Abstract: The purpose of this experiment was to study the effect of RH-3 fusion hybrid of Bacillus subtilis and Lactobacillus rhamnosus on the immune function and intestinal microflora of three buff chickens.96 one-day-old chickens were randomly divided into 4 groups with 3 replicates per group and 8 chickens per replicate.Chickens in control group were drinking water that had not added the RH-3 fusion hybrid culture;Chickens in the experimental group were drinking water that supplemented with 0.5%, 1.0% and 1.5% RH-3 fusion hybrid culture, respectively.The whole experiment period was 42 days, including two phases of days 1 to 21 and days 22 to 42.The results showed that compared with the control group, the supplementation of RH-3 fusion hybrid increased the Newcastle disease HI antibody titer, SOD activity, lymphocyte transformation rate in serum and the immune organ index of three buff chickens at days 21 and 42, and the difference was significant of 0.5% level (P<0.05).Compared with the control group, the supplementation of RH-3 fusion hybrid reduced the number of Salmonella and E.coli and increased the number of the Bifidobacterium and Lactobacillus in jejunum, ileum and cecum of three buff chickens at days 21 and 42, and the difference was significant of 0.5% level (P<0.05).In summary, RH-3 fusion hybrid could improve the immune function and regulate the intestinal microflora of three buff chickens, promote the growth of beneficial bacteria and inhibit the growth of harmful bacteria, but the effects showed a downward trend with the increasing of the amount of RH-3 fusion hybrid.So the adding amount of RH-3 fusion hybrid in the drinking water of three buff chickens was suggested as 0.5% under this experimental condition.

Key words: Bacillus subtilis; Lactobacillus rhamnosus; fusion hybrid; immune function; intestinal microflora