Submitted to: Southern Poultry Science Society Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/18/1999
Publication Date: N/A
Technical Abstract: Feed removal during forced molt of aging hens decreases resistance to Salmonella enteritidis (SE) and increases the risk of SE positive eggs. The crop is the first hostile environment encountered by bacteria after oral entry and may therefore influence the spread of SE to other parts of the intestinal tract and the invasion of tissues. During the present study, we evaluated the effect of forced molt induced by feed withdrawal on the environment of the crop, SE crop and cecal colonization, and spleen-liver invasion. Aging leghorn hens were divided into two groups designated either unmolted controls or molted. Forced molt was induced by 9 days of feed withdrawal. Individual hens in both groups were challenged orally with 10**5 SE on day 4 of feed removal. The study was repeated in two replicated trials. Compared with the unmolted control hens, the population of resident lactobacilli that are normally present in the crop was significantly depleted (P<0.05) in the molted hens and the concentrations of lactic acid and volatile fatty acids were decreased (P<0.05). Additionally, the pH of the crop increased (P<0.05) in the molted hens compared with the controls. Colonization of the crop and ceca by SE increased significantly (P<0.05) in the molted hens compared with the controls. Tissue invasion by SE as indicated by spleen-liver colonization also increased (P<0.05) in the molted hens compared with the controls. The results of the study demonstrated that the hostile microenvironment of the crop is moderated by feed withdrawal and is accompanied by increased SE colonization in the crop, ceca, and spleen- liver.