Table 1_Effects of Lactobacillus brevis additives on nutrient composition, fermentation quality, microflora structure and metabolites of Pennisetum giganteum silage.docx

The current situation of feed resource shortage can be effectively solved by high-value utilization of Pennisetum giganteum. This study investigated the effects of Lactobacillus brevis R-09 on P. giganteum silage quality, microbial structure and metabolites. In a randomized experimental design, silage was treated with (LT: 1.5 × 107 CFU/kg L. brevis R-09) or without (LC: control) inoculant, each replicated six times. The LT group exhibited elevated crude fat (p < 0.05), lactic acid (p < 0.05), and isocaproic acid (p < 0.05) content, alongside reduced crude fiber, butyric acid, and mycotoxin levels (p < 0.05). High-throughput sequencing (16S/18S rDNA) revealed comparable microbial diversity across treatments, with Lactobacillus dominating the bacterial community. Notably, LT increased microbial uniformity and suppressed mold proliferation, diminishing their ecological impact. Liquid chromatography-mass spectrometry (LC–MS) profiling identified 464 differentially abundant metabolites, primarily linked to amino acid and lipid metabolism, suggesting a stabilized metabolic network. Taken together, these results suggest that the addition of L. brevis R-09 can improve the quality of P. giganteum silage by modulating microbial communities and metabolic pathways, thus providing mechanistic insights into the optimization of Lactobacillus-mediated silage fermentation.

巨菌草（Pennisetum giganteum）的高值化利用可有效缓解当前饲料资源短缺的现状。本研究探究了短乳杆菌R-09（Lactobacillus brevis R-09）对巨菌草青贮品质、微生物群落结构及代谢产物的影响。本实验采用随机设计，将青贮物料分为添加组（LT：添加1.5×10^7 CFU/kg的短乳杆菌R-09）与对照组（LC：不添加接种剂），每组设置6次生物学重复。LT组的粗脂肪、乳酸及异己酸含量显著升高（p<0.05），同时粗纤维、丁酸及真菌毒素水平显著降低（p<0.05）。高通量测序（16S/18S rDNA）结果显示，两组处理的微生物多样性无显著差异，但乳杆菌属为细菌群落的优势菌属。值得注意的是，LT组提升了微生物群落的均匀度，并抑制了霉菌增殖，削弱了其生态影响。液相色谱-质谱联用（LC-MS）代谢组分析共鉴定出464个差异丰度代谢物，这些代谢物主要与氨基酸代谢和脂质代谢相关，表明巨菌草青贮的代谢网络趋于稳定。综合上述结果，添加短乳杆菌R-09可通过调控微生物群落与代谢通路提升巨菌草青贮品质，为解析乳杆菌介导的青贮发酵优化机制提供了理论依据。