Figure 5

Bacterial serum resistance assay. Bacteria were incubated with the normal duck sera at different dilutions at 37 °C, and were enumerated at 30 min incubation. A significant reduced resistance of RA1067 to the normal duck sera than that of CH3 was shown (**, p < 0.01). The survival rate (%) was calculated as follows: (bacterial CFU with sera treatment/bacterial CFU with PBS treatment) × 100.