Changes in proteolitic activity of digestive system of Beluga sturgeon, Huso huso during larval ontogeny

The development of proteolysis digestive enzymes from the stomach and pancreas were studied in Beluga, Huso huso from hatching up to 50th day post hatching (dph). Larvae were obtained from ShahidMarjaniSturgeonRearingCenter, Gorgan province, Iran. Sampling was carried out immediately after hatching, 7, 14, 19, 24, 29, 35, 42 and 50 dph. The results showed that at the onset of exogenous feeding, gastric glands were already functional, which was indicated by an increase in proteolitic activity of stomach. In contrast, proteolitic activity of pancreas decreased after the onset of exogenous feeding, showing the importance of these types of enzymes in the cleavage of yolk proteins during the endogenous feeding phase. The present study indicated that larvae of Beluga at the onset of exogenous feeding had an advanced digestive system to accept exogenous food and to digest the formulated diets.