Effects of Diet on Rumen Proliferation and Fecal Shedding of Escherichia coli O157:H7 in Calves
| Autor: | Karen L. Jacobsen, Scott A. Martin, Suzana Tkalcic, Tong Zhao, Barry G. Harmon, Eric P. O. Mueller, Andrew H. Parks, Anant V. Jain, Michael P. Doyle, Cathy A. Brown |
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| Rok vydání: | 2000 |
| Předmět: |
Dietary Fiber
Rumen Time Factors animal structures Colony Count Microbial Biology Escherichia coli O157 medicine.disease_cause Microbiology Abomasum Cattle feeding Feces Animal science medicine Animals Escherichia coli chemistry.chemical_classification Fatty acid Hydrogen-Ion Concentration biology.organism_classification Animal Feed Diet chemistry Fermentation Cattle Bacteria Food Science |
| Zdroj: | Journal of Food Protection. 63:1630-1636 |
| ISSN: | 0362-028X |
| Popis: | Calves inoculated with Escherichia coli 0157:H7 and fed either a high-roughage or high-concentrate diet were evaluated for rumen proliferation and fecal shedding of E. coli O157:H7. Calves fed the high-roughage diet had lower mean rumen volatile fatty acid concentrations and higher rumen pH values than did calves fed the high-concentrate diet. Despite these differences in rumen conditions, the calves fed the high-roughage diet did not have greater rumen populations of E. coli 0157: H7 and did not exhibit increased or longer fecal shedding compared with the calves fed the high-concentrate diet. Two calves shedding the highest mean concentrations of E. coli O157:H7 were both fed the high-concentrate diet. There was a significant (P < 0.05) positive correlation between fecal shedding and rumen volatile fatty acid concentration in calves fed a high-concentrate diet. The effects of diet on E. coli 0157:H7 proliferation and acid resistance were investigated using an in vitro rumen fermentation system. Rumen fluid collected from steers fed a high-roughage diet, but not from steers fed a high-concentrate diet, supported the proliferation of E. coli O157:H7. Rumen fluid from steers fed a high-concentrate diet rapidly induced acid resistance in E. coli O157:H7. The impact of diet on fecal shedding of E. coli 0157:H7 is still unclear and may depend on dietary effects on fermentation in the colon and on diet-induced changes in the resident microflora. However, rapid development of acid tolerance by E. coli 0157:H7 in the rumens of calves fed high-concentrate diets, allowing larger populations to survive passage through the acidic abomasum to proliferate in the colon, may be one factor that influences fecal shedding in cattle on feed. |
| Databáze: | OpenAIRE |
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