Colonization of internal organs by Salmonella Enteritidis in experimentally infected laying hens housed in enriched colony cages at different stocking densities

• Published in: Poultry science Vol. 95; no. 6; pp. 1363 - 1369
• Main Authors: Gast, Richard K, Rupa Guraya, Deana R. Jones, Kenneth E. Anderson, Darrin M. Karcher
• Format: Journal Article
• Language: English
• Published: England Poultry Science Association, Inc 01.06.2016
• Subjects: animal ovaries; animal welfare; Animals; cages; Chickens; disease resistance; eggs; epidemiological studies; Female; flocks; food safety; Housing, Animal; human diseases; laying hens; liver; nesting; pathogens; Population Density; Poultry Diseases - microbiology; poultry housing; Salmonella Enteritidis; Salmonella enteritidis - physiology; Salmonella Infections, Animal - microbiology; salmonellosis; serotypes; spleen; stocking rate; tissues; conventional cages; Enteritidis; laying hens; stocking density; enriched colony cages; Salmonella Enteritidis
• ISSN: 1525-3171; 0032-5791; 1525-3171
• DOI: 10.3382/ps/pew037

Epidemiologic analyses have linked the frequency of human infections with Salmonella enterica subspecies enterica serovar Enteritidis to the consump- tion of contaminated eggs and thus to the prevalence of this pathogen in commercial egg-laying flocks. Con- tamination of the edible contents of eggs by Salmonella Enteritidis is a consequence of the colonization of re- productive tissues in systemically infected hens. The animal welfare implications of laying hen housing sys- tems have been widely debated, but no definitive con- sensus has yet emerged about the food safety significance of poultry housing options. The present study sought to determine the effects of two different bird stocking densities on the invasion of internal organs by Salmonella Enteritidis in groups of experimentally infected laying hens housed in colony cages enriched with perching and nesting areas. In two trials, groups of laying hens were distributed at two different stocking densities into colony cages and (along with a group housed in conventional cages) orally inoculated with doses of 1.0 × 10(7) cfu of Salmonella Enteritidis. At 5 to 6 d post-inoculation, hens were euthanized and samples of internal organs were removed for bacteriologic culturing. For both trials combined, Salmonella Enteritidis was recovered at a significantly (P < 0.05) greater frequency from hens in enriched colony cages at the higher stocking density than at the lower density from livers (75.0% vs. 51.4%) and ovaries (51.4% vs. 30.6%). However, spleens from hens in enriched colony cages at the higher stocking density were significantly less often positive for Salmonella Enteritidis than from hens in conventional cages at that same density (90.3% vs. 68.1%). These results suggest that stocking density can influence the susceptibility of hens to Salmonella Enteritidis, but other housing systems parameters may also contribute to the outcome of infections.