Thorsteinsson M, Maigaard M, Lund P, Weisbjerg M R, Nielsen M O
Department of Animal and Veterinary Sciences, Aarhus University, AU Viborg-Research Centre Foulum, DK-8830 Tjele, Denmark.
JDS Commun. 2023 Jul 13;4(5):335-339. doi: 10.3168/jdsc.2022-0259. eCollection 2023 Sep.
Reduction in enteric methane (CH) emissions from cattle can be achieved through use of feed additives, which often results in increased emission of hydrogen (H). The objective of this study was to investigate in vitro effects of a known hydrogen sink, fumaric acid, in combination with either of 2 methane inhibitors, the macroalga or nitrate, on CH and H production, feed degradability, pH, and redox potential. A corn silage (0.5 g; control) was incubated in buffered rumen fluid with the addition of 0.025 g of nitrate (Nit), 0.025 g of dried (Asp), 0.025 g of nitrate + 0.025 g of fumaric acid (Nit+Fum), or 0.025 g of dried + 0.025 g of fumaric acid (Asp+Fum). Accumulated gas production was determined using the Ankom system equipped with airtight gasbags. There were 9 replicates per treatment with 3 replicates per treatment stopped after 24, 36, and 48 h of incubation. The amount of undegraded feed was determined by filtration. Gas composition was determined by gas chromatography. Degradable dry matter, degradable organic matter, pH, redox potential, and gas production data were analyzed using a mixed model. Asp and Asp+Fum reduced CH production by 98% or greater at all incubation times, whereas Nit and Nit+Fum reduced CH production (mL of CH/g of dry matter) by 52% to 63% compared with the control. Hydrogen was only detectable in gas from Asp and Asp+Fum treatments, with no difference in H production between the 2 treatments. The treatments had only minor effects on redox potential in the fermented rumen fluid, and pH was lowest for treatments including In conclusion, both and nitrate reduced CH production. Fumaric acid in combination with did not reduce H production, and treatments including nitrate did not result in any detectable levels of H. Future dose-response in vitro studies will contribute to investigating the potential of fumaric acid as a hydrogen sink during CH mitigation.
通过使用饲料添加剂可以减少牛的肠道甲烷（CH）排放，而这通常会导致氢气（H）排放增加。本研究的目的是调查已知的氢汇富马酸与两种甲烷抑制剂（大型藻类或硝酸盐）之一联合使用对CH和H产生、饲料降解率、pH值和氧化还原电位的体外影响。将0.5克玉米青贮饲料（对照）在缓冲瘤胃液中孵育，并添加0.025克硝酸盐（Nit）、0.025克干大型藻类（Asp）、0.025克硝酸盐 + 0.025克富马酸（Nit+Fum）或0.025克干大型藻类 + 0.025克富马酸（Asp+Fum）。使用配备气密气袋的Ankom系统测定累积产气量。每个处理有9个重复，每个处理的3个重复在孵育24、36和48小时后停止。通过过滤测定未降解饲料的量。通过气相色谱法测定气体成分。使用混合模型分析可降解干物质、可降解有机物、pH值、氧化还原电位和产气量数据。在所有孵育时间，Asp和Asp+Fum使CH产生减少98%或更多，而与对照相比，Nit和Nit+Fum使CH产生（每克干物质产生的CH毫升数）减少52%至63%。仅在来自Asp和Asp+Fum处理的气体中可检测到氢气，两种处理之间的H产生没有差异。这些处理对发酵瘤胃液中的氧化还原电位影响较小，包括大型藻类的处理pH值最低。总之，大型藻类和硝酸盐都减少了CH产生。富马酸与大型藻类联合使用并未减少H产生，包括硝酸盐的处理未产生任何可检测水平的H。未来的体外剂量反应研究将有助于调查富马酸在减轻CH过程中作为氢汇的潜力。
