Effect of Zinc Supplementation on Antioxidant Status and Immune Response in Buffalo Calves

Eighteen buffalo calves with an average BW of 125±2.5 kg were randomly allotted to three groups in a completely randomized design to investigate the effect of dietary Zn supplementation on antioxidant enzyme activities and immune response. The dietary treatments were viz., basal diet (control; 29.72 ppm zinc from feed ingredients) alone or supplemented with 80 and 140 ppm Zn as ZnSO₄.7H₂O. Calves were fed the respective diets individually at 3% of BW to meet the nutrient requirements throughout 120 days of experiment. Blood was collected after 110 days of feeding trial for estimating antioxidant enzyme activities. The humoral immune response against Brucella abortus and chicken RBC was assessed after 95 days of feeding and delayed type hypersensitivity (DTH) reaction against phytohaemagglutinin phosphate (PHA-P) indicative of cell mediated immune response (CMI) was assessed at 120 days of experiment. Lipid peroxidation was higher (Pd”0.05) in calves fed BD, which reduced with Zn supplementation and was lowest with 140 ppm Zn supplementation. The glutathione peroxidase and glutathione reductase activities were higher (P<0.01) in 140 ppm Zn supplemented calves, while RBC catalyse activity was higher (P<0.05) in 80 ppm Zn supplemented calves compared to those fed the control diet. Humoral immune response against Brucella abortus was higher (P<0.05) in Zn supplemented calves and highest response was observed with 140 ppm Zn supplementation. The haemagglutination titers against chicken RBC did not differ significantly with variation in dietary Zn supplementation. The DTH reaction against PHA-P was maximum at 24h post inoculation, maximum response was observed with 140 ppm Zn supplementation and lowest (P<0.05) in those fed the basal diet. Thus results of present study indicated that 140 ppm Zn supplementation to a basal diet containing 29.72 ppm Zn resulted in higher antioxidant activities and immune responses in buffalo calves.