■高产奶牛通常饲喂高谷物口粮。然而,这可能导致亚急性瘤胃酸中毒(SARA),奶牛的一种代谢紊乱,通常伴有瘤胃微生物群的菌群失调。含有功能性代谢产物的益生菌为瘤胃微生物组的有影响力的成员提供了有竞争力的生态位,可以稳定和促进他们的人口,and,因此,可减轻SARA的不良反应。
■这项研究使用了总共32头瘤胃插管的泌乳奶牛,将其随机分配到四种治疗中:无SCFP(对照),14g/d原始XPC(SCFPa),19克/天NutriTek(SCFPb-1X),和38克/天NutriTek(SCFPb-2X)(钻石V,雪松急流,IA)从分娩前4周到分娩后12周。在分娩后第5周(SARA1)和第8周(SARA2)进行基于谷物的SARA攻击,方法是用含有50%大麦和50%小麦的颗粒代替基础总混合日粮(TMR)的20%干物质。提取瘤胃固体消化物的DNA并进行V3-V416SrRNA基因测序。在非SARA(前SARA1,第4周;后SARA1,第7周;后SARA2,第10周和第12周)和SARA阶段(SARA1/1,SARA1/2,SARA2/1,SARA2/2)之间比较了瘤胃固体微生物群的特征,以及在治疗中。
■两种SARA挑战都降低了微生物群的丰富度和多样性以及纤维杆菌门的相对丰富度。补充SCFP促进了几种纤维化细菌的生长,包括蛇床子科UCG-009,密螺旋体,未分类的仙人掌科,以及在SARA挑战期间未分类的反刍动物科。这些挑战还减少了微生物群中的积极相互作用和枢纽分类群的数量。在SARA和非SARA阶段,SCFPb处理增加了固体消化物的微生物成员之间的正相互作用以及枢纽分类单元的数量。SCFPb-2X处理防止了网络特性的变化,包括组件的数量,聚类系数,模块性,正边缘百分比,以及SARA挑战期间微生物群的边缘密度。这些挑战降低了微生物群中预测的碳水化合物和氮代谢,而SCFP补充减弱了这些减少。
■补充SCFP,特别是SCFPb-2X减弱了基于谷物的SARA对瘤胃固体微生物群多样性和预测功能的不利影响。
UNASSIGNED: High-yielding dairy cows are commonly fed high-grain rations. However, this can cause subacute ruminal acidosis (SARA), a metabolic disorder in dairy cows that is usually accompanied by dysbiosis of the rumen microbiome.
Postbiotics that contain functional metabolites provide a competitive niche for influential members of the rumen microbiome, may stabilize and promote their populations, and, therefore, may attenuate the adverse effects of SARA.
UNASSIGNED: This study used a total of 32 rumen-cannulated lactating dairy cows, which were randomly assigned into four treatments: no SCFP (control), 14 g/d Original XPC (SCFPa), 19 g/d NutriTek (SCFPb-1X), and 38 g/d NutriTek (SCFPb-2X) (Diamond V, Cedar Rapids, IA) from 4 weeks before until 12 weeks after parturition. Grain-based SARA challenges were conducted during week 5 (SARA1) and week 8 (SARA2) after parturition by replacing 20% dry matter of the base total mixed ration (TMR) with pellets containing 50% ground barley and 50% ground wheat. The DNA of rumen solids digesta was extracted and subjected to V3-V4 16S rRNA gene sequencing. The characteristics of rumen solids microbiota were compared between non-SARA (Pre-SARA1, week 4; Post-SARA1, week 7; and Post-SARA2, weeks 10 and 12) and SARA stages (SARA1/1, SARA1/2, SARA2/1, SARA2/2), as well as among treatments.
UNASSIGNED: Both SARA challenges reduced the richness and diversity of the microbiota and the relative abundances of the phylum Fibrobacteres. Supplementation with SCFP promoted the growth of several fibrolytic bacteria, including Lachnospiraceae UCG-009, Treponema, unclassified Lachnospiraceae, and unclassified Ruminococcaceae during the SARA challenges. These challenges also reduced the positive interactions and the numbers of hub taxa in the microbiota. The SCFPb treatment increased positive interactions among microbial members of the solids digesta and the number of hub taxa during the SARA and non-SARA stages. The SCFPb-2X treatment prevented changes in the network characteristics, including the number of components, clustering coefficient, modularity, positive edge percentage, and edge density of the microbiota during SARA challenges. These challenges reduced predicted carbohydrate and nitrogen metabolism in microbiota, whereas SCFP supplementation attenuated those reductions.
UNASSIGNED: Supplementation with SCFP, especially the SCFPb-2X attenuated the adverse effects of grain-based SARA on the diversity and predicted functionality of rumen solids microbiota.