Abstract: The experiment was conducted to study the effects of Enteroccus faecium on the growth performance, immune and antioxidant function of piglets. One hundred and twenty Duroc×Landracex×Jinhua crossbred piglets with average body weight of about 19.7 kg were randomly distributed in two treatment groups with three replicates of twenty pigs each. The control group was fed only with basal diet and the trial group was fed with basal diet supplemented with Enteroccus faecium(E. faecium 1×106 colony forming unit (CFU)·g-1 of feed). The results showed that compared with the control, supplementation of E. faecium significantly improved the growth performance of piglets, with the ADG increased by 11.46% (P<0.05) and F/G decreased by 6.20% (P<0.05). The immune function and antioxidant ability of the treated piglets were improved i.e. the concentration of albumin, the levels of IgA, IgG, the complement component 3 (C3), the complement component 4 (C4) and the lysozyme activity in serum increased by 28.06%(P<0.05), 16.48%(P<0.05), 25.43%(P<0.05), 37.84%(P<0.05), 25.00%(P<0.05) and 76.08%(P<0.05), respectively. The level of serum glutathione increased by 46.80%(P<0.01), whereas the total superoxide dismutase activity decreased by 10.38%(P<0.05). In addition, supplementation with E. faecium decreased the counts of Salmonella and Escherichia coli by 15.37% (P<0.01) and 11.79% (P<0.05) in piglets feces respectively, and increased the lactic acid bacteria (LAB) counts by 18.78% (P<0.05). This study indicated that supplementation of E. faecium could significantly improve the growth performance of piglets, and this may due to enhanced specific and non-specific immunity function, and improved intestinal flora composition．

Key words: Enteroccus faecium, piglet, growth performance, antioxidation, immunity