Efficacy of oral and immersion vaccination in african catfish, clarias gariepinus against streptococcosis

Abstract EN

The present study was carried out using oral and immersion vaccination in 54 African catfish, Clarias gariepinus, to compare the efficacy of Streptococcus faecalis formalin-killed vaccines (SFFKV) against infection with S faecalis.

The fish were divided into 3 groups each contained 18 fish.

First group was kept as control while group 2 was vaccinated with SFFKV by oral route (5 mg / g of food) and group 3 was vaccinated by immersion route (2 mg / ml for 3 minutes).

Blood samples were collected from 2 fish of each group, weekly, for 4 weeks for determining the level of specific immune response.

The remaining fish in each group were challenged with virulent strain of S.

faecalis one month post-vaccination for determination of the relative percent survival (RPS) among the three groups.

The results of specific antibody response showed that the antibody titers of fish vaccinated by oral and immersion routes were similar to that of control group (2 by log2) from 1st to 4th week post-vaccination.

After challenge, mortality rates reached 90, 10 and 20 % among the fish of the three groups.

The RPS was 88.8 and 77.7 % in oral and immersion vaccinated groups.