Ontogeny of Fertilized Eggs and Yolk Sac Larvae of Sea Bass (Dicentrarchus labrax)

Abstract

The biochemical compositions of fertilized eggs, yolk sac larvae, and larvae at the beginning of exogenous feeding of sea bass (Dicentrarchus labrax) were determined. Eggs and yolk sac lar- vae contain more monounsaturated and polyunsaturated fatty acids than saturated fatty acids. Essential and non-essential amino acid contents tended to drop at hatching, then sharply increase by the end of endogenous feeding. Amylase and trypsin activity was detected in fertil- ized eggs. Trypsin activity peaked at the beginning of exogenous feeding. The alkaline phos- phatase activity was lowest in fertilized eggs, higher at hatching, and highest at the end of the experiment. Leucine alanine peptidase activity was higher than other enzymatic activity in all three stages. Aminopeptidase N activity increased until hatching, then stabilized until the begin- ning of exogenous feeding.