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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #315826
Title: Effect of thymol-ß-D-glucopyranoside on Salmonella and E. coli in the weaned pig gut

Author
item Anderson, Robin
item LEVENT, GIZEM - Istanbul University
item He, Louis
item Genovese, Kenneth - Ken
item CIFTCIOGLU, GURHAN - Istanbul University
item Beier, Ross
item Hume, Michael
item Harvey, Roger
item Nisbet, David

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/22/2015
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The gut of food-producing animals is a reservoir for human foodborne pathogens. Thymol is bactericidal against pathogens including Salmonella and E. coli, but its rapid absorption from the proximal gut reveals a need for protective technologies to deliver effective concentrations to the lower gut where the pathogens mainly colonize. Thymol-ß-D-glucopyranoside is more resistant to absorption than free thymol in everted jejunal segments and because of its ß-glycosidic bond could function as a prebiotic, being undegradable in the proximal gut but hydrolysable by microbial ß-glycosidases in the distal gut. This study was conducted to determine if oral administration of thymol-ß-D-glucopyranoside could reduce gut colonization of Salmonella and E. coli in pigs. Eighteen weaned pigs (24±5 kg live body weight) were orally infected with 2x10^9 CFU of a novobiocin and naladixic acid resistant Salmonella Typhimurium upon arrival (11:00) to the rearing facility and randomly allocated to 6 pens (3 pigs/pen) and twice-treated via oral gavage (2 pens/treatment) that same day (16:00 and 21:00) with 0, 1X, or 3X thymol-ß-D-glucopyranoside (x=6 mg/kg body weight). Pigs were euthanized 12 h after the last treatment, and cecal and rectal contents collected at necropsy were diluted and plated to MacConkey agar for enumeration of generic E. coli and to Brilliant Green agar supplemented with 25 and 20 µg novobiocin and naladixic acid/mL, respectively, for enumeration of the challenge Salmonella. Counts were log transformed and analyzed for effects of treatment using a 2x3 factorial design. Cecal, but not rectal, concentrations of the challenge Salmonella were reduced in a dose dependent fashion by treatment (P<0.05), averaging (±SD) 3.5±1.1, 3.2±1.2, and 2.4±1.1 log10 CFU/g in cecal contents and 3.6±1.6, 3.0±1.3, and 2.8±1.3 log10 CFU/g from rectal contents. The lack of a significant effect of thymol-ß-D-glucopyranoside on rectal Salmonella suggests that hydrolysis of ß-glycosidic bond may have been too rapid to allow its escape from the cecum. Neither cecal nor rectal concentrations of wildtype E. coli were affected by treatment (P>0.05), averaging 6.1±0.7 and 7.0±0.7 log10 CFU/g, respectively. The lack of an effect of thymol-ß-D-glucopyranoside on cecal or rectal E. coli concentrations is consistent with observations from an earlier study where Campylobacter jejuni but not E. coli was significantly reduced in the crop of broilers orally-treated with thymol-ß-D-glucopyranoside. Similarly, in vitro studies have indicated that E. coli may be less sensitive to thymol than some other bacteria. These results provide evidence that thymol-ß-D-glucopyranoside may be an effective prebiotic to bypass absorption and degradation in proximal gut but further studies are needed to optimize dosages and administration procedures to yield a practical and economically viable feed additive to reduce carriage of important foodborne pathogens in food-producing animals.