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The effects of zinc on growth performance, activities of enzymes, and concentrations of hormones were investigated in this study. Crossbred (Duroc × Landrace × Large White) piglets (initial body weight: 26.66 ± 2.45 kg) were randomly assigned into 4 groups receiving a basal diet and were supplemented with 60, 300, 1000, or 3000 mg/kg of zinc (as ZnSO4.7H2O). The results showed that supplementation of zinc at 3000 mg/kg increased (P < 0.05) the average daily feed intake, weight gain, gain/feed, and relative organ weight, and promoted the activities of alkaline phosphatase and Cu-Zn superoxide (P < 0.05) by 84.17% and 49.86%, respectively, when compared with the control group. It also led to higher hepatic metallothionein content and tissue zinc concentration (P < 0.05) than in the control group. Furthermore, the concentrations of insulin and neuropeptide Y (NPY) in the 3000 mg/kg group were increased (P < 0.05) by 55.19% and 26.53%, respectively, compared to the control group. The present study suggests that pharmacological dietary supplementation of zinc increased growth performance, activities of enzymes, tissue zinc concentrations, and plasma insulin and NPY concentrations. Key words: Zinc, growth performance, tissue zinc concentration, enzyme activity, hormone concentration, piglet