Author
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Moore, Randle |
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Holt, Peter |
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Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/22/2005 Publication Date: 8/1/2006 Citation: Moore, R.W., Holt, P.S. 2006. The effect of feed deprivation on tissue invasion by salmonella enteritidis. Poultry Science.85:1333-1337 Interpretive Summary: A tissue culture was used to investigate infection of tissues by Salmonella enteritidis and what effect feed withdrawal might have on the ability of Salmonella to infect the tissues. Crop, ileal, cecal, and ovarian tissues were obtained from full-fed adult Leghorn and from adult Leghorn hens which had undergone 14 days of feed withdrawal. The tissues were incubated for 2 hours with Salmonella enteritidis. The Salmonella which had not penetrated the tissues was removed with an antibiotic, and the amount of Salmonella which had infected the tissues was counted. Salmonella was more able to infect cecal tissues from non-fed hens. However, the was no significant difference in the ability of Salmonella to infect crop and ileal tissues from full-fed and non-fed hens. Additionally, Salmonella could not infect ovarian tissues in non-fed hens as easily as it could ovarian tissues from full-fed hens. These data suggest that the difference in the ability of Salmonella to infect hens which have had feed withdrawn may not be directly related to a change in the individual tissue itself, and that additional mechanisms are involved in the susceptibility of fasted hens to Salmonella infection. By better understanding the mechanisms involved in Salmonella infection, we may be able to help to prevent Salmonella infections. Technical Abstract: A tissue culture procedure was utilized to compare tissue cell invasion by Salmonella enteritidis from molted and full feed hens. Three identical trials were performed in which 80 wk-old active laying hens were divided into two groups of 6 birds each. The molted hen group was subjected to a 14 day feed withdrawal and full fed hen group was administered a standard layer ration. After feed treatment, crop, ileum, cecum, and ovary (small and large yellow follicles removed) were collected, rinsed in PBS, and placed into 50 ml of RPMI medium. The ends of intestine and crop tissues were tied to allow attachment of Salmonella only to the lumen surface. RPMI medium containing 107-108 cfu of novobiocin and nalidixic acid resistant phage type 13 Salmonella enteritidis was injected into the lumen of the intestine and crop tissues. Additionally, ovaries were incubated in 50 ml of RPMI medium containing 1,000,000-10,000,000 cfu of the Salmonella enteritidis. Tissues were incubated with Salmonella at 37°C for 2 hr, after which tissues were placed in 50 ml of fresh RPMI medium containing 500 ug/mL of gentamicin and incubated for 5 hr at 37°C to remove any Salmonella which had not penetrated tissues. Tissues were rinsed, stomached in 10 ml of PBS, serially diluted, and plated onto No/Na BGA agar for Salmonella enumeration. Salmonella invasion of ovaries was reduced in tissues from molted hens in trials 1 and 2 as compared to full fed controls (> 1.2 log reduction), but not in trial 3. Salmonella invasion of ceca from molted hens was numerically increased in trials 1 and 2 and significantly increased in trial 3 as compared to controls (> 0.8 log increase). No significant differences in Salmonella invasion were detected for crops and ileum. These data suggest that molting may effect invasion of tissues by Salmonella enteritidis. |
