Comparison of the effects of LHRAH-A2 alone and in combination with pimozide (a dopamine antagonist) on spawning and reproduction quality indicators in Rutilus frisii kuttum broodstocks

The objective of this research was to evaluate the effects of LHRAH-A2 alone and in combination with pimozide (dopamine antagonist) on percentage of ovulated females, latency period, ovulation index, work fecundity, egg weight to body weight ratio, fertilization success and Hatching rate of kuttum. 63 fish were treated and hormone treatments included: 1- LHRAH-A2 (1µg kg-1 bw), 2- pimozide (5 mg kg-1 bw), 3- combination pimozide and LHRAH-A2 (5 mg kg-1 bw + 1µg kg-1 bw), 4- carp pitatury extract (positive control), 5- saline solution 0.7% (negative control) 6- untreated group (without injection). The injection was performed intramuscularly. fish ovary in each treatment were analyzed using classical histology. The highest percentage of ovulated females (77.8 %), lowest latency period (34.2 ± 4.7), highest egg weight to body weight ratio (14.2 ± 1.3), fertilization success (95.9 ± 0.8) and hatching rate (44.2 ± 10.4) were observed in treatment 3. In ovulated fish, histological analysis revealed six stages in ovaries, while ovaries in non-ovulated ones were developed only in fourth stage. It seems that Because of ovulation can be induced successfully in kutum broodstocks with 1µg kg-1 bw LHRAH-A2+ 5 mg kg-1 bw pimozide treatment in a single injection with high percentage of ovulated females, lowest negative effect on propagation quality and its more cost-effectiveness than CPE, so Application of this combination could be beneficial for the development of artificial propagation methods in kutum brood stocks.