Effect of dietary ascorbic acid (vitamin C) supplementation on the performance of broiler chickens in a tropical environment

Abstract

Two experiments, the first lasting eight weeks and the second nine weeks, were conducted with day-old Ross broiler chicks to evaluate the effect of dietary ascorbic acid supplementation on the performance of broiler chickens during the hot months (March–May) of the year in Zaria, Nigeria. In Experiment I, 0, 200, 400 or 600 mg ascorbic acid per kg feed was added to a maize and soya bean meal basal diet. In Experiment II, 100, 200 or 300 mg ascorbic acid per kg feed was added to portions of the control diets. The starter and finisher diets in each experiment were formulated to be isonitrogenous and isocaloric. Results from Experiment I showed that by eight weeks, ascorbic acid supplementation had significant linear ( P < 0.05) and quadratic ( P < 0.001) effects on body weight gain in the broilers, gain being highest at 200 mg ascorbic acid per kg feed. Feed intake was unaffected by treatment, but feed:gain ratio at both 4 and 8 weeks showed linear ( P < 0.05) and quadratic ( P < 0.01) responses. In Experiment II, the following respective average eight-week body weight gains (kg) were obtained for 0, 100, 200 and 300 mg ascorbic acid supplementation per kg feed: 1.65, 1.72, 2.08, 1.92. Feed :gain response was also best with 200 mg kg −1 ascorbic acid. In periods of heat stress that occur in some months in the tropics, dietary supplementation of broiler chicken diets with 200 mg ascorbic acid per kg is necessary and economically advantageous.