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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #178428


item Franklin, Sharon
item Carlson, Steven
item Rasmussen, Mark

Submitted to: Conference on Gastrointestinal Function
Publication Type: Abstract Only
Publication Acceptance Date: 2/16/2005
Publication Date: 4/11/2005
Citation: Franklin, S.L., Carlson, S.A., Rasmussen, M.A. 2005. Rumen defaunation using essential oils [abstract]. Conference on Gastrointestinal Function. p. 35.

Interpretive Summary:

Technical Abstract: Research in our laboratory has shown that engulfment and survival within rumen protozoa increases virulence of Salmonella strains carrying the DT104 gene cluster. These strains recovered from a mixed population of rumen protozoa following lysis demonstrated an 8-fold increase in virulence as measured by a tissue culture invasion assay (HEp-2 human carcinoma cells). When inoculated into calves, these bacterial strains caused a more rapid disease progression, including pyrexia (105 F), greater recovery of the bacterial pathogen from lymph nodes and spleen, and a less favorable prognosis resulting in premature euthanasia. These observations have implications for disease pathogenesis, fecal shedding of foodborne pathogens from ruminants, and pathogen reservoir status of the rumen. Periodic defaunation of the rumen could reduce these implications. Research has shown that plant-derived oils can reduce protozoal numbers, but their effectiveness as defaunation agents in the rumen has not been fully examined. We screened nineteen essential oils derived from common culinary spices for anti-protozoal activity using cell integrity and motility as indicators of viability. Of those screened showing substantial anti-protozoal activity, we selected rosemary oil for further study. Increasing concentrations of the essential oil from rosemary decreased protozoal viability and suppressed rumen fermentation as indicated by VFA (volatile fatty acids) production. Of the concentrations tested, 100 ppm had no effect upon VFAs or protozoa whereas 10,000 and 40,000 ppm greatly reduced protozoal viability (90%) and VFA production (70%). Rosemary oil at a concentration of 1,000 ppm was intermediate in effect, resulting in at least a 50% reduction of protozoal viability and a 19% decrease in VFA production.