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The glycine plus serine requirement of broiler chicks fed low-crude protein, corn-soybean meal diets1
©2009 Poultry Science Association, Inc.
The glycine plus serine requirement of broiler chicks fed low-crude protein, corn-soybean meal diets1 A. M. Waguespack, S. Powell, T. D. Bidner, and L. L. Southern2 School of Animal Sciences, Louisiana State University Agricultural Center, Baton Rouge 70803
SUMMARY Low-protein, amino acid-supplemented, all-vegetable diets for broilers may not result in optimal FCR unless they are supplemented with Gly. Three experiments were conducted to determine the Gly + Ser requirement in a low-CP, corn- and soybean meal-based diet with 0.25% l-Lys·HCl, a level which previously had been shown to result in optimal growth performance of broilers as long as it is supplemented with Gly to maintain a minimum of 2.32% total Gly + Ser. Glycine addition to the diet did not affect ADG or ADFI but decreased FCR. When the FCR data from all 3 experiments were combined, the total Gly + Ser minimum requirement was estimated to be 2.10% (P < 0.014) in 0- to 18-d-old broilers. The response to Gly was not a result of added N from Glu. Key words: broiler, glycine, low crude protein 2009 J. Appl. Poult. Res. 18:761–765 doi:10.3382/japr.2009-00062
DESCRIPTION OF PROBLEM Previous research has shown decreased FE of broilers fed low-CP, amino acid (AA)-supplemented diets [1–5], unless these diets are supplemented with Gly [6–8]. This improved growth performance is due to Gly because the response does not occur when mixtures of nonessential AA are fed [9, 10]. Some researchers have reported that Gly supplementation to low-CP diets does not improve performance to the level of broilers fed a standard CP (approximately 23% CP) diet [9, 10], whereas others have reported that broilers fed a low-CP diet with supplemen-
1
tal Gly have G:F equal to that of broilers fed a positive control (PC) diet [6–8]. The total Gly + Ser recommendation for 0- to 21-d-old broiler chicks is 1.25% [11]. However, Corzo et al. [12] reported that the Gly + Ser requirement is 1.80% in a low-CP, all-vegetable, corn and soybean meal (C-SBM) diet. Others have suggested that no less than 2.32% Gly + Ser should be in a low-CP, C-SBM diet fed to 0- to 17-d-old broiler chicks [7]. Therefore, the objective of this research was to determine the Gly + Ser requirement in a low-CP, AA-supplemented diet for broiler chicks.
Approved for publication by the Louisiana Agricultural Experiment Station (Baton Rouge) as manuscript number 2009-2303737. 2 Corresponding author: [email protected]
Downloaded from http://japr.oxfordjournals.org/ at University of Hawaii - Manoa on June 10, 2015
Primary Audience: Nutritionists, Researchers
JAPR: Research Report
762 Table 1. Percentage composition of broiler diets with incremental levels of crystalline Gly in experiments 1, 2, and 3 (as-fed basis)1 Item
1
NC
52.04 37.24 4.96 1.52 1.48 0.50 0.25 0.05 0.25 0.197 — 0.043 1.470
58.61 30.15 4.20 1.58 1.52 0.50 0.25 0.05 0.25 0.274 0.250 0.156 2.210
3,200 22.16 1.00 0.72 0.45 0.36 0.96 1.26 0.88 2.05 2.03 2.03 1.99 0.91 1.05 1.49 0.95 0.27 1.90 0.60 1.88
3,200 19.70 1.00 0.70 0.45 0.41 0.83 1.26 0.88 1.78 1.77 1.71 1.75 0.91 0.91 1.27 0.82 0.23 1.65 0.52 1.68
A basal diet was mixed for diets 2 through 9 for experiments 2 and 3 to contain the minimum of all ingredients except for crystalline Gly, l-Glu, and cornstarch, which were added as needed to each diet. Diets 2 through 8 contained 0.125, 0.250, 0.375, 0.500, 0.625, and 0.750% incremental crystalline Gly additions, respectively, which were added to replace cornstarch. Diet 9 contained 1.47% l-Glu. The analyzed values for total Lys, Thr, and TSAA averaged 1.23, 0.88, and 0.85, respectively. PC = positive control; NC = negative control. 2 Provided per kilogram of diet: copper (copper sulfate), 7 mg; iodine (calcium iodate), 1 mg; iron (ferrous sulfate·H2O), 50 mg; manganese (manganese sulfate), 100 mg; selenium (sodium selenite), 0.15 mg; zinc (zinc sulfate), 75 mg. 3 Contains 447,700 mg/kg of choline. 4 Provided per kilogram of diet: vitamin A, 8,003 IU; vitamin D3, 3,004 IU; vitamin E, 25 IU; menadione, 1.5 mg; vitamin B12, 0.02 mg; biotin, 0.1 mg; folic acid, 1 mg; niacin, 50 mg; pantothenic acid, 15 mg; pyridoxine, 4 mg; riboflavin, 10 mg; thiamine, 3 mg. 5 Analyzed Gly + Ser values for experiment 1. 6 Analyzed Gly + Ser values for experiment 2. 7 Analyzed Gly + Ser values for experiment 3.
Three experiments were conducted with male Ross 308 or 708 broilers. Broilers were obtained from House of Raeford in Gibsland, Louisiana (experiment 1), Pilgrim’s Pride in Farmerville, Louisiana (experiment 2), and Pilgrim’s Pride in Athens, Louisiana (experiment 3). On d 0 posthatching, broilers were weighed, wing banded, and randomly allotted to treatments. Broilers were housed in temperature-controlled Petersime starter batteries with continuous fluorescent lighting. Each experiment was conducted for 18 d. Feed in mash form and water were available on an ad libitum basis. Chicks and feeders were weighed on d 0 and 18 for the determination of growth performance. All experimental animal use was in compliance with the Louisiana State University Agricultural Center Animal Care and Use Committee. Diets were C-SBM based and were formulated to contain 1.26% total dietary Lys (Table 1). The ratio of TSAA to Lys was set at 0.72 and the ratio of Thr to Lys was set at 0.70 in all diets, which met or exceeded suggested ratios [13, 14]. All diets were formulated to contain 3,200 kcal of ME/kg of diet, 1.0% Ca, and 0.45% nonphytate P, and to meet the requirements of all other nutrients suggested for 0- to 21-d-of-age broilers [11]. The AA composition of the diets was determined after acid hydrolysis, and Met and Cys composition in the diets was determined after performic acid oxidation, followed by acid hydrolysis [15]. Nitrogen analysis to determine CP for diets was measured with a Leco N combustion analyzer [16]. The 3 experiments were conducted to determine the Gly + Ser requirement in a low-CP, C-SBM diet with 0.25% l-Lys·HCl [8]. The experiments were similar except experiments 1 and 3 used male Ross 708 broilers and experiment 2 used male Ross 308 broilers. There were 7 replicate pens (6 birds per pen) per treatment in each experiment, for a total of 21 replicate pens per treatment across the 3 experiments. Diet 1 was the PC diet with no crystalline Gly or l-Lys·HCl, and it contained 22.2% CP. Diets 2 to 8 contained 0.25% l-Lys·HCl and added crystalline Gly in 0.125% increments from 0 to 0.75% (Table 1). Diet 9 contained no crystalline
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Ingredient Corn Soybean meal (47.5% CP) Soybean oil Monocalcium phosphate Limestone Sodium chloride Mineral premix2 Choline chloride3 Vitamin premix4 dl-Met l-Lys·HCl l-Thr Cornstarch Calculated composition ME, kcal/kg CP, % Ca, % P, % Nonphytate P, % Cl, % K, % Lys, % Thr, % Gly + Ser, % Analyzed Gly + Ser,5 % Analyzed Gly + Ser,6 % Analyzed Gly + Ser,7 % TSAA, % Val, % Arg, % Ile, % Trp, % Phe + Tyr, % His, % Leu, %
PC
MATERIALS AND METHODS
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Table 2. Glycine + serine requirement of Ross broiler chicks as assessed by growth performance1 Item
ADFI, g
FCR2
34.38 33.60 34.09 33.54 34.29 34.09 34.30 34.06 34.21 1.875 0.049 0.754
43.65 44.60 44.31 43.36 43.93 44.11 43.93 43.27 44.72 2.107 0.066 0.390
1.27 1.33 1.30 1.29 1.28 1.29 1.28 1.27 1.31 0.010 0.010 0.001
0.246 0.615 0.745 0.257 0.773 0.145 0.540
0.125 0.786 0.125 0.859 0.039 0.170 0.582
0.001 0.040 0.001 0.094 0.001 0.001 0.950
1
Data are means of 21 replications with 6 chicks per pen. When the FCR data from all 3 experiments were combined, a single-slope breakpoint analysis estimated the Gly + Ser requirement to be 2.10% (P < 0.014). 3 The calculated CP contents of diets 1 to 9 were 22.16, 19.70, 19.85, 19.99, 20.14, 20.28, 20.43, 20.58, and 20.58%, respectively. 4 Linear and quadratic contrasts were run on diets 2 to 8. 2
Gly and was formulated to be isonitrogenous to diet 8 by containing 1.47% l-Glu. The data for each experiment were combined and analyzed with the MIXED procedure of SAS [17]. The initial model considered treatment and experiment as fixed effects. The treatment × experiment interaction was significant (P < 0.01) for FCR. The interaction was due to variation in response to Gly at dietary levels above the determined requirement, and there was no consistent relationship among the experiments. Thus, the data were reanalyzed with treatment considered a fixed effect and experiment considered a random effect. Five contrasts were used to analyze diet comparisons of interest: 1.47% Glu diet vs. PC diet, 1.47% Glu diet vs. 0% Gly diet, and 1.47% Glu diet vs. 0.75% Gly diet, and PC diet vs. 0 or 0.75% Gly diet. In addition, linear and quadratic contrasts were determined, and the data also were analyzed by broken-line analysis using the NLIN procedure of SAS to estimate the Gly + Ser requirement [18].
RESULTS AND DISCUSSION Incremental crystalline Gly addition had no significant linear or quadratic effect on ADG or ADFI of broilers; however, FCR decreased linearly and quadratically (P < 0.10) with Gly addition (Table 2 and Figure 1). Based on FCR, there was a consistent response to crystalline Gly in low-CP, AA-supplemented diets. When the FCR data from all 3 experiments were combined (Figure 1), a single-slope breakpoint analysis estimated the Gly + Ser requirement to be 2.10% (P < 0.014, r2 = 0.88). Broilers fed the 0% supplemental Gly diet had increased FCR (P < 0.01) compared with broilers fed the PC. Broilers fed the 0.75% supplemental Gly diet had similar FCR (P > 0.10) compared with broilers fed the PC. Diet 9 was formulated to be isonitrogenous to the 0.75% supplemental Gly diet by supplementing 1.47% l-Glu. This diet was included to evaluate whether the broilers were responding to
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Treatment 1: Positive control (PC)3 2: 0% Crystalline Gly (NC) 3: NC + 0.125% crystalline Gly 4: NC + 0.250% crystalline Gly 5: NC + 0.375% crystalline Gly 6: NC + 0.500% crystalline Gly 7: NC + 0.625% crystalline Gly 8: NC + 0.750% crystalline Gly 9: NC + 1.470% crystalline l-Glu SEM Treatment × experiment interaction Overall treatment P-value Contrast Linear4 Quadratic4 Diet 9 vs. diet 1 Diet 9 vs. diet 2 Diet 9 vs. diet 8 Diet 1 vs. diet 2 Diet 1 vs. diet 8
ADG, g
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Gly or to nonspecific N. The addition of Glu did not affect (P > 0.10) ADG compared with broilers fed the 0 or 0.75% supplemental Gly diet. The FCR of broilers fed the diet with Glu was not different from that of broilers fed the negative control diet, but the FCR of broilers fed the PC diet or the diet with 0.75% supplemental Gly was lower than that of broilers fed the diet with Glu. This report agrees with the reports of other researchers, suggesting that the improvement in FCR with the supplementation of Gly in a 17% CP diet is not due to nonessential AA supplementation [19]. Other researchers have reported a lack of improvement in broiler performance with supplementation of varying levels of l-Glu to low-CP diets [1–4, 20]. Broilers fed the 0% supplemental Gly diet had increased FCR compared with broilers fed the PC diet. Therefore, we conclude that 1.77% total Gly + Ser is below the requirement for FCR. The suggested total Gly + Ser required for 0- to 21-d-old broilers is 1.25% [11]. However, we suggest, based on our data, that the Gly + Ser recommendation is higher in low-CP diets. Similarly, others [12] have suggested that the Gly + Ser recommendation may be inadequate for broiler chicks fed low-CP diets. These scientists reported that the Gly + Ser requirement in 7- to 20-d-old broilers was 1.80% in a low-CP diet. Our results are based on a 0-d posthatching broiler through 18 d, whereas the recommendation of the other researchers [12] is based on a 7- to 20-d-old broiler. Previous researchers have reported that the Gly + Ser requirement might be higher in posthatching birds (0 to 5 or 9 d of age), whereas a 6- or 10- to 15-d-old broiler
CONCLUSIONS AND APPLICATIONS
1. Crystalline Gly supplementation in a low-CP, AA-supplemented diet consistently improved FCR of 0- to 18-d-old broiler chicks. 2. A low-CP, C-SBM diet that contains 0.25% l-Lys·HCl and supplemental dlMet, l-Thr, and a minimum of 2.10% Gly + Ser results in the maximum performance of broilers.
REFERENCES AND NOTES 1. Fancher, B. I., and L. S. Jensen. 1989a. Dietary protein level and essential amino acid content: Influence upon female broiler performance during the grower period. Poult. Sci. 68:897–908. 2. Fancher, B. I., and L. S. Jensen. 1989b. Male broiler performance during the starting and growing periods as affected by dietary protein, essential amino acids, and potassium levels. Poult. Sci. 68:1385–1395. 3. Pinchasov, Y., C. X. Mendonca, and L. S. Jensen. 1990. Broiler chick response to low protein diets supplemented with synthetic amino acids. Poult. Sci. 69:1950– 1955. 4. Bregendahl, K., J. L. Sell, and D. R. Zimmerman. 2002. Effect of low-protein diets on growth performance and body composition of broiler chicks. Poult. Sci. 81:1156– 1167. 5. Si, J., C. A. Fritts, D. J. Burnham, and P. W. Waldroup. 2004. Extent to which crude protein may be reduced in cornsoybean meal broiler diets through amino acid supplementation. Int. J. Poult. Sci. 3:46–50. 6. Corzo, A., C. A. Fritts, M. T. Kidd, and B. J. Kerr. 2005. Response of broiler chicks to essential and non-essential amino acid supplementation of low crude protein diets. Anim. Feed Sci. Technol. 118:319–327. 7. Dean, D. W., T. D. Bidner, and L. L. Southern. 2006. Glycine supplementation to low protein, amino acid-supple-
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Figure 1. Feed conversion ratio for broilers to determine the Gly + Ser requirement for experiments 1, 2, and 3 combined. When the FCR data from all 3 experiments were combined, a single-slope breakpoint analysis estimated the Gly + Ser requirement to be 2.10% (P < 0.014; r2 = 0.88).
would have a lower Gly + Ser requirement [21, 22]. Others [7] have reported that the minimum level of total Gly + Ser in a low-CP diet should be 2.32% to achieve optimal performance of 0to 17-d-old broilers, but this diet contained 16% CP. Based on these 3 experiments, the Gly + Ser requirement in a low-CP, C-SBM diet supplemented with 0.25% l-Lys·HCl is 2.10% total Gly + Ser. We conclude that a low-CP, C-SBM diet that contains 0.25% l-Lys·HCl and supplemental dl-Met and l-Thr with a minimum of 2.10% total Gly + Ser is a practical diet that can be fed to 0- to 18-d-old broilers to obtain maximum performance.
Waguespack et al.: GLYCINE REQUIREMENT OF BROILERS
15. Association of Official Analytical Chemists. 2002. Official Methods of Analysis of AOAC International. 17th ed. AOAC Int., Gaithersburg, MD. Official Method 994.12. 16. Model FP-2000, Leco Corp., St. Joseph, MI; according to the Dumas procedure. 17. SAS Institute. 2003. SAS Version 9.1. SAS Inst. Inc., Cary, NC. 18. Robbins, K. R., A. M. Saxton, and L. L. Southern. 2006. Estimation of nutrient requirements using broken-line regression analysis. J. Anim. Sci. 84(E. Suppl.):E155– E165. 19. Heger, J., and M. Pack. 1996. Effects of dietary glycine + serine on starting broiler chick performance as influenced by dietary crude protein levels. Agribiol. Res. 49:257–265. 20. Kerr, B. J., and M. T. Kidd. 1999. Amino acid supplementation of low-protein broiler diets: 1. Glutamic acid and indispensable amino acid supplementation. J. Appl. Poult. Res. 8:298–309. 21. Coon, C. N., V. B. Grossie Jr., and J. R. Couch. 1974. Glycine-serine requirement for chicks. Poult. Sci. 53:1709– 1713. 22. Ngo, A., and C. N. Coon. 1976. The effect of feeding various levels of dietary glycine in a pre-experimental diet to one-day old chicks on their subsequent glycine plus serine requirement. Poult. Sci. 55:1672–1677.
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mented diets supports optimal performance of broiler chicks. Poult. Sci. 85:288–296. 8. Waguespack, A. M., S. Powell, T. D. Bidner, R. L. Payne, and L. L. Southern. 2009. Effect of incremental levels of l-lysine and determination of the limiting amino acids in low crude protein corn-soybean meal diets for broilers. Poult. Sci. 88:1216–1226. 9. Jiang, Q., P. W. Waldroup, and C. A. Fritts. 2005. Improving the utilization of diets low in crude protein for broiler chicken. 1. Evaluation of special amino acid supplementation to diets low in crude protein. Int. J. Poult. Sci. 4:115–122. 10. Parr, J. F., and J. D. Summers. 1991. The effect of minimizing amino acid excesses in broiler diets. Poult. Sci. 70:1540–1549. 11. National Research Council. 1994. Nutrient Requirements of Poultry. 9th rev. ed. Natl. Acad. Press, Washington, DC. 12. Corzo, A., M. T. Kidd, D. J. Burnham, and B. J. Kerr. 2004. Dietary glycine needs of broiler chicks. Poult. Sci. 83:1382–1384. 13. Baker, D. H. 1997. Ideal amino acid profiles for swine and poultry and their applications in feed formulation. Pages 15–17 in Biokyowa Tech. Rev. No. 9. Biokyowa, Cape Girardeau, MO. 14. Dozier, W. A. III, M. T. Kidd, and A. Corzo. 2008. Dietary amino acid responses of broiler chickens. J. Appl. Poult. Res. 17:157–167.
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The glycine plus serine requirement of broiler chicks fed low-crude protein, corn-soybean meal diets1 A. M. Waguespack, S. Powell, T. D. Bidner, and L. L. Southern2 School of Animal Sciences, Louisiana State University Agricultural Center, Baton Rouge 70803
SUMMARY Low-protein, amino acid-supplemented, all-vegetable diets for broilers may not result in optimal FCR unless they are supplemented with Gly. Three experiments were conducted to determine the Gly + Ser requirement in a low-CP, corn- and soybean meal-based diet with 0.25% l-Lys·HCl, a level which previously had been shown to result in optimal growth performance of broilers as long as it is supplemented with Gly to maintain a minimum of 2.32% total Gly + Ser. Glycine addition to the diet did not affect ADG or ADFI but decreased FCR. When the FCR data from all 3 experiments were combined, the total Gly + Ser minimum requirement was estimated to be 2.10% (P < 0.014) in 0- to 18-d-old broilers. The response to Gly was not a result of added N from Glu. Key words: broiler, glycine, low crude protein 2009 J. Appl. Poult. Res. 18:761–765 doi:10.3382/japr.2009-00062
DESCRIPTION OF PROBLEM Previous research has shown decreased FE of broilers fed low-CP, amino acid (AA)-supplemented diets [1–5], unless these diets are supplemented with Gly [6–8]. This improved growth performance is due to Gly because the response does not occur when mixtures of nonessential AA are fed [9, 10]. Some researchers have reported that Gly supplementation to low-CP diets does not improve performance to the level of broilers fed a standard CP (approximately 23% CP) diet [9, 10], whereas others have reported that broilers fed a low-CP diet with supplemen-
1
tal Gly have G:F equal to that of broilers fed a positive control (PC) diet [6–8]. The total Gly + Ser recommendation for 0- to 21-d-old broiler chicks is 1.25% [11]. However, Corzo et al. [12] reported that the Gly + Ser requirement is 1.80% in a low-CP, all-vegetable, corn and soybean meal (C-SBM) diet. Others have suggested that no less than 2.32% Gly + Ser should be in a low-CP, C-SBM diet fed to 0- to 17-d-old broiler chicks [7]. Therefore, the objective of this research was to determine the Gly + Ser requirement in a low-CP, AA-supplemented diet for broiler chicks.
Approved for publication by the Louisiana Agricultural Experiment Station (Baton Rouge) as manuscript number 2009-2303737. 2 Corresponding author: [email protected]
Downloaded from http://japr.oxfordjournals.org/ at University of Hawaii - Manoa on June 10, 2015
Primary Audience: Nutritionists, Researchers
JAPR: Research Report
762 Table 1. Percentage composition of broiler diets with incremental levels of crystalline Gly in experiments 1, 2, and 3 (as-fed basis)1 Item
1
NC
52.04 37.24 4.96 1.52 1.48 0.50 0.25 0.05 0.25 0.197 — 0.043 1.470
58.61 30.15 4.20 1.58 1.52 0.50 0.25 0.05 0.25 0.274 0.250 0.156 2.210
3,200 22.16 1.00 0.72 0.45 0.36 0.96 1.26 0.88 2.05 2.03 2.03 1.99 0.91 1.05 1.49 0.95 0.27 1.90 0.60 1.88
3,200 19.70 1.00 0.70 0.45 0.41 0.83 1.26 0.88 1.78 1.77 1.71 1.75 0.91 0.91 1.27 0.82 0.23 1.65 0.52 1.68
A basal diet was mixed for diets 2 through 9 for experiments 2 and 3 to contain the minimum of all ingredients except for crystalline Gly, l-Glu, and cornstarch, which were added as needed to each diet. Diets 2 through 8 contained 0.125, 0.250, 0.375, 0.500, 0.625, and 0.750% incremental crystalline Gly additions, respectively, which were added to replace cornstarch. Diet 9 contained 1.47% l-Glu. The analyzed values for total Lys, Thr, and TSAA averaged 1.23, 0.88, and 0.85, respectively. PC = positive control; NC = negative control. 2 Provided per kilogram of diet: copper (copper sulfate), 7 mg; iodine (calcium iodate), 1 mg; iron (ferrous sulfate·H2O), 50 mg; manganese (manganese sulfate), 100 mg; selenium (sodium selenite), 0.15 mg; zinc (zinc sulfate), 75 mg. 3 Contains 447,700 mg/kg of choline. 4 Provided per kilogram of diet: vitamin A, 8,003 IU; vitamin D3, 3,004 IU; vitamin E, 25 IU; menadione, 1.5 mg; vitamin B12, 0.02 mg; biotin, 0.1 mg; folic acid, 1 mg; niacin, 50 mg; pantothenic acid, 15 mg; pyridoxine, 4 mg; riboflavin, 10 mg; thiamine, 3 mg. 5 Analyzed Gly + Ser values for experiment 1. 6 Analyzed Gly + Ser values for experiment 2. 7 Analyzed Gly + Ser values for experiment 3.
Three experiments were conducted with male Ross 308 or 708 broilers. Broilers were obtained from House of Raeford in Gibsland, Louisiana (experiment 1), Pilgrim’s Pride in Farmerville, Louisiana (experiment 2), and Pilgrim’s Pride in Athens, Louisiana (experiment 3). On d 0 posthatching, broilers were weighed, wing banded, and randomly allotted to treatments. Broilers were housed in temperature-controlled Petersime starter batteries with continuous fluorescent lighting. Each experiment was conducted for 18 d. Feed in mash form and water were available on an ad libitum basis. Chicks and feeders were weighed on d 0 and 18 for the determination of growth performance. All experimental animal use was in compliance with the Louisiana State University Agricultural Center Animal Care and Use Committee. Diets were C-SBM based and were formulated to contain 1.26% total dietary Lys (Table 1). The ratio of TSAA to Lys was set at 0.72 and the ratio of Thr to Lys was set at 0.70 in all diets, which met or exceeded suggested ratios [13, 14]. All diets were formulated to contain 3,200 kcal of ME/kg of diet, 1.0% Ca, and 0.45% nonphytate P, and to meet the requirements of all other nutrients suggested for 0- to 21-d-of-age broilers [11]. The AA composition of the diets was determined after acid hydrolysis, and Met and Cys composition in the diets was determined after performic acid oxidation, followed by acid hydrolysis [15]. Nitrogen analysis to determine CP for diets was measured with a Leco N combustion analyzer [16]. The 3 experiments were conducted to determine the Gly + Ser requirement in a low-CP, C-SBM diet with 0.25% l-Lys·HCl [8]. The experiments were similar except experiments 1 and 3 used male Ross 708 broilers and experiment 2 used male Ross 308 broilers. There were 7 replicate pens (6 birds per pen) per treatment in each experiment, for a total of 21 replicate pens per treatment across the 3 experiments. Diet 1 was the PC diet with no crystalline Gly or l-Lys·HCl, and it contained 22.2% CP. Diets 2 to 8 contained 0.25% l-Lys·HCl and added crystalline Gly in 0.125% increments from 0 to 0.75% (Table 1). Diet 9 contained no crystalline
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Ingredient Corn Soybean meal (47.5% CP) Soybean oil Monocalcium phosphate Limestone Sodium chloride Mineral premix2 Choline chloride3 Vitamin premix4 dl-Met l-Lys·HCl l-Thr Cornstarch Calculated composition ME, kcal/kg CP, % Ca, % P, % Nonphytate P, % Cl, % K, % Lys, % Thr, % Gly + Ser, % Analyzed Gly + Ser,5 % Analyzed Gly + Ser,6 % Analyzed Gly + Ser,7 % TSAA, % Val, % Arg, % Ile, % Trp, % Phe + Tyr, % His, % Leu, %
PC
MATERIALS AND METHODS
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Table 2. Glycine + serine requirement of Ross broiler chicks as assessed by growth performance1 Item
ADFI, g
FCR2
34.38 33.60 34.09 33.54 34.29 34.09 34.30 34.06 34.21 1.875 0.049 0.754
43.65 44.60 44.31 43.36 43.93 44.11 43.93 43.27 44.72 2.107 0.066 0.390
1.27 1.33 1.30 1.29 1.28 1.29 1.28 1.27 1.31 0.010 0.010 0.001
0.246 0.615 0.745 0.257 0.773 0.145 0.540
0.125 0.786 0.125 0.859 0.039 0.170 0.582
0.001 0.040 0.001 0.094 0.001 0.001 0.950
1
Data are means of 21 replications with 6 chicks per pen. When the FCR data from all 3 experiments were combined, a single-slope breakpoint analysis estimated the Gly + Ser requirement to be 2.10% (P < 0.014). 3 The calculated CP contents of diets 1 to 9 were 22.16, 19.70, 19.85, 19.99, 20.14, 20.28, 20.43, 20.58, and 20.58%, respectively. 4 Linear and quadratic contrasts were run on diets 2 to 8. 2
Gly and was formulated to be isonitrogenous to diet 8 by containing 1.47% l-Glu. The data for each experiment were combined and analyzed with the MIXED procedure of SAS [17]. The initial model considered treatment and experiment as fixed effects. The treatment × experiment interaction was significant (P < 0.01) for FCR. The interaction was due to variation in response to Gly at dietary levels above the determined requirement, and there was no consistent relationship among the experiments. Thus, the data were reanalyzed with treatment considered a fixed effect and experiment considered a random effect. Five contrasts were used to analyze diet comparisons of interest: 1.47% Glu diet vs. PC diet, 1.47% Glu diet vs. 0% Gly diet, and 1.47% Glu diet vs. 0.75% Gly diet, and PC diet vs. 0 or 0.75% Gly diet. In addition, linear and quadratic contrasts were determined, and the data also were analyzed by broken-line analysis using the NLIN procedure of SAS to estimate the Gly + Ser requirement [18].
RESULTS AND DISCUSSION Incremental crystalline Gly addition had no significant linear or quadratic effect on ADG or ADFI of broilers; however, FCR decreased linearly and quadratically (P < 0.10) with Gly addition (Table 2 and Figure 1). Based on FCR, there was a consistent response to crystalline Gly in low-CP, AA-supplemented diets. When the FCR data from all 3 experiments were combined (Figure 1), a single-slope breakpoint analysis estimated the Gly + Ser requirement to be 2.10% (P < 0.014, r2 = 0.88). Broilers fed the 0% supplemental Gly diet had increased FCR (P < 0.01) compared with broilers fed the PC. Broilers fed the 0.75% supplemental Gly diet had similar FCR (P > 0.10) compared with broilers fed the PC. Diet 9 was formulated to be isonitrogenous to the 0.75% supplemental Gly diet by supplementing 1.47% l-Glu. This diet was included to evaluate whether the broilers were responding to
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Treatment 1: Positive control (PC)3 2: 0% Crystalline Gly (NC) 3: NC + 0.125% crystalline Gly 4: NC + 0.250% crystalline Gly 5: NC + 0.375% crystalline Gly 6: NC + 0.500% crystalline Gly 7: NC + 0.625% crystalline Gly 8: NC + 0.750% crystalline Gly 9: NC + 1.470% crystalline l-Glu SEM Treatment × experiment interaction Overall treatment P-value Contrast Linear4 Quadratic4 Diet 9 vs. diet 1 Diet 9 vs. diet 2 Diet 9 vs. diet 8 Diet 1 vs. diet 2 Diet 1 vs. diet 8
ADG, g
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Gly or to nonspecific N. The addition of Glu did not affect (P > 0.10) ADG compared with broilers fed the 0 or 0.75% supplemental Gly diet. The FCR of broilers fed the diet with Glu was not different from that of broilers fed the negative control diet, but the FCR of broilers fed the PC diet or the diet with 0.75% supplemental Gly was lower than that of broilers fed the diet with Glu. This report agrees with the reports of other researchers, suggesting that the improvement in FCR with the supplementation of Gly in a 17% CP diet is not due to nonessential AA supplementation [19]. Other researchers have reported a lack of improvement in broiler performance with supplementation of varying levels of l-Glu to low-CP diets [1–4, 20]. Broilers fed the 0% supplemental Gly diet had increased FCR compared with broilers fed the PC diet. Therefore, we conclude that 1.77% total Gly + Ser is below the requirement for FCR. The suggested total Gly + Ser required for 0- to 21-d-old broilers is 1.25% [11]. However, we suggest, based on our data, that the Gly + Ser recommendation is higher in low-CP diets. Similarly, others [12] have suggested that the Gly + Ser recommendation may be inadequate for broiler chicks fed low-CP diets. These scientists reported that the Gly + Ser requirement in 7- to 20-d-old broilers was 1.80% in a low-CP diet. Our results are based on a 0-d posthatching broiler through 18 d, whereas the recommendation of the other researchers [12] is based on a 7- to 20-d-old broiler. Previous researchers have reported that the Gly + Ser requirement might be higher in posthatching birds (0 to 5 or 9 d of age), whereas a 6- or 10- to 15-d-old broiler
CONCLUSIONS AND APPLICATIONS
1. Crystalline Gly supplementation in a low-CP, AA-supplemented diet consistently improved FCR of 0- to 18-d-old broiler chicks. 2. A low-CP, C-SBM diet that contains 0.25% l-Lys·HCl and supplemental dlMet, l-Thr, and a minimum of 2.10% Gly + Ser results in the maximum performance of broilers.
REFERENCES AND NOTES 1. Fancher, B. I., and L. S. Jensen. 1989a. Dietary protein level and essential amino acid content: Influence upon female broiler performance during the grower period. Poult. Sci. 68:897–908. 2. Fancher, B. I., and L. S. Jensen. 1989b. Male broiler performance during the starting and growing periods as affected by dietary protein, essential amino acids, and potassium levels. Poult. Sci. 68:1385–1395. 3. Pinchasov, Y., C. X. Mendonca, and L. S. Jensen. 1990. Broiler chick response to low protein diets supplemented with synthetic amino acids. Poult. Sci. 69:1950– 1955. 4. Bregendahl, K., J. L. Sell, and D. R. Zimmerman. 2002. Effect of low-protein diets on growth performance and body composition of broiler chicks. Poult. Sci. 81:1156– 1167. 5. Si, J., C. A. Fritts, D. J. Burnham, and P. W. Waldroup. 2004. Extent to which crude protein may be reduced in cornsoybean meal broiler diets through amino acid supplementation. Int. J. Poult. Sci. 3:46–50. 6. Corzo, A., C. A. Fritts, M. T. Kidd, and B. J. Kerr. 2005. Response of broiler chicks to essential and non-essential amino acid supplementation of low crude protein diets. Anim. Feed Sci. Technol. 118:319–327. 7. Dean, D. W., T. D. Bidner, and L. L. Southern. 2006. Glycine supplementation to low protein, amino acid-supple-
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Figure 1. Feed conversion ratio for broilers to determine the Gly + Ser requirement for experiments 1, 2, and 3 combined. When the FCR data from all 3 experiments were combined, a single-slope breakpoint analysis estimated the Gly + Ser requirement to be 2.10% (P < 0.014; r2 = 0.88).
would have a lower Gly + Ser requirement [21, 22]. Others [7] have reported that the minimum level of total Gly + Ser in a low-CP diet should be 2.32% to achieve optimal performance of 0to 17-d-old broilers, but this diet contained 16% CP. Based on these 3 experiments, the Gly + Ser requirement in a low-CP, C-SBM diet supplemented with 0.25% l-Lys·HCl is 2.10% total Gly + Ser. We conclude that a low-CP, C-SBM diet that contains 0.25% l-Lys·HCl and supplemental dl-Met and l-Thr with a minimum of 2.10% total Gly + Ser is a practical diet that can be fed to 0- to 18-d-old broilers to obtain maximum performance.
Waguespack et al.: GLYCINE REQUIREMENT OF BROILERS
15. Association of Official Analytical Chemists. 2002. Official Methods of Analysis of AOAC International. 17th ed. AOAC Int., Gaithersburg, MD. Official Method 994.12. 16. Model FP-2000, Leco Corp., St. Joseph, MI; according to the Dumas procedure. 17. SAS Institute. 2003. SAS Version 9.1. SAS Inst. Inc., Cary, NC. 18. Robbins, K. R., A. M. Saxton, and L. L. Southern. 2006. Estimation of nutrient requirements using broken-line regression analysis. J. Anim. Sci. 84(E. Suppl.):E155– E165. 19. Heger, J., and M. Pack. 1996. Effects of dietary glycine + serine on starting broiler chick performance as influenced by dietary crude protein levels. Agribiol. Res. 49:257–265. 20. Kerr, B. J., and M. T. Kidd. 1999. Amino acid supplementation of low-protein broiler diets: 1. Glutamic acid and indispensable amino acid supplementation. J. Appl. Poult. Res. 8:298–309. 21. Coon, C. N., V. B. Grossie Jr., and J. R. Couch. 1974. Glycine-serine requirement for chicks. Poult. Sci. 53:1709– 1713. 22. Ngo, A., and C. N. Coon. 1976. The effect of feeding various levels of dietary glycine in a pre-experimental diet to one-day old chicks on their subsequent glycine plus serine requirement. Poult. Sci. 55:1672–1677.
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mented diets supports optimal performance of broiler chicks. Poult. Sci. 85:288–296. 8. Waguespack, A. M., S. Powell, T. D. Bidner, R. L. Payne, and L. L. Southern. 2009. Effect of incremental levels of l-lysine and determination of the limiting amino acids in low crude protein corn-soybean meal diets for broilers. Poult. Sci. 88:1216–1226. 9. Jiang, Q., P. W. Waldroup, and C. A. Fritts. 2005. Improving the utilization of diets low in crude protein for broiler chicken. 1. Evaluation of special amino acid supplementation to diets low in crude protein. Int. J. Poult. Sci. 4:115–122. 10. Parr, J. F., and J. D. Summers. 1991. The effect of minimizing amino acid excesses in broiler diets. Poult. Sci. 70:1540–1549. 11. National Research Council. 1994. Nutrient Requirements of Poultry. 9th rev. ed. Natl. Acad. Press, Washington, DC. 12. Corzo, A., M. T. Kidd, D. J. Burnham, and B. J. Kerr. 2004. Dietary glycine needs of broiler chicks. Poult. Sci. 83:1382–1384. 13. Baker, D. H. 1997. Ideal amino acid profiles for swine and poultry and their applications in feed formulation. Pages 15–17 in Biokyowa Tech. Rev. No. 9. Biokyowa, Cape Girardeau, MO. 14. Dozier, W. A. III, M. T. Kidd, and A. Corzo. 2008. Dietary amino acid responses of broiler chickens. J. Appl. Poult. Res. 17:157–167.
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