Induction of Spawning in Common carp Cyprinus carpio,Using Pituitary Extract and GnRH Analogue in Combination with Domperidone

The effectiveness of the first Iranian made gonadotropin releasing hormone analogue, [D-Ala6des-Gly10] GnRH ethylamide, alone or in combination with domperidone, a dopamine antagonist on spawningrate, latency period, working fecundity and embryo viability in common carp, Cyprinus carpio, was investigated.Fifty two fish were divided into 5 groups and treated intrapretoneally as follows: 3 mg/Kg b.w. of carp pituitary extract (C.P.E.) as a positive control, GnRHa alone, 10 μg/Kg b.w.. or in combination with domperidone, 5 mg/Kg b.w. in a single or double injections 7h apart. A group was treated with propylene glycol 0.2 ml/Kg b.w. alone and considered as control. No female ovulated in groups receiving either propylene glycol or 10 μg/Kg b.w. of GnRHa alone. The spawning rate was higher in female GnRHa+domperidone (10 μg/Kg b.w..+5 mg/Kg) in double injections (11 out of 12) as compared to fish which injected either with C.P.E (7 out of 16) or GnRHa + domperidone in a single injection (3 out of 12)(P<0.05). The mean working fecundity, was significantly higher for fish receiving GnRHa+domperidone in single (126214 ±24315) or double injections (145600 ± 27113) compared to C.P.E treated group (52435 ± 1224) (P<0.05). There were no significant differences for latency period or embryo viability among the groups.