Assessment of digestive enzymes activities during the early development of Nibea japonica

Abstract:

Kinds of digestive enzymes activities were studied in Nibea japonica of the early development stage. The results showed: amylase, lipase and alkaline phosphatase activities can be detectable during embryonic development stage, while pepsin and acid phosphatase could not be detected. Activities of amylase, lipase and pepsin changed significantly with the growth of fish larvae, amylase and lipase activity in the larvae increased rapidly after hatching, and reached the higher level before first feeding stage, mounted respectively (0.433 ± 0.010) U/mg and (388.53 ± 16.16) U/g. It showed that kinds of digestive enzymes had existed in the body of Nibea japonica for the preparation of their food intake, which could help the digestion of carbohydrates and lipids. The activities of pepsin were earliest detectable in the 8d larvae, specific activity was valued at only (0.33 ± 0.09) U / mg. The activities rapidly increased during the later 15 days, and reached the highest value in the 23 day larvae, amount（1.83±0.12）U/mg. The weak alkaline phosphatase activity which could detected in the fertilized eggs increased slowly after hatching, and it reach the peak value (156.74± 5.17) U / g in the 13 day larvae, afterward the values stabilized at a higher level, which indicated that intestine was the main digestive place, and its digestive function had been perfected gradually during the development of Nibea japonica larvae.