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ARS Home » Southeast Area » Mississippi State, Mississippi » Poultry Research » Research » Publications at this Location » Publication #226119

Title: Impact of dietary isoleucine status on heavy-broiler production

Author
item CORZO, A
item Dozier Iii, William
item KIDD, M
item HOEHLER, D

Submitted to: International Journal of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/27/2008
Publication Date: 6/15/2008
Citation: Corzo, A., Dozier III, W.A., Kidd, M.T., Hoehler, D. 2008. Impact of dietary isoleucine status on heavy-broiler production. International Journal of Poultry Science 7(6):526-529.

Interpretive Summary: Feed cost represents 65% of the total live production cost for broiler chickens that supports an industry that produces 8 billion birds annually. Feed cost approximates 65% of the total cost for producing broilers. Large percentage of the cost of the diet is protein/amino acid contributing ingredients. Isoleucine is the fifth limiting amino acid for broiler chickens fed corn-soybean meal based diets. Experimental diets consisted of a control diet (0.71% dig Ile) and a diet marginal in dietary dig Ile (0.58%). Experiment 2 evaluated the addition of three graded levels of dietary dig Ile (0.58, 0.62, 0.66% Ile). A similar amount (weight basis) of Arg was supplemented to the 0.58% dig Ile diet to observe if any possible Ile response was specific for Ile, non-essential N, or a limitation of the essential amino acid arginine. Results indicated that supplementation with equal amounts of Arg did not alleviate the dietary Ile limitation, thus validating the essentiality of Ile in practical corn-soybean meal diets when at least 2% of meat-and-bone meal is present in diet formulation.

Technical Abstract: Two experiments were conducted to evaluate the importance of Ile as a limiting amino acid in diets fed to broilers up to heavy market weights. The first experiment compared a control diet formulated to meet all critical limiting amino acids vs. a diet that also met all limiting amino acid needs except for Ile (0.71 vs. 0.58% standardized ileal digestibility). Results from Experiment 1 showed poorer BW gain, feed conversion and feed cost/BW gain in birds fed the Ile-marginal diet when compared to the control. Experiment 2 evaluated the supplementation of three graded levels of Ile (0.58, 0.62 and 0.66% standardized ileal digestibility) to the Ile-reduced diet used in Experiment 1. Results for Experiment 2 showed that BW gain and feed conversion improved when L-Ile was supplemented to the lowest dietary Ile level fed. Supplementation with equal amounts of Arg did not alleviate the dietary Ile limitation, thus validating the essentiality and marginality of Ile in practical corn-soybean meal diets when at least 2% of meat-and-bone meal is present in diet formulation.