Recycling of Lycium barbarum by-products and bioactive substance application in silage - Insight into antioxidant activity and the regulation mechanism of anaerobic fermentation

Lycium barbarum, originating from East Asia, is a well-known traditional Chinese herbal medicine with significant medicinal and nutritional benefits. It has gained attention for its various bioactive compounds, such as Lycium barbarum polysaccharides (LBPs), flavonoids (FLA), betaine (BET), polyphenols, vitamins, and trace elements, which exhibit anti-tumor, anti-inflammatory, antioxidant, hypoglycemic, and hypolipidemic properties. The by-products of Lycium barbarum processing, known as Lycium barbarum by-products (LBB), including fruit residues and fruit stalks, are often discarded despite containing valuable nutrients and bioactive compounds. This wasteful practice not only leads to resource depletion and environmental pollution but also results in significant economic losses. Therefore, it is essential to enhance the efficiency of resource recycling and promote social sustainability by utilizing LBB effectively.LBB, LBP, FLA and BET improved fermentation quality by increasing the lactic acid (LA) content and reducing the pH values and ammonia nitrogen (NH3-N) content. They also enhanced nutrient quality by decreased the acid detergent fiber (ADF) content and increased the water-soluble carbohydrate (WSC) content. DM loss was significantly reduced in LBB-treated silages. The active components and LBB significantly affected the metabolite profiles of silage, with differential metabolites enriched in flavonoid biosynthesis, isoflavonoid biosynthesis, plant hormone signal transduction and flavone and flavonol biosynthesis. Integrated correlation analysis also provided a link between the high abundance microbiota and metabolites. Thus, these findings offer a new insight into utilizing LBB as an additive for improving silage quality of alfalfa.

枸杞（Lycium barbarum）源自东亚，是广受认可的传统中药材，兼具显著的药用与营养价值。其多种活性成分备受关注，包括枸杞多糖（Lycium barbarum polysaccharides, LBPs）、黄酮类（flavonoids, FLA）、甜菜碱（betaine, BET）、多酚、维生素及微量元素，这些成分具备抗肿瘤、抗炎、抗氧化、降血糖与降血脂的药理活性。
枸杞加工过程中产生的副产物——枸杞加工副产物（Lycium barbarum by-products, LBB），涵盖果渣与果梗，尽管富含珍贵营养物质与活性成分，却常被直接废弃。这种浪费行为不仅造成资源耗竭与环境污染，还会带来显著的经济损失。因此，通过高效利用LBB以提升资源循环利用效率、推动社会可持续发展，实属必要。

LBB、枸杞多糖（Lycium barbarum polysaccharides, LBP）、FLA与BET可通过提升乳酸（lactic acid, LA）含量、降低pH值与氨氮（ammonia nitrogen, NH3-N）含量，改善青贮发酵品质；同时还可通过降低酸性洗涤纤维（acid detergent fiber, ADF）含量、提升水溶性碳水化合物（water-soluble carbohydrate, WSC）含量，优化青贮的营养品质。经LBB处理的青贮饲料，其干物质（Dry Matter, DM）损失量显著降低。
活性成分与LBB可显著调控青贮饲料的代谢物谱，差异代谢物显著富集于黄酮类生物合成、异黄酮类生物合成、植物激素信号转导以及黄酮与黄酮醇生物合成通路中。整合关联分析还揭示了高丰度微生物群落与代谢物之间的内在关联。综上，本研究结果为将LBB作为添加剂以提升苜蓿青贮品质提供了全新的研究视角。