Effects of Mongolian Bergenia crassifolia L. (root) extract on rumen methane emission and microbial community.

Objective: The study aims to research the effects of Mongolian plants on reducing methane emissions, fermentation parameters, and microbial communities in grazing systems.

Methods: Initially, various Mongolian plants were screened to assess their ability to reduce methane production in an in vitro experiment. The most effective plant was selected for extracting active components, and their concentrations were determined. In vitro rumen fermentation used rice straw and alfalfa as substrates. Extract were added at 0%, 1%, 2%, 3%, 4%, and 5% of dry matter. Measured parameters included gas production, methane production, and rumen fermentation parameters. After the fermentation experiments, we extracted DNA from the rumen fluid for quantitative PCR and 16S high-throughput sequencing analysis.

Results: Bergenia crassifolia L. exhibited the most significant methane reduction, its root extract containing approximately 70% condensed tannin, decreased methane production in the rice straw substrate (p<0.01). The 5% addition also showed notable effcacy in the alfalfa substrate (p<0.01). Furthermore, 1% addition of the extract had no significant effect on rumen fermentation parameters. Ruminococcus and Christensenellaceae R-7 were emerged as key methane-reducing taxa (p<0.01).

Conclusion: Bergenia crassifolia L. (root) extract demonstrated stronger methane reduction efficacy in low-quality roughage compared to high-quality roughage, with 1% being the optimal dose. This finding suggests Bergenia crassifolia L. potential as a new strategy for sustainable rumen methane mitigation in grazing systems.