Effect of the alcoholic extract of the grape (Vitis Vinifera L.) and pomegranate (Punica Granatum L.) seed on the immunogenicity of the inactivated avian influenza virus subtype H9N2 in broilers

Mineral oil-adjuvants remain in chicken meat and may be carcinogenic. Plant-based oils comprise different components, but they have suitable safety to use as an adjuvant. In this study, we investigated the adjuvant activity of pomegranate seed oil (PSO) and grape seed oil (GSO) on the immunogenicity of the inactivated avian influenza virus subtype H9N2. For this purpose, the hexanic extract of PS and red GS was separately emulsified with inactivated H9N2 virus. One hundred broiler chickens were assigned into five groups (n = 20). Group A received PSO+H9N2 emulsion, group B received GSO+H9N2 emulsion, group C received PBS+inactivated H9N2 virus, group D received a commercial vaccine, and group E did not receive anything. The chickens were treated at 14 days of age. At 21 days post-vaccination, all chickens were challenged by the H9N2 virus. Hemagglutination inhibition test, anamnestic response, and clinical signs were used to assess immunogenicity. The results showed that although the PSO and GSO have adjuvant activity and significantly increase antibody titers to the H9N2 virus after two weeks of vaccination, but the antibody titers significantly decrease after three weeks of vaccination. In conclusion, PSO and red GSO seem to have biologically active molecules and potentially adjuvant properties, but they alone cannot induce protective immunity against the avian influenza H9N2 virus.