Document Type : Original Article
Rajaei Fish Farm, P.O. Box: 833, Sari, Iran
To study the impact of plasma sex steroids including testosterone (T), 17β-estradiol (E2), progesterone (P) on gonad development stages in Persian sturgeon (Acipenser persicus) at different seasons, 86 female specimens were sampled and investigated. Results showed that before vitellogenesis stage (stage II), the values of T, E2 and P were relatively low (0.25, 0.55, and 0.32 ng/ml, respectively). Nevertheless, during the vitellogenesis (stage III), the levels of T, E2 and P increased considerably up to 8.55, 4.53 and 0.52 ng/ml, respectively, and showed a significant difference, compared with those of previous stage (p < /em> < 0.05). In stage IV, when nucleus had migrated, level of sex steroids decreased (T = 7.44, E2 = 2.65, and P = 0.36 ng/ml). GSI (Gonadosomatic index) at stages II, III, and IV of gonad maturity, were 2.55%, 13.11%, and 21.18%, respectively. Sex steroids therefore showed the considerable role in growth and development of gonad in Persian sturgeon and their concentrations were changed, depending on different stage of gonad maturity stage and season.