Effects of Tannic Acid and Lactic Acid Bacteria on Alfalfa Silage Quality and Ruminal Fermentation in Vitro

To evaluate the potential of tannic acid with or without lactic acid bacteria on alfalfa (Medicago sativa L.) silage quality and ruminal fermentation in vitro, alfalfa at the flowering stage was used as the ensiling material, and was air-dried to a moisture content about 55%. Alfalfa was prepared with four treatments, including no additives (CK), tannic acid (TC), lactic acid bacteria (L) and tannic acid + lactic acid bacteria (TL). The silage samples were obtained after 60 days of ensiling, which were subsequently analyzed for the related indexes of fermentation quality and rumen fermentation characteristics in vitro. The results showed that all additive treatments reduced (P<0.05) the pH value and the content of acetic acid and non-protein nitrogen, while dry matter and true protein content of alfalfa silage was increased significantly (P<0.05). The additive treatments can enhance propionic acid production and microbial protein synthesis in the rumen(P<0.05). In conclusion, the combined addition of tannic acid and lactic acid bacteria has the best effect on modulating alfalfa silage fermentation quality and rumen fermentation in vitro.