University of Tehran Press Journal of Veterinary Research 2008-2525 56 3 2001 10 23 - - 16506 FA Journal Article Avian influenza (Al) is a viral disease with worldwide distribution. It is caused by influenza A viruses of the family Orthomyxoviridae. In May 1998, clinical signs and high mortaity in broiler chickens in Iran were associated with H9N2 avian influenza subtype. Vaccination was adapted as an alternative method to control it in poultry industry. The aim of this study was to compare the Immunogenesis of different local and imported H9N2 avian influenza vaccines. Arian broiler chickens were divided randomly into 21 groups of 30 birds. Each group received standardized dose of Lohmman, Ivaz, and FVM vaccines in 1,5,10,15 and 20 days old by subcutaneously in the nape of the neck. Sera were collected from each chicken for antibody analysis 1,2,3,4 and 5 weeks post vaccination. The sera were tested for antibodies against avian influenza H9N2 subtype with hemagglutination inhibition (HI) tests. Antiboby levels in broiler chickens immunized with local H9n2 avian influevza vaccines were higher than those Immunized with imported H9N2 avian influenza vaccines (P Avian influenza (Al) is a viral disease with worldwide distribution. It is caused by influenza A viruses of the family Orthomyxoviridae. In May 1998, clinical signs and high mortaity in broiler chickens in Iran were associated with H9N2 avian influenza subtype. Vaccination was adapted as an alternative method to control it in poultry industry. The aim of this study was to compare the Immunogenesis of different local and imported H9N2 avian influenza vaccines. Arian broiler chickens were divided randomly into 21 groups of 30 birds. Each group received standardized dose of Lohmman, Ivaz, and FVM vaccines in 1,5,10,15 and 20 days old by subcutaneously in the nape of the neck. Sera were collected from each chicken for antibody analysis 1,2,3,4 and 5 weeks post vaccination. The sera were tested for antibodies against avian influenza H9N2 subtype with hemagglutination inhibition (HI) tests. Antiboby levels in broiler chickens immunized with local H9n2 avian influevza vaccines were higher than those Immunized with imported H9N2 avian influenza vaccines (P https://jvr.ut.ac.ir/article_16506_720788047c0f22a0d3b25150007b2618.pdf