Electrolytes and Sex steroids profiles of cultured Beluga (Huso huso)

Abstract

In this study electrolytes and sex steroids levels of beluga (Huso huso) were determined. Forty-one fish selected randomly from different age groups (4, 6, 7 and 8 year-old) including 23 females and 18 males in Shahid Marjani Sturgeon Culture Center located in the Golestan Province (Gorgan, Iran). Blood sampling was taken from the caudal vein of fish. After serum separation, electrolytes (calcium, sodium and potasium) and sex steroids were determined. No significant differences were seen between male and female for blood serum electrolytes. There is not any difference in electrolytes fluctuation of Beluga between males and females when evaluated with sex maturation. The results of linear regression analysis in male and female showed that with the increase in gonad maturation the level of calcium was increased. Testosterone and 17α-hydroxyprogestrone levels showed significant difference in males at the stage V. The level of estradiol-17β (E2) in males showed chaotic fluctuations in different stages. By six years, all males could be separated from females based on T content (>5 ng/ml). In females, T, E2 and 17-OHP levels were relatively low before vitellogenesis, but during the vitellogenesis (stage IV) the level of T and E2 dramatically increased. The level of 17α-hydroxyprogestrone showed chaotic fluctuations in different stages. In conclusion, T, E2 and 17-OHP hormones are most important indices of sexual maturation.