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）起源于东亚，是一种知名的传统中药材，兼具显著的药用与营养价值。其因含多种生物活性成分而受到广泛关注，包括枸杞多糖（Lycium barbarum polysaccharides，LBPs）、黄酮类（flavonoids，FLA）、甜菜碱（betaine，BET）、多酚、维生素及微量元素等，这些成分具有抗肿瘤、抗炎、抗氧化、降血糖及降血脂的功效。枸杞加工过程中产生的副产物——枸杞副产物（Lycium barbarum by-products，LBB），包含果渣与果柄，尽管其富含珍贵的营养物质与生物活性成分，却常被直接丢弃。这种浪费行为不仅造成资源耗竭与环境污染，还带来了显著的经济损失。因此，通过高效利用枸杞副产物以提升资源循环利用效率、推动社会可持续发展，具有重要意义。枸杞副产物、枸杞多糖、黄酮类及甜菜碱可通过提升乳酸（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。经枸杞副产物处理的青贮饲料，其干物质（DM）损失显著降低。活性成分与枸杞副产物可显著影响青贮的代谢物谱，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。整合关联分析还揭示了高丰度菌群与代谢物之间的关联机制。综上，本研究结果为将枸杞副产物作为添加剂以改善苜蓿青贮品质提供了全新的思路。