State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China; College of Animal Sciences, Shanxi Agricultural University, Taigu 030801, PR China.
State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, PR China; Probiotics and Life Health Research Institute, Lanzhou University, Lanzhou 730000, PR China.
J Hazard Mater. 2024 Nov 5;479:135700. doi: 10.1016/j.jhazmat.2024.135700. Epub 2024 Aug 29.
The study of antibiotic resistance in the silage microbiome has attracted initial attention. However, the influences of lactic acid bacteria inoculants and dry matter (DM) content on antibiotic resistance genes (ARGs) reduction in whole-plant corn silage remain poorly studied. This study accessed the ARGs' risk and transmission mechanism in whole-plant corn silage with different DM levels and treated with Lactiplantibacillus plantarum or Lentilactobacillus buchneri. The macrolide and tetracycline were the main ARGs in corn silage. The dominant species (Lent. buchneri and Lactobacillus acetotolerans) were the main ARGs carriers in whole-plant corn silage. The application of Lent. buchneri increased total ARGs abundance regardless of corn DM. Whole-plant corn silage with 30 % DM reduced the abundances of integrase and plasmid compared with 40 % DM. The correlation and structural equation model analysis demonstrated that bacterial community succession, resulting from changes in DM content, was the primary driving factor influencing the ARGs distribution in whole-plant corn silage. Interestingly, whole-plant corn silage inoculated with Lent. buchneri reduced abundances of high-risk ARGs (mdtG, mepA, tetM, mecA, vatE and tetW) by regulating pathogens (Escherichia coli), mobile genetic elements (MGEs) genes (IS3 and IS1182), and this effect was more pronounced at 30 % DM level. In summary, although whole-plant corn silage inoculated with Lent. buchneri increased the total ARGs abundance at both DM levels, it decreased the abundance of high-risk ARGs by reducing the abundances of the pathogens and MGEs, and this effect was more noticeable at 30 % DM level.
该研究最初关注青贮微生物组中的抗生素抗性。然而，关于乳酸菌接种剂和干物质 (DM) 含量对全株玉米青贮中抗生素抗性基因 (ARGs) 减少的影响仍研究甚少。本研究通过不同 DM 水平的全株玉米青贮和添加植物乳杆菌或戊糖片球菌处理，研究了 ARGs 在全株玉米青贮中的风险和传播机制。大环内酯类和四环素类是玉米青贮中主要的 ARGs。在全株玉米青贮中，优势种（戊糖片球菌和耐酸乳杆菌）是 ARGs 的主要载体。无论玉米 DM 如何，应用戊糖片球菌都会增加总 ARGs 丰度。与 40% DM 相比，30% DM 的全株玉米青贮减少了整合酶和质粒的丰度。相关性和结构方程模型分析表明，由于 DM 含量的变化而导致的细菌群落演替是影响全株玉米青贮中 ARGs 分布的主要驱动因素。有趣的是，全株玉米青贮接种戊糖片球菌通过调节病原菌（大肠杆菌）、移动遗传元件（MGEs）基因（IS3 和 IS1182）降低了高风险 ARGs（mdtG、mepA、tetM、mecA、vatE 和 tetW）的丰度，在 30% DM 水平下效果更为明显。总之，尽管全株玉米青贮接种戊糖片球菌在两个 DM 水平上均增加了总 ARGs 的丰度，但通过降低病原菌和 MGEs 的丰度降低了高风险 ARGs 的丰度，在 30% DM 水平下效果更为明显。
