Evaluation of biofilm of Aeromonas hydrophila for oral vaccination of Channa striatus

• Aeromonas hydrophila biofilm and free cell vaccine were incorporated in feed.
• Channa striatus were orally vaccinated (1010 CFU/g fish/day) for 20 days.
• Fish were bled on different day post vaccination and serum collected.
• Antibody concentration was significantly higher in biofilm vaccinated C. striatus.
• RPS was found to be significantly higher in C. striatus fed with BF vaccine.

Our laboratory has developed a biofilm oral vaccine of Aeromonas hydrophila, which has given significantly higher antibody agglutination titre and protection in herbivorous carps and omnivorous walking catfish compared to that with free cell vaccine. Against this background, in the present study A. hydrophila biofilm oral vaccine was evaluated in Channa striatus, a carnivorous fish model. The fish was fed with biofilm (BF) and free cell (FC) of A. hydrophila vaccine at 1010 cells/g fish/day for 20 d. Serum antibody production monitored with a monoclonal antibody based ELISA for 60 day post vaccination. Significantly higher antibody titre was recorded with BF compared to that with FC. Furthermore, BF vaccinated fish upon challenge with A. hydrophila at 109 cfu/ml had significantly higher relative per cent survival (88) than that with FC (29.6).