Submitted to: Avian Diseases
Publication Type: Abstract only
Publication Acceptance Date: 4/13/2006
Publication Date: 7/1/2007
Citation: Holt, P.S., Vaughn, L.E., Moore, R.W., Gast, R.K. 2007. Comparison of s. enterica serovar enteritidis levels in crops of fed or fasted infected hens. Avian Diseases: 50:425-429 Interpretive Summary:
Technical Abstract: Long term feed withdrawal has been shown to increase ileocecal intestinal colonization and fecal shedding of S. enterica serovar Enteritidis (SE) in challenged hens. Less information is available regarding effects of fasting on crop colonization. Two trials were conducted to compare effects of 14-day feed withdrawal vs full feed on crop colonization in hens challenged with SE. The levels of SE in the crop of fasted hens were significantly higher than in nonfasted hens on days 3 and 10 and days 3, 9 and 16 post-infection (PI) in trials 1 and 2, respectively. Fecal shedding of SE was significantly increased in the fasted hens on day 10 PI in trial 1. Analysis of crop IgA anti-SE lipopolysaccharide levels in crop lavage samples of hens in trial 1 revealed a humoral response post-infection in both treatment groups with no significant differences, although peak response for fasted hens occurred one week later. Histologic evaluation of H & E crop sections from trial 1 birds revealed mild to moderate heterophilic infiltration within the crop LP or LP and epithelium of nonfasted infected hens at 24 and 96 hours PI. In comparison, heterophils in crops of fasted hens infected at this time point were sparse, indicating a possible diminished heterophil response in the fasted birds. Multifocal areas of tissue inflammation, as indicated by marked heterophil infiltration, with necrosis and sloughing of epithelium, were observed in crops from fasted hens at day 11 PI (14th day of feed withdrawal) but not in the fed groups. This severe heterophilic inflammation was observed in both challenged and non-challenged fasted hens, suggesting some factor other than SE was responsible. These results indicate that feed withdrawal can have a dramatic effect on the integrity of the crop and its ultimate response to infection.