EARLY WEANING OF SEA BASS (DICENTRARCHUS-LABRAX) LARVAE WITH A COMPOUND DIET - EFFECT ON DIGESTIVE ENZYMES

Sea bass (Dicentrarchus labrax) larvae were weaned with a microparticulated diet at various times after hatching: 10, 15, 20 and 25 days; a control group was fed live prey (Artemia salina). The earlier the weaning, the lower the larval growth obtained. The amylase activity in the pancreatic segment increased swiftly after the weaning in all groups. This increase was the result of an extensive synthesis induced by the starch content (12%) of the compound diet. The enhancement of specific activities of intestinal peptidases, leucine aminopeptidase and gamma-glutamyl transpeptidase after weaning was the result of compensatory adaptation, as was described in the case of malnutrition. The depressed activities of alkaline phosphatase, in the brush border membrane fraction, indicated malnutrition in weaned groups. Weaning before day 20 stops or delays larval development, particularly maturation of some digestive processes in larvae, such as the onset of pancreas secretory functions.