Evaluation of side effects of adjuvanted viral haemorrhagic septicaemia vaccines following intra-peritoneal administration to olive flounder (Paralichthys olivaceus)

Adjuvants are added to vaccines to enhance the immune response of a given antigen. Mineral oil adjuvant is a very common adjuvant used in fish vaccines, and it displays severe side effects in vaccinated fish. In this study, we have compared the effects of Freud's incomplete adjuvant (FIA), Freud's complete adjuvant (FCA) with squalene (Sq), saponin (Sp) and aluminium-hydroxide-based vaccine adjuvants with formalin inactivated viral haemorrhagic septecemia (VHS) vaccine. The average intra-abdominal lesions recorded were 0 in control, inactivated vaccine (IV) and (IV+Sp groups), and it varied from 0 to 1.5 in squalene (Sq+IV) and squalene and aluminum hydroxide (Sq+Al+IV) groups. The side effects were severe in FIA and FCA groups with intra-abdominal lesions varying from 2 to 5 during the experimental periods. These results show that VHS vaccine adjuvanted with FIA and FCA (Mineral oil-based adjuvants) show severe side effects and Sq, alum, and Sp-based adjuvants can be evaluated for vaccine efficacy in Olive flounder (Paralichthys olivaceus).