Reproductive biology spermatogenesis and biochemical characteristics of male sparid fish Dentex dentex from the south eastern Mediterranean coast

The present study focuses on reproductive biology parameters and histological and fine structure investigations of testes maturation, in respect to steroid hormones and fatty acids’ profile. All males over 30 cm in length were found to be mature. Gonadosomatic index (GSI) of males increased progressively to reach a peak value in May and June. In Dentex dentex, the spermatogonia were detected throughout the year in the peripheral zone of the testes. Spermatocytes are characterized by large nuclei with higher electron density and a layer of cytoplasm. The nuclei of spermatids were characterized by a condensed chromatin material. The early spermatid had a central nucleus and a large number of mitochondria. One big mitochondrion lies beneath the head of the sperm. The seasonal change of serum testosterone correlates with gonadal development. The presence of nearly ripe and ripe male D. dentex coincides with the surge of testosterone and the decrease in estradiol continues throughout the spawning periods. In males, higher GSI was accompanied by the highest lipid content of the testis. The high concentration of polyunsaturated fatty acids n-3 (PUFA) for testis, liver and muscles was as follows: docosahexaenoic (DHA, 22: 6 n-3) and eicosapentaenoic (EPA, 20:5 n-3) acids. The higher concentration of polyunsaturated fatty acids n-6 (PUFA) for testis, liver and muscles was as follows: linoleic (18:2 n-6) and arachidonic acids (20:4 n-6) with significant differences in relation to maturation stages at (P < 0.001).