Effect of diet on the concentration of complex Shiga toxin-producing Escherichia coli and EHEC virulence genes in bovine faeces, hide and carcass

Gilbert, Rosalind Ann, Denman, Stuart Edward, Padmanabha, Jagadish, Fegan, Narelle, Al Ajmi, Dawood and McSweeney, Christopher S. (2008) Effect of diet on the concentration of complex Shiga toxin-producing Escherichia coli and EHEC virulence genes in bovine faeces, hide and carcass. International Journal of Food Microbiology, 121 2: 208-216. doi:10.1016/j.ijfoodmicro.2007.11.019


Author Gilbert, Rosalind Ann
Denman, Stuart Edward
Padmanabha, Jagadish
Fegan, Narelle
Al Ajmi, Dawood
McSweeney, Christopher S.
Title Effect of diet on the concentration of complex Shiga toxin-producing Escherichia coli and EHEC virulence genes in bovine faeces, hide and carcass
Journal name International Journal of Food Microbiology   Check publisher's open access policy
ISSN 0168-1605
1879-3460
Publication date 2008-01-31
Year available 2007
Sub-type Article (original research)
DOI 10.1016/j.ijfoodmicro.2007.11.019
Volume 121
Issue 2
Start page 208
End page 216
Total pages 9
Place of publication Amsterdam, Netherlands
Publisher Elsevier BV
Language eng
Formatted abstract
An experiment was conducted to determine whether diets based on structural carbohydrate and/or simple sugars, as found in roughage and/or molasses-based diets, reduce the bovine faecal populations of Shiga toxin-producing Escherichia coli (STEC) isolates containing the eaeA and ehxA genes, referred to as complex STEC (cSTEC), compared with typical high starch, grain-based feedlot diets. In addition, whether commercial lairage management practices promote or diminish any diet-induced responses on the contamination of carcasses was also investigated.

After 13 days on the dietary treatments total faecal E. coli numbers were approximately one log lower in the roughage (R) and roughage + 50% molasses (RM) diets compared with grain (G) fed animals, this difference varying between 0.5 and 1 log at lairage. Fermentation patterns were similar in the R and RM diets whereas decreased pH and enhanced butyrate fermentation pathways were associated with the G diet.

A significant decrease in the faecal concentration of the eaeA gene occurred when animals were changed from high grain to R and RM diets for 6–13 days, compared with animals maintained on the G diet. Significantly lower concentrations of the ehxA gene were also associated with the R diet. Concentrations of the stx2 gene however, were unaffected by diet.

cSTEC were infrequently isolated, with the faecal concentrations of these organisms being low (< 3 log10 MPN per g faeces). cSTEC were only isolated from animals fed G or RM diets, but were never isolated from cattle fed the roughage-based diet, with this diet-induced effect sustained following lairage. These organisms were not detected on the hide and carcass of animals found to shed cSTEC in their faeces and thus appeared uncontaminated with cSTEC.
Keyword cSTEC
STEC
Bovine
Diet
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes Available online 17 November 2007

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Agriculture and Food Sciences
 
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Created: Thu, 03 Sep 2009, 10:30:02 EST by Mr Andrew Martlew on behalf of School of Agriculture and Food Sciences