Comparative effect of thymol or its glucose conjugate, thymol-β-d-glucopyranoside, onCampylobacterin avian gut contents

Abstract

Campylobacter jejuni is an important human food-borne pathogen that can contaminate meat and poultry during processing. Consequently, strategies are sought to reduce the carriage of C. jejuni in food animals before they arrive at the abattoir. Thymol is a natural product that reduces survivability of Campylobacter in vitro, but its rapid absorption from the proximal alimentary tract limits its bactericidal efficacy in vivo. Thymol-β-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-β-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 1.10-2.32 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-β-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-β-D-glucopyranoside nor 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-β-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 encapsulation of thymol-β-D-glucopyranoside or similar glycosides may yield an efficacious additive to reduce carriage of Campylobacter as well as other pathogens throughout the avian gut.

Single components of botanicals and nature-identical compounds as a non-antibiotic strategy to ameliorate health status and improve performance in poultry and pigs

“…As another example, David Nisbet's research group (47) investigated the use of a terpene glycoside form compared with the free form of the same terpene. They observed that the glycoside form showed 60 % higher resistance in absorption in pigs (48) and antimicrobial activity in the crops in poultry (49) . Moreover, Hébert et al (50) demonstrated that the microencapsulation of an aldehyde allowed the delivery of a higher dose, avoiding the acute toxic effects of a bolus dose.…”

Monoterpenes and Their Derivatives—Recent Development in Biological and Medical Applications

“…All derivatives are also better antioxidants than the parent compound [ 30 ]. Thymol- β -D-glucopyranoside 25 exhibits anticampylobacter activity ( Figure 8 ) [ 31 ].…”

Field Interventions Against Colonization of Broilers by Campylobacter

“…Trials with the antimicrobial phytochemical thymol in small groups of naturally colonized slaughter‐age birds showed a reduction of up to 1.5 log 10 units in Campylobacter counts in the crop, but not ceca, of birds dosed 9 hours previously (Epps et al., ). Similar results were obtained when the conjugate thymol‐β‐ᴅ‐glucopyranoside, which is more stable to foregut digestive processes, was used.…”