[Variation in the level of free amino acids during larva development of Penaeus japonicus (Crustacea, Decapoda, Penaeidae]. / Variations des concentrations des acides aminés libres au cours du développement larvaire de Penaeus japonicus Bate (Crustacea, Decapoda, Penaeidae).

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.