Submitted to: European Association of Fish Pathologists
Publication Type: Abstract Only
Publication Acceptance Date: June 4, 2003
Publication Date: September 21, 2003
Citation: KLESIUS, P.H., EVANS, J.J., SHOEMAKER, C.A., FITZPATRICK, B.T. VACCINATION STRESS IN NILE TILAPIA, OREOCHROMIS NILOTICUS. THE EUROPEAN ASSOCIATION OF FISH PATHOLOGISTS. INTERNATIONAL CONFERENCE "DISEASES OF FISH AND SHELLFISH". 2003. Technical Abstract: The objective of this study was to develop information on the associations between vaccination stress and subsequent streptococcal infection. Tilapia, Oreochromis niloticus (38 g) were divided into two treatment groups (vaccinated and unvaccinated) of 10 fish each and maintained in separate 57 L aquaria. Significantly (P < 0.05) increased blood glucose levels were used to measure stress in the fish of each group at 0, 2, 6, 24 h following intraperitoneal (IP) vaccination or injection with tryptic soy broth. Significant increases in blood glucose levels were observed only in association with the injection of the vaccine after 2 h. At 28 d post vaccination (PV) fish were IP challenge with 1.5 x 104 colony forming units (CFU) of Streptococcus. Blood glucose and cumulative mortality were monitored at 0, 2, 6, 24, 48,72 h and 13 days post challenge (PC). The blood glucose levels of the vaccinates and controls were significantly increased at 2 h and then returned to pre challenge levels at 24 h. Significantly increased blood glucose levels were observed in association with infection of the controls at 24, 48 and 72 h PC. Blood glucose levels and the mortality of the infected controls were significantly correlated (r2=0.9236, P = 0.0134). The vaccinates also showed significantly increased blood glucose levels at the same times, but these levels were significantly lower than the controls at 24 and 48 h PC. The cumulative mortality of the vaccinates and non-vaccinates was 10 and 60% after 13 d PC, respectively. The relative percent survival (RPS) of 83.4% indicated that the vaccine was efficacious and it had induced short-term stress in tilapia. These preliminary results also suggest, for the first time, that vaccination may significantly reduce or mitigate the physiological stress associated with streptococcal infection in tilapia.