Abstract: H5 or H7 subtype highly pathogenic avian influenza is a highly lethal infectious disease. It not only causes great harm and loss to the poultry industry, but also threatens the safety of human life and health. The purpose of this study is to analyze antibody levels of the trivalent inactivated vaccine of recombinant avian influenza virus（H5+H7）based on H5N1 Re-11 strain+Re-12 strain and H7N9 Re-3 strain. In this study, nearly 20 000 yellow chickens from 14 farms in Rugao city were intramuscularly injected with recombinant avian influenza virus trivalent inactivated vaccine. After three weeks of immunization, 420 blood samples were randomly collected for HI antibody titer detection. The results showed that there were no obvious adverse reactions in all the vaccinated chickens, and the yellow chickens could be induced to produce good antibodies with high antibody titers. The average antibody titer of H5 subtype Re-11 strain and Re-12 strain were 7.8log2 and 8.2log2 respectively. The average antibody titer of H7 subtype Re-3 strain was 6.81og2, and the pass rate of immune antibody was more than 70%. It had good safety and immune protection effect on yellow chickens. The results provide a reference basis for the effective control of highly pathogenic avian influenza.

Key words: recombinant avian influenza virus, H5+H7 subtypes, trivalent inactivated vaccine, immunity, antibody levels