ISSN 2167-0447
International Journal of Agricultural Sciences ISSN 2167-0447 Vol. 9 (9), pp. 001-008, September, 2019. © International Scholars Journals
Review
A review of the control of reproduction and hormonal manipulations in finfish species
Yousefian Mehdi* and Mousavi, Seyed Ehsan
Islamic Azad University, Qaemshahr branch, Iran.
Accepted 15 May, 2019
Abstract
Control of reproductive is essential for the sustainability of commercial aquaculture production. The reason for breakage of ovulation and spawning is failure of the pituitary to release gonadotropin hormones. Gonadotropin hormones secretion is under a dual control, by gonadotropin releasing hormone (GnRH), and inhibition by dopamine on the actions of GnRH. The inhibitory actions of dopamine on GTH secretion can vary in potency between species. In some fish it is necessary to use dopamine blocker, such as domperidone, results in potentiation of the actions of GnRH analoge, leading to a large release of GTH-II and ovulation. In some other injection of a high dose of GnRH analoge alone is effective. In several marine species GTH-II secretion is not under dopaminergic inhibitory control but sensitive to exogenous analoge hormones (GnRHa). In many fishes, synthetic analoges of lutenizing hormone-releasing hormone (LHRHa) are widely used for inducing spawning. In several tropical freshwater and marine finfishes the human chorionic gonadotropin (HCG), pituitary homogenate and semi-purified fish gonadotropin are used. Rrecently the replacement of natural GnRH are used and had resulted in a centuple increase in the effectiveness of luteinizing hormones secretion induction.
Key words: Reproduction induced spawning, dopamine antagonists, GTH-II- HCG.