Aquaculture Canada and WAS North America 2022

August 15 - 18, 2022

St Johns, Newfoundland, Canada

Aeromonas salmonicida INFECTION KINETICS AND AUTOGENOUS VACCINE EVALUATION IN SABLEFISH Anoplopoma fimbria

Ignacio J. Vasquez*1, Trung Cao1, Ahmed Hossain1, Katherinne Valderrama1, Hajarooba Gnanagobal1, My Dang1, Robine Leeuwis2, Michael Ness3, Briony Campbell4, Robert L. Gendron5, Kenneth Kao5, Jillian Westcott6, Kurt Gamperl2, Javier Santander1.

 

1Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Science, Memorial University of Newfoundland, St John´s, NL, Canada; mail: ivasquezsoli@mun.ca / jsantander@mun.ca

 



Cultured sablefish (Anoplopoma fimbria), is one of the most valuable cultured fish species in Canada’s Pacific coast. Effective vaccine programs against A. salmonicida are high priority for sablefish production. In this study, an infection model in cultured sablefish was established, a vaccine challenge model and the evaluation of the immune protection provided by an A. salmonicida autogenous vaccine preparation compared to two commercial vaccines (Forte and Alpha Ject). Atypical A. salmonicida J410 lethal dose 50 (LD50) was estimated to be ~3x105 CFU/dose in sablefish. Immune protection for the different vaccine preparations was evaluated in a common garden experiment. Blood samples were taken bi-weekly to evaluate IgM titers. After 10 weeks post-immunization the fish were intraperitoneally challenged with 100 times the LD50 dose (107 CFU ml-1). Thirty days post-challenge the relative percent survival (RPS), compared to the control, was calculated for each vaccine. The RPS for the bacterin mix was 63.7%, 54.57% for the Forte vaccine, and 27.28% for the Alpha Ject vaccine. A. salmonicida tissue colonization 10 days post-challenge negatively correlated with the RPS. Additionally, ELISA assays indicated differences in IgM titers between vaccines at 6-8 weeks post-challenge. It was determined that A. salmonicida A-layer binds to immunoglobulins F(ab)’ in a non-specific fashion. These study results indicate that vaccine design influences sablefish immunity and provides a guide for future sablefish vaccine programs.