Effect of Varying Dietary Energy to Protein Ratio Level on Growth and Productivity of Indigenous Venda Chickens

摘要

Two experiments were conducted to determine the effect of varying dietary energy to protein ratio on growth and productivity of indigenous Venda chickens raised in closed confinement from day-old up to 13 weeks old. In each experiment the diets had asimilar energy value of 12.2 MJ ME kg~(-1)DM, but with five different levels of protein concentration of 220, 190, 180, 170 and 160 g kg~(-1)DM, thus ending up with different energy to protein ratios of 55, 64, 68, 72 and 76 MJ ME kg~(-1)protein. A complete randomized design was used in each experiment, the one to six weeks old growing period (unsexed Venda chickens) and the seven to 13 weeks old growing period (male Venda chickens) experiments. A quadratic type equation was used to determine the ratiosfor optimum production variable. A single E:P ratio of 62 MJ ME kg~(-1)protein supported optimum feed intake and growth rate while an E:P ratio of 63 MJ ME/kg protein supported optimum feed conversion ratio in Venda chickens aged between one and six weeks. In contrast, an E:P ratio of 60 MJ ME kg~(-1)protein supported optimum growth rate and feed conversion ratio in male Venda chickens aged between seven and 13 weeks. However, an E:P ratio of 62 MJ ME kg~(-1)protein supported optimum feed intake in male Venda chickens aged seven to 13 weeks. The results indicate that a single E:P ratio of 62 MJ ME kg~(-1)protein optimized feed intake in Venda chickens irrespective of differences in sex and age. These findings have implications on ration formulation for Venda chickens.