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United States Department of Agriculture

Agricultural Research Service


item Looper, Michael
item Edrington, Thomas
item Rosenkrans, Charles
item Burke, Joan
item Flores, Rene
item Callaway, Todd
item Aiken, Glen

Submitted to: Western Section of Animal Science Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/13/2005
Publication Date: 6/22/2005
Citation: Looper, M.L., Edrington, T.S., Rosenkrans, C.F., Burke, J.M., Flores, R., Callaway, T.R., Aiken, G.E. 2005. Effects of feeding endophyte-infected tall fescue seed to sheep experimentally infected with Escherichia coli O157:H7. Western Section of Animal Science Proceedings. 56:213.

Interpretive Summary:

Technical Abstract: Objectives were to determine the effects of short-term exposure to endophyte-infected tall fescue seed on fecal shedding and intestinal concentrations of E. coli O157:H7 in sheep. Twelve ewes were fed a diet containing either 50% (DM basis) endophyte-infected (E+) or endophyte-free (E-) tall fescue seed for 7 d. Ewes were experimentally inoculated with E. coli O157:H7 on d 2 of feeding treatment and fecal shedding of inoculated pathogens was monitored daily. On d 7, ewes were euthanized, tissues and contents sampled from the ileum, cecum, and rectum for quantification and qualification of the challenge strain of E. coli O157:H7, and urine collected to determine ergot alkaloid concentrations. Ewes fed E+ seed had lower (P < 0.05) DMI than E- ewes; consequently, E+ ewes lost 0.3 kg/d and E- ewes gained 0.2 kg/d during the 7 d (P = 0.06). Concentrations of urinary ergot alkaloids were increased (P < 0.0001) in ewes fed E+ than E- ewes. Fecal shedding of E. coli O157:H7 was decreased (P < 0.06) in E- ewes compared with E+ ewes. Population of E. coli O157:H7 in luminal contents from the ileum, cecum, and rectum did not differ (P > 0.10) among treatments. Treatment did not influence (P > 0.10) the occurrence of E. coli O157:H7 in cecal or rectal tissues; however, ileum tissues from E+ ewes tended (P = 0.12) to have an increased incidence of E. coli O157:H7. Short-term consumption of endophyte-infected tall fescue seed decreased DMI and subsequent ADG, and increased fecal shedding of E. coli O157:H7 in sheep. Further research is needed to determine if the observed increase in pathogen shedding is caused by ingestion of endophyte-infected tall fescue or alterations in nutrition.

Last Modified: 07/20/2017
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