M. Farran, C.B. Tamplin, and A.I. Zuckerman, 1987. Broiler starter studies. I. The threonine requirements of male and female broiler chicks. II. The body composition of males fed varying levels of protein and energy. Pages 38–42 in: Proc. Maryland Nutr. Conf., Baltimore, MD. 6. Uzu, G., 1986. Threonine requirement for broilers. AEC information Poultry 252, Rhoˆ ne-Poulenc, 03600 Commentry, France. 7. Robbins, K.R., 1987. Threonine requirement of the broiler chick as affected by protein level and source. Poultry Sci. 66:1531– 1534.
of growth, carcass, and economic responses. J. Appl. Poultry Res. 8:160–169. 11. Balnave, D., and A. Oliva, 1990. Responses of finishing broilers at high temperatures to dietary methionine source and supplementation levels. Australian J. Agric. Res. 41:557–564. 12. McNaughton, J.L., J.D. May, F.N. Reece, and J.W. Deaton, 1977. Lysine requirements of broilers as influenced by environmental temperatures. Poultry Sci. 56:1354–1355. 13. Leeson, S., 1986. Nutritional considerations of poultry during heat stress. World’s Poultry Sci. J. 42:69–81. 14. Teeter, R.G., M.O. Smith, F.N. Owens, S.C. Arp, S. Sangiah, and J.E. Breazile, 1985. Chronic heat stress and respiratory alkalosis: Occurrence and treatment in broiler chicks. Poultry Sci. 61:1060–1064. 15. Smith, M.O., 1993. Parts yield of broilers reared under cycling high temperatures. Poultry Sci. 73:1146–1150. 16. Cahaner, A., Y. Pinchasov, I. Nir, and Z. Nitsan, 1995. Effects of dietary protein under high ambient temperature on body weight, breast meat yield, and abdominal fat deposition of broiler stocks differing in growth rate and fatness. Poultry Sci. 74:968–975. 17. Ross Breeders, Inc., Huntsville, AL 35805.
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18. SAS Institute, 1988. SAS/STAT User’s Guide. Release 6.03 Edition. SAS Institute, Inc., Cary, NC. The percentages of carcass defects and grade were analyzed as arc sine √%.
9. National Research Council, 1994. Nutrient Requirements of Poultry. 9th Rev. Edition. Natl. Acad. Press, Washington, DC.
19. Kidd, M.T., and B.J. Kerr, 1999. Repuesta del pollo de engorda a aminoa´cidos limitantes dietarios durante las etapas de crecimiento y finalizacio´ n. Pages 1–30 in: Decimo Primer Ciclo de Conferencias Sobre Aminoa´cidos Sinteticos, Mexico City, Mexico.
10. Kidd, M.T, S.P. Lerner, J.P. Allard, S.K. Rao, and J.T. Halley, 1999. Threonine needs of finishing broilers: An evaluation
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CONCLUSIONS AND APPLICATIONS