Evaluation of the immunoprotective effect of gel 01 hydrogel inactivated vaccine against Pasteurella multocida infection in chickens.

Abstract

Avian Pasteurella multocida (Pm) infection is a contagious bacterial disease causing huge economic loss in the poultry industry worldwide. Vaccination is the most widely used strategy to prevent avian Pm infection, however fowl cholera still frequently outbreaks, leading to huge economic losses to the poultry production. In this study, the genotypes of 16 strains of Pm isolated from Sichuan poultry farm between 2007 and 2022 were identified. Based on the identified genotypes of Pm, an inactivated Gel 01-adjuvanted Pm vaccine was prepared and its immunoprotective effect was comparatively assessed against aluminum hydroxide-adjuvanted, propolis-adjuvanted inactivated vaccines, and the commercial live attenuated Pm vaccine (GE). These results indicated that all 16 strains of avian Pm were identified as genotype A: L1. The Gel 01-adjuvanted inactivated Pm vaccine could provide 80 % protection, which is higher than that of aluminum hydroxide-adjuvanted inactivated vaccine (70 %), propolis-adjuvanted inactivated vaccine (70 %), and commercial live attenuated Pm vaccine (50 %). The Gel 01-adjuvanted inactivated Pm vaccine reduced pathological damage and provided high antibody level. The results demonstrated that A: L1 is the predominant genotype of avian Pm in the Sichuan region, and the Gel 01 adjuvant provided better immune enhancement than aluminum hydroxide and propolis adjuvant. The Gel 01 adjuvant can be used as a candidate adjuvant for avian bacterial vaccines.