Lactobacillus casei TH14 and Hydrolysable Tannin as Corn Silage Additives Modify In Vitro Rumen Fermentation and...

This study evaluated L. casei TH14 (TH14) and two levels of hydrolysable tannin (HT; sweet chestnut, Castanea sativa) as corn ensiling additives, hypothesising that their combination would improve fermentation quality and reduce in vitro CH₄. Whole-plant corn was ensiled for 21 days in a completely randomised design (seven treatments, four replicates) combining Molasses, TH14, and HT at 20 or 40 g/kg DM. Silage pH was significantly affected by treatment (p < 0.01), with T4 reaching the lowest final pH (3.83), whereas the primary nutrients (DM, OM, CP, and NDF) were unchanged (p > 0.05). Hydrolysable tannin reduced ruminal NH₃-N at 24 h (11.12 vs. 13.06 mg/dL; p < 0.05) and, at 40 g/kg DM, lowered CH₄ by 50.0% at 24 h (2.45 vs. 4.90 mL/g DM; p < 0.01) in a dose-dependent manner, accompanied by a higher propionate proportion and a lower acetate-to-propionate ratio (p < 0.01). Independent of tannin, TH14 reduced CH₄ by 12.7% (p < 0.05). Digestibility was transiently reduced at 24 h but unaffected at 48 h (p > 0.05). Corn silage with HT at 40 g/kg DM, alone or combined with TH14, is a promising strategy to mitigate CH₄ without impairing nutrient digestibility.