Figure 1 Newcastle disease virus, infectious bronchitis virus and infectious bursal disease, respectively virus-specific antibody titers in
chickens (n=12) immunized with 0.1 mL of virus activated vaccine. Blood samples were collected on 0, 7, 14, 21, 28, 35 and 42 days postimmunization
for ELISA assay. Bars with different letters at the same time point are significantly different (P < 0.05).