大量的甲烷,目前推动气候变化的温室气体的主要成分,是由牲畜排放的,和有效的方法来遏制这种排放是迫切需要的,以减少全球变暖。喂奶牛时,红藻沙参(AT)可以减少高达80%的肠甲烷排放,但是取得的结果可能相差很大。家畜产生甲烷作为甲烷生成的副产物,这发生在瘤胃中微生物分解饲料的过程中。反刍动物微生物组是一个由细菌组成的多样化生态系统,原生动物,真菌,和古细菌,产甲烷古细菌与细菌协同作用产生甲烷。这里,我们发现,通过高剂量AT(0.5%干物质摄入量)有效减少甲烷排放与瘤胃内利用甲醇的甲烷减少有关。这表明它们在甲烷形成中的作用可能比以前认为的要大。然而,后来甲烷的峰值表明了后天的抗性,可能是通过溴仿的还原脱卤。虽然我们发现AT对甲烷生成的抑制间接影响瘤胃细菌和发酵途径,这是由于备用H2的增加,我们还发现丁酸盐合成的增加是由于AT对丁酸盐产生细菌的直接影响,例如Butyrivibrio,Moryella,和真细菌。一起,我们的发现为AT对甲烷排放和微生物组的影响提供了一些新的见解,从而阐明可能需要靶向的其他途径,以保持其抑制作用,同时保持微生物组健康和动物生产力。
目标:家畜排放大量甲烷,目前推动气候变化的温室气体的主要成分。牛瘤胃内的产甲烷菌在饲料分解期间产生甲烷。虽然红藻Asparagopsistaxiformis(AT)可以显着减少饲喂奶牛时的甲烷排放量,它的影响似乎是短暂的。这项研究表明,AT有效减少了甲烷的排放,同时几乎完全消除了产生甲烷的甲烷。然而,甲烷菌种种群随后因其失活溴莫型的能力而反弹,在AT中发现的甲烷形成的主要抑制剂。这项研究提出了有关甲烷对瘤胃甲烷生成的贡献的新发现,AT的作用方式,以及补充不同策略以有效遏制甲烷排放的可能性。
Copious amounts of
methane, a major constituent of greenhouse gases currently driving climate change, are emitted by livestock, and efficient methods that curb such emissions are urgently needed to reduce global warming. When fed to cows, the red seaweed Asparagopsis taxiformis (AT) can reduce enteric methane emissions by up to 80%, but the achieved results can vary widely. Livestock produce methane as a byproduct of methanogenesis, which occurs during the breakdown of feed by microbes in the rumen. The ruminant microbiome is a diverse ecosystem comprising bacteria, protozoa, fungi, and archaea, and methanogenic archaea work synergistically with bacteria to produce methane. Here, we find that an effective reduction in methane emission by high-dose AT (0.5% dry matter intake) was associated with a reduction in methanol-utilizing Methanosphaera within the rumen, suggesting that they may play a greater role in methane formation than previously thought. However, a later spike in Methanosphaera suggested an acquired resistance, possibly via the reductive dehalogenation of bromoform. While we found that AT inhibition of methanogenesis indirectly impacted ruminal bacteria and fermentation pathways due to an increase in spared H2, we also found that an increase in butyrate synthesis was due to a direct effect of AT on butyrate-producing bacteria such as Butyrivibrio, Moryella, and Eubacterium. Together, our findings provide several novel insights into the impact of AT on both methane emissions and the microbiome, thereby elucidating additional pathways that may need to be targeted to maintain its inhibitory effects while preserving microbiome health and animal productivity.
OBJECTIVE: Livestock emits copious quantities of methane, a major constituent of the greenhouse gases currently driving climate change. Methanogens within the bovine rumen produce
methane during the breakdown of feed. While the red seaweed Asparagopsis taxiformis (AT) can significantly reduce methane emissions when fed to cows, its effects appear short-lived. This
study revealed that the effective reduction of
methane emissions by AT was accompanied by the near-total elimination of
methane-generating Methanosphaera. However, Methanosphaera populations subsequently rebounded due to their ability to inactivate bromoform, a major inhibitor of methane formation found in AT. This
study presents novel findings on the contribution of Methanosphaera to ruminal methanogenesis, the mode of action of AT, and the possibility for complementing different strategies to effectively curb methane emissions.