维生素E对高精料诱导亚急性瘤胃酸中毒奶牛粪便微生物群落的影响

Vitamin E alters the fecal microbial community in dairy cows with subacute rumen acidosis induced by a high-concentrate diet

摘要:

【目的】研究高精料诱导亚急性瘤胃酸中毒(subacute rumen acidosis, SARA)和添加维生素E (vitamin E, VE)调控下，奶牛粪便中微生物群落的变化，评估其对奶牛机体代谢的潜在影响，以期为探索SARA的生理机制提供数据支撑。【方法】选取7头装有瘤胃瘘管的经产荷斯坦奶牛，分为3期开展，每期18 d。第一期为对照期(CON期)，日粮精粗比为50:50 [干物质基础(dry matter basis, DM基础)]；第二期为诱导期(HG期)，用占日粮15% (DM基础)的细粉小麦替代日粮中粗饲料，以期诱导奶牛发生SARA；第三期为调控期(HGE期)，在诱导期日粮基础上添加12 000 IU/d/头的VE。每期第18天为采样期，采集粪便用来测定微生物群落。【结果】3个处理期的粪便中微生物群落结构存在差异，并且HG期的Shannon指数显著低于CON期(P<0.05)。对门和属水平上的物种进行分析发现，与CON期相比，HG期的Proteobacteria和Blautia相对丰度显著升高(P<0.05)，unidentified_bacteria、Euryarchaeota、Desulfobacterota、Rikenellaceae_RC9_gut_group和Alistipes相对丰度显著降低(P<0.05)。与HG期相比，HGE期的Blautia相对丰度显著升高(P<0.05)。功能预测分析表明，SARA造成奶牛机体代谢紊乱，VE可能通过提高微生物生长繁殖的稳定性，促进肠道健康微生物群落增殖，以调节肠道内环境和促进肠道健康。【结论】高精料诱导SARA导致奶牛肠道微生物多样性降低，使奶牛机体代谢紊乱；在VE调控下，能通过促进有益肠道微生物群增殖，调控奶牛肠道健康和维持肠道稳态。

Abstract:

[Objective] This study aims to observe the changes of the fecal microbial communities in the dairy cows with subacute rumen acidosis (SARA) induced by a high-concentrate diet and modulated by the addition of vitamin E (VE). The potential effects on the metabolism of dairy cows were evaluated to provide data for exploring the physiological mechanisms of SARA. [Methods] Seven multiparous Holstein cows with rumen fistulas were selected for this trial which was carried out in three phases of 18 days each. The first phase was the control (CON) phase, with a concentrate-to-forage ratio of 50:50 in the diet (dry matter basis). The second phase was the induction (HG) phase, in which the forage was replaced with wheat flour at 15% of the diet (dry matter basis) to induce SARA. The third phase was the regulation (HGE) phase, in which VE was added at 12 000 IU/d/cow on the basis of the diet in the HG phase. The feces samples were collected on day 18 in each phase, and the microbial communities in the samples were examined. [Results] The fecal microbial community structure showed significant differences between three phases and the Shannon index in the HG phase was lower than that in the CON phase (P<0.05). The HG phase had higher relative abundance of Proteobacteria and Blautia and lower relative abundance of unidentified_bacteria, Euryarchaeota, Desulfobacterota, Rikenellaceae_RC9_gut_group, and Alistipes than the CON phase (P<0.05). The relative abundance of Blautia in the HGE phase was higher than that in the HG phase (P<0.05). The functional prediction results showed that SARA caused metabolic disorders in the dairy cows, while VE regulated the intestinal microbiota and health by improving the stability of microbial growth and promoting microbial reproduction. [Conclusion] The SARA induced by a high-concentrate diet led to reduced intestinal microbial diversity and metabolic disorders in dairy cows. VE can regulate intestinal health and maintain intestinal homeostasis by promoting the proliferation of beneficial intestinal microorganisms.