Evaluation of various factors to increase the efficiency of channel-blue hybrid catfish embryo production

The hybrid between the female channel catfish, Ictalurus punctatus , and the male blue catfish, I. furcatus, has superior performance for aquaculture traits to the commonly grown channel catfish. However, reproductive impediments have limited the commercial production of this hybrid. Our primary objective was to examine factors that will increase the production of channel-blue hybrid catfish embryos. To accomplish this the effect of pheromones, the effect of injecting male blue catfish with luteinizing hormone releasing hormone analogue, LHRHa, the optimum dosage of LHRHa, the effect of post-manufacturing handling of LHRHa and the efficacy of gonadotropin hormone releasing hormone (GnRH), OvaRH and ovaprim on production of channel-blue hybrid embryo were determined.; Although it is probably a conservative and safe approach to ship LHRHa on dry ice, there were no differences in the efficacy of LHRHa shipped with or without dry ice. There were differences in efficacy in regards to post manufacturing bottling. HW (hand weighed) gave more consistent and better result compared to RW (reconstituted in water, aliquoted and relypholyzed), either because HW was a more uniform product, or because RW was too potent necessitating readjustment of dosage as the spawning season progressed. More detailed research is needed to determine the exact cause of the differences in effectiveness of the LHRHa bottled with different procedures.; Exposure to conspecific males had a positive impact on hybrid embryo production, however, inconsistent results among separate experiments indicates that the method used to present the males may be important. The success of various hormone treatments varied as the spawning season progressed. This was likely a result of the gonad development responding to the temperature degree days and the ova being more advanced requiring less hormone for final oocyte maturation and ovulation. In general carp pituitary extract, CPE was consistent in terms of latency time, but had inconsistent and lower fry production than LHRHa. Overall, LHRHa was the most promising hormone for production of hybrid embryos via artificial fertilization procedure. OvaRH also showed potential to be an effective ovulating agent for the production of hybrid embryos.