中文摘要：

在实验室条件下以老芒麦（Elymus sibiricns L．）为原料，设置对照（CK）、青宝Ⅱ号（FS）、植物乳杆菌（LP）、布氏乳杆菌（LB）、丙酸（PAT）、青宝Ⅱ号＋丙酸（FS＋PAT）、植物乳杆菌＋丙酸（LP＋PAT）、布氏乳杆菌＋丙酸（LB＋PAT）等8个处理探讨乳酸菌和丙酸对青贮饲料发酵品质和营养成分的影响。结果表明：乳酸菌和丙酸单独处理能够降低青贮饲料pH值和AN／TN比值，增加乳酸含量和挥发性脂肪酸含量，提高可溶性碳水化合物含量，降低酸性洗涤纤维含量，改善老芒麦青贮饲料发酵品质和营养成分；FS＋PAT处理能够改善老芒麦青贮饲料营养成分，LP＋PAT处理和LB＋PAT处理能够改善老芒麦青贮饲料的发酵品质。

英文摘要：

In this paper, the experiment took Elymus sibiricns L. as raw material to study the effect of adding propionic acid, lactic acid bacteria, and their combination on the fermentation quality and chemical composition of Elymus sibiricns L. Silage. The treatment was detailed as follows： the control group （CK）, FAST SILE （FS）, Lactobacillus plantarum （LP）, Lactobacillus buchneri （LB）, propionic acid （PAT）, FS ＋ PAT, LP ＋ PAT, LB ＋ PAT. The results showed that： the treatment by adding lactic acid bacteria and propionic acid separately can improve the fermentation quality and chemical composition of the silages because that pH value and ammonia nitrogen/total ni- trogen （AN/TN） of Elymus sibiricns L. Silages tended to decrease, lactic acid and volatile fatty acid content increased with high levels of dry matter content and water soluble carbohydrate content and low acid detergent fiber content ; FS ＋ PAT treatment can improve the chemi- cal composition of the silages, both LP ＋ PAT treatment and LB ＋ PAT treatment can improve the fermentation quality and chemical compo- sition of the silages.