Abstract: The experiment was conducted to study the effect of Bacillus Subtilis on growth performance and nutrient metabolic rate in broilers.sixty seven-week yellow broilers were randomly assigned to five treaments with four replicate and three broilers with each pen. The groups received the same basal diet supplemented with 0, 0.05, 0.1, 0.15, 0.2 g/kg praeparatum of Bacillus subtilis, respectively. The feeding trial lasted thirty days. The results showed that compared to the control, the average daily gain in group Ⅱ, Ⅲ, Ⅳ increased significantly by 49.03% (P <0.05), 46.39% (P <0.05) and 37.04% (P <0.05); the metabolic rate of crude protein of test group were significantly increased (P <0.01), calcium, phosphorus absorption and utilization rate of Ⅲ group were significantly increased (P <0.01). Therefore, the appropriate levels of Bacillus Subtilis for yellow broiler are 0.15 g/kg.

Key words: Bacillus subtilis; yellow broiler; growth performance; nutrition metabolize rate