Subacute Rumen Acidosis Microbiome Metagenome. bovine gut metagenome

Subacute ruminal acidosis (SARA) negatively impacts the dairy industry by decreasing dry matter intake, milk production, profitability, and increasing culling rate and death loss. Six lactating Holstein cows were used in a replicated Latin square design to determine the effects of SARA induction on the ruminal microbiome and epithelium. Experimental periods were 10 d with d 1 - 3 for ad libitum intake of control diet, followed by 50% feed restriction on d 4, and ad libitum access on d 5 to the basal diet or the basal diet with an additional 10% of a 50:50 wheat/barley pellet. Based on subsequent ruminal pH, cows were classified as Non-SARA or SARA based on time < 5.6 pH (0 and 3.4 h, respectively). Ruminal samples were collected on d 1 and 6 of each period prior to feeding and separated into liquid and solid fractions. Bacterial DNA was extracted for microbiome analysis using 16S rRNA gene paired-end sequencing on the MiSeq Illumina platform and quantitative PCR (qPCR).

亚急性瘤胃酸中毒（Subacute ruminal acidosis, SARA）可通过降低干物质采食量、产奶量与养殖盈利能力，提高淘汰率与死亡损失，对乳品工业造成负面影响。本研究采用重复拉丁方设计，选用6头泌乳荷斯坦奶牛，旨在探究SARA诱导对瘤胃微生物组与瘤胃上皮组织的影响。实验周期为10天：第1至3天为自由采食对照日粮阶段，第4天实施50%限饲，第5天恢复自由采食基础日粮，或为基础日粮额外添加10%比例的50:50小麦大麦混合颗粒料。基于后续测得的瘤胃pH值，以pH<5.6的持续时长（分别为0小时和3.4小时）将奶牛划分为非SARA组与SARA组。每个实验周期的第1天和第6天于饲喂前采集瘤胃样本，并将其分离为液相与固相组分。提取细菌基因组DNA后，采用Illumina MiSeq测序平台的16S rRNA基因双端测序技术与定量PCR（quantitative PCR, qPCR）开展微生物组分析。