Abstract: This experiment was conducted to study the dynamic changes of the quality and enzyme activity of mixed silage of oats （Avena sativa） and vetch （Vicia sativa） after lactic acid bacteria addition in alpine pastures. In this experiment， a mixture of oats and vetch were silaged with two lactic acid bacteria additives [Lactobacillus plantarum （CI）， Lactobacillus plantarum （6H2）]， and quality and enzyme activity were determined at 7， 14， 45 and 90 d of silage， using direct silage as control （CK）. The results showed that pH and ammoniacal nitrogen content of the 6H2 and CI groups were significantly lower than that of the CK group at all silage time points （P<0.05）. At 45 and 90d of silage， lactic and acetic acid contents of 6H2 group were significantly higher than those of CI and CK groups； pH values were significantly lower than those of CI and CK groups （P<0.05）. Dry matter and crude protein contents were significantly higher （P<0.05） in the 6H2 and CI groups than in the CK group at all silage time points. Acid protease activity was significantly higher in the 6H2 group than in the CI and CK groups at 45 and 90 d of silage （P<0.05）. Accordingly， lactic acid bacteria 6H2 and CI improved the nutrient composition， fermentation quality and enzyme activity of mixed oat and vetch silage to a certain extent， and lactic acid bacteria 6H2 showed superior fermentation quality and nutrient optimisation in mixed oat and vetch silage， which is suitable for being used as silage additives in alpine pasture area.

Key words: Oats, Vetch, Mixed silage, Low-temperature-resistant lactic acid bacteria, Silage quality, Enzyme activity

摘要： 本研究旨在探讨乳酸菌添加剂对高寒牧区燕麦（Avena sativa）与箭筈豌豆（Vicia sativa）混合青贮品质及酶活性的动态变化规律。本试验将燕麦和箭筈豌豆混合青贮，采用了2种乳酸菌添加剂[植物乳杆菌（CI）、植物乳杆菌（6H2）]，以直接青贮为对照（CK），青贮7，14，45和90 d时测定其品质和酶活性。结果表明：6H2与CI组pH值和氨态氮含量在各个青贮时间点均显著低于CK组（P<0.05）。青贮45和90 d时，6H2组的乳酸和乙酸含量显著高于CI，CK组；pH值显著低于CI，CK组（P<0.05）。在各个青贮时间点6H2，CI组干物质和粗蛋白含量显著高于CK组（P<0.05）。6H2组在青贮45和90 d时，酸性蛋白酶活性显著高于CI，CK组（P<0.05）。因此，乳酸菌6H2和CI改善了燕麦与箭筈豌豆混合青贮的营养成分，发酵品质和酶活性。乳酸菌6H2在高寒牧区燕麦与箭筈豌豆混合青贮中表现出更优越的发酵品质和营养成分优化效果，适宜作为该地区青贮饲料添加剂。

关键词: 燕麦, 箭筈豌豆, 混合青贮, 耐低温乳酸菌, 青贮品质, 酶活性