Abstract:

In this study, the induced antibody level of rainbow trout immunized by Yersinia ruckeri bacterin was determined using two serological techniques, namely, indirect fluorescent antibody (IFAT) and enzyme-linked immunosorbent assay (ELISA). The induced humoral antibody levels were studied after intraperitonal injection of Yersinia ruckeri bacterin inoculates containing Freund's incomplete adjuvant or PBS in rainbow trout during the experimental period of 20 weeks. The control and experimental groups each contained 20 fish. The group which was immunized by the PBS containing bacterin inoculate received a booster injection. Experiments were carried out in 11-12°C water. Low antibodies titres were detected by ELISA and faint and but distinct fluoresence by IFAT 2-3 weeks after immunization in the experimental fish blood. Humoral antibody production increased and after 5-6 weeks it reached its peak and then persisted during the experimental period of 20 weeks. All fish were protected against experimental challenge 35 days after immunization with Yersinia ruckeri bacterin.

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