Physiological and immunological effects of adjuvanted Aeromonas salmonicida vaccines on juvenile rainbow trout

The effects of injectable vaccines against Aeromonas salmonicida on oxygen consumption, growth, kidney lysozyme activity, and anti-ii. salmonicida pla sma antibody titers of juvenile rainbow trout Oncorhynchus mykiss were exam ined. The vaccines were A. salmonicida bacterin only, bacterin adjuvanted w ith levamisole, bacterin in emulsified oil, microencapsulated bacterin, mic roencapsulated bacterin with muramyl dipeptide, microencapsulated bacterin with beta - 1,3-glucan, and microencapsulated bacterin with Vibrio anguilla rum lipopolysaccharide (LPS). The greatest and broadest ranges of responses were caused by the microencapsulated bacterin with V. anguillarum LPS. Oxy gen consumption rates and specific growth rates were significantly higher o ver the course of I month among fish treated with the LPS vaccine. These fi sh also maintained a higher anti-ii. salmonicida plasma antibody titer and kidney lysozyme activity for a substantially longer period than fish receiv ing the other treatments.