activities in digestive organ in largemouth bass （ Micropterus salmoides）
GUAN Sheng-jun, WU Rui-quan, XIE Jun, WANG Guang-jun, XIE Yi-rong, Ye Fu-liang, CHEN Gang
1. College of Fisheries, Guangdong Ocean University, Zhanjiang 524088 ,China; 2. Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 5103801 ,China
Abstract: Protease activities were determined in different parts of digestive organs in largemouth bass （Micropterus salraoides） at different temperature, pH and casein concentration by means of enzymological analysis. The results showed that the protease activities in different parts of digestive organs were arranged in a descent order as： stomach 〉 pyloric caeca 〉 foregut 〉 midgut 〉 hindgut. The protease activities changed with variations in temperature, pH and casein concentration in different organs. The optimum temperatures and pH were （40℃, 2.4 ） for stomach, （55℃ ,7.6） for pyloric caeca（45℃ ,8.0） for gut. The optimum temperature for protease activity was higher than that in the fish body. The highest activity of protease occurred in strong acidic condition in stomach, but in neutral or weak alkaline condition in pyloric caeca and gut. The activity of the protease also changed with concentrations of the casein, the optimum casein concentration of 20 g/L for stomach. 20 g/L for pyloric caeca, and 10 g/L for gut.
2007, Vol. 22 
