Stability of Effective Edwardsiella tarda Vaccine Developed for Japanese Eel (Anguilla japonica)

摘要

This study aimed to design to evaluate the immunogenicity as well as the stability of inactivated bacterins in storage conditions to prevent edwardsiellosis in fish species. Three vaccine formulations, formalin (0.4%, FKC), pressure (600 kgf cm super(-2) for 5 min, PKC) and electric current (100 mA at 12v DC for 5 sec, ECKC) killed bacterin and a routes of administration with intraperitoneal injection (i.p.) was tested. The effectiveness of the immunization strategies was evaluated in terms of Relative Percent Survival (RPS) and antibody levels. On the basis of the results pressure inactivated vaccine via i.p. which confers RPS values over 85% at least 6 months post-vaccination. In the search for a more stable bacterin, inactivated E. tarda antigen was subjected to different storage temperatures. Storage at 4 degree C did not significantly affect the titer of PKC and antigenic potency remained stable for 6 month. However, with the bacterins FKC and ECKC there is a considerable loss of potency during stored at 4 degree C. Bacterins were discarded if exposed to temperature of 0 degree C or below, because the precise freezing point is not established. Bacterins loosed significant potency after 1 month when stored at 25 degree C.