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 8 males and 16 females) over 6 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), 17β-estradiol (E2) 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 10.86±1.63, 54.14±3.1, 112.41±7.4; 0.84±0.12, 15.66±2.18, 50.75±3.63 ng/ml in males and 9.0±1.39, 6.51± 0.64, 2.95±2.29, 5.45±0.29, 9.47±0.97 and 4.15±0.7 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 (8.05 ± 0.09, 10.4 ± 0.34 and 9.6 ± 0.6 mg/dl) was more than males (7.73 ± 0.16, 8.58 ± 0.13 and 8.76 ± 0.11 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

Study on the propagation possibility in reared great sturgeon, Huso huso by GnRH synthetic hormone for production of fingerling

This study was carried out in the International Sturgeon Research Institute of Dr. Dadman during 2007–2011. A total of 24 beluga 7- year – old (Huso huso) including 8 males and 16 females were selected after morphological assay, biopsy and sexing based on histological routine methods and then stocked separately based on sex in 3 concrete circled ponds (with 4m diameter, 1.5 depth) an were fed by diet include 38–40 % protein, 13–15 % fat, 19.5 – 20 Mg/kg energy and 2-3 % different kind of vitamins and minerals produced by mentioned institute. Bleeding was carried out in order to separating serum for study on biochemical and hormonal parameters. The GnRH hormone was injected to fishes at two stages each 12 hours after GV detection, evaluation of sexual hormone levels and water temperature. Females were injected at two stages each 6 hours with ration 20% to 80 % and concentration of 10 µg/kg of fish body weight. Males were injected by GnRH for one time according with the second injection in females with concentration 20 µg/kg of fish body weight. Obtaining of eggs was carried out by micro incision of oviduct without killing fish. Mean concentration of Glucose showed no significance different at stages II and III, but showed significance different at stage IVof sexual maturation stages (P<0.05). Cholesterol, triglycerides and total lipid levels of males and females blood serum were changed significantly from stage II to stage IV and in different seasons (P<0.05). Calcium level of blood serum was different at various sexual maturity stages in males and females and was more in females than males at each stage. So that showed significant difference at stage III between them. Sodium ion showed no significant difference in males and females at each condition. Mean concentration of testosterone (T) in males and females at stages II, III and IV was 10.86 ± 1.63, 0.84 ± 0.12, 54.14 ± 3.1, 15.66 ± 2.18, 112.41 ± 7.4 and 50.75 ± 3.63 ng/ml respectively, that showed significant difference with each other and at different sexual maturity stages (P<0.05), that reached to a maxim in males at stage III and IV in Autumn and in females at stages II and III in Winter. But, at stage IV, it was similar to males. Testosterone levels at all stages in males was more than females. Mean concentration of progesterone level in males and females at stages II, III and IV was 0.5±0.01, 0.5±0.00, 0.5±0.08, 0.11±0.02, 0.36±0.04 and 0.19±0.03 ng/ml respectively, that showed significant difference at stage III. But showed similar results in males and females seasonally. Estradiol (E2) level in males and females at stages II, III and IV was 9±1.39, 5.45±0.29, 6.51±0.64, 9.47±0.97, 2.95±2.29 and 4.15±0.7 ng/ml, respectively that showed significant difference in males and females at different stages (P<0.05). Results showed that by good management and using endocrinology sciences (such as biochemical and hormonal indices), we can produce breeders with having good quality eggs and sperms for artificial propagation by using micro incision of oviduct method in order to without killing them (for several time breeding), caviar and farmed larvae and fry. Results also showed that Testosterone (T), Estradiol and Calcium were the most important detective indices for sexual maturity and the accurate time of synthetic hormone injection for artificial breeding. Testosterone (T) level limit in males and females for positive reply to artificial propagation was 90–120 and 40–60 ng/ml, respectively. By using the obtained results, we can reduce rearing cost of Huso huso, because the decrease of sexual maturity duration, increase of propagation recruitment, decrease of pressure to natural sources and help to restocking, commercializing of it for improvement of sturgeon rearing and propagation in order to caviar and fry production

Study and evaluation of economical and hygienic effects of aflatoxin B1 in cultured Huso huso

In the present study, the impacts of various concentrations of Aflatoxin B1 (AFB1) on Beluga, Huso huso, under controlled conditions were investigated. Belugas (120±10 g) were fed diets containing 0, 25, 50, 75, and 100 ppb AFB1/kg of diet for 3 months. Results showed that various levels of AFB1 do not significantly affect the specific growth ratio (SGR) (p< 0.05) of fish in different treatments. However, weight gain and food conversion ratio (FCR) varied significantly (p< 0.05 between control and treatments with diets contaminated with 75 and 100ppb AFB1/kg after 90 days). The increase in level of AFB1 did not affect the percent of survival rate (SR) and no mortality was observed in treatments (SR=100%). Various levels of AFB1 under experimental conditions of the present study affect some growth factors, such as, weight gain and FCR but have no significant impact on SGR. Histopathological studies showed that different level of AFB1 can cause broad range of changes in liver, kidney, spleen and gills tissues, particularly at concentration of 75 and 100 ppb AFB1/kg of diets after 60 days. No tumor formation observed. With regard to toxin concentration and time of exposure to AFB1 in experimental fish, different degree of skin lesions (simple hemorrhage to progressive wounds) were observed in different parts of body especially in vent, caudal peduncle, fins, and head. "Yellow sores" on head and trunk regions are considerable and led to deterioration of appearance. Prevalence of skin lesion in different treatments was 8 -53.3 %, which after stop feeding with toxic diets, 16-24 % healing observed. Haematological changes included chronic anemia and lymphocyteopenia. Also neutrophilia observed with increasing of skin lesions. Meat accumulation of AFB1 in different treatments is not so considerable and harmful for human consumption, but is significantly different with control fishes (P<0.01)