March 10, 2009

Scientists at the USDA 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 trout.

Researcher Caird Rexroad said that the goal of the National Centre for Cool and Cold Water Aquaculture (NCCCWA) Breeding Program is to identify genetic variation for important aquaculture production traits including growth, stress response and disease resistance in brood stock populations of trout.

Rexroad explained that once genetic variation has been identified, their 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 characterising additional traits relating to reproduction, nutrient utilisation and carcass quality.

The researcher added that the next phase of the 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, it would produce fish with high growth rates and are sterile.