Submitted to: American Association of Avian Pathologist
Publication Type: Abstract Only
Publication Acceptance Date: 12/20/2013
Publication Date: 7/26/2014
Citation: Gast, R.K., Guraya, R., Jones, D.R., Anderson, K.E. 2014. Salmonella Enteritidis organ invasion and egg contamination in experimentally infected laying hens housed in conventional or enriched cages. American Association of Avian Pathologist. p.20.
Technical Abstract: Both disease surveillance and epidemiologic analyses have confirmed a strong association between human salmonellosis and the prevalence of Salmonella Enteritidis (SE) in commercial egg flocks. The majority of human illnesses caused by this pathogen are attributed to contaminated eggs. Animal welfare concerns have increasingly influenced commercial poultry production practices in recent years, but the food safety implications of different housing systems for egg-laying hens are not definitively understood. The present study assessed the effects of two housing systems (conventional cages and colony cages enriched with perching and nesting areas) on the frequency of SE colonization of internal organs and deposition inside eggs after experimental oral infection of laying hens. In a pair of trials with phage type 4 and 13a strains, SE colonized the ceca of nearly all inoculated hens, but was recovered from significantly more livers, spleens, ovaries, and oviducts from hens in conventional cages than from hens in enriched colony cages (58.9% vs. 35.2% of all samples for these organs). However, in a second pair of trials, SE was found inside similar percentages of eggs from the two types of cages (4.0% from conventional cages and 3.6% from enriched cages). No significant differences between the two SE phage types were observed for either organ invasion or egg contamination. These results demonstrate that differences in housing systems for egg-laying flocks may affect the susceptibility of hens to Salmonella Enteritidis infection, but these differences may not necessarily lead to corresponding effects on egg contamination.