EFFECT OF THE DOPAMINE ANTAGONIST, DOMPERIDONE ALONE AND IN COMBINATION WITH THYROXINE, CLOMIPHENE, hCG OR GnRH ON SERUM SEX STEROIDS PROFILE, GONADAL MATURATION AND SPAWNING OF NILE CATFISH, CLARIAS LAZERA.

The present investigation was carried out on one hundred and twenty mature Clarias lazera fish during the prespawning season (March - April). Fish were allocated into two main groups (sixty fish of each sex). Fish weight ranged between 200-220 g. b. wt. Each main group was sub- divided into six equal groups (Ten fish each). Fish of each group; both males and females were sub-jected to the same regimen of intraperitoneal exogenous treatment, as follows: 1st Group: Saline”0.65% NaCl solution.”(Con- trol) 2nd Group: Domperidone 5µg/g. b. wt. in saline. 3rd Group: Domperidone 5µg/g. b. wt. plus thy- Roxine 1ng/g. b. wt. in saline. 4th Group: Domperidone 5µg/g. b. wt. plus Clomiphene citrate 1µg/g. b. wt. in saline. 5th Group: Domperidone 5µg/g. b. wt. plus hCG 2 IU/g. b. wt. in saline.  6th Group: Domperidone 5µg/g. b. wt. plus GnRH 10µg/kg. b. wt. in saline. The present study revealed that “ Domperidone” administration alone, in each sex of Clarias fish: increased serum sex steroid hormones (testoste- rone and 17-β estradiol), gonadal weights (testes and ovaries), final gonadal maturation and gona- dosomatic indices of both sexes as compared to respective controls. Exogenous administration of domperidone plus gonadotropin releasing hormone (GnRH) was the most effective treatment for production of sex hormones, final gonadal maturation and spawning in both sexes of Clarias lazera fish, followed by domperidone plus thyroxine; domperidone plus clomiphene citrate and domperidone plus hCG., respectively, In conclusion, the exogenous administration of dopamine antagonist plus GnRH is the more efficient regimen for enhancement of gonads maturation (gonadal recrudescence), spawning and spernuation of Clarias lazera fish throughout the prespawning season.