Preparation of a Newly Developed Trivalent Pasteurella multocida, Avibacterium paragallinarum, and Ornithobacterium rhinotracheale Vaccine with an Evaluation of its Protective Efficacy in Chickens

Poultry, mainly chickens, and their white meat represent one of the main, nutritionally valuable, and affordable red meat replacer sources of protein throughout the whole world with special reference to developing countries. A long list of microbial agents especially bacterial pathogens threatens chickens’ production cycles.  They constitute one of the major problems facing the rapidly expanding poultry industry and are responsible for considerable economic losses. Fowl cholera, infectious coryza, and ornithobacteriosis (ORT) were among the serious bacterial infections that affect the respiratory tract of chickens with a global adverse effect on poultry production. A formalinized whole culture vaccine composed of Pasteurella multocida serotypes A5, A8, A9, and D2, Avibacterium paragallinarum serotypes A and C, and Ornithobacterium rhinotracheale serotype A was prepared. This polyvalent vaccine proved to be safe producing no adverse side effects when injected in chickens. The immunizing efficacy of this vaccine was evaluated in specific pathogen-free (SPF) chickens, which were immunized at 6 weeks of age. The protective efficacy of the vaccine was determined using a challenge test. The developed vaccine was effective in protecting chickens against fowl cholera, infectious coryza, and ornithobacteriosis in chickens against challenge with these pathogens. Vaccinated chickens challenged with virulent Pasteurella multocida serotypes A5, A8, A9, and D2 showed protection rates of 86.6%, 93.3%, 93.3%, and 93.3%, respectively, as compared with 100% mortality in the non-vaccinated control. Vaccinated chickens challenged with Avibacterium paragallinarum serotypes A and C showed 86.6% and 93.3% protection rates, respectively. Also, the protection rate against challenges with virulent Ornithobacterium rhinotracheale serotype A reached 96.6%.