Abstract

In the present study, efficacy of two prepared combined vaccines against salmonellosis and infectious coryza in poultry has been studied. Two vaccines were prepared using Salmonella Typhimurium and Enteritidis combined with Avibacterium paragallinarum serovars A, B, and C. one vaccine was adjuvanated with aluminium hydroxide gel and the other adjuvanated with montanide ISA71. The two vaccines were assayed in six weeks old Specific Pathogen Free (SPF) white Lohman layer chickens by injecting two doses of each vaccine 3 weeks apart. These chickens were challenged with either Salmonella virulent strains or Avibacterium paragallinarum different serovars 3 weeks post second dose. Antibody titers in sera of chickens against different antigens were higher in groups vaccinated with montanide oil vaccine than those vaccinated with aluminium hydroxide gel vaccine as detected by different serological tests; ELISA, micro-agglutination test and haem-agglutination inhibition test. Protection rate against challenge test were 80% and 85% for Salmonella and (80%; 90%, and 70%) and (90%; 100%, and 90%) to Avibacterium paragallinarum serovars A, B, and C respectively for combined vaccine adjuvanated by aluminum hydroxide gel and montanide ISA71. The protection rate was 15% against Salmonella Typhimurium and Enteritidis and 0% against infectious coryza among the unvaccinated chicken group.it could be concluded that producing a vaccine from locally isolated Salmonella and Avibacterium (Haemophilus) paragallinarum strains adjuvanated with montanide ISA71 is recommended to aid in controlling avian salmonellosis and Infectious coryza at the same time.