Scientists at the U.S. Department of Agriculture's Agricultural Research Service (ARS) have released a new genetic map of rainbow trout, paving the way for advances in farmed trout production.
The research combines information from physical and genetic maps to pinpoint genes that affect key aquaculture production traits, such as disease resistance, growth, and stress response.
By isolating specific genes from chromosome fragments, scientists can now reconstruct the order of the genes and determine whether those specific genes explain certain traits that influence growth and disease resistance in rainbow trout.
"The goal of the NCCCWA Breeding Program is to identify genetic variation for important aquaculture production traits including growth, stress response and disease resistance in broodstock populations of rainbow trout," said Caird Rexroad, research leader and center director of the USDA/ARS National Center for Cool and Cold Water Aquaculture (NCCCWA) in Leetown, W.Va. "Once genetic variation has been identified, we aim to select only superior performing fish to contribute to the next generation, thereby improving the performance of the population in each successive generation."
ARS research has shown that specific genes play a large role in determining how trout adapt to stress and disease. Scientists were able to increase trout resistance to specific bacterial pathogens without negatively affecting growth, and are working on characterizing additional traits relating to reproduction, nutrient utilization and carcass quality.
"Our efforts to identify genes that affect these traits are aimed at developing genetic markers that will predict how a fish performs in aquaculture production," Rexroad said. "This information will help us develop marker assisted breeding strategies and other technologies that facilitate simultaneous improvement of multiple traits in a single broodstock population."
Added Rexroad, "the impact of this research will be in developing advanced technologies for selective breeding and transfer of superior performing broodstock for the production environment. The next phase of our five-year project planning cycle includes collaboration with members of the trout industry to conduct on-farm evaluations of the performance of our select lines of fish."
In addition, ARS scientists have developed a tetraploid strain of trout that, when bred with normal diploid trout, produce fish with high growth rates and are sterile.
March 5, 2009
