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United States Department of Agriculture

Agricultural Research Service

Research Project: INTERVENTIONS TO REDUCE FOODBORNE PATHOGENS IN SWINE AND CATTLE

Location: Food and Feed Safety Research

Title: Comparative effect of thymol or its glucose conjugate, thymol-beta-D-glucopyranoside on Campylobacter in avian gut contents

Authors
item Epps, Sharon -
item Harvey, Roger
item Byrd, James
item Petrujkic, Branko -
item Sedej, Ivana -
item Beier, Ross
item Phillips, Timothy -
item Hume, Michael
item Anderson, Robin
item Nisbet, David

Submitted to: Journal of Environmental Science and Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 10, 2014
Publication Date: N/A

Interpretive Summary: Campylobacter is a bacterium found in animals, poultry, and edible products from food-producing animals. Human consumption of Campylobacter-contaminated food (particularly undercooked chicken) is responsible for more human cases of foodborne disease in the United States than any other bacteria, including Salmonella. Because of the human disease associated with this organism, the poultry industry and the medical community have a high priority to reduce the presence of this bacterium in food products. New non-antibiotic treatments are needed. In the present study, thymol and thymol-related compounds decreased Campylobacter in broiler chickens. This treatment is important because, if successfully adopted by the poultry industry, it could improve the wholesomeness of poultry, reduce the use of antibiotics in animal agriculture, and save billions of dollars spent for medical care of patients affected by disease from Campylobacter.

Technical Abstract: Campylobacter jejuni is an important human foodborne pathogen that can contaminate meat and poultry during processing. Consequently, strategies are sought to reduce the carriage of C. jejuni in animals before they arrive to the abattoir. Thymol is a natural product that reduces survivability of Campylobacter in vitro, but its rapid absorption from the proximal alimentary tract likely limits its bactericidal efficacy in vivo. Thymol-ß-D-glucopyranoside is more resistant to absorption than free thymol, but its administration to chickens has not been reported. In the present studies, 1 mM thymol-ß-D-glucopyranoside was shown to exhibit near equal anti—Campylobacter activity as 1 mM thymol when incubated anaerobically in avian crop or cecal contents in vitro, resulting in reductions of 1.10 to 2.32 log10 colony forming units mL-1 in C. jejuni concentrations after 24 h incubation. In a follow up live animal study, oral administration of thymol-ß-D-glucopyranoside, but not free thymol, significantly lowered (> 10—fold) recovery of Campylobacter from the crop of market—aged broilers when compared to placebo—treated controls (n = 6 broilers/treatment). Neither thymol-ß-D-glucopyranoside or thymol affected recovery of Campylobacter from cecal contents of the treated broilers. These results indicate that rapid absorption or passage of free thymol from the crop precluded its anti—Campylobacter activity at this site and throughout the entire gastrointestinal tract. Conversely, lower recovery of Campylobacter from the crop of birds treated with thymol-ß-D-glucopyranoside indicates this conjugate was retained and able to be hydrolyzed to biologically active free thymol at this site as intended yet was not sufficiently protected to allow passage of efficacious amounts of the intact glycoside to the lower gut. Nevertheless, these results warrant further research to see if higher doses or additional encapsulation of thymol-ß-D-glucopyranoside or similar glycosides may yield an efficacious additive to reduce carriage of Campylobacter as well as other pathogens throughout the avian gut.

Last Modified: 10/21/2014
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