This means the biological function of CS-Zn is better than ZnSO4 or CS+ZnSO4 in pigs. Cu/Zn-SOD could be used as biological
parameters to evaluate Zn status in the body [36]. The fact that Cu/Zn-SOD was affected by dietary zinc levels has been proved by many studies [37, 38]. It is well-known that mechanism prevents the formation of highly cytotoxic oxygenderived free radicals [39].