Majallah-i ̒Ilmī-i Shīlāt-i Īrān (Jan 2008)
A MEASUREMENT AND COMPARISON OF DIGESTIVE ENZYMES ACTIVITY IN LARVAE OF CASPIAN BROWN TROUT AND RAINBOW TROUT AT INITIATION OF EXOGENOUS FEEDING
Abstract
To determine the digestive capacity of larvae in Caspian brown trout and Rainbow trout, activity of digestive enzymes including pepsin, trypsin, chymotrypsin, a-amylase, lipase and alkaline phosphatase in 2/3 and complete yolk-sac absorption stages were assessed. Results showed enzyme activity was significantly higher in Rainbow trout than in Caspian brown trout at 2/3 yolk-sac absorbtion stage (P0.05). At the start of feeding, activity of pepsin, trypsin, chymotrypsin and alkaline phosphatase were higher in Rainbow trout than in Caspian brown trout but the difference was not significant for pepsin (P>0.05) whereas trypsin, chymotrypsin and alkaline phosphatase were significant different between the two (P0.05). Lipase was similar in both fish. Higher enzyme activity in Rainbow trout than in Caspian brown trout at 2/3 yolk-sac absorption shows the high ability for digesting food in rainbow at this stage. Also, low enzyme activity in Caspian brown trout at this stage is believed to be one of the reasons for low food intake and digestion at this stage.
