Dietary selenium and zinc supplementation alters growth and immunity of broiler chicken

Abstract

This study evaluated the influence of varying dietary levels of selenium (Se) and Zinc (Zn) on the performance index, carcass characteristics, and immune response in broiler chicken. The experimental trial was carried for 42 days with a 3 × 3 factorial design involving three levels of each Se (0.15, 0.30, and 0.45 mg/kg diet) and Zn (40, 80, and 120 mg/kg diet) resulting in nine treatments. Six replicate groups with eight birds in each were assigned to each treatment (48 birds/treatment). During starter phase (0-3 weeks), optimum growth performance and growth efficiency of chicken was observed at 0.30 mg Se/kg diet. However, during finisher phase (4-6 week) and overall growth phase (0-6 week), 0.15 mg Se/kg diet was found to be optimum. Similarly, weight gain during starter phase was higher in birds fed at least 80 mg Zn/kg diet. The carcass characteristics did not reveal significant effect of Se and Zn supplementation in broiler chicken. And, on similar lines, cell mediated immunity remained unaffected. However, better humoral immunity was observed in birds supplemented with NRC recommended Se level in diet, but the NRC recommendation of 40 mg Zn/kg diet was inadequate for better humoral immune response compared to 80 or 120 mg level. Further, higher spleen and thymus weight was observed at 0.3 mg Se/kg diet and higher spleen weight at 80 mg Zn/kg diet. In conclusion, Se supplementation of 0.30 mg /kg diet and Zn supplementation of 80 mg/kg diet resulted in optimum growth performance, efficiency, and immunity of broiler chicken.