The onset of exogenous feeding in marine fish larvae

The evolution of the digestive enzyme equipment in seabream from hatching to 30 days old larvae was studied; there was a progressive increase in the activity of protease, amylase and acid and alkaline phosphatase from day 15 onwards. The use of specific inhibitors, and SDS-PAGE provided evidence to suggest that most of the proteases belonged to the serine group. A high α-amylase activity was also denoted. Zymograms of larval extracts indicated that exogenous food has more a qualitative than a quantitative role in the secretion of digestive enzymes in this species.