Biotechnic of brood stocking, artificial propagation and some physiological indices in farmed Acipenser nudiventris

This study was conducted on farmed Acipenser nudiventris at the International Sturgeon Research Institute from the winter of 2007 till summer 2010. A total of 11 farmed A. nudiventris specimens (7 male and 4 female) were stocked in groups of 4 fish in eight fiberglass tanks (4 tons capacity) on the basis of their sex. Males were fed with a diet with no soybean but containing vitamins. Females were fed with a diet containing soybean and vitamins with 38-40% protein, 13-15% fat, 19.5-20Mj/kg energy, respectively. GnRH was used for artificial propagation of Acipenser nudiventris brood stocks twice for females (dose 10µg/kg with 80:20 ration) and during one occasion for males with a dose of 20 µg/kg. The results of the study indicated that food composition (soybean and vitamins C and E) played a significant and positive role in the reproduction system for females. No significant effect of treatment was observed in Testosterone levels between mature (Mean ±SD: 60.6±8.07ng/ml) and immature (24.42±4.87ng/ml) males, Likewise, no significant differences were found in17α-Hydroxy Progestrone for female (Mean ±SD: 0.106±0.019ng/ml) and for immature fishes (0.031±0.006ng/ml) significant differences was detected in the concentration of Albomine (1.54±0.05mg/dl for females and 1.35±0.07mg/dl for immature females), but there were no significant differences in other biochemical parameters including Glocose, Cortisol, Chlosterole and Triglisride in males and females. There were no significant differences in total weight and length, WBC, RBC, Hb, Hct, MCH, MCHC and MCV parameters in males and females. This study is a step forward towards the development of artificial breeding and rearing sturgeon fish in the country

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

A new method for artificial breeding of Acipenser stellatus

A new formulation of GnRH and synthetic compound of anti-dopamine domperidone was used for the first time in Iran to determine suitable physiological indexes for reproduction and to resolve the present problems of artificial reproduction in stellate sturgeon Acipenser stellatus. The study was conducted on 60 breeder Acipensers including 40 female and 20 male specimens. The fish were caught at stations in the vicinity of the SefidRud River in Guilan Province. Male spawners were treated using single injection method while females received dual injection (Bio-physiological control). Propylene glycole (PG) was administered after the muscular injection near the second dorsal suite to increase theviscosity of the solution during absorption. Depending on the stage of sexual maturity in the fish, GnRH at doses of 5, 10, 15, 20, 30 mg I kg BW was used in combination with a dose of I or 2 mg I kg of domperidone. The position of GV was used as an index to determine sexual maturity in females while in males sexual maturity was determined on the basis of testis and sperm quality. The female fish showed GV in a range of 3.64 to 1430. The results indicated that reduction of stress during catch, transportation, maintenance and handling and selection of breeders with suitable morphology will result in increased reproduction success. It was also found that male breeders given a dose of 20 and 30 ;_tg I kg BW GnRH along with I and 2 mg I kg of domperidone respectively were the most successful in spermiation. For female breeders, those received a dose of 10, 15 and 20 lig I kg BW GnRH along with 2 mg I kg of domperidone exhibited the most suitable conditions in ovulation. These females responded well to artificial breeding provided they possessed GV in the range of 3.64 to 1430 depending on the water temperature until the germinal vesicle broke down (in vivo). Alleviating stress during capture, handling, transport and confinement, selecting breeders with suitable morphology and identifying correct stage of sexual maturity are the factors that help achieve higher production by substituting GnRH with a combination of GnRH and domperidone. Therefore, this compound is recommended as a suitable substitute for pituitary extract and other gonadotrophic analogues in the artificial breeding of Acipenser stellatus