Study on digestive enzyme activities of Brachymystax lenok at differ ent growth stages

Distribution and peculiarity of digestive enzyme in the alimentary system of Brachy-mystax lenok were detected in this study.Fish in three developmental stages were used,including juvenile,fingerling and reproductive fish.Protease,amylase and lipase were mainly investigated in this study.The results showed that the activity of protease was the highest among these digestive enzymes in stomach;the activity of protease in juvenile fish was lower than that in fingerling and reproductive fish,which were maintained at the same level.The activity of amylase increasing from juvenile to fingerling stage,until parent fish was the highest.The activity of lipase had high level in juvenile and fingerling fish,then lessened down in the reproductive fish.Distribution of three digestive enzymes activities in the alimentary system of B.lenok was studied.The activity of protease was the highest in the pylorus,and the distribution trend in different organs was esophaguspyloric caecumintestine stomach.The distribution of amylase activity was detected in all organs of alimentary system.The highest activity of amylase was in the foregut,the lowest was in the pyloric caecum and hindgut.The highest activity of lipase was in the stomach and at least in the pyloric caecum and hindgut.The distribution of the trend reduced from the stomach down in the alimentary system.The highest activity of lipase was in the stomch,following in the pyloric caecum,and the lowest activity was in the intestines.