Some biochemical aspects of reproduction in female trachinotus ovatus (carangidae)

Abstract

General pattern of gonadal development in female Trachinotus ovatus was divided into six maturity stages, which are; immature, maturing, nearly ripe, ripe, spawning and spent stages. The maximum value of gonadosomatic index (GSI) was attained in June and July. Total protein content in ovaries varied according to different maturity stages recording maximum value at immature ovaries and minimum at spawning and spent ovaries. The values of GSI in ovaries were inversely correlated to their total protein content at different maturity stages. Seven amino acids (proline, alanine, valine, methionine, isoleucine, leucine and histidine) were found to increase significantly in ripe ovary, followed by a significant decrease in both spawning and completely spent ovaries. While, arginine and threonine reached their maximum concentration in the spawning period. On the other hand, serine amino acid reached their minimum value in the ripe ovary. Total lipid contents of ovaries reached their minimal values at immature stage, while the maximum recorded value was at the nearly ripe gonad. The ovarian total lipid contents approximately followed the same manner of the GSI according to the different maturity stages except in spawning period. Many differences were detected in fatty acid concentrations in female Trachinotus ovatus ovaries in relation to different maturity stages. Eicosapentaenoic acid content varied according to the stage of sexual maturity. While, the maximum recorded value of arachidonic acid was at the ripe stage. Palmitic acid and oleic acid had the highest concentrations among fatty acids, while those with low concentrations were pentadecanoic acid and gadoleic acid.