|Guraya, Rupinder - Rupa|
|ANDERSON, KENNETH - North Carolina State University|
|KARCHER, DARRIN - Michigan State University|
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/6/2016
Publication Date: 7/11/2016
Citation: Gast, R.K., Guraya, R., Jones, D.R., Guard, J.Y., Anderson, K.E., Karcher, D. 2016. Colonization of internal organs by Salmonella serovars Heidelberg and Typhimurium in experimentally infected laying hens housed in enriched colony cages at different stocking densities. Poultry Science Association Meeting Abstract. Paper No. 72.
Technical Abstract: Contaminated eggs produced by infected commercial laying flocks are often implicated as sources of human infections with Salmonella Enteritidis, but Salmonella serovars Heidelberg and Typhimurium have also been significantly associated with egg-transmitted illness. Contamination of the edible contents of eggs is principally a consequence of Salmonella colonization of reproductive tissues in systemically infected hens. In recent years, the animal welfare implications of diverse poultry housing and management systems have been vigorously debated, but the food safety significance of laying hen housing remains uncertain. The present study evaluated the effects of two different bird stocking densities on the invasion of internal organs by S. Heidelberg and S. Typhimurium in groups of experimentally infected laying hens housed in colony cages enriched with perching and nesting areas. Laying hens were distributed at two different stocking densities (648 and 973 cm2/bird) into colony cages and (along with a group housed in conventional cages) orally inoculated with doses of 107 cfu of two-strain cocktails of either S. Heidelberg or S. Typhimurium. At 5-6 d post-inoculation, hens were euthanized and samples of internal organs (cecum, liver, spleen, ovary, and oviduct) were removed for bacteriologic culturing. The overall frequency of isolation of S. Heidelberg from ceca (83.3%) was significantly (P < 0.001) greater than the corresponding value for S. Typhimurium (53.8%). Conversely, S. Typhimurium was recovered significantly more often from both livers (85.2% vs. 53.7%; P < 0.0001) and spleens (78.7% vs. 56.5%; P = 0.0008) than was S. Heidelberg. However, there were no significant differences (P > 0.05) between stocking densities or cage systems in the frequencies of isolation of either S. Heidelberg or S. Typhimurium from any of the five sampled tissues. These results contrast with prior studies which reported increased susceptibility to internal organ invasion by S. Enteritidis among hens in conventional cages at higher stocking densities.