Figure 4

Determination of the bacterial growth curves and virulence. A Strains CH3 and RA1067 were grown in TSB at 37 °C with shaking respectively, and the bacteria numbers of CFU were measured at 2 h intervals. This experiment was repeated three times, and the data were presented as the means. Error bars represent standard deviations. Asterisks indicate statistically significant differences between groups. B Bacterial loads in blood of infected ducks with CH3 or RA1067 at 6, 12, 24 and 48 h post infection (hpi). After 72 hpi more than half of the WT CH3 infected ducks were dead, no data of bacterial loads in blood was collected. The error bars represent means ± standard deviations from six ducks. Asterisks indicate statistically significant differences between groups (***, p < 0.001).