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Buford, GA, United States

Dozier W.A.,Auburn University | Tillman P.B.,Poultry Technical Nutrition Services LLC | Usry J.,Ajinomoto Co.
Journal of Applied Poultry Research

Two experiments were conducted to examine the growth and meat yield responses of Ross × Ross 708 male broilers fed diets varying in digestible (dig) Val- and Ile-to-Lys ratios from 28 to 42 d or 26 to 40 d of age. In each experiment, dietary treatments consisted of a 3 × 3 factorial arrangement of treatments with at least 1 additional positive control. Digestible Val-to-Lys ratios were 74, 78, and 82 for both experiments, whereas digestible Ile-to-Lys ratios were 63, 68, and 73 (experiment 1) and 62, 67, and 72 (experiment 2). In experiment 1, increasing dig Ile and Val interacted to decrease the FCR. As dig Val increased in the diet to a Val-to-Ile ratio of 82, feed conversion was optimized when the Ile-to-Lys ratio increased to 68, but increasing the Ile with the 2 lower concentrations of Val did not decrease feed conversion. Feeding broilers diets having increasing dig Ile-to-Lys ratios led to a higher total breast meat yield. In experiment 2, no interactions between Val and Ile were observed for the variables measured. Broilers fed gradient additions of Val-to-Lys ratios grew faster and more efficiently, whereas broilers provided diets having progressive Ile-to-Lys ratios had lower feed conversion and higher total breast meat yield. These data indicated that dig Ile and Val did not interact to a large extent with the variables measured, and the Ile-to-Lys ratio may be higher than 67. © 2012 Poultry Science Association, Inc. Source

Sriperm N.,University of Georgia | Pesti G.M.,University of Georgia | Tillman P.B.,Poultry Technical Nutrition Services LLC
Journal of the Science of Food and Agriculture

BACKGROUND: The crude protein (CP) of feedstuffs is important as an indicator of essential and non-essential amino acids for livestock. The protein (P) level needs to be known accurately, to minimize the feeding of excess nitrogen (N) and to reduce N pollution. Laboratory methods for determining N content report N from amino acids, but also N from ammonia and from non-amino acid sources. The determined CP based on 6.25 × N level typically overestimates the true protein of feedstuffs. RESULTS: Determined ingredient-specific N:P conversion factors k A, k P and k were not equal to the standard 6.25 factor. The k A had the highest value in all ingredients, which leads to the estimation of specific crude protein (SCP), which is closer to true protein (the summation of the total amino acid residues from amino acid analyses). The SCP(k A) was lower than CP and true protein in all ingredients, demonstrating that CP might overestimate the actual protein in feedstuffs. CONCLUSION: Based on data from 677 feedstuff samples from 2009, it is concluded that the mean k A should be 5.68 for corn, 5.64 for soybean meal, 5.74 for corn DDGS, 5.45 for poultry by-product meal and 5.37 for meat and bone meal. © 2011 Society of Chemical Industry. Source

Mejia L.,Mississippi State University | Zumwalt C.D.,Mississippi State University | Tillman P.B.,Poultry Technical Nutrition Services LLC | Shirley R.B.,Ajinomoto Co. | Corzo A.,Mississippi State University
Journal of Applied Poultry Research

The digestible Arg (dArg)-to-digestible Lys (dLys) ratio of broilers exposed to a constant, elevated ambient temperature was evaluated in commercial high-yielding male broilers. Common starter and grower diets were fed to all broilers from 0 to 28 d of age. Experimental diets were provided from 28 to 42 d of age. The experimental test diets were formulated with corn, soybean meal, corn distillers dried grains with solubles, and an animal by-product blend. The diets were formulated to satisfy all nutrient recommendations, with the exception of dArg. To create the experimental finisher diets, 2 experimental diets were formulated to contain 0.95 and 1.24% dArg and a common dLys level of 0.95%. These 2 diets were then blended to create 5 intermediate dArg:dLys levels (7 treatment diets in total), which were fed from 28 to 42 d of age. A diet made exclusively with conventional ingredients, with a dArg:dLys ratio of 107%, served as a positive control. Body weight gain was unaffected by the 7 experimental diets. Feed efficiency was improved in the experimental diets when the dArg:dLys ratio was 110%. However, no difference was observed for this parameter when compared with the FE of the control diet (dArg:dLys = 107%). Carcass traits were unaffected by the experimental treatments. Therefore, an adequate dArg:dLys ratio during a period of constant, elevated temperature was satisfied at a minimum of 110%. © 2012 Popultry Science Association, Inc. Source

Mejia L.,Mississippi State University | Zumwalt C.D.,Mississippi State University | Kim E.J.,U.S. Department of Agriculture | Tillman P.B.,Poultry Technical Nutrition Services LLC | Corzo A.,Mississippi State University
Journal of Applied Poultry Research

An experiment was conducted to evaluate the digestible Ile:Lys ratio (%) in finisher (28 to 42 d of age) phase diets fed to broilers, based on live performance and carcass trait responses. A total of 1,248 Ross × Ross 708 male broiler chicks were randomly allotted to 8 dietary treatments varying in digestible Ile:Lys ratios. A feed made exclusively with conventional ingredients served as a positive control. Digestible Ile:Lys ratios ranged from 57.8 to 74.4% with increments of approximately 2.8 percentage points, and a positive control was formulated to have a ratio of 67%. Step-wise regression analysis did not allow for the calculation of an optimal digestible Ile:Lys ratio for any of the parameters evaluated; thus, means separation was used to analyze treatment effects. No significant differences were observed among treatments for BW gain. However, feed conversion and feed intake were significantly lower for the control diet, which had a considerably higher CP level. An irregular response was observed for feed intake that was due to the dietary Ile:Lys ratio; however, we conclude that feed conversion improved when the ratio approximated 68.9%. No effect was observed for carcass weight or yield among dietary treatments. The digestible Ile:Lys ratio did not affect breast meat weight, but differences were observed in breast meat yield. The diet with a digestible Ile:Lys ratio of 71.7% resulted in improved breast meat yield and was observed to be similar to the control, despite the difference in CP. We conclude that a digestible Ile:Lys ratio of 68.9% was adequate for live performance, but a slightly higher ratio may be required for breast meat yield optimization (71.7%). © 2011 Poultry Science Association, Inc. Source

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