Gene expression profiling of catfish after treatment with Flavobacterium columnare DnaK protein

Catfish farming remains number one among U.S. aquaculture production. Flavobacterium columnare, the causative agent of columnaris disease, produces substantial mortality during the production of freshwater farmed finfish species. F. columnare is ubiquitous in the aquatic environment, and outbreaks of disease are often triggered during the spring and summer months of the catfish production cycle. As food fish production continues to increase, the frequency of columnaris disease will only continue to rise within the aquaculture industry and thus new preventative measures will be required. Vaccination against different fish pathogens has proven to be an effective disease management practice within the aquaculture industry. To evaluate the immunological effect of bath immunization on catfish with a recombinant F. columnare DNAk protein vaccine, we performed RNA sequencing on skin samples from control and rDNAK immunized catfish at different time intervals. We evaluated the different gene expression patterns between the groups with a focus on identifying differences in innate and adaptive immune function. Overall design: Channel catfish were spawned and reared at the Stuttgart National Aquaculture Research Center. Catfish averaging 5 g were either sham-bath immunized (control) or immunized in a solution of 200 ug/mL of recombinant Flavobacterium columnare Dnak protein. Skin was sampled from euthanized catfish from each group at different time intervals and skin was placed into RNA later. Skin samples from six catfish from the non-immunized, six from the rDNAK group at week 1, and six from the rDNAk group at week 6 were used to isolate total RNA and construct sequencing libraries.