AN INDUSTRIALSCALE STUDY ON THE IMPACT OF VACCINATION UPON RAINBOW TROUT

The effect of intraperitoneal (ip) vaccination upon the performance of rainbow trout (n = 1611), maintained under commercial production conditions (aerated spring water, 9.8 ºC, 150 L/min), was evaluated over a 7week period. Vaccine impact was examined with reference to control (n = 1683) and injected control (sterile filtered water; n = 1537) animals. All groups were run in triplicate (i. e., n ≥ 500 fish per gorup). Animals were fed to satiation twice daily. Vaccination suppressed (P <0.05) growth in weight over the entire period of study when compared to control treatments. A corresponding decline in specific growth rates (P < 0.05), over the first 29 d of the trial, was also observed for vaccinated fish. Feed conversion efficiencies and feed ratio were similarly negatively affected in vaccinated animals for 29 d postvaccination (P <0.05). The vaccine caused abdominal adhesions although no differences were observed in body composition