Demand for aquaculture products, such as rainbow trout, is rising because of increased recognition of the health benefits from consuming seafood, as well as the limits to harvesting wild-caught seafood. Bacterial cold water disease is a common problem for rainbow trout growers and a frequent cause of antibiotic use in aquaculture. Since 2005, scientists at the National Center for Cool and Cold Water Aquaculture have demonstrated how selective breeding can be used to develop a line of rainbow trout with increased resistance to the disease.
The new line of rainbow trout, designated ARS-Fp-R, represents the first line of rainbow trout with specific disease resistance that has been made publicly available. Advantages of the ARS-Fp-R line include stable disease resistance that, unlike vaccination and antibiotics, requires no application or treatment by farmers. The innate disease resistance is particularly advantageous in young fish that are too small to be vaccinated and most susceptible to the disease.
Recipients of the ARS-Fp-R line include Troutlodge, Inc.; Clear Springs Foods, Inc.; and the Utah Division of Wildlife Resources. Troutlodge is the world's largest producer of rainbow trout eggs and annually distributes approximately 500 million eggs to customers in more than 50 countries. Clear Springs Foods, a vertically integrated breeder, producer, processor, and distributor of fresh and frozen rainbow trout products to food service and retail markets in the United States and Canada, is responsible for approximately 60% of domestic rainbow trout food fish production. The Utah Division of Wildlife Resources operates ten production hatcheries and annually stocks the state?s streams, rivers, lakes, and reservoirs with approximately 12 million sport fish.
In addition, the ARS-Fp-R line and associated control and susceptible lines have been provided as a resource to understand the genetic basis of disease resistance to university and government researchers, including the Virginia Institute of Marine Science; College of William and Mary; U.S. Fish and Wildlife Service in Bozeman, Montana; and the University of Pennsylvania. These fish have also been utilized in research reported in more than 20 scientific and trade publications.
Because of the ARS-Fp-R line, commercial rainbow trout producers have access to the first publically available bacterial cold water disease-resistant line, and are continuing to propagate the line in their own selective breeding programs. The line has been tested on farms in Idaho, Utah, North Carolina, and West Virginia where the pathogen was known to be present, and has not exhibited signs of bacterial cold water disease. The line continues to be tested in large-scale farm trials and evaluated for resistance against different pathogens and bacterial cold water disease strain variants. To date, the release of the new germplasm has led to healthier animals, improved product quality, and reduced antibiotic use on-farm.