DOI: 10.11118/nutrinet2026_010

THE EFFECT OF (QUEBRACHO) TANNINS ON METABOLICAL PROCESSES IN THE RUMEN DURING SIMULATED DIGESTION IN BIOREACTOR (IN VITRO)

Filip Kupča¹, Ludmila Křížová¹, Kateřina Dadáková¹, Tomáš Kašparovský¹

¹ Department of Biochemistry, Faculty of Science, Masaryk University, Kotlářská 267/2, 611 37 Brno, Czech Republic

The present study investigated the effect of dietary tannins on ruminal fermentation parameters using a continuous in vitro bioreactor system (Sartorius Biostat A plus Bioreactor System). The experiment was carried out in the form of a cross-over design and compared a control diet with a tannin-enriched diet supplemented with 5 % of quebracho tannins. The incubation lasted 16 days, during which each diet was fed for 8 days, consisting of 5 days of adaptation followed by 3 days of sampling. The incubations were repeated three times. The results demonstrated that tannin supplementation increased pH, altered redox potential, and significantly reduced dry matter digestibility. Furthermore, a marked decrease in volatile fatty acid (VFA) concentrations was observed, although the acetate-to-propionate ratio remained unaffected. These findings indicate that tannins primarily suppress rumen fermentation by limiting substrate degradation and microbial activity, thereby influencing overall fermentation efficiency.

Keywords: in vitro rumen fermentation; gas chromatography; pH; redox potential; digestibility; volatile fatty acids

pages: 87-95, online: 2026