Figure 6

Bacterial serum resistance assay. Bacteria were incubated with normal duck sera at different dilutions at 37 °C and enumerated after 30 min of incubation. Three experimental replicates were performed and the data presented as the mean ± standard deviation. Resistance of RA1062 to normal duck sera was significant decreased, as compared to CH3 (*p < 0.05; **p < 0.01). The survival rate (%) was calculated as follows: (bacterial CFU with sera treatment/bacterial CFU with PBS treatment) × 100.