Abstract: The objective of this study was to investigate the effect of microbial protease hydrolyzed soybean meal on the growth performance and nutrient digestibility of 1 to 21-day-old broilers. A total of 336 female Cobb broilers were allocated into 4 treatments, including control group, experimental Ⅰ,Ⅱand Ⅲ group. Control diet was based on corn-soybean meal, and microbial protease hydrolyzed soybean meal was used to replace common soybean meal at 5%,10%,15% in experimentalⅠ,Ⅱand Ⅲ group, respectively. Results showed that experimental groups increased feed intake by 12% to 21% and body weight gain by 8% to 16% (P<0.05), and decreased ratios of feed to gain by 3% to 7% (P<0.05); and also improved the digestibility of dry matter, crude protein, energy, calcium and phosphorus of broilers (P<0.05), compared to the control group. There were significant differences among experimental groups in growth performance and the digestibility of dry matter, crude protein and calcium (P<0.05), but not for energy and phosphorus digestibility (P>0.05). The results suggested that soybean meal treated with microbial protease can improve the nutritional value of soybean protein and the growth performance and nutrient digestibility of broilers.

Key words: enzyme hydrolyzed soybean meal; broilers; growth performance; nutrient digestibility