عنوان مقاله [English]
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 glycol (PG) was administered after the muscular injection near the second dorsal scute to increase the viscosity of the solution during absorption. Depending on the stage of sexual maturity in the fish, GnRH at doses of 5, 10, 15, 20, 30 µg/kg BW was used in combination with a dose of I or 2 mg kg of domperidone.
The position of G V 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 14.30. 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 µg/kg BW GnRH along with 1 and 2 mg kg of domperidone respectively were the most successful in spermiation. For female breeders, those received a dose of 10, 15 and 20 µg/kg BW GnRH along with 2 mg/kg of domperidone exhibited the most suitable conditions in ovulation. These females responded well to artificial breeding provided they possessed G V in the range of 3.64 to 14.30 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.