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Feeding Supplemental Dried Distiller’s Grains Increases Faecal Shedding of Escherichia coli O157 in Experimentally Inoculated Calves
Author(s) -
Jacob M. E.,
Parsons G. L.,
Shelor M. K.,
Fox J. T.,
Drouillard J. S.,
Thomson D. U.,
Renter D. G.,
Nagaraja T. G.
Publication year - 2008
Publication title -
zoonoses and public health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.87
H-Index - 65
eISSN - 1863-2378
pISSN - 1863-1959
DOI - 10.1111/j.1863-2378.2008.01115.x
Subject(s) - feces , caecum , inoculation , escherichia coli , biology , zoology , nalidixic acid , veterinary medicine , eimeria , microbiology and biotechnology , medicine , immunology , biochemistry , gene
Summary Escherichia coli O157 is an important foodborne pathogen and asymptomatic cattle serve as major reservoirs for human infection. We have shown a positive association between feeding distiller’s grains and E. coli O157 prevalence in feedlot cattle. The objective of this study was to determine the effect of feeding dried distiller’s grain (DDG) on faecal shedding of E. coli O157 in calves experimentally inoculated with E. coli O157. Holstein calves (five per treatment group), fed steam‐flaked corn‐based high‐grain diets supplemented with 0% (control) or 25% DDG, were orally inoculated with a five‐strain mixture (6 × 10 9 CFU/calf) of nalidixic acid‐resistant ( Nal R ) E. coli O157. Faecal samples were taken three times per week for 6 weeks to determine the prevalence and concentration of Nal R E. coli O157. At the end of the study (day 43), calves were euthanized and necropsied. Ruminal, caecum, colon, and rectal contents, and rectoanal mucosal swab (RAMS) samples were collected at necropsy to determine Nal R E. coli O157 concentration. There was a trend for an interaction between treatment and faecal sampling day. The concentration of Nal R E. coli O157 in the faeces was significantly higher in faecal samples from calves fed DDG compared with control calves on days 35, 37, 39 and 42. At necropsy, the concentration of Nal R E. coli O157 was higher in the caecum ( P = 0.01), colon ( P = 0.03) and rectum ( P = 0.01) from calves fed DDG compared with control animals. The number of sites at necropsy positive for Nal R E. coli O157 was higher in calves fed DDG compared with calves in the control treatment ( P < 0.001). Our results indicate that E. coli O157 gut persistence and faecal prevalence increased in calves fed DDG, which potentially have important implications for food safety.