Wang Siran, Shao Tao, Li Junfeng, Zhao Jie, Dong Zhihao
Institute of Ensiling and Processing of Grass, College of Agro-Grassland Science, Nanjing Agricultural University, Nanjing, China.
Front Microbiol. 2022 Feb 8;13:830888. doi: 10.3389/fmicb.2022.830888. eCollection 2022.
This study aimed to investigate the effect of epiphytic microbiota from alfalfa and red clover on the fermentative products, bacterial community compositions, and their predicted functional characteristics in Italian ryegrass silage. By microbiota transplantation and γ-ray irradiation sterilization, the irradiated Italian ryegrass was treated as follows: (1) sterile distilled water (STIR); (2) epiphytic microbiota on Italian ryegrass (IRIR); (3) epiphytic microbiota on alfalfa (IRAL); and (4) epiphytic microbiota on red clover (IRRC). The irradiated Italian ryegrass was ensiled for 1, 3, 7, 15, 30, and 60 days. STIR had similar chemical components with fresh Italian ryegrass. IRAL had higher lactic acid concentrations [64.0 g/kg dry matter (DM)] than IRIR (22.3 g/kg DM) and IRRC (49.4 g/kg DM) on day 3. IRRC had the lowest lactic acid concentrations (59.7 g/kg DM) and the highest pH (4.64), acetic acid (60.4 g/kg DM), ethanol (20.4 g/kg DM), and ammonia nitrogen (82.6 g/kg DM) concentrations and Enterobacteriaceae [9.51 log cfu/g fresh weight (FW)] populations among treatments on day 60. On days 3 and 60, was dominant in both IRIR (42.2%; 72.7%) and IRAL (29.7%; 91.6%), while was predominant in IRRC (85.2%; 48.9%). IRIR and IRAL had lower abundances of "Membrane transport" than IRRC on day 3. IRIR and IRAL had lower abundances of phosphotransacetylase and putative ATP-binding cassette transporter and higher abundances of arginine deiminase on day 3. IRAL had the highest abundance of fructokinase on day 3. Overall, inoculating epiphytic microbiota from different legume forages changed the fermentative products, bacterial community compositions, and their predicted functional characteristics in Italian ryegrass silage. The microbial factors that result in the differences in fermentative profiles between legume forage and grass were revealed. Knowledge regarding the effect of epiphytic microbiota could provide more insights into the improvement of silage quality.
本研究旨在探讨紫花苜蓿和红三叶草附生微生物群对意大利黑麦草青贮发酵产物、细菌群落组成及其预测功能特性的影响。通过微生物群移植和γ射线辐照灭菌，对辐照后的意大利黑麦草进行如下处理：（1）无菌蒸馏水（STIR）；（2）意大利黑麦草上的附生微生物群（IRIR）；（3）紫花苜蓿上的附生微生物群（IRAL）；（4）红三叶草上的附生微生物群（IRRC）。将辐照后的意大利黑麦草青贮1、3、7、15、30和60天。STIR的化学成分与新鲜意大利黑麦草相似。在第3天，IRAL的乳酸浓度[64.0 g/kg干物质（DM）]高于IRIR（22.3 g/kg DM）和IRRC（49.4 g/kg DM）。在第60天，IRRC的乳酸浓度最低（59.7 g/kg DM），pH值最高（4.64），乙酸（60.4 g/kg DM）、乙醇（20.4 g/kg DM）和氨氮（82.6 g/kg DM）浓度以及肠杆菌科[9.51 log cfu/g鲜重（FW）]数量在各处理中最高。在第3天和第60天， 在IRIR（42.2%；72.7%）和IRAL（29.7%；91.6%）中均占主导地位，而 在IRRC中占优势（85.2%；48.9%）。在第3天，IRIR和IRAL的“膜转运”丰度低于IRRC。在第3天，IRIR和IRAL的磷酸转乙酰酶和假定的ATP结合盒转运蛋白丰度较低，精氨酸脱亚氨酶丰度较高。在第3天，IRAL的果糖激酶丰度最高。总体而言，接种不同豆科牧草的附生微生物群改变了意大利黑麦草青贮的发酵产物、细菌群落组成及其预测功能特性。揭示了导致豆科牧草和禾本科牧草发酵谱差异的微生物因素。关于附生微生物群作用的知识可为提高青贮质量提供更多见解。
