Effect of high zinc diets on growth performance and serum antioxidative enzyme activities in early weanling stress piglets

One hundred Duroc ×Landrace×Yorkshire crossbred weanling piglets(26±2 days of age) were randomly divided into 5 groups with 20 piglets each by weight and sex,fed with basal diet,basal diet plus(2 000) or 3 000 mg·kg~(-1) zinc(from ZnO),and basal diet plus 250 or 500 mg·kg~(-1) zinc(from Zn-Met),respectively.The trial was conducted for 14 d.Body weights and feed intakes were determined on 0,7,(14 d) postweaned,and diarrhea rates were evaluated.Blood samples in fifty piglets were taken from the anterior vena cava on 0,7,14 d postweaned for measuring serum antioxidative enzyme activities.The results showed that high zinc diets increased absolute weight(AW),average daily gain(ADG) and average daily feed intake(ADFI) in weanling stress piglets,significantly;decreased the ratio of feed to gain(F/G) and diarrhea rates postweaned;enhanced serum CuZn-SOD and GSH-Px activities.