Figure 5.

Postchallenge OMPs-specific antibody response in chickens vaccinated orally with OMPs-F-PNPs.

Notes: Layer chickens were inoculated orally three times at 3-week intervals with PBS (Groups 1 and 2), or soluble OMPs and F-protein (Group 3), or OMPs-F-PNPs (Group 4). Except mock (Group 1) other groups were challenged orally with 1×10⁹ CFU/mL of live S. enteritidis and euthanized at day 10 postchallenge. Samples collected from birds were analyzed for OMPs-specific antibody response by ELISA: (A) IgG in serum; (B) IgG in bile; (C) IgA in bile; (D) IgA in cloacal swab; (E) IgA in small intestinal wash; (F) IgA in tracheal wash. Each bar is the mean ± SEM of 8–10 chickens, and the data were analyzed by nonparametric Kruskal–Wallis test followed by P-value differences in between the groups determined by Mann–Whitney test. Asterisk refers to statistical difference between the two indicated groups (^*P<0.05, ^**P<0.01, and ^***P<0.001). OMPs-F-PNPs, OMPs and F-protein-entrapped and surface F-protein-coated PNPs.

Abbreviations: CFU, colony-forming unit; Ch, challenge; F, flagellar; OMPs, outer membrane proteins; PNPs, polyanhydride nanoparticles; SEM, standard error of the mean.