Reductions in antimicrobial usage in broiler diets resulted in a search for alternative ways to establish beneficial microbiota in chickens to ensure optimal gut health and performance. Amongst the most popular alternatives are phytogenic products. Berberine, an alkaloid isolated from medicinal plants like Coptis chinensis, is a potential candidate with antimicrobial and anti-inflammatory effects, although the mechanism of action is still poorly understood. One of the possible mechanisms is related to its transformation in the gut into several berberine-derived bioactive metabolites. The extent to which the gut microbiota is involved in the metabolism of berberine and whether the berberine-derived metabolites can influence gut health remain to be determined.
How we investigated or researched the problem
Berberine was supplemented to the feed of broiler chickens for 21 days. Berberine and targeted berberine metabolites were quantified in plasma samples using a validated LC-MS/MS method. To characterize the effect of in-feed berberine and resulting metabolites on the intestinal morphology, villus length, crypt depth and area percentage of CD3+ T-cells were measured in duodenal tissue sections and correlated to the plasma concentrations of products. In vitro, different dilutions of caecal content were inoculated in anaerobic conditions in M2GSC medium pH 6 containing 10 µg/mL berberine. Human intestinal epithelial cell lines Caco-2 and T84 were treated with 0.1 µg/mL berberine. Metabolites were measured after 48h incubation in bacterial and cell cultures, to study the contribution of both the microbiota and the intestinal epithelium to berberine metabolism. In addition, to explore Short-Chain Fatty Acids (SCFAs)-induced indirect positive effect on the host, caecal content was incubated with berberine and relevant metabolites in anaerobic conditions, and supernatants were collected after 24h to determine SCFA content by gas chromatography.
Berberine and seven phase-I metabolites were quantified in plasma samples. Berberrubine was one of the most abundant metabolites of berberine in the plasma of chickens and was positively correlated with gut morphology parameters and negatively correlated with CD3+ lymphocyte infiltration in the gut tissue, suggesting an anti-inflammatory effect. Berberrubine was the most abundant metabolite in caecal fermentates in vitro. Berberrubine significantly increased the production of SCFAs in the caecal fermentates. The gut microbiota transformed berberine in berberrubine that could in turn influence the metabolism of the gut microbiota. Intestinal cell cultures displayed a different metabolite profile than the gut microbiota cultures, in which berberrubine was not detected.
Implications / Conclusions
After oral administration, berberine interacts with the gut microbiota and host cells and is transformed into berberine-derived metabolites. Berberrubine seems to be a major metabolite that is selectively generated by intestinal bacteria, and it can influence host health either directly by promoting optimal gut morphology and controlling inflammation, or indirectly, by stimulating the production of SCFAs with known beneficial effects for host cells.
Presented at the 7th International Conference on Poultry Intestinal Health, Cartagena, Colombia, 2022. For information on the next edition, click here.