Fig. 7.

HI antibody titers against AIV H5N1 in commercial ducks vaccinated with DEV-H5(UL55). A total of 50 2-week-old commercial ducks were randomly divided into five groups of A-AI(2D), B-AI(2D), C-AI(2D), D-AI(2D), and E-AI(2D). Birds in groups A-AI(2D), B-AI(2D), and C-AI(2D) were vaccinated intramuscularly with DEV-H5(UL55) at a dose of 1 × 10⁷ TCID₅₀ (Lane: 10⁷), 1 × 10⁶ TCID₅₀ (Lane: 10⁶) and 1 × 10⁵ TCID₅₀ (Lane: 10⁵), respectively. Birds in group D-AI(2D) were inoculated subcutaneously with a dose of 0.5 ml and 1 ml of inactivated AIV H5N1 Re-6 vaccine (QYH) at 2 w and 5 w, respectively, according to the manufacturer’s instructions (Lane: Re-6). Birds in the control group E-AI(2D) were inoculated with 0.2 ml of PBS (Lane: Control). Serum samples of all birds were collected prior to inoculation and at 1, 2, 3, 4, 5, and 6 weeks after vaccination to measure the HI titers, which are shown here