تاثير به كارگيري GnRHبر روند رسيدگي جنسي ماهيان مولد ازون برون (Acipenser stellatus) پرورشي

The effect of GnRH (ovafact) on process of sexual maturation in farmed stellate sturgeon (Acipenser stellatus) brood stock

ماهي ازون برون (Acipenser stellatus) يكي از گونه‌هاي مهم تجاري تاسماهيان درياي خزر محسوب مي‌‌شود. به منظور تعيين مقادير شاخص‌هاي هورمون استرس در زمان تكثير در مولدين ازون‌برون پرورشي و ارتباط آن با موفقيت يا عدم موفقيت تكثير، به نمونه‌برداري از 11 عدد مولد پرورشي 8 ساله (شامل 5 عدد مولد ماده و 6 عدد مولد نر) در بهار1385 در انستيتو تحقيقات بين‌المللي ماهيان خاوياري اقدام گرديد. پس از بررسي‌هاي ظاهري و فيزيولوژيك، به تكثير با هورمونGnRH (در مولدين ماده طي دو مرحله با دوز µg/kg10 با فاصله زماني 12 ساعت و در مولدين نر يك مرحله با دوز µg/kg15 همزمان با تزريق دوم ماده‌ها) اقدام شد. در مولدين نر و ماده در 3 مرحله به‌ترتيب (0 و 12 ساعت پس از تزريق) و (0، 12 و 24 ساعت پس از تزريق) خونگيري، و فاكتورهاي هورموني و بيوشيميايي آنها مورد بررسي قرار گرفت. نتايج به‌دست آمده در مرحله تكثير نشان داد كه غلظت هورمون كورتيزول (ng/ml 89/30±187) 24 ساعت پس از تزريق در مولدين ماده با اوولاسيون موفق (3= n) نسبت به اوولاسيون ناموفق و مقدار گلوكز (mg/dl33/9±66/96) در مولدين نر با اسپرم‌ريزي مناسب (3= n) نسبت به اسپرم‌ريزي نامناسب (3= n) اختلاف معني‌داري نشان داد (P < 0.05). براساس نتايج فوق مي‌توان بيان كرد كه هورمون كورتيزول در تكثير موفق و گلوكز در اسپرم‌دهي مناسب اختلاف معني‌داري را در مقايسه تكثير ناموفق و اسپرم‌ريزي نامناسب دارند (05/0 > P).

Stellate sturgeon (Acipenser stellatus) is one of the important commercial sturgeon fishes of Caspian Sea. In order to study the indices of stress hormones in culture brood stock during spawning period and their relation to success or failure in artificial reproduction of these fishes, blood sample were taken from 11 cultured eight years old brood stock (which included 5 female and 6 male). The study was carried out at sturgeon research of Dr. Dadman in spring of 2006-2007. After analyzing the morphological and physiological characteristics of brood stocks, induced reproduction was carried out by injection of GnRH hormone (female were injected twice with total dose of 10(Mg/kg. The interval between the first and second injection was 12 hrs. The males were injected once using a 15 (Mg/kg dose. After the injection, two blood samples from male (0 hrs and 6 hrs after injection) and three blood samples from female (0 hrs/12 hrs and 24 hrs after the injection) were taken to analyze the biochemical and hormonal parameters. Result obtained show that the concentration of cortisole levels (187±30.89 Ng/kg) 24hrs after injection in female brood stock in which ovulation had occurred compared with the once without ovulation showed a significant relationship. On the other hand the concentration glucose (96.66±9.33mg/dl) 24hrs the injection in male brood stock in which spermiation had occurred compared with the once without spermiation showed a significant relationship, we can conclude that there was a significant difference in concentration of cortisole and glucose in female and male brood stock, respectively which have been successfully induced to spawn in comparison to once in which induction of spawning has not been successful.