INTEGRATED APPROACHES FOR IMPROVING AQUATIC ANIMAL HEALTH IN COOL AND COLD WATER AQUACULTURE
Location: Cool and Cold Water Aquaculture Research
Title: Field evaluation of rainbow trout selectively bred for resistance to bacterial cold water disease
Submitted to: Flavobacterium Meeting
Publication Type: Abstract Only
Publication Acceptance Date: April 12, 2012
Publication Date: June 7, 2012
Citation: Wiens, G.D., Leeds, T.D., La Patra, S.E., Wilson, C., Cavendar, W., Rexroad III, C.E. 2012. Field evaluation of rainbow trout selectively bred for resistance to bacterial cold water disease. Flavobacterium Meeting. 126.
Bacterial cold water disease (BCWD) is a frequent cause of elevated mortality in rainbow trout and the development of effective control strategies is a priority within the U.S. Since 2005, the NCCCWA has implemented a selective breeding program and has created three genetic lines of outbred rainbow trout: ARS-Fp-R (resistant), ARS-Fp-C (control) and ARS-Fp-S (susceptible). Factors influencing BCWD resistance under field conditions remain poorly understood and optimal field-trial design has not been investigated. Studies were initiated in 2010 and 2011, as part of a multi-year field evaluation process, to address: 1) egg transport and hatching under different commercial production conditions; 2) evaluation of different trial designs utilizing first-use and re-use water, 3) determine survival at locations that routinely experience natural BCWD outbreaks; and 4) investigate the distribution and impact of F. psychrophilum strain variants on resistance. Field evaluation was carried out at multiple sites in Utah in cooperation with the Utah Division of Wildlife Resources, and at one site in Idaho in cooperation with Clear Springs Foods, Inc. To date, we have observed evidence that BCWD resistance is under genetic control and there is improvement following multiple generations of selection. We have observed a high survival after swim-up and no BCWD outbreaks in the ARS-Fp-R line while clinical BCWD has been documented in the ARS-Fp-S line in several field trials. In response to laboratory challenge, the ARS-Fp-R line has demonstrated higher survival than all other tested lines of rainbow trout. These preliminary findings support the release of germplasm and the continued evaluation of the ARS-Fp-R genetic line in large-scale production trials.