Abstract
This study was conducted to investigate the effects of dietary supplementation with chromium chloride, CrCl3 center dot 6H(2)O(2mg kg(- 1) basal diet) on the performance and immune response of broiler chickens under heat stress condition (25-43 C). A total of 80 one-day-old broiler chicks (Ross-308) were assigned to two treatment groups according to a completely randomized design. Each treatment consisted of four equal replicates, each contained ten chicks. Chicks were fed on basal diets supplemented with different concentrations of chromium (0 and 2 mg kg(- 1) CrCl3) from 1 to 35 days of age. Chromium supplementation as feed additives resulted in a slightly lower rectal temperature, and significantly (P< 0.05) lower respiration rate for the broiler chickens received diet supplemented with chromium compared to the control (0 mg kg(- 1) CrCl3). Dietary chromium supplementation increased final body weight (BW) at the end of the production period (5 weeks). Average weight gain was significantly (P< 0.05) higher in chickens fed on chromium supplemented diet. Feed intake was not influenced by dietary chromium supplementation, however, the efficiency of feed conversion was improved (P< 0.05) in chromium supplemented chickens. Furthermore, dressing percentage was significantly ( P< 0.05) higher in Cr- treated chickens compared to control chickens. Chromium supplementation significantly (P< 0.05) improved the immune response to Newcastle Disease Virus vaccine (NDV). The present results suggest that dietary chromium supplementation provides a good nutritional management approach to ameliorate heat stress induced depression in production performance and immune response of broiler chickens.