Host genetic background influence on early molecular signatures of vaccine responsiveness.

Bacterial diseases are responsible for considerable mortality in U.S. aquaculture and a primary reason for medicated feed application. The NCCCWA instituted a selective breeding program that has increased rainbow trout resistance against the causative agent of bacterial cold water disease, Flavobacterium psychrophilum (Fp). We have demonstrated: 1) a strong genetic gain (>60%) after five generations of intensive selection as measured by standardized challenge; 2) negligible mortality of the selected, ARS-Fp-R (resistant) line at locations experiencing epizootics of BCWD; 3) global differences in gene regulation during infection (Marancik et al. 2015). This project identifies and compares rainbow trout early gene expression patterns in response to formalin-killed F. psychrophilum or Yersinia ruckeri bacterins using individual fish and whole-body RNA-Seq. We also measure the fish response to live F. psychrophilum challenge. We identify the impact of genetic line on the expression kinetics of innate-gene modules influencing response to vaccination.