Title : Steps to Modern Conversions in use of Autogenous bacterin of Vibrio algenolyticus induce Cross-protection against Listonella anguillarum in sea bass Dicentrarchus labrax L and vice versa
In order to develop more effective immunological strategies to prevent vibriosis of farmed juvenile’s sea bass Dicentrarchus labrax in Egypt, vaccine preparations of formalin-killed whole cell bacterins and used by different administration routes, were investigated. The efficacy of an FKC bacterin of V. algenolyticus and L. anguillarum was tested on single - and booster intraperitoneal injection - immersion (dip and prolonged immersion) vaccinated sea bass Dicentrarchus labrax juveniles. We carried out 2 challenge tests by both V. algenolyticus and L. anguillarum alternatively on the single - and booster intraperitoneal injection - immersion (dip and prolonged immersion) vaccinated fish 28 d after final vaccination to be tested cross-protection. The results revealed that the relative percent survival (RPS) was 86.66 and 70% in V. algenolyticus and L. anguillarum respectively in fish received a booster vaccination 28 d after the final vaccination. RPS was 73.66 and 80.0; 20.0 and 30.0 % in case of dip immersion (2 min) and prolonged immersion (2 hr) in FKC of V. alginolyticus and FKC of L. anguillarium respectively; during challenged by virulent strain of V. alginolyticus. On the other hand, RPS was 30.0 and 40.0; 52.66 and 60.0 % in case of dip immersion (2 min) and prolonged immersion (2 h) in FKC of V. alginolyticus and FKC of L. anguillarium respectively; during challenged by virulent strain of L. anguillarium. Antibody titres were tested only among 10 prime-vaccinated and 10 unvaccinated (control) sea bass, 28 d postimmunisation, and were found to rise to 7.67 ± 0.67 after 7 days from last vaccination in intraperitoneal injection (Booster dose), while these reading became 10.67 ± 0.49 after 21 days from last vaccination during challenged by virulent strain of V. alginolyticus. The antibody during challenged by virulent strain of L. anguillarium was 5.67 ± 0.33 after 7 days from last vaccination; and 7.33 ± 0.67 after 21 days from last vaccination in the vaccinated fish. Our results demonstrate that FKC of V. alginolyticus by prolonged immersion (2h) and intraperitoneal injection (Booster dose) vaccine can effectively protect juvenile sea bass from V. alginolyticus infection. While the same types and routes of vaccine not able to protect juvenile sea bass from L. anguillarum infection. Also, in conclusion, autogenous bacterin of V. algenolyticus not induces cross-protection to L. anguillarum.
What will audience learn from your presentation?
• Aquacultured farmer
• Researchers in the field of culture marine fish
• Biosecurity in the management of cultured marine fish
• Hatchery of marine fish
• This research provides a practical solution to a problem of control of fish diseases
• This research could simplify in less use of antibiotics
• This research will improve and benefits in increase the immune status of cultured marine fish.