RESUMO
Two experiments were carried out to determine the effect of dietary ascorbic acid supplementation levels on productivity, carcass characteristics, and mortality of indigenous Venda chickens. The first experiment determined the effect of dietary ascorbic acid supplementation levels on productivity and mortality rate of 175 unsexed Venda chickens between 1 and 6 weeks old. The second experiment determined the effect of dietary ascorbic acid supplementation levels on productivity, carcass characteristics, and mortality rate of 140 female Venda chickens between 8 and 13 weeks old. A completely randomized design was used in both experiments. Supplementation of grower diets with ascorbic acid ranged from 0 to 2,000 mg per kg DM feed in both experiments. Levels of ascorbic acid supplementation for optimum feed intake, feed conversion ratio, growth rate, live weight, and breast meat yield were determined using a quadratic equation. The optimal dietary ascorbic acid supplementation levels for feed conversion ratio, growth rate, and live weight of Venda chickens during the starter phase were 1,050, 1,301, and 1,500 mg/kg DM feed, while, at the grower phase, the optimal supplementation levels for feed conversion ratio, growth rate, live weight, and breast meat yield were 1,000, 1,250, 1,482, and 769 mg/kg DM feed, respectively. Results indicate that different levels of ascorbic acid supplementation optimized feed conversion ratio, growth rate, and live weight of Venda chickens at each growth phase. However, levels of ascorbic acid supplementation for optimum feed conversion ratio, growth rate, and live weight were higher than that for breast meat yield. These findings have implications on ration formulation for Venda chickens.
