Abstract of research

INDUCED SPAWNING OF AFRICAN CATFISH, CLARIAS GARIEPINUS USING (GnRHa) COMBINED WITH DOPAMINE ANTAGONISTS.

Ramy, M. Shourbela 1; Ashraf, M. Abd El-latif 2 and Abd-El-Azem .M.A3.

Abstract

A study was conducted to evaluate the effects of Gonadotropin relasing hormone analogue (GnRHa) alone or with dopamine antagonists (pimozide or domperidone) on induced spawning of African catfish (Clarias gariepinus). Fifty four female C. gariepinus were divided into 9 groups. Latency period, mass of eggs, ovulation rate, fertilization %, hatching rate, % of deformity, survival rate and estradiol (E2) were estimated. Results of the current study indicated successful spawning induction of African catfish using ( GnRHa) with dopamine antagonists. The highest ovulation rate (100 %) was observed in groups 6, 8 and 9 which were injected with GnRHa 40 ug\kg.b.w plus 16mg pimozid,10 and 20mg domperidone /kg.b.w respectively. Meanwhile, the lowest ovulation rate (16.67 %) was observed in group 3 which was injected only with GnRHa80 ug/kg.b.w and group 4 which was injected with GnRHa 40 ug plus pimozid 4 mg/kg.b.w . The egg mass produced per female showed significant difference (P < 0.05) among different groups with the highest values in group 6, while the lowest value was observed in group 4. There was significant highest percentage of deformed larvae (11.2 %) in group 4 and the lowest (4.17 %) was in group 5. Data showed that the level of 17β-estradiol (E2) increased at 6 h in all treated groups with a significant difference (P< 0.05). The peak level of E2 was observed at 12 hr post injection in group 9. In contrast, there is A significant decrease in E2 at 24 hr post injection in all ovulated groups. In conclusion , the experiment clearly indicated that the use of GnRHa combined with dopamine antagonists was more effective in induction of spawning compared with the use of GnRHa alone in African catfish.