Pathological findings in the intestinal tract and liver of chicks after exposure to Salmonella serotypes Typhimurium or Kedougou.

Day-old chicks were inoculated either via the feed or by direct oral inoculation with salmonellas which were either invasive or non-invasive (serotypes Typhimurium and Kedougou, respectively). Colonization of the alimentary tract and visceral organs, determined by microbiological examination, occurred more quickly in birds inoculated orally with S. serotype Typhimurium compared with feed-challenged birds. By contrast, S. serotype Kedougou remained confined to the alimentary tract. In birds inoculated either orally or via the feed, S. serotype Typhimurium, but not serotype Kedougou, was identified in the lamina propria of the caecum by immunostaining. Electron microscopic examination confirmed that the organisms were within macrophages.