Abstract: This experiment was conducted to investigate the effects of Bacillus preparation on performance, serum related index, cecal flora in layers. Three thousand and six hundred 259-day- old 'jing fen yi hao' layers were randomly divided into 2 groups, with 6 replications per group and 300 layers each replication. Layers in control group were fed basal diet. The trail groups were fed diet supplemented with 3% Bacillus preparation. The experiment lasted for 40 d. On day 41,three layers was selected from each replication, blood from wing vein were obtained and used to determine serum related index, then a layer were slaughtered, cecal was collected to determine contents of Escherichia coli and Lactobacillus. The results showed:①there was no significant effect of Bacillus preparation on performance of layers;②there was no significant effect of Bacillus preparation on serum related index,except that the content of serum superoxide dismutase (SOD) was significantly improved(P＜0.05);③the diet added with Bacillus preparation significantly reduced the contents of Escherichia coli in cecal(P＜0.05), and increased the contents of Lactobacillus in cecal(P＞0.05). It was concluded that supplementation of Bacillus preparation in diets increased the antioxidant capacity and improve intestine microbial flora of layers.

Key words: Bacillus preparation; layer; serum index; performance; cecal flora