Characterization of European sea bass transcripts by RNA SEQ after oral vaccine against V. anguillarum.

The European sea bass (Dicentrarchus labrax) is, along with the gilthead sea bream (Sparus aurata), one of the most extensively cultured species in European aquaculture productions. Massive mortalities may be caused by bacterial or viral infections in intensive aquaculture production. Evaluation of the efficacy of an oral vaccine against Vibrio anguillarum (Aquavac Vibrio Oral) in sea bass revealed specific immune gene expression profiles in the gut as well as protection of fish. In the present study, we performed RNA SEQ in two different tissues: the hind gut and the head kidney. For each tissue, one control sample (where a sample presents a pool of four to five individuals) and one sample after oral vaccine against V. anguillarum were submitted to 454 next-generation sequencing. In total, 269,043 sequences were obtained, 143,007 for head kidney and 125,036 for gut. The read lengths ranged from 40 to 706 bp with an average length of 348 bp. The total number of clustered sequences for head kidney is accounting to 49,089 (∼34 %) and for gut to 71,676 (~57 %). Differential expression was detected for 496 transcripts in head kidney and for 336 in gut. The results not only enrich the present collection of expressed sequence tag sequences including rare transcripts like leukocyte immune-type receptors, cullin, or supervillin but also show the efficacy of oral vaccination against V. anguillarum.