Table_1_Tannic acid reduced apparent protein digestibility and induced oxidative stress and inflammatory response without altering growth performance and ruminal microbiota diversity of Xiangdong black goats.XLSX

The present study was performed to evaluate the impacts of tannic acid (TA) supplementation at different levels on the growth performance, physiological, oxidative and immunological metrics, and ruminal microflora of Xiangdong black goats. Twenty-four goats were randomly assigned to four dietary treatments: the control (CON, basal diet), the low-dose TA group [TAL, 0.3 % of dry matter (DM)], the mid-dose TA group (TAM, 0.6 % of DM), and the high-dose TA group (TAH, 0.9 % of DM). Results showed that the growth performance was unaffected (P > 0.05) by adding TA, whilst the 0.3 % and 0.6 % TA supplementation significantly decreased (P < 0.05) the apparent digestibility of crude protein (CP) and ruminal NH3-N concentration, and raised (P < 0.05) the level of total volatile fatty acid (TVFA) in rumen. The increments of alanine aminotransferase (ALT), triglyceride (TG), cortisol (CORT), total antioxidant capacity (T-AOC), interleukin (IL)-1β, IL-6, and serumamyloid A (SAA), and decrements of globulin (GLB), immunoglobulin G (IgG), cholinesterase (CHE), glutathione reductase (GR), creatinine (CRE), growth hormone (GH), high-density lipoprotein cholesterol (HDLC), and insulin-like growth factor 1 (IGF-1) to different extents by TA addition were observed. Although the Alpha and Beta diversity of rumen bacterial community remained unchanged by supplementing TA, the relative abundance of the predominant genus Prevotella_1 was significantly enriched (P < 0.05) in TAL. It could hence be concluded that the TA supplementation in the present trial generally decreased CP digestion and caused oxidative stress and inflammatory response without influencing growth performance and ruminal microbiota diversity. More research is needed to explore the premium dosage and mechanisms of effects for TA addition in the diet of goats.

本研究旨在评估不同水平单宁酸（tannic acid, TA）添加剂量对湘东黑山羊生长性能、生理、氧化及免疫学指标，以及瘤胃微生物区系的影响。试验将24只湘东黑山羊随机分为4组日粮处理组：对照组（CON，基础日粮）、低剂量单宁酸组（TAL，占干物质[dry matter, DM]的0.3%）、中剂量单宁酸组（TAM，占干物质的0.6%）以及高剂量单宁酸组（TAH，占干物质的0.9%）。
结果显示，添加单宁酸对山羊生长性能无显著影响（P > 0.05）；而0.3%与0.6%的单宁酸添加量可显著降低粗蛋白质（crude protein, CP）的表观消化率及瘤胃氨态氮（NH3-N）浓度，同时显著提升瘤胃总挥发性脂肪酸（total volatile fatty acid, TVFA）水平（P < 0.05）。此外，单宁酸添加可不同程度地升高血清丙氨酸氨基转移酶（alanine aminotransferase, ALT）、甘油三酯（triglyceride, TG）、皮质醇（cortisol, CORT）、总抗氧化能力（total antioxidant capacity, T-AOC）、白细胞介素（interleukin, IL)-1β、IL-6及血清淀粉样蛋白A（serum amyloid A, SAA）的含量，同时降低球蛋白（globulin, GLB）、免疫球蛋白G（immunoglobulin G, IgG）、胆碱酯酶（cholinesterase, CHE）、谷胱甘肽还原酶（glutathione reductase, GR）、肌酐（creatinine, CRE）、生长激素（growth hormone, GH）、高密度脂蛋白胆固醇（high-density lipoprotein cholesterol, HDLC）及胰岛素样生长因子1（insulin-like growth factor 1, IGF-1）的水平。
尽管添加单宁酸未改变瘤胃细菌群落的α及β多样性，但TAL组中优势菌属Prevotella_1的相对丰度显著升高（P < 0.05）。
据此可得出结论：本试验中添加单宁酸总体上降低了粗蛋白质消化率，引发氧化应激与炎症反应，但未对生长性能及瘤胃微生物群落多样性产生影响。未来仍需开展更多研究，以探索山羊日粮中添加单宁酸的适宜剂量及作用机制。