Effects of LHRHa implantation on oocyte maturation, hormonal profile and breeding of Iranian sturgeon (Acipenser persicus borodin)

The Persian sturgeon (Acipenser persicus) is one of the most commercially important sturgeon species. It is cnsidered as an endemic sturgeon in the south part of the Caspian Sea and provides the highest Iranian caviar production. Due to overfishing, degradation of the rivers conditions for natural reproductive on the fish stocks is continuously decreased. This leads Iran to embark in a program to release millions of Acipenser persicus fingerlings into the rivers for conservation in Iran. The sturgeon industry is having problems due to a high cost of artificial propagation for fingerlings production, decreasing of the natural stocks and also low quality and immature caught broodstocks. The immature breeders do not response to hormonal therapy at sturgeon hatcheries as most having polarization Index (more than 10) and large numbers of breeders caughtand transported to the hatcheries were unable to reproduce. This study was attempted to determine the effects of luteinizing hormone releasing hormone analogue then decreased when progesterone showed a rapid increased in the fish serum. The results suggested that final maturation can be achieved and lead to high fertilization rate (78.33% ±13.87, 68.33% ±4.16 in treatment 2 and 3, respectively) and hatching rate (85.3% ±9.07, 68.33% ±7.64 in treatment 2 and 3, respectively). Larval growth performance study was conducted for 80 days in rearing tanks of 2× 2× 0.5 m³ in volume. The average weight, total length, survival rate and specific growth rate showed that the best result was obtained in treatment 3 (larvae produced via fish implanted with luteinizing hormone releasing hormone analog at 20 ug/kg Body Weight) with values of 3.93±0.8g, 92.0±1 mm, 71 ±2.00, 5.3±0.1 respectively in comparison with the other treatments: treatment 1 (larvae produced via fish implanted with luteinizing hormone releasing hormone analogue at 10 ug/kg Body Weight),treatment 2 (larvae produced via fish implanted with luteinizing hormone releasing hormone analogue at (15 ug/kg Body Weight) and control group (larvae produced via fish propagated in Shahid Marjani Centre). Thus, the information from this study will be very useful for artificial propagation of not-fully-matured females of Persian sturgeon at sturgeon hatcheries especially in Iran. In future this new method can be suggested to be used for other fishes having the same maturation problem