Effect of intrinsic tannins on the fermentation quality and as-sociated with the bacterial and fungi community of sainfoin silage
Sainfoin (Onobrychis viciifolia) is a legume rich in condensed tannins. Condensed tannins function includes inhibit bacterial and fungi activity, and decreased protein degradation during ensiling process. In order to investigate the effects of condensed tannins on the bacterial and fungi com-munity, and fermentation during sainfoin ensiling, polyethylene glycol (PEG) was used to deac-tivate tannin activity. The results show that the addition of PEG increased dry matter loss (8.32% vs. 14.15%, on a dry matter basis) after 60 d of ensiling, also increased lactic acid (10.90% vs. 15.90%, on a dry matter basis) and acetic acid content (7.32% vs. 13.85%, on a dry matter basis) after 30 d of ensiling. PEG treated group increased the Pediococcus relative abundance (0.37%–3.38% vs. 7.82%–23.5%,) during the ensiling process. PEG treated group increased Gibellulopsis relative abundance after 3 d of ensiling (5.96% vs. 19.52%), Vishniacozyma relative abundance af-ter 3 d and 7 d of ensiling (2.36% vs. 17.02%, 3.65% vs. 17.17%), and increased Aspergillus rela-tive abundance after 7 d ,14 d and 60 d of ensiling (0.28% vs. 1.32%, 0.49% vs. 2.84% and 1.74% vs. 7.56%). However, PEG treated group decreased Alternaria relative abundance during entire ensiling process (14.00 %–25.21% vs. 3.33%–7.49%). These results suggest that condensed tannins inhibit lactic acid bacteria fermentation by reducing Pediococcus activity, inhibit fungi activity depend on different strains.