同/异质型乳酸菌添加对苏丹草青贮酵母菌群落结构及发酵品质的影响

Effect of homo-and hetero-fermentative lactic acid bacteria on yeast community structure and fermentation characteristics during the silage process of Sudangrass

为探讨同/异质型乳酸菌添加对苏丹草青贮过程中酵母菌群落结构及发酵品质的影响,进而改善苏丹草青贮饲料的发酵特性及提高其营养品质。本研究采用真空包装袋作为青贮容器,设置不添加任何菌剂对照(CK),植物乳杆菌(Lactobacillus plantarum, LP),布氏乳杆菌(Lactobacillus buchneri, LB),植物乳杆菌+布氏乳杆菌(LP+LB)4个处理,在苏丹草青贮发酵的1、7、15及60 d进行青贮酵母菌群落结构及发酵品质的测定。结果表明,随着发酵时间的推移,各处理酵母菌种类不同程度的减少,至60 d时,LB和LP+LB处理酵母菌数量在检出限以下;与对照相比,同/异质型乳酸菌添加可显著(P <0.05)降低苏丹草青贮饲料的pH值、丙酸、丁酸、乳酸/乙酸、NH3-N以及酵母菌数量,同时显著(P <0.05)增加乳酸和乳酸菌的数量;V-score评分从高到低为LP> LP+LB> LB> CK。

The overall aim of the study was to provide a theoretical basis for the improvement of the fermentation characteristics and nutritional quality of Sudangrass (Sorghum sudanense) silage. We investigated the effect of homo- and hetero-lactic acid bacteria on yeast community structure and fermentation characteristics during the silage process of Sudangrass. The control (CK) had no added inoculant;the LP group contained Lactobacillus plantarum;the LB group contained L. buchneri;and the LP + LB group contained L. plantarum and L. buchneri. All additives were added to Sudangrass and sealed in a vacuum bag. The indices of chemical characteristics, fermentation characteristic, microbial populations, and species were analyzed to evaluate the dynamic change of the yeast community and fermentation characteristics during 1, 7, 15, and 60 days. The results showed that yeast species decreased in all of the treatments during fermentation, and the number of yeast was below the limit of detection in the LB and LP + LB groups after 60 day.Compared with CK, the addition of the homo- and hetero-lactic acid bacteria can significantly decrease pH, propionic acid, butyric acid, ratio of lactic acid to acetic acid, NH3-N, and number of yeast species, and significantly increase lactic acid and the number of lactic acid bacteria (P < 0.05). The treatment V-score was ranked in the order: LP > LP + LB > LB > CK.