Stergiadis Sokratis, Cabeza-Luna Irene, Mora-Ortiz Marina, Stewart Robert D, Dewhurst Richard J, Humphries David J, Watson Mick, Roehe Rainer, Auffret Marc D
School of Agriculture, Policy and Development, Department of Animal Sciences, University of Reading, Animal, Dairy and Food Chain Sciences, Reading, United Kingdom.
Beef and Sheep Research Centre, Scotland's Rural College (SRUC), Roslin Institute Building, Edinburgh, United Kingdom.
Front Microbiol. 2021 Jan 21;11:590441. doi: 10.3389/fmicb.2020.590441. eCollection 2020.
Milk products are an important component of human diets, with beneficial effects for human health, but also one of the major sources of nutritionally undesirable saturated fatty acids (SFA). Recent discoveries showing the importance of the rumen microbiome on dairy cattle health, metabolism and performance highlight that milk composition, and potentially milk SFA content, may also be associated with microorganisms, their genes and their activities. Understanding these mechanisms can be used for the development of cost-effective strategies for the production of milk with less SFA. This work aimed to compare the rumen microbiome between cows producing milk with contrasting FA profile and identify potentially responsible metabolic-related microbial mechanisms. Forty eight Holstein dairy cows were fed the same total mixed ration under the same housing conditions. Milk and rumen fluid samples were collected from all cows for the analysis of fatty acid profiles (by gas chromatography), the abundances of rumen microbiome communities and genes (by whole-genome-shotgun metagenomics), and rumen metabolome (using 500 MHz nuclear magnetic resonance). The following groups: (i) 24 High-SFA (66.9-74.4% total FA) vs. 24 Low-SFA (60.2-66.6%% total FA) cows, and (ii) 8 extreme High-SFA (69.9-74.4% total FA) vs. 8 extreme Low-SFA (60.2-64.0% total FA) were compared. Rumen of cows producing milk with more SFA were characterized by higher abundances of the lactic acid bacteria , and , the acetogenic Proteobacteria and , two fungi ( and ), and at a lesser extent and the protist . Cows carrying genes correlated with milk FA also had higher concentrations of butyrate, propionate and tyrosine and lower concentrations of xanthine and hypoxanthine in the rumen. Abundances of rumen microbial genes were able to explain between 76 and 94% on the variation of the most abundant milk FA. Metagenomics and metabolomics analyses highlighted that cows producing milk with contrasting FA profile under the same diet, also differ in their rumen metabolic activities in relation to adaptation to reduced rumen pH, carbohydrate fermentation, and protein synthesis and metabolism.
乳制品是人类饮食的重要组成部分，对人类健康有益，但也是营养方面不良的饱和脂肪酸（SFA）的主要来源之一。最近的发现表明瘤胃微生物群对奶牛健康、代谢和生产性能具有重要意义，这突出表明牛奶成分以及潜在的牛奶SFA含量可能也与微生物、它们的基因及其活动有关。了解这些机制可用于制定具有成本效益的策略来生产SFA含量较低的牛奶。这项工作旨在比较生产脂肪酸组成不同的牛奶的奶牛之间的瘤胃微生物群，并确定潜在的与代谢相关的微生物机制。48头荷斯坦奶牛在相同的饲养条件下饲喂相同的全混合日粮。从所有奶牛采集牛奶和瘤胃液样本，用于分析脂肪酸谱（通过气相色谱法）、瘤胃微生物群落和基因的丰度（通过全基因组鸟枪法宏基因组学）以及瘤胃代谢组（使用500兆赫核磁共振）。比较了以下几组：（i）24头高SFA（总脂肪酸的66.9 - 74.4%）奶牛与24头低SFA（总脂肪酸的60.2 - 66.6%）奶牛，以及（ii）8头极端高SFA（总脂肪酸的69.9 - 74.4%）奶牛与8头极端低SFA（总脂肪酸的60.2 - 64.0%）奶牛。生产SFA含量更高的牛奶的奶牛瘤胃的特征在于乳酸菌、产乙酸变形菌、两种真菌（和）的丰度更高，以及在较小程度上和原生生物的丰度更高。携带与牛奶脂肪酸相关基因的奶牛瘤胃中丁酸盐、丙酸盐和酪氨酸的浓度也更高，而黄嘌呤和次黄嘌呤的浓度更低。瘤胃微生物基因的丰度能够解释最丰富的牛奶脂肪酸变异的76%至94%。宏基因组学和代谢组学分析突出表明，在相同日粮条件下生产脂肪酸组成不同的牛奶的奶牛，其瘤胃代谢活动在适应瘤胃pH值降低、碳水化合物发酵以及蛋白质合成和代谢方面也存在差异。
