EXPERIMENTAL STUDIES ON THE EFFICACY AND SIDE-EFFECTS OF INTRAPERITONEAL VACCINATION OF ATLANTIC SALMON (SALMO-SALAR L) AGAINST FURUNCULOSIS

Efficacy and side-effects of anti-furunculosis vaccination were studie d in an experimental trial. One unadjuvanted and eight adjuvanted bact erins were administered by intraperitoneal injection to Atlantic salmo n (Salmo salar L.) presmolts held in fresh water. Adjuvant systems rep resented were mineral oil, aluminium salts, glucan and levamisole. Pro tection, plasma antibodies, and side-effects were determined six weeks , three months, and six months after vaccination. After six weeks, fou r vaccination groups were significantly protected compared to unvaccin ated fish. Only two groups; being vaccinated with a trivalent and a mo novalent mineral oil adjuvanted vaccine, respectively, were protected after three and six months. Fish from these two groups were increasing ly protected with time. These two groups also displayed significant in tra-abdominal lesions. Plasma antibody levels measured against A-layer protein and sonicated cells of Aeromonas salmonicida differed greatly between groups, though all vaccinated groups mounted a significant re sponse in at least one of the samplings. High antibody levels increasi ng with time were found in the two long-term protected groups. At all sampling times, a positive association between antibody levels and sur vival was found. In conclusion, only use of mineral oil adjuvanted vac cines induced durable protective immunity against virulent waterborne furunculosis challenge. (C) 1996 Academic Press Limited.