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Trout DNA May Help Improve Fish
By Sharon Durham
June 17, 2003
One hundred forty-five families of rainbow trout at an Agricultural Research Service lab in Leetown, W.Va., are providing genetic material that may help ARS scientists breed fish that grow faster and resist diseases under varying production conditions.
The ARS National Center for Cool and Cold Water Aquaculture (NCCCWA), which opened in 2001, oversees this research. It includes studies on fish genetics and breeding, aquatic animal health, nutrition, production system development and environmental compatibility, according to lab director William Hershberger. Initial research has focused on rainbow trout and other salmonids. Future research may include striped bass, walleye and yellow perch.
The first generation of breeder fish, formed by cross-breeding two commercially used strains, is complete. Breeder fish siblings were shipped to other locations to evaluate their performance under different conditions. Some have been sent to the University of Idaho's Hagerman Fish Culture Experiment Station as part of the cooperative program to test fish diets. Other fish from the same family are being raised at West Virginia University, to evaluate their performance in small production unit conditions.
Molecular biologist Caird E. Rexroad III is working on a genetic map of the rainbow trout, Oncorhynchus mykiss, to assist in developing improved strains. Rexroad and his colleagues have extracted genetic material, called DNA, from each of the 145 families of trout and are adding to the genetic map 500 microsatellite markers they have produced. When finished, this trout map will be used to identify genome areas that affect production trait differences and allow the development of a fish useful to producers and consumers. Researchers are working with the University of Connecticut's Biotechnology Center in Storrs, Conn., to find genes that enhance growth rate, increase disease resistance and improve stress response.
NCCCWA includes a 20,000-square-foot aquarium building with the latest in water-treatment and recirculation technology, developed mostly from research at the Conservation Fund's Freshwater Institute in Shepherdstown, W.Va., another NCCCWA cooperator.
More information on this research is in the June issue of Agricultural Research magazine.
ARS is the U.S. Department of Agriculture's chief scientific research agency.