Digestive enzyme activity during larval development of the Senegal sole (Solea senegalensis)

The activities of the main digestive enzymes (proteases, amylase, lipase) a s well as those of acid and alkaline phosphatases were assessed during the larval development of the Senegal sole, Solea senegalensis. Important varia tions in specific activities of all the enzymes were observed during the pe riod of study and were mostly related to the beginning or the end of metamo rphosis. Both acid and alkaline protease activities were identified at earl y stages of development. Acid proteases accounted for only 10% of total pro tease activity in a 9 days-old larva, but exceeded 75% in a 33 days-old ind ividual. Maximum lipase activity was related to the development of exocrine pancreas (days 6 to 10) and to metamorphosis. It is suggested this can be related to the metabolism of lipid reserves taking place during this morpho logical change. Activity of alkaline phosphatase decreased from day 5 to da y 20 but therafter revealed a sharp increase, possibly linked to the develo pment of enterocytes. The pattern of development of the main digestive enzy mes found in S. senegalensis is similar to that described in other flatfish species.