Effect of dietary lysine to energy ratio on performance of unsexed indigenous Venda chickens.

Abstract

Two experiments were conducted with the aim of determining the effect of dietary lysine to energy ratio on performance of unsexed indigenous Venda chickens raised in closed confinement from day-old up to 13 weeks old. In each experiment the diets were isocaloric and isonitrogenous but with different lysine to energy ratios. A complete randomized design was used in both experiments, the starter (1-6 weeks) and grower (7-13 weeks) experiments. The three starter diets, based on lysine to energy ratios, were T0 (0.84), T1 (1.04) and T2 (1.23) g MJ-1 ME, while grower diets were T3 (0.52), T4 (0.71) and T5 (0.89) g MJ-1 ME, respectively. A quadratic type equation was used to determine ratios for optimum growth, feed conversion ratio, breast meat yield and breast meat nitrogen content. The results indicate that at each phase different dietary lysine to energy ratios optimized both growth rate and feed conversion ratio. Dietary lysine to energy ratios of 1.20 and 1.17 g MJ-1 ME supported optimum growth rate and feed conversion ratio, respectively, during the starter period. Dietary lysine to energy ratios of 0.76 and 0.84 g MJ-1 ME supported optimum growth rate and breast meat nitrogen content during the grower phase. However, a single ratio of 0.81 g MJ-1 ME supported optimum breast meat yield and optimum feed conversion ratio. Dietary lysine to energy ratio had no effect on diet intake, digestibility and carcass weight. These findings have implications on ration formulation for indigenous Venda chickens.