Evaluation of LHRH-a acute release implantation on final maturation and spawning in not-fully matured broodstocks of Persian sturgeon (Acipenser persicus Borodin, 1897)

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Abstract

 The Persian sturgeon (Acipenser persicus) is considered as an endemic sturgeon of the
south part of the Caspian Sea and provides the highest Iranian caviar
production. Due to overfishing, degradation of the rivers conditions of the
natural reproductive habitats, the fish stocks is decreasing. The immature
breeders do not response to hormonal therapy at the sturgeon hatcheries as most
having PI (above 10) and large numbers of breeders caught and transported to
the hatcheries were unable to reproduce. This study was attempted to find the
effect of LHRHa implantation on oocytes maturation and spawning of Persian
sturgeon. Broodstocks were caught from the southeast region of the Caspian Sea.
The selected female broodstocks (PI>10) ranged in size from 24.0 to 37.5 kg
were implanted with LHRHa cholesterol pellets at concentrations of 0 μg/kg (control),
and treatments of 10, 15  and 20 μg/ kg (in
three replicates. The results from this study indicated that females treated with LHRHa
hormone implantation at 10, 15, 20 µg per kg body weight reached final maturation.
These results were observed for all fish from treatment numbers 2 (15 μg/ kg) and 3
(20 μg/kg), however only one fish reached final maturation in treatment 1(10 μg/ kg). The
current implantation of LHRHa was able to enhance breeders with PI above 10 to
final maturation which under normal condition at sturgeon’s hatcheries this is
not possible. The results suggested that final maturation can be achieved that
lead to high fertilization (78.33% ±13.87, 68.33% ±4.16 in treatment 2 and 3, respectively) and hatching rates (85.3% ±9.07, 68.33% ±7.64 in treatment 2 and 3, respectively) and also total larvae production. Thus, the information from this
study is very useful for artificial propagation of not-fully-matured females of
Persian sturgeon at Sturgeon hatcheries especially in Iran.  

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