Host response to various treatments to reduce Salmonella infections in swine.

Host response was evaluated following the administration of various treatments, such as probiotics, prebiotics, and vaccination, to reduce Salmonella in swine. Response to the treatments were studied by the evaluation of phagocytosis rates by flow cytometry, by studying the activation of whole-blood phagocytes by bioluminescence, the production of IgA against S. Typhimurium, and by histopathology. Significant differences were observed in the activation of whole-blood phagocytes in all groups of treated pigs (P = 0.0001). In SC54 vaccinated pigs, a significant reduction of Salmonella in the ileum was observed (P < 0.05) and the production of IgA against S. Typhimurium was higher in this group in comparison to uninfected control pigs (P = 0.0007). Furthermore, significant histopathological (P < 0.05) changes were observed in SC54 vaccinated pigs. Villus height and mucus and goblet cells density in the small intestine were reduced in vaccinated pigs in comparison to infected control pigs. Taken together, these findings suggest that SC54 vaccine can stimulate local immunity and reduce the presence of Salmonella in the ileum in swine. Use of SC54 vaccine should thus be considered in further field experiments.