Le metabolisme amino-acide de Palaemon serratus: Variations des acides amines libres du muscle et de l'hepatopancreas au cours du cycle de mue

Abstract

1.1. Changes in the relative water content and the free amino acid pool in the abdominal muscle and the hepatopancreas of the shrimp Palaemon serratus have been measured in detail throughout the molting cycle.2.2. Relative water content remains nearly unchanged in the muscle during the molting cycle. In the hepatopancreas its variations are more pronounced, with a maximum at stage B1.3.3. In the abdominal muscle, total free amino acids increase prior to the molting process up to a maximum at stage D3–4. The large fall just after molt is due to non-essential amino acids, and mainly to some known to be involved in osmoregulation: glycine, proline and asparagine-glutamine. Essential amino acids vary quite differently: their decline just preceding molt is followed by a marked increase at and shortly after molting process (maximum at stage A1). During the intermolt period, essential amino acids as well as non-essential ones decrease down to a minimum at stage D0.4.4. In the hepatopancreas, total free amino acids reach their maximal level at stage D0, then fall during stages d1 and D2. A second rise just preceding molt is followed by a large decrease due to essential amino acids as well as non-essential ones, with a minimal level at stage B2. During the intermolt stage, total amino acids restore their level up to the maximum at D0.5.5. These changes in muscle and hepatopancreas are discussed in relation to the physiological role of free amino acid pools in water content regulation and protein biosynthesis.