Stressful situations reduce the welfare, production indices and immune status of chickens. Salmonella spp. are a major zoonotic pathogens that annually cause over 1 billion infections worldwide. We therefore designed the current experiment to analyse the effects of 31±1°C
heat stress (HS) (from 35 to 41 days) on performance parameters, Salmonella invasion and small intestine integrity in broiler chickens infected with Salmonella Enteritidis. We observed that HS decreased body weight gain and feed intake. However, feed conversion was only increased
when HS was combined with Salmonella Enteritidis infection. In addition, we observed an increase in serum corticosterone levels in all of the birds that were subjected to HS, showing a hypothalamus–pituitary–adrenal axis activation. Furthermore, mild acute multifocal lymphoplasmacytic
enteritis, characterized by foci of heterophil infiltration in the duodenum, jejunum and ileum, was observed in the HS group. In contrast, similar but more evident enteritis was noted in the heat-stressed and Salmonella-infected group. In this group, moderate enteritis was observed
in all parts of the small intestine. Lastly, we observed an increase in Salmonella counts in the spleens of the stressed and Salmonella-infected chickens. The combination of HS and Salmonella Enteritidis infection may therefore disrupt the intestinal barrier, which would
allow pathogenic bacteria to migrate through the intestinal mucosa to the spleen and generate an inflammatory infiltrate in the gut, decreasing performance parameters.
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Document Type: Research Article
Neuroimmunomodulation Research Group, Department of Pathology, School of Veterinary Medicine,University of São Paulo, São Paulo,05508-270, Brazil
Laboratory of Ornithopathology, School of Veterinary Medicine,University of São Paulo, São Paulo,05508-270, Brazil
Publication date: October 1, 2012
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