Data_Sheet_2_Bacterial Community and Fermentation Quality of Ensiling Alfalfa With Commercial Lactic Acid Bacterial Additives.PDF

The aim of this study was to determine the effects of six common commercial lactic acid bacteria (LAB) additives [A1, Lactobacillus plantarum, L. buchneri, and Enterococcus faecalis; A2, L. plantarum and L. casei; A3, L. plantarum and L. buchneri; A4, L. plantarum, L. buchneri, L. casei, and Pediococcus acidilactici; A5, L. plantarum (producing feruloyl esterase); and A6, L. buchneri, P. acidilactici, β-glucanase, and xylanase] on the bacterial community and fermentation quality of alfalfa silage. Alfalfa was harvested at the squaring stage, wilted in the field for 24 h, and ensiled without any additives (Control) or with A1, A2, A3, A4, A5, or A6. Microbial counts, bacterial community, fermentation parameters, and nutritional composition were determined after ensiling for 90 days. The total abundance of LAB genera on alfalfa pre-ensiling was 0.38% in bacterial community. The abundances of Lactobacillus, Enterococcus, and Pediococcus in the Control silage were 42.18, 40.18, and 8.09% of abundance, respectively. The abundances of Lactobacillus in A1-, A2-, A3-, A4-, and A5-treatments were 89.32, 92.93, 92.87, 81.12, and 80.44%, respectively. The abundances of Pediococcus and Lactobacillus in A6-treatment were 70.14 and 24.86%, respectively. Compared with Control silage, LAB-treated silage had lower pH and less ammonia nitrogen and water-soluble carbohydrates concentrations (p < 0.05). Further, the A5- and A6-treatments contained lower neutral detergent fiber, acid detergent fiber, and hemicellulose than other treatments (p < 0.05). Overall, LAB genera were presented as minor taxa in alfalfa pre-ensiling and as dominant taxa in alfalfa silage. Adding LAB additives improved the fermentation quality and altered the bacterial community of alfalfa silage. The main bacterial genera in Control silage were Lactobacillus, Enterococcus, and Pediococcus. Lactobacillus dominated the bacterial communities of A1-, A2-, A3-, A4-, and A5-treatments, while Pediococcus and Lactobacillus were dominant bacterial genera in A6-treatment. Inoculating A5 and A6 degraded the fiber in alfalfa silage. It is necessary to ensile alfalfa with LAB inoculants.

本研究旨在探究6种商用常见乳酸菌（lactic acid bacteria, LAB）添加剂对苜蓿青贮的细菌群落与发酵品质的影响，该6种添加剂具体组成为：A1（植物乳杆菌（Lactobacillus plantarum）、布氏乳杆菌（Lactobacillus buchneri）与粪肠球菌（Enterococcus faecalis））；A2（植物乳杆菌与干酪乳杆菌（Lactobacillus casei））；A3（植物乳杆菌与布氏乳杆菌）；A4（植物乳杆菌、布氏乳杆菌、干酪乳杆菌与乳酸片球菌（Pediococcus acidilactici））；A5（产阿魏酸酯酶的植物乳杆菌）；A6（布氏乳杆菌、乳酸片球菌、β-葡聚糖酶与木聚糖酶）。试验于现蕾期收获苜蓿，经田间萎蔫24 h后，设置不添加任何添加剂的对照组（Control）以及添加A1至A6的处理组进行青贮发酵，青贮90天后，对各组样品的微生物数量、细菌群落结构、发酵参数与营养组成进行测定。青贮前苜蓿样品中乳酸菌属的总相对丰度占细菌群落的0.38%，对照组青贮样品中，乳杆菌属、肠球菌属与片球菌属的相对丰度分别为42.18%、40.18%与8.09%；A1、A2、A3、A4、A5处理组的乳杆菌属相对丰度依次为89.32%、92.93%、92.87%、81.12%与80.44%，A6处理组的片球菌属与乳杆菌属相对丰度分别为70.14%与24.86%。与对照组青贮相比，添加乳酸菌添加剂的青贮样品pH值更低，氨态氮与水溶性碳水化合物浓度也更低（p < 0.05）；此外，A5与A6处理组的中性洗涤纤维、酸性洗涤纤维与半纤维素含量均低于其余处理组（p < 0.05）。总体而言，乳酸菌属在青贮前的苜蓿样品中为稀有类群，而在苜蓿青贮中则为优势类群；添加乳酸菌添加剂可改善苜蓿青贮的发酵品质，并改变其细菌群落结构。对照组青贮的核心细菌属为乳杆菌属、肠球菌属与片球菌属，A1至A5处理组的细菌群落均以乳杆菌属为优势类群，而A6处理组的优势细菌属为片球菌属与乳杆菌属；接种A5与A6可降解苜蓿青贮中的纤维组分，综上，使用乳酸菌接种剂进行苜蓿青贮具有必要性。