The objective of this study was to investigate the effect of adding protease additive,Aquagrow,on the growth and digestive protease activities of common carp.Common carps with body weight of 48.7 g,were fed with basal diet(6% fish meal content)added without(control group)or with 175mg/kg protease additive Aquagrow for 30 days.The growth rate of control group and protease additive group were 99.4%,105.8%,and the FCR were 1.85,1.75.Growth rate was increased by 6.4%(P〈0.05)and FCR decreased by 5.4%(P〈0.05)by a...