Study on digestive enzymes activities of Trachinotus ovatusⅠ. Comparison of their distribution in different digestive organs of adult and young fish

A comparative study was conducted on the activities of digestive enzymes in different digestive organs of adult and young Trachinotus ovatus. Results show that: 1) For adults, the order of protease activity from strong to weak is as follows: stomach＞foregut＞midgut＞pyloric caecum＞hindgut＞liver; amylase activity foregut＞hindgut＞pyloric caecum＞midgut＞liver＞stomach; lipase activity: foregut＞midgut＞hindgut＞pyloric caecum＞liver＞stomach. 2) For young fish, the order of protease activity is: stomach＞intestine＞caecum＞liver;amylase activity is intestine＞pyloric caecum＞liver＞stomach; lipase activity: intestine＞ caecum＞liver＞stomach. 3) Both the protease and amylase activities in different digestive organs of adults are weaker than those in young fish, and there is significant difference in amylase activity in stomach and pyloric caecum between adults and young fish (P＜0.05). The lipase activity in stomach of young fish is stronger than that in adults but weaker than that in the other digestive organs of adults. The order of digestive enzyme activity in young fish is similar with adults.