Rainbow trout is the most cultivated cold-water fish in the United States, and muscle fillet is its most valuable product. Increasing fillet yield and improving fillet quality in rainbow trout can improve aquaculture production efficiency and economic benefits.
Classical breeding approaches can improve fillet yield and quality but are time-consuming because of the long time from when adult fish produce offspring – called generation interval. A more efficient approach is to use genomic selection, where thousands of genetic markers are used to increase the accuracy of the breeding process, thereby reducing the generation interval.
With support from USDA’s National Institute of Food and Agriculture, researchers at the University of Maryland are using genomic analyses to identify genetic markers that can predict muscle yield and quality and, more importantly, use genomic selection to selectively breed fish with these traits.
“There is immense interest from the industry to implement genomic selection in their breeding populations, similar to what has been recently achieved in livestock,” said University of Maryland associate professor and lead researcher Mohamed Salem. “This research develops technologies that make animal protein production in the U.S. more efficient, competitive and environmentally cleaner.”
The impact of this research would be substantial. Animal selection for breeding would be reduced from two to three years to three weeks, and there would be an increase in production efficiency by 30 to 50%. The research will benefit both the commercial fishing industry and fish lines bred by USDA’s Agricultural Research Service.
The total value of fish sales received by trout growers in the United States totaled $97.3 million for 2021. The estimated value of trout distributed for restoration, conservation, enhancement or recreational purposes, primarily by state and federal hatcheries in 2021, totaled $139 million.
Salem explained that increasing fillet yield is central to production efficiency. For a large commercial fish producer like Clear Springs Foods/Riverence Holdings, the nation's largest rainbow trout producer, a 0.5 percent improvement in fillet yield--an increase from 48 to 48.5% fillet yield--would be economically significant, Salem said. Research efforts with outcomes of increased fillet yield will increase production capacity and efficiency.
Recently researchers discovered the presence of heritable fillet yield-associated microbiome components. Going forward, they will investigate feasibility of improving genetic prediction accuracy when microbiome information is integrated into genomics-metagenomics analyses.
Additional information about this research will be presented at a NIFA education session at Aquaculture America 2023 Feb. 23-26 in New Orleans. NIFA national program leader Dr. Tim Sullivan, who provides leadership for programs in aquaculture, animal health and biotechnology, will moderate a session highlighting the breadth and impact of NIFA-funded aquaculture research and outreach.