Abstract: During silage fermentation and aerobic exposure,the growth activity of microorganisms is taking the key role to silage quality and aerobic stability. The aim of this experiment was to investigate the effect of fermentation inhibitors on quality,aerobic stability and microbial population of Leymus chinensis silage. Four groups of L. Chinese silage were set up in the experiment:control group (no additives),propionic acid addition group (0.2 % FM),sodium benzoate addition group (0.2 % FM),and potassium sorbate addition group (0.2 % FM),with three replicates in each group at room temperature after cut-up and bagging-off,and sampled for analysis at 60 d and then 8 d of aerobic exposure. The results showed that propionic acid was effective in the enhancement of the dry matter,soluble sugars,acetic acid and propionic acid content of L. chinensis silage,reducing its pH value and ammonia nitrogen content,and suppressing the number of yeast and aerobic bacteria in the silage during the fermentation and aerobic exposure. Under this test condition,the addition of the tested fermentation inhibitors were all effective in improving silage quality and aerobic stability,but the effects were in descending order of propionic acid,potassium sorbate and sodium benzoate. By using fermentation inhibitors,the risk of secondary fermentation and aerobic deterioration of L. chinensis silage can be effectively reduced,and the utilization rate of silage and the health of livestock can be guaranteed.

Key words: Leymus chinensis, Silage, Fermentation inhibitor, Aerobic stability

摘要： 在青贮饲料发酵和有氧暴露期间，微生物的生长活动是影响青贮品质和有氧稳定性的关键。为了研究发酵抑制剂对羊草青贮品质、有氧稳定性和微生物数量的影响，设置4个处理组，分别为对照组(无添加剂)、丙酸组(0.2% FM)、苯甲酸钠组(0.2 % FM)、山梨酸钾组(0.2 % FM)，每组3个重复，切碎羊草袋装青贮，在室温青贮60 d和有氧暴露8 d时取样分析。结果显示，在发酵和有氧暴露过程中，丙酸能有效提高羊草青贮的干物质、可溶性糖、乙酸和丙酸含量，降低pH值和氨态氮含量，减少酵母菌和好气性细菌的数量。在本试验条件下，添加发酵抑制剂均能有效改善青贮品质和有氧稳定性，但作用效果由高到低依次为丙酸、山梨酸钾和苯甲酸钠。通过使用发酵抑制剂，能有效降低青贮饲料二次发酵和有氧变质的风险。

关键词: 羊草, 青贮, 发酵抑制剂, 有氧稳定性