Seaweeds are macroalgae, which can be of many different morphologies, sizes, colors, and chemical profiles. They include brown, red, and green seaweeds. Brown seaweeds have been more investigated and exploited in comparison to other seaweed types for their use in animal feeding studies due to their large sizes and ease of harvesting. Recent in vitro and in vivo studies suggest that plant secondary compound-containing seaweeds (e.g., halogenated compounds, phlorotannins, etc.) have the potential to mitigate enteric methane (CH₄) emissions from ruminants when added to the diets of beef and dairy cattle. Red seaweeds including Asparagopsis spp. are rich in crude protein and halogenated compounds compared to brown and green seaweeds. When halogenated-containing red seaweeds are used as the active ingredient in ruminant diets, bromoform concentration can be used as an indicator of anti-methanogenic properties. Phlorotannin-containing brown seaweed has also the potential to decrease CH₄ production. However, numerous studies examined the possible anti-methanogenic effects of marine seaweeds with inconsistent results. This work reviews existing data associated with seaweeds and in vitro and in vivo rumen fermentation, animal performance, and enteric CH₄ emissions in ruminants. Increased understanding of the seaweed supplementation related to rumen fermentation and its effect on animal performance and CH₄ emissions in ruminants may lead to novel strategies aimed at reducing greenhouse gas emissions while improving animal productivity.

海藻是大型藻类，具有多种不同的形态、大小、颜色和化学特征。它们包括棕色、红色和绿色海藻。与其他海藻类型相比，由于褐海藻体积大且易于收获，因此在动物饲养研究中的应用得到了更多的研究和开发。最近的体外和体内研究表明，当添加到肉牛和奶牛的日粮中时，含有植物次生化合物的海藻（例如卤代化合物、叶草单宁等）有可能减少反刍动物的肠道甲烷（CH 4 ）_排放。红海藻，包括Asparagopsis spp。与棕色和绿色海藻相比，富含粗蛋白和卤代化合物。当含卤红海藻用作反刍动物日粮中的活性成分时，三溴甲烷浓度可用作抗产甲烷特性的指标。含有叶皮单宁的褐海藻也有可能降低 CH ₄的产生。然而，大量研究探讨了海洋海藻可能的抗产甲烷作用，但结果不一致。这项工作回顾了与海藻、体外和体内瘤胃发酵、动物性能以及反刍动物肠道 CH ₄排放相关的现有数据。加深对与瘤胃发酵相关的海藻补充及其对动物性能和反刍动物 CH ₄排放的影响的了解可能会导致旨在减少温室气体排放同时提高动物生产力的新策略。