Abstract: In this study, total 90 fattening pigs were randomly divided into 5 groups with 3 replicates(6 pigs per replicate).The basic diet of these 5 groups was similar. Experiment groups were basal diet added: 1% probiotics,0.2% Iso-malto oligosaccharides,0.075‰ chlortetracycline and 1% probiotics+0.1% Iso-malto oligosaccharides. The effect of additive on growth performance and ability of antioxidation in fattening pigs were observed. The results showed that the average daily gain of 1% probiotics groups, 0.2% Iso-malto oligosaccharides groups and 1% probiotics+0.1% Iso-malto oligosaccharides groups were obviously higher than control group(P<0.05). Compared with the 0.075‰ chlortetracycline group, there was no significant difference.The SOD contents of 1% probiotics groups, 0.2% Iso-malto oligosaccharides groups and 1% probiotics+0.1% Iso-malto oligosaccharides groups were also higher than control group, but was no significant difference(P>0.05) . Compared with the 0.075‰ chlortetracycline group, there was no significant difference (P>0.05) too.

Key words: Iso-malto oligosaccharides; probiotics; fattening pig; growth performance; ability of antioxidantion