添加剂对苜蓿青贮料品质和乳酸菌群的影响

Effects of Different Additives on Medicago sativa Silage Quality and the Lactic Acid Bacterial Community

以紫花苜蓿(Medicago sativa)为原料,分别添加植物乳杆菌WN5(Lactobacillus plantarum WN5,保藏号为CGMCC NO.7469)和干酪乳杆菌SN3(L.casei SN3,CGMCC NO.7470)的菌液,以及菌液与蔗糖、纤维素酶的混合液后青贮,探讨添加剂对苜蓿青贮料品质和乳酸菌群的影响。结果表明:苜蓿直接青贮发酵品质差;添加剂可改善苜蓿青贮料的发酵品质;添加乳酸菌和蔗糖对于苜蓿青贮饲料的营养价值和乳酸菌群有更明显的改善,青贮饲料中乳酸菌群占绝对优势,植物乳杆菌WN5和其他乳酸菌存活,但乳酸菌种类因蔗糖浓度不同而有差异;添加10mL乳酸菌和2.0g蔗糖的效果最好,其苜蓿青贮饲料的pH最低,粗蛋白、甲酸、乙酸和丙酸的含量最高,乳酸菌群的遗传差异大。乳酸菌和蔗糖作为优质添加剂,在苜蓿青贮发酵过程中可以保留大量不同种类的乳酸菌群,从而有利于形成品质良好的青贮苜蓿。

To determine the effects of bacterial inoculant, sucrose and cellulose enzyme on the ensiling fer- mentation and bacterial community of alfalfa （Medicago sativa） silage, the chemical composition, fermen- tation quality, lactic acid bacteria （LAB） counts and the 16S-23S rDNA internal transcribed spacer （ITS） profiles of LAB in alfalfa silage were determined. The results showed that alfalfa silage was not good with- out additives was added. Additives can improve fermentation qualities and chemical compositions of silage. The additive of Lactohacilli and sucrose improved silage qualities markedly . Specially, the best quality of silage in this study, such as the lowest pH value, the highest contents of crude protein and formic acid and acetic acid and propionic acid, the highest diversity of LAB, was produced by the additive of 10 mL Lacto- bacilli and 2.0 g sucrose. The results suggested that the types of detected LAB varied due to the combina- tion of Lactobacilli with different concentrations of sucrose, which is good to high quality alfalfa silage making.