First comparison of adjuvant for trivalent inactivated Haemophilus parasuis serovars 4, 5 and 12 vaccines against Glässer's disease.

Haemophilus parasuis has had a huge impact in the swine industry throughout the world. Inactivated bacterium for H. parasuis is a traditional vaccine that can elicit efficient protection against homologous challenges. The objective of this study was to screen for the adjuvant-enhanced immune effect of trivalent inactivated H. parasuis serovars 4, 5 and 12 (prevalent serovars in China) vaccines against Glässer's disease. The adjuvants of mineral oil, aluminum hydroxide, Montanide GEL 01 PR, Montanide IMS 1313N VG and Montanide ISA 760 VG were used to make emulsified inactivated H. parasuis serovars 4, 5 and 12, respectively. Safety, antibody titer and protective efficacy of these vaccines were examined separately in piglets, and the feasibility of microagglutination test for detecting antibody titer of H. parasuis was confirmed for the first time. Due to easy of injection, high safety, rapidly immune responses, high concentrations of antibody, and 100% of protective efficacy for piglets, Montanide GEL 01 PR adjuvant can provide more homologous serovar protection than other domestically developed inactivated vaccines and should be used as a candidate adjuvant.