Effects of Thymol and Thymol α-D-Glucopyranoside on Intestinal Function and Microbiota of Weaned Pigs

Abstract

The present study evaluated gluco-conjugation as a measure to delay thymol absorption and enhance its antimicrobial activity in the gut of weaned piglets. The three dietary treatments consisted of a basal diet without additives (TCON), supplemented with thymol at 3.7 mmol/kg dry matter (TTHY), or with an equimolar amount of thymol α-D-glucopyranoside (TTαG). Each dietary treatment was replicated in 6 pens with 2 piglets per pen (n = 12 for analytical parameters) and was supplemented for 14 days. The total (free plus gluco-conjugated) thymol concentrations in the stomach contents were 14% lower in TTαG as compared to TTHY piglets. Neither of the additives could be detected further down the gut. E.coli counts in the proximal small intestine were significantly lower in TTHY than in TTαG pigs (3.35 vs. 4.29 log10 CFU/g); however, other bacterial counts and their metabolites were unaffected by treatment. A metagenomic bacterial analysis revealed a great relative abundance of Lactobacillus spp. in the distal small intestine (range 88.4–99.9%), irrespective of treatment. The intestinal barrier function was improved by TTHY, but not TTαG, compared to TCON. In conclusion, gluco-conjugation did not result in higher thymol concentrations in the gut, but conversely, it seemed to diminish the biological effects of thymol in vivo.

Effects of essential oil mixtures on nitrogen metabolism and odor emission via in vitro simulated digestion and in vivo growing pig experiments

“…It is reported that when feeding weaned pigs with unprotected thymol, around 75% free thymol appears in the stomach, and thymol is hardly detected in the small intestine 26 . Even though thymol is undetectable in the small intestine, weaned pigs with thymol supplementation have a lower diarrhea incidence and less watery feces compared to control pigs 27 . Compositions of gut microbiota are modulated in these thymol‐fed pigs as well.…”

Bioactive compounds, antibiotics and heavy metals: Effects on the intestinal structure and microbiome of monogastric animals – a non-systematic review

“…Studies involving pigs revealed that a mix of thyme and peppermint essential oils and a plant extract of oregano had a positive effect on the microbiological profile of the large intestine, which was manifested by a significant increase in the count of probiotic bacteria (Ruzauskas et al, 2020). Thymol fed to piglets decreased the count of Escherichia coli in the proximal part of the small intestine compared to control piglets (Van Noten et al, 2020).…”

The Effect of Amino Acids on Production of SCFA and bCFA by Members of the Porcine Colonic Microbiota

“…The mid-colon refers to a 20-cm section cranial to the end of the centripetal coils of the colon. After weaning, the pig was fed a cereal-soy-based weaner (2 weeks) and starter (4 weeks) diet without antimicrobial growths promoters or probiotics until collection (Table 1 in Van Noten et al, 2020 [24]). After euthanasia, the abdominal cavity of the pig was opened, and the mid-colonic section was clamped with forceps and excised.…”