Comparison of artificial spawning effectiveness of hCG, CPH and GnRHa in combination with dopamine inhibitors in a wild strain of ide Leuciscus idus (L.) in hatchery conditions.

Optimization of artificial reproduction, by increasing the survival rate of embryos and hatching rate, is of major importance for reducing genetic diversity, especially in fish captured from their natural habitat that subsequently spawn in hatcheries. The artificial reproduction of ide, Leuciscus idus (L.) was conducted in controlled conditions. The spawning agents included: different doses of human chorionic gonadotropin (hCG) that was compared with common carp pituitary homogenate (CPH), Ovopel - a commercial agent for induction of spawning that contains mammalian gonadotropin releasing hormone analogue (mGnRHa) with dopamine antagonists (DA): metoclopramide (MET) and Ovaprim - a commercial agent containing salmon gonadotropin releasing hormone analogue (sGnRHa) and a dopamine antagonists (DA): domperidone (DOM). There were no ovulations in females from control groups. There were no differences between the ovulation rates (90 %) or embryo survival (> 92 %) and hatching rates (> 91 %) when there was administration of hCG doses between 500 and 1000 IU/kg. When there was comparison of different spawning agents, the ovulation rate was 100 % for all treated groups. There were the shortest and longest latency times to the time of ovulation after administration of CPH (26 h) and hCG (79 h), respectively. The greatest embryo survival (> 93 %) and hatching (> 91 %) rates occurred as a result of hCG administration with these values being slightly greater than when there was treatment with Ovaprim. The association between latency time and hatching rate indicated that when there was a slower final oocyte maturation (FOM) there were greater hatching rates.