Results of First Experiments on Application of Electrical Stimulation of Blue Catfish Testes for Production of Channel Catfish × Blue Catfish Hybrids

Abstract

Commercial interest in production of F₁ hybrids of female channel catfish Ictalurus punctatus × male blue catfish I. furcatus has increased dramatically. However, current production methods are unable to provide large numbers of hybrid fingerlings for commercial producers. Increasing the hatch rates of hybrid embryos will aid in making large-scale hybrid production a feasible option for the catfish industry. The objectives of this study were to determine (1) whether electrical stimulation of excised testes of Rio Grande and D&B strain blue catfish (Kincaid et al. 2000) produce changes in the motility rank, motility time, and concentration of spermatozoa and (2) whether differences exist between the fertilization rates for spermatozoa obtained from electrically stimulated testes and those from nonstimulated testes for the two strains. Testes were excised from the males of both strains and one testis was subjected to electrical stimulation. Spermatozoa were removed, counted, checked for motility ranking, and used to fertilize eggs. Electrical stimulation did not significantly affect motility rank, motility time, or spermatozoa concentration for either strain. The fertilization of channel catfish eggs was significantly higher for spermatozoa from electrically stimulated Rio Grande strain testes (93.0 ± 3.5%) than for those from nonstimulated testes (76.2 ± 16.8%). The fertilization rate was not significantly higher for spermatozoa from electrically stimulated testes in D&B strain blue catfish. Hatch rate was not significantly different for eggs fertilized with spermatozoa from electrically stimulated testes in either strain. Modulation of voltage, amperage, and cycle times with larger sample sizes should be investigated further to determine whether a range of effects exists among the parameters measured and the intensity of stimulation.