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Variations of free amino-acids (FAA) content during the larval development of Penaeus japonicus have been studied.FAA content increases from 83 to 687 μmoles/g dry weight from egg to post-larval (20 days old: P20) development. There is a sharp increase between zoe and mysis stages, and another one between one day post-larvae (P1) and P20. After the mysis stage, free essential and non essential amino-acids evolve in a different way: the non essential FAA content, mainly glycine, increases continuously, whereas essential FAA content decreases (about 40%) from the mysis stage to metamorphosis in post-larvae (P1).FAA content evolution during larval development exhibits the same trend as the variation of the digestive enzyme activity.ResumeLes variations des concentrations des acides amines libres (AAL) ont ete etudiees au cours du developpement larvaire de Penaeus japonicus.La concentration totale des AAL de l'aeuf a la post-larve de 20 jours (P20) augmente de 83 a 687 μmoles/g de poids sec. Cette augm...

Variations of free amino-acids (FAA) content during the larval development of Penaeus japonicus have been studied. FAA content increases from 83 to 687 mumoles/g dry weight from egg to post-larval (20 days old: P20) development. There is a sharp increase between zoe and mysis stages, and another one between one day post-larvae (P1) and P20. After the mysis stage, free essential and non essential amino-acids evolve in a different way: the non essential FAA content, mainly glycine, increases continuously, whereas essential FAA content decreases (about 40%) from the mysis stage to metamorphosis in post-larvae (P1). FAA content evolution during larval development exhibits the same trend as the variation of the digestive enzyme activity.

Lipids content of the haemolymph and the hepatopancreas in the decapod Crustacean P. japonicus exhibits a bicircadian rhythm characterized by one maximum in the night and another one during the day. The maximal values in the haemolymph are approximatively two and a half times greater (8 mg/ml) than minimal ones (3 mg/ml). Variations are less important in the hepatopancreas.A bicircadian rhythm of lipid classes in the haemolymph is observed very significantly in concentration of polar lipids and free sterols with maximal values (6.87 mg/ml and 0.59 mg/ml) and minimal values (2.63 mg/ml and 0.23 mg/ml) respectively.Polar lipids are the major lipid fractions in the haemolymph (87%). The electrophoretic behaviour of haemolymph lipoproteins is determined.