Location: Food and Feed Safety ResearchTitle: Fate of Salmonella Seftenberg in broiler chickens evaluated by challenge experiments Author
|Kogut, Michael - Mike|
Submitted to: Avian Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2014
Publication Date: 5/13/2014
Publication URL: http://handle.nal.usda.gov/10113/59500
Citation: Kallapura, G., Kogut, M.H., Morgan, M.J., Pumford, N.R., Bielke, L.R., Wolfenden, A.D., Faulkner, O.B., Latorre, J.D., Merconi, A., Hernandez-Velasco, X., Kuttappam, V.A., Hargis, B.M., Tellez, G. 2014. Fate of Salmonella Senftenberg in broiler chickens evaluated by challenge experiments. Avian Pathology. 17:1-5. Interpretive Summary: During the first week of life after hatching, the immune system of the baby chick is not very good at fighting bacterial infections such as Salmonella. Normally, the baby chickens get infected with germs such as Salmonella by ingesting feces-contaminated feed. In this paper, we found that the baby chicks can also get infected by breathing the bacteria into their lungs. The results of these experiments are important to the poultry industry in the United States because it shows that dry, dusty conditions in the chicken house can lead to infections in baby chicks simply by breathing the contaminated air.
Technical Abstract: Recently, our laboratory has hypothesized that transmission by the fecal-respiratory route may be a viable portal of entry for Salmonella that could explain some clinical impressions of relatively low-dose infectivity under field conditions in relation to the high oral laboratory challenge dose. The purpose of this study was to evaluate and compare the infectivity of Salmonella Senftenberg following oral gavage (OR), intratracheal (IT), or intravenous (IV) challenge in chickens. Seven-day-old chicks were challenged with either 104 or 106 28 CFU of S. Senftenberg/chick, OR, IT, or IV, respectively, in two independent trials. Chickens were humanely killed 24 h post challenge and cultured for enumeration of S. Senftenberg from cecal contents, as well as organ enrichment ceca31 cecal tonsils (CCT) and liver and spleen (LS). In both trials, IT delivery of S. Senftenberg was the only route able to colonize the ceca of the chickens when compared with OR or IV challenge in a dose response fashion (P < 0.05). Low levels of S. Senftenberg recovery from selectively enriched LS samples were found only after high dose administration of S. Senftenberg by either route in both trials. The results of the present study suggest that S. Senftenberg entering the blood is likely to be cleared and will not be able to colonize ceca to the same extent as compared to IT challenge. Clarification of the potential importance of the respiratory tract for Salmonella transmission under field conditions may be of critical importance to develop intervention strategies to reduce its transmission in poultry.