Oral Vaccination Against Lactococcosis in Rainbow Trout (Oncorhynchus mykiss) Using Sodium Alginate and Poly (lactide-co-glycolide) Carrier [1]

As an alternative immunization procedure against lactococcosis in rainbow trout, encapsulated antigens immobilized in sodium alginate (SA) and poly lactide-co-glycolide (PLGA) polymers were administrated as a feed additive. Positive controls were intraperitoneally (IP) administered with aqueous-based bacterin (vaccine) while negative controls were not vaccinated. Positive control groups were immunized intraperitoneally by using the aqueous-based bacterin. Relative percentage survival (RPS) values of groups immunized orally with SA and (PLGA) encapsulated vaccines were not significantly different and was 53.48% and 62.79% respectively (on the 30 day). No statistically significant difference was determined between the SA and (PLGA) vaccine groups and relative percentage survival (RPS) values of the two groups determined to be 53.48% and 62.79%, respectively. To determine the effect of the booster immunization by using encapsulated immobilized vaccines, booster immunization was performed on the 61 day after oral administration of the same vaccines and RPS value was more than 60% on the 90 120 days. After an aqueous-based vaccine followed by an immobilized vaccine for booster, the RPS value has increased over more than 80% indicating that booster application has increased the protection of rainbow trout against lactococcosis. It can be suggested that both SA and PLGA oral vaccines can be effectively used in rainbow trout against lactococcosis and there was no significant differences between the protection levels, however, since the preparation costs of SA oral vaccines are relatively lower compared to PLGA ones its usage for vaccination appears more appropriate.