Author
CORZ0, A - MISSISSIPPI STATE UNIV. | |
KIDD, M - MISSISSIPPI STATE UNIF. | |
VIRDEN, W - MISSISSIPPI STATE UNIV. | |
Dozier Iii, William |
Submitted to: Southern Poultry Science Society Meeting Abstracts
Publication Type: Proceedings Publication Acceptance Date: 10/30/2004 Publication Date: 1/15/2005 Citation: Corzo, A., Kidd, M.T., Virden, W.S., Dozier III, W.A. 2005. Lysine needs of heavy late-developing broilers. Southern Poultry Science Society Meeting. Abstract 106. p. 26. Interpretive Summary: Technical Abstract: Data related to Lys needs for late-developing broilers is sparse. Two studies were conducted simultaneously to evaluate Lys needs for growth and carcass traits from 42 to 56 d of age for male and female broilers. In each study, 480 d-old Hubbard Ultra broiler chicks were randomly allocated to 96 pens and fed common feeds from placement up to 42 d of age. Then, a corn-soybean meal basal diet (3,200 kcal/kg; 15.0% CP) with progressive amounts of 0.08% dietary Lys from 0.68% (0.60% digestible) up to 1.10% was fed to broilers (7 treatments; 6 replications/treatment). In both studies, an isocaloric corn-soybean meal diet with 17% CP and 0.96% Lys (0.86% digestible) served as control (12 replications). Dietary Lys supplementation was accomplished by adding L-Lys-HCl to the basal diet at the expense of an inert filler. Regression analysis (95% of the maximum or minimum response) was performed to extrapolate dietary Lys optimization values. In both studies, broilers fed the control diet did not differ (P > 0.05) in BW, feed intake, or feed conversion when compared to those fed the dose-response diet at 0.96%, thus validating the dose-response diet's ability to support adequate growth. Female broilers did not respond to dietary Lys for any parameter measured. Gradient addition of Lys improved feed conversion linearly (P < 0.01) with male broilers. Fillet weight, tender weight, and their composite had a linear increase (P < 0.05) with Lys supplementation in male broilers. Carcass yield, fillet yield, and total breast meat yield displayed quadratic responses, resulting in Lys optimization levels of 0.87, 0.93, and 0.93 %, respectively in male broilers. Based on results from this study, high-yield male broilers should be fed a minimum of 0.93 % Lys (0.85 % digestible) from 42 to 56 d of age. Lack of response on female broilers indicates that less dietary Lys may be needed for adequate growth. |