The motility, adherence and colonization assays of bacterial. A, Flagella related motility assays. A1: F18ab; A2: F18abΔhcp1; A3: F18abΔhcp1/phcp1. B, Adherence ability towards IPEC-J2 cell line. C, Invasion ability towards IPEC-J2 cell line. D, Intestinal colonization test.  * Significant difference, p<0.05.