Classification of sex and maturity stages of farmed Great sturgeon (Huso huso) using blood plasma steroid hormone and calcium ion levels

Twenty four farmed great sturgeon, Huso huso (including ۸ males and ۱۶ females) over ۶ years old were used to develop a method for determination of sex and maturity stages. Seasonal gonadal tissue and blood samples were collected from farmed great sturgeon for three years. The sex and stages of maturity were determined by histology and laparoscopy at the beginning and end of experiment. Plasma sex steroid hormone levels [testosterone (T), ۱۷β-estradiol (E۲) and progesterone (P)] were measured by radioimmunoassay, and plasma calcium ion levels were measured by spectrophotometer. Mean concentrations of testosterone, progesterone and estradiol in blood plasma of H. huso at maturity stages II, III and IV were ۱۰.۸۶±۱.۶۳, ۵۴.۱۴±۳.۱, ۱۱۲.۴۱±۷.۴ ۰.۸۴±۰.۱۲, ۱۵.۶۶±۲.۱۸, ۵۰.۷۵±۳.۶۳ ng/ml in males and ۹.۰±۱.۳۹, ۶.۵۱± ۰.۶۴, ۲.۹۵±۲.۲۹, ۵.۴۵±۰.۲۹, ۹.۴۷±۰.۹۷ and ۴.۱۵±۰.۷ ng/ml in females, respectively. Testosterone and estradiol levels showed significant differences at various stages. Calcium level at stages II, III and IV of sexual maturity in females (۸.۰۵ ± ۰.۰۹, ۱۰.۴ ± ۰.۳۴ and ۹.۶ ± ۰.۶ mg/dl) was more than males (۷.۷۳ ± ۰.۱۶, ۸.۵۸ ± ۰.۱۳ and ۸.۷۶ ± ۰.۱۱ mg/dl). Results showed that steroid hormone concentration and calcium level of blood plasma in males and females vary between different stages of sexual maturity. Therefore it can be used to determine the stages of sexual maturity in farmed H. huso.