Effect of different environmental factors on the activities of digestive enzymes and alkaline phosphatase of Macrobrochium nipponense

The activities of digestive enzymes and alkaline phosphatase from the hepatopancreas of Macrobrochium nipponense were determined under different environmental factors (calcium concentrations 20 mg·L^-1, 35 mg·L^-1, 60 mg·L^-1, 80 mg·L^-1, 150 mg·L^-1; salinity 7‰, 14‰, 20‰; pH 7.6,8.8,9.8). The results showed that higher Ca²⁺ concentration could enhance the pepsin activity, but inhibit the trysin-like activity in hepatopancreas of M. nipponense. The activities of pepsin, trysin-like, alkaline phosphatase in hepatopancreas of M. nipponense were higher under salinity of 14‰ than under salinity of 7‰ and 20‰. It showed that the activities of digestive enzymes and alkaline phosphatase of shrimp increased gradually with increasing pH value from 7.6 to 9.8.