Vibriosis is one of the most important diseases of Dicentrarchus labrax (European Sea bass). Two protective vaccines were prepared from formalized cultures of Vibrio alginolyticus and Vibrio damsela. Relative percent survival index (RPS), lysozyme activity and nitric oxide production were detected in vaccinated fish by oral, immersion and injection routes. RPS ranged from 82.86 to 91.99 % in fish vaccinated by the two vaccines. Detectable rise of lysozyme and nitric oxide by both vaccines compared with that of control group. It could be concluded that Vibrio formalized vaccine protect against Vibriosis and enhance immune parameters.
Key words: Vibriosis, Sea bass, Formalized Killed Vaccine FKV, RPS, lysozyme activity and respiratory burst.