EVALUATION OF MONTANIDE GR01 FOR ORAL VACCINATION IN NILE TILAPIA (Oreochromis niloticus): LABORATORY AND ON-FARM TRIALS

Abstract

An emerging infectious disease called Streptococcosis caused by Streptococcus agalactiae has adversely affecting Nile tilapia (Oreochromis niloticus) aquaculture. The vaccines against this disease have been developing to prevent disease and increase the specific immune response in fish to a particular pathogen. The application of adjuvants registered under the trademark Montanide have been optimized to improve vaccine formulation efficacy and stability while reducing side effects. In this study, this study plans to optimize the use of a novel adjuvant Montanide GR01 for use in fish, Nile tilapia. Initially, stable formulations containing a killed S. agalactiae was prepared. Three formulations of feed-based vaccine were compared the responses elicited in the fish with those elicited by oral vaccine to this disease. The immune response and protective efficacy of formalin-killed cell (FKC) vaccine only and mixed FKC vaccine with a new adjuvant MontanideTM GR01 in Nile tilapia for oral vaccination were investigated. The present study found that vaccination of FKC emulsified with Montanide GR01 could significantly improve innate and adaptive immune parameters tested in both the laboratory and field-trial experiments. Moreover, it was clearly demonstrated that Montanide GR01, which was formulated in fish feed as adjuvant, effectively improve Nile tilapia immunity and clearly elevate disease resistance against streptococcosis. The levels of immune responses in fish fed dietary vaccine formulated with Montanide GR01 for four months were higher compared to those fed with vaccine alone or commercial diet (control group); although it was not effective to enhance growth performance of tilapia in this study. In overall, Montanide GR01 is a very useful adjuvant for oral vaccination and could be applied as potential adjuvants for vaccine development to control and prevent of streptococcosis in Nile tilapia aquaculture.

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