Location: Cool and Cold Water Aquaculture Research
2011 Annual Report
1: Conduct selective breeding and determine, under field and laboratory conditions, whether rainbow trout bred for bacterial cold water disease resistance exhibit superior performance traits. • 1.a. Evaluate and selectively breed NCCCWA rainbow trout for increased disease resistance and quantify improvement due to selection. • 1.b. Compare improved and reference lines of NCCCWA rainbow trout under farm conditions.
2: Characterize virulence determinants involved in the emergence of vaccine-resistant Yersinia ruckeri strains and develop novel therapeutics to treat or prevent disease. • 2.a. Elucidate the genetic basis of the biotype 2 phenotype. • 2.b. Evaluate the role of flagellar secretion in the function of the traditional ERM immersion vaccine and vaccine failure. • 2.c. Develop novel phage therapeutics for control of ERM and BCWD.
3: Identify genes and non-genetic factors in rainbow trout critical to innate and acquired immunity. • 3.a. Determine if heritable differences in spleen structure and function account for the superior BCWD survival and clearance traits of resistant fish. • 3.b. Determine whether orally-delivered immunostimulants modulate the gut immune system and whether variation exists between resistant and susceptible lines of rainbow trout. • 3.c. Initiate development of a rainbow trout immune-pathway database that is integrated with pathogen genomic information.
A major focus of our current work is to determine if the ARS-Fp-R line exhibits significant resistance when exposed to natural challenge under farm conditions. This year, we completed field trials initiated in 2010 and also initiated another set of field trials in 2011. In the 2010 experiments, eggs were shipped to three locations for evaluation by cooperators Clear Springs Foods Inc (agreement #58-1930-0-038) and Utah State Fish and Wildlife Service (agreement # 58-1930-0-042N). Egg hatch rate was above 80% at each location. In the Utah trials, survival of ARS-Fp-R line was compared to age-matched, BCWD susceptible rainbow trout (Gunnison River/Harrison Lake triploids, GHTP). Survival was measured over an 80 day period post-first feeding when bacterial cold water disease is most severe. The GHTP line exhibited an outbreak of bacterial cold water disease at two Utah trial sites. At these sites, survival of the ARS-Fp-R line was significantly greater than the GHTP line and no bacterial cold water disease was observed in the resistant-line fish. In the Idaho field trial, no bacterial cold water disease was diagnosed in either ARS-Fp-R or control line ARS-Fp-S fish. The overall survival and growth of the ARS-Fp-R line was positive and warranted additional field evaluation.
Progress towards Objective 3 (NP106 Component.
Welch, T.J. 2011. Rapid genotyping assays for the identification and differentiation of Yersinia ruckeri biotype 2 strains. Letters in Applied Microbiology. DOI: 10.1111/j.1472-765X.2011.03114.x.
Welch, T.J., Verner-Jeffreys, D.W., Dalsgaard, I., Wiklund, T., Evenhuis, J., Garcia Cabrera, J.A., Hinshaw, J.M., Drennan, J.D., Lapatra, S.E. 2011. Independent emergence of biotype 2 Yersinia ruckeri in the United States and Europe. Applied and Environmental Microbiology. 2011 May;77(10):3493-9
Carrias, A., Welch, T.J., Waldbieser, G.C., Mead, D.A., Terhune, J.S., Liles, M.R. 2011. Comparative genomic analysis of bacteriophages specific to the channel catfish pathogen Edwardsiella ictaluri. Virology Journal. 8:6. DOI: 10.1186/1743-422X-8-6.
Wiens, G.D. 2011. Bacterial kidney disease (Renibacterium salmoninarum). Fish Diseases and Disorders. 3:338-374.
Wiens, G.D., Glenney, G.W. 2011. Origin and evolution of TNF and TNF receptor superfamilies. Developmental and Comparative Immunology. DOI: 10.1016/j.dci.2011.03.031.