Internal organ colonization by Salmonella Enteritidis in experimentally infected layer pullets reared under different housing conditions

Authors: Gast, Richard; Jones, Deana; Guraya, Rupinder - Rupa; Garcia, Javier; KARCHER, DARRIN - Purdue University

Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/30/2022
Publication Date: 2/15/2023
Citation: Gast, R.K., Jones, D.R., Guraya, R., Garcia, J.S., Karcher, D.M. 2023. Internal organ colonization by Salmonella Enteritidis in experimentally infected layer pullets reared under different housing conditions. Poultry Science Association Meeting Abstract. 101(1):157-158.

Interpretive Summary:

Technical Abstract: Invasive Salmonella Enteritidis infection involving the reproductive organs of laying hens can result in the production of internally contaminated eggs, which continue to be prominent sources of disease transmission to consumers. The poultry housing environment exerts substantial influences on the dissemination and prevalence of S. Enteritidis in laying flocks, and the ongoing transition of the egg industry toward cage-free housing has raised new questions about the food safety ramifications. The present study assessed internal organ colonization by S. Enteritidis in egg-type pullets reared under different housing conditions. In one trial, pullets reared in either conventional cage or cage-free housing systems were moved at 16 wk of age into 4 isolation rooms simulating commercial cage-free barns in groups of 72 birds per room. One-third of the pullets in 2 rooms were orally inoculated with S. Enteritidis immediately after transfer and pullets in 2 rooms were similarly infected at 19 wk. At 6-12 d post-inoculation, all pullets were euthanized and samples of liver, spleen, and intestinal tract were removed for bacteriologic culturing. In a second trial, pullets were reared in cage free housing at either low or high bird stocking densities and transferred to the containment facility for S. Enteritidis infection as in the first trial. In Trial 1, S. Enteritidis was isolated significantly (P < 0.05 in Fisher’s Exact Test) more frequently from spleens (55.9% v. 46.5%) and intestines (89.9% v. 82.6%) from pullets that had been reared in cages than from those reared in cage-free housing, especially when the birds were infected on the day after transfer from the rearing facility. In Trial 2, no significant differences in S. Enteritidis isolation frequencies from any tissue were observed between high and low density rearing groups following infection at either age, but S. Enteritidis was found significantly (P < 0.05) more often from pullets infected at 19 wk of age than at 16 wk in livers (38.9% v. 29.2%) and spleens (39.9% v. 28.1%). These results reinforce the importance of attentive pathogen risk reduction practices at this critical phase (at or just prior to sexual maturity) in the productive life of egg-laying flocks.