Commercial-Scale Implementation of Blue-Catfish Germplasm for Hybrid Production

The channel catfish industry must rapidly improve efficiency. Production of hybrid catfish can increase efficiency. This proposal is intended to improve hybrid production. Four objectives: 1)optimize methods of collecting and handling blue catfish sperm; 2)adapt protocols to accommodate use of equipment developed for mammals;3)evaluate the quality of fresh and thawed sperm in the laboratory,and 4)evaluate the quality of thawed sperm in the hatchery.With the commercialscale availability of blue catfish sperm, development of new markets for genetic improvement and germplasm become possible. Production of channel catfish is an important regional and national market.Between 2001 and 2007 the number of fingerlings produced by the four major producing regions (Louisiana, Alabama, Arkansas, and Mississippi) shrank by approximately 22% during this time,due to reduced profit margins.The hybrid of channel catfish (female) x blue catfish Ictalurus furcatus (male)is a superior production animal with fast growth,superior disease resistance,and high carcass yield and could dramatically contribute towards increased efficiency and profitability in the catfish industry as it rebuilds. However, channel and blue catfish do not readily hybridize naturally and can only be produced by a labor-intensive process of manually collecting and fertilizing eggs with sperm (termed controlled reproduction or artificial spawning),Current technology allows collection of commercial quantities of channel catfish eggs, but catfish males must be killed to obtain sperm.Seasonal differences in temperature regimes are not conducive to transfer of valuable blue catfish genetic material between hatcheries because of differences in seasonal thermal profiles. Artificial spawning represents the future of genetic improvement for the catfish industry. Sperm cryopreservation is a crucial part of artificial spawning. Sperm cryopreservation, or the storage of sperm cells in liquid nitrogen (-196C), bridges the gap between the availability of ripe channel catfish eggs and blue catfish sperm for artificial spawning to produce hybrids. Our goal is to build directly on previous and ongoing research to make hybrid catfish widely available to farmers by overcoming barriers to commercialization of sperm cryopreservation for blue catfish and other aquatic species, maximizing the quality of males, and by developing production markets for sperm. This will be accomplished during Phase I through refinement of sperm collection protocols, adoption of commercialscale straw handling and cryopreservation technology, laboratory evaluation of gamete quality, and hatchery evaluation of gamete quality, and during Phase II through improving male quality and developing markets for frozen sperm and hybrid production. We believe that blue catfish sperm production and distribution through cryopreservation and shipping could evolve into a separate enterprise within the catfish industry, and that the increased availability of sperm will facilitate business development by enabling producers to focus on fingerling production for growout.