SEASONAL CHANGES IN AMINO ACID COMPOSITION IN THE MRBICULA JAPONICA GONADS

Abstract

Knowledge of the reproductive process features of Corbicula japonica is necessary not only to understand the formation of the species’ reproductive strategy in the evolution, but also to arrange the fishing efficiently for the purpose to produce biologically active substances. Methods. There was a research of the shellfish clamed in MarchNovember, 2008 in the estuary of Razdolnaya river from the depth of 0.8-1m. The external features and histological changes in the gonads have been reviewed supplemented with morphometry. Results. In the Corbicula japonica’s sexual cycle the following maturity stages for a gonad have been identified according to the season’s specificity: 1) sexual inertia, 2) the beginning of the oocytes’ growth, 3) active gametogenesis, 4) prespawning, 5) spawning, 6) postspawning. The content of individual amino acids in the male gonads was higher than in the female gonads. A tendency to increase the number of amino acids in the gonads was observed in the stages of active gametogenesis and spawning, while a tendency to decrease - in the postspawning stage. Conclusions. At all sexual cycle stages of the Corbicula japonica, like other bivalves, the dominant amino acids are glutamic and aspartic. The results of the chemical composition study showed that the essential nutrients content in the clam’s soft tissues is changeable and depends on the season.