Dopamine Antagonists Potentiate the Effect of Gonadotropins on Spawning Performance in Catfish (Clarias lazera)

This study was to evaluate the effect of some hormones and dopamine antagonists on spawning success and measuring 17- estradiol and cortisol levels in Clarias lazera.35 mature, ripe female Clarias lazera with mean weight of 0.6 0.1kg were divided into 7 groups (5 fish each) as follow G1 1 ml saline (control), G2 GnRHa1mg /kg bw, G3 GnRHa 1mg + 1mg Dom/kg bw, G4 GnRHa 1mg +2.5mg Met/kg bw, G5 hCG 300iu/kg bw, G6 hCG 300iu + 1mg Dom /kg bw and G7 hCG 300iu + 2.5mg Met/kg bw. The results showed that, using GnRHa or hCG together with dopamine antagonists were more effective in induction of ovulation, increasing egg mass, fecundity and hatchability rate compared with the other spawning stimulators used in the experiment. It was clear that dopamine antagonists are effective for spawning induction in catfish and metaclopramide was more effective than domperidone. This study indicated that using dopamine antagonists potentiate the effect of GnRHa and hCG for spawning induction with reduction of its cost.