Reduction in lignin content and increase in the antioxidant capacity of corn and sugarcane silages treated with an enzymatic complex produced by white rot fungus

The objective was to evaluate the effect of the addition of 0, 10, 20, and 30 mg.kg-1 of natural matter of a lignocellulosic enzymatic complex produced by the white rot fungus on the chemical composition, cumulative gas production in vitro, and antioxidant compounds of corn and sugarcane silages. After being chopped and treated with the enzymatic complex, the plants were packed in vacuum-sealed bags. After 60 days, the mini silos were opened and the samples were dried in a forced ventilation oven at 55 °C for analysis of the proposed parameters. The experiment was conducted in a completely randomized design with four replicates per treatment. In the corn silage, there was a linear reduction in the lignin concentration. In the sugarcane silage showed a reduction of 12% in the lignin concentration, a linear reduction in the hemicellulose content, and a decrease of 8% in the cellulose concentration compared to the control treatment. The lignin monomers had linear increases in the syringyl:guaiacil ratio. This reflected on significant increases in the concentration of the non-fibrous carbohydrates and the A + B1 fraction of the carbohydrates, and a reduction in the C fraction. The in vitro gas production increased, the time of colonization and initiation of in vitro fermentation linearly decreased in both silages. The phenolic compounds and the antioxidant capacity increased linearly with the addition of the enzymes in both silages. The addition of the lignocellulolytic enzymes to the silages caused changes in the cell wall, resulting in improvements in the in vitro fermentative parameters, besides the additional effect on the antioxidant capacity. There was an effect of the addition of the enzymes on the evaluated fodder, and the best concentration was, on average, 20 mg kg-1 MN for corn silage and 10 mg kg-1 NM for sugarcane silage.

本研究旨在探究添加0、10、20、30 mg·kg⁻¹的白腐真菌（white rot fungus）所产木质纤维素酶复合物（lignocellulosic enzymatic complex）天然组分，对玉米与甘蔗青贮饲料的化学成分、体外累计产气量及抗氧化成分的影响。将原料切碎并经该酶复合物处理后，装入真空密封袋中制备微型青贮罐；60天后开启样品袋，将试样置于55℃强制通风烘箱中干燥，用于后续目标参数的分析。本实验采用完全随机设计，每个处理设置4次生物学重复。在玉米青贮饲料组中，木质素浓度随酶添加量呈线性降低；甘蔗青贮饲料组的木质素浓度较对照组降低12%，半纤维素含量呈线性下降，纤维素浓度较对照组降低8%。木质素单体的丁香基-愈创木基（syringyl:guaiacil）比值呈线性升高，该变化使得非纤维碳水化合物与碳水化合物A+B1组分浓度显著升高，而碳水化合物C组分浓度降低。两种青贮饲料的体外产气量均有所提升，发酵定植时间与体外发酵启动时间均呈线性缩短。酚类物质含量与抗氧化能力均随酶添加量增加呈线性升高。向青贮饲料中添加木质纤维素分解酶可改变细胞壁结构，不仅改善体外发酵参数，还可提升抗氧化能力。酶添加量对受试饲料均产生显著影响，其中玉米青贮饲料的最优添加浓度平均为20 mg·kg⁻¹天然组分，甘蔗青贮饲料的最优添加浓度为10 mg·kg⁻¹天然组分。