EFFECT OF DIFFERENT DOSES OF SYNTHETIC HORMONE LHRH-A2 ON SERUM SEX HORMONES, OVULATION PERCENT AND EGG HATCHING RATES OF PERSIAN STURGEON Acipenser persicus

Abstract

Acipenser persicus is one of the economically valuable fishes in the Caspian Sea. Due to the economically and culturally importance of sturgeons in the world, understanding of sturgeon reproduction is necessary for successful management of their populations in aquaculture and nature. To improve the culture methods and to facilitate captive breeding programs to support restocking, it is necessary to understand the steroid hormones changes during artificial reproduction. The administration of sturgeon luteinizing hormone- releasing hormone analogue (LHRH-A2) induces changes in serum sex steroid levels. To study the effects of different doses of LHRH-A2 hormone on induction of final maturation and ovulation of Persian sturgeon, 18 maturating females and 18 maturating males were used. All brooders were injected with LHRH-A2 in dosages of 4, 6 and 8 µg kg-1. In this study LHRH-A2 successfully induced final maturation and ovulation in females, and highest percentage of ovulated females was observed in the groups treated with dose of 4 µg kg-1 LHRH-A2. There were significant differences in serum cortisol (C), testosterone (T) and Gonadotropin hormone (GTHII) concentrations at tested dosages. In hormonal treatment groups, the highest hatching rate was observed in the groups receiving 4 µg kg-1 LHRH-A2. Finally the LHRH-A2 in dose of 4 µg kg-1 is effective in stimulating oocyte maturation and ovulation in Persian sturgeon.