Abstract: To explore the effect of formic acid (FA) treatments on silage quality of hempleaf nettle, freshly-harvested plants were treated without FA (control), with 2 mL穔g^-1 FA (FA-low), 4 mL穔g^-1 FA (FA-med), and 6 mL穔g^-1 FA (FA-high) of fresh weight, respectively. There were 15 silage replicates per treatment. All bags were stored indoors at room temperature for 60 days. Chemical composition, in vitro digestibility and fermentative parameters of the products after 0, 3, 5, 15, 20, and 60 days of ensiling were assessed. Results showed that nettle untreated or treated with 2~4 mL穔g^-1 FA produced badly preserved silage while those treated with 6 mL穔g^-1 FA significantly reduced the pH value, ammonia-N and butyric acid concentrations of silage. Not improved fermentation quality for silage preservation was seen. It also had a significantly higher dry matter, water-soluble carbohydrate (WSC) and in vitro digestibility of NDF than the control silage. Medium and high FA treatments tended to have a lower fiber fraction (P=0.132; P=0.087) than the control, indicating that fresh forage with 6 mL穔g^-1 FA could improve utilization of fiber fractions. These results contribute information for producing improved silages of nettles and other forages with high moisture and protein contents.

Key words: Hempleaf nettle, Formic acid, Silage quality

摘要： 为探讨甲酸对麻叶荨麻(Urtica cannabina)发酵品质和青贮保存效果的影响,设置2, 4, 6 mL·kg^-1 FM共3个甲酸添加剂处理(分别为低、中、高水平),以不添加甲酸处理为对照,室温袋贮60 d后开封取样,测定其pH值、化学成分、体外消化率和乳酸含量,分析评价其发酵品质及保存效果。结果表明:无甲酸处理或添加2~4 mL·kg^-1甲酸青贮麻叶荨麻,其青贮品质和保存效果很差;添加高剂量(6 mL·kg^-1)甲酸虽然同样未能生产出品质优良的青贮饲料,但显著降低了pH值、乳酸含量和氨态氮(P<0.05),有降低纤维组分的趋势(P=0.132; P=0.087),显著增加了干物质、可溶性糖含量和中性洗涤纤维体外消化率(P<0.05),有利于改善发酵品质和提高植物细胞壁利用效率。试验结果将为荨麻属植物及与之类似的高水分、高蛋白质牧草青贮技术提供基础数据。

关键词: 麻叶荨麻, 甲酸, 青贮品质