Agro-Biotechnology Malaysia Institutes (ABI), National Institutes of Biotechnology Malaysia (NIBM), Ministry of Science, Technology and Innovation (MOSTI), c/o MARDI Headquarters, 43400, Serdang, Selangor, Malaysia.
Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
Sci Rep. 2022 May 2;12(1):7107. doi: 10.1038/s41598-022-08819-4.
Silage produced in tropical countries is prone to spoilage because of high humidity and temperature. Therefore, determining indigenous bacteria as potential inoculants is important to improve silage quality. This study aimed to determine bacterial community and functional changes associated with ensiling using amplicon metagenomics and to predict potential bacterial additives associated with silage quality in the Malaysian climate. Silages of two forage crops (sweet corn and Napier) were prepared, and their fermentation properties and functional bacterial communities were analysed. After ensiling, both silages were predominated by lactic acid bacteria (LAB), and they exhibited good silage quality with significant increment in lactic acid, reductions in pH and water-soluble carbohydrates, low level of acetic acid and the absence of propionic and butyric acid. LAB consortia consisting of homolactic and heterolactic species were proposed to be the potential bacterial additives for sweet corn and Napier silage fermentation. Tax4fun functional prediction revealed metabolic pathways related to fermentation activities (bacterial division, carbohydrate transport and catabolism, and secondary metabolite production) were enriched in ensiled crops (p < 0.05). These results might suggest active transport and metabolism of plant carbohydrates into a usable form to sustain bacterial reproduction during silage fermentation, yielding metabolic products such as lactic acid. This research has provided a comprehensive understanding of bacterial communities before and after ensiling, which can be useful for desirable silage fermentation in Malaysia.
在热带国家生产的青贮料由于湿度和温度高容易变质。因此，确定土著细菌作为潜在的接种物对于提高青贮料的质量非常重要。本研究旨在使用扩增子宏基因组学来确定与青贮相关的细菌群落和功能变化，并预测与马来西亚气候下青贮质量相关的潜在细菌添加剂。制备了两种饲料作物（甜玉米和象草）的青贮料，并分析了它们的发酵特性和功能细菌群落。青贮后，两种青贮料均以乳酸菌（LAB）为主，具有良好的青贮品质，乳酸显著增加，pH 和水溶性碳水化合物降低，乙酸水平低，丙酸和丁酸不存在。拟议将由同质乳酸和异质乳酸组成的 LAB 共生体作为甜玉米和象草青贮发酵的潜在细菌添加剂。Tax4fun 功能预测显示，与发酵活动相关的代谢途径（细菌分裂、碳水化合物运输和分解代谢以及次生代谢产物的产生）在青贮作物中富集（p<0.05）。这些结果可能表明，在青贮发酵过程中，植物碳水化合物的主动运输和代谢转化为可用形式，以维持细菌的繁殖，并产生乳酸等代谢产物。这项研究提供了对青贮前后细菌群落的全面了解，这对于马来西亚理想的青贮发酵非常有用。
