Departamento de Mejora Genética Animal, INIA-CSIC, 28040 Madrid, Spain.
Departamento de Mejora Genética Animal, INIA-CSIC, 28040 Madrid, Spain; Universidad San Pablo-CEU, CEU Universities, Madrid, Spain.
Animal. 2023 Jun;17 Suppl 2:100780. doi: 10.1016/j.animal.2023.100780. Epub 2023 Mar 17.
Interest on methane emissions from livestock has increased in later years as it is an anthropogenic greenhouse gas with an important warming potential. The rumen microbiota has a large influence on the production of enteric methane. Animals harbour a second genome consisting of microbes, collectively referred to as the "microbiome". The rumen microbial community plays an important role in feed digestion, feed efficiency, methane emission and health status. This review recaps the current knowledge on the genetic control that the cow exerts on the rumen microbiota composition. Heritability estimates for the rumen microbiota composition range between 0.05 and 0.40 in the literature, depending on the taxonomical group or microbial gene function. Variables depicting microbial diversity or aggregating microbial information are also heritable within the same range. This study includes a genome-wide association analysis on the microbiota composition, considering the relative abundance of some microbial taxa previously associated to enteric methane in dairy cattle (Archaea, Dialister, Entodinium, Eukaryota, Lentisphaerae, Methanobrevibacter, Neocallimastix, Prevotella and Stentor). Host genomic regions associated with the relative abundance of these microbial taxa were identified after Benjamini-Hoschberg correction (P < 0.05). An in-silico functional analysis using FUMA and DAVID online tools revealed that these gene sets were enriched in tissues like brain cortex, brain amigdala, pituitary, salivary glands and other parts of the digestive system, and are related to appetite, satiety and digestion. These results allow us to have greater knowledge about the composition and function of the rumen microbiome in cattle. The state-of-the art strategies to include methane traits in the selection indices in dairy cattle populations is reviewed. Several strategies to include methane traits in the selection indices have been studied worldwide, using bioeconomical models or economic functions under theoretical frameworks. However, their incorporation in the breeding programmes is still scarce. Some potential strategies to include methane traits in the selection indices of dairy cattle population are presented. Future selection indices will need to increase the weight of traits related to methane emissions and sustainability. This review will serve as a compendium of the current state of the art in genetic strategies to reduce methane emissions in dairy cattle.
近年来，人们对来自牲畜的甲烷排放产生了浓厚的兴趣，因为甲烷是一种人为的温室气体，具有重要的变暖潜力。瘤胃微生物群对肠道甲烷的产生有很大的影响。动物体内存在着由微生物组成的第二个基因组，通常被称为“微生物组”。瘤胃微生物群落在饲料消化、饲料效率、甲烷排放和健康状况方面发挥着重要作用。这篇综述回顾了奶牛对瘤胃微生物群落组成的遗传控制的现有知识。文献中，瘤胃微生物群落组成的遗传力估计值在 0.05 到 0.40 之间，具体取决于分类群或微生物基因功能。在同一范围内，描述微生物多样性或汇总微生物信息的变量也是可遗传的。本研究包括对微生物群落组成进行全基因组关联分析，考虑了先前与奶牛肠道甲烷有关的一些微生物类群（古菌、Dialister、Entodinium、真核生物、 Lentisphaerae、Methanobrevibacter、Neocallimastix、Prevotella 和 Stentor）的相对丰度。在 Benjamini-Hoschberg 校正（P<0.05）后，确定了与这些微生物类群相对丰度相关的宿主基因组区域。使用 FUMA 和 DAVID 在线工具进行的计算机功能分析表明，这些基因集在大脑皮层、杏仁核、脑垂体、唾液腺和消化系统的其他部位富集，并与食欲、饱腹感和消化有关。这些结果使我们对奶牛瘤胃微生物组的组成和功能有了更深入的了解。本文综述了在奶牛群体中选择指数中纳入甲烷性状的最新技术。全世界都在研究将甲烷性状纳入奶牛选择指数的策略，包括使用生物经济学模型或理论框架下的经济函数。然而，它们在育种计划中的应用仍然很少。本文提出了一些将甲烷性状纳入奶牛群体选择指数的潜在策略。未来的选择指数将需要增加与甲烷排放和可持续性相关的性状的权重。本文综述将作为遗传策略减少奶牛甲烷排放的最新技术的纲要。
