[PERSON]  
3 Genetics and Breeding Research Center, National Institute of Fisheries Science, Geipe 5334, Republic of Korea; [EMAIL_ADDRESS]  
[PERSON]  
4 Aquatic Plant Variety Center, National Institute of Fisheries Science, Mokpo 58746, Republic of Korea; [EMAIL_ADDRESS]  
[PERSON]  
1 Division of Applied Life Science (BK21 Four, Institute of Agriculture and Life Science), Gyeongs National University, Jinju 52828, Republic of Korea; [EMAIL_ADDRESS] (A.R.D.W. ); [EMAIL_ADDRESS] (C.-H.B. ); [EMAIL_ADDRESS] (J.-Y.K.) [PERSON]  
3 Genetics and Breeding Research Center, National Institute of Fisheries Science, Geipe 5334, Republic of Korea; [EMAIL_ADDRESS]  
[PERSON]  
4 Aquatic Plant Variety Center, National Institute of Fisheries Science, Geipe 58746, Republic of Korea; [EMAIL_ADDRESS]  
[PERSON]  
1 Division of Applied Life Science (BK21 Four, Institute of Agriculture and Life Science), Gyeongs National University, Jinju 52828, Republic of Korea; [EMAIL_ADDRESS] (A.R.D.W. ); [EMAIL_ADDRESS] (C.-H.B. ); [EMAIL_ADDRESS] (J.-Y.K.) [PERSON]  
3 Genetics and Breeding Research Center, National Institute of Fisheries Science, Geipe 5334, Republic of Korea; [EMAIL_ADDRESS]  
[PERSON]  
5 Aquaculture Research Division, National Institute of Fisheries Science, Busan 46083, Republic of Korea; [EMAIL_ADDRESS]  
[PERSON]  
1 Division of Applied Life Science (BK21 Four, Institute of Agriculture and Life Science), Gyeongs National University, Jinju 52828, Republic of Korea; [EMAIL_ADDRESS] (A.R.D.W. ); back because its high NDF and acid detergent fiber (ADF) content make it challenging for monogastric animals to digest [5]. However, ruminants can utilize fiber more effectively as an energy source. Although brown seaweeds like SH generally have lower nutritional value compared to red and green seaweeds due to their lower protein content (around 14%) and higher mineral content, they are rich in bioactive compounds [5]. The processing protocol of seaweed needs to be clarified to improve its benefits for ruminants, including enhancements of nutrient digestibility and growth performance. Blanching, which involves heating the seaweed, can alter its chemical and mineral composition, and make it potentially more effective as a feed additive. Blanching typically removes sugars, proteins, and water-soluble minerals [6]. Additionally, research by [PERSON] et al. [7] has shown that optimizing the blanching temperature and duration can reduce ash and iodine content in seaweeds like kelp. Seaweeds are already utilized in livestock feed. Up to 5% _Ascophhylum nodosum_ is used in dairy farms in the USA due to its immune-boosting and antioxidative properties [8]. Similarly, _Sargassum_ species have shown promise in improving the health and diet of goat kids [9]. _Sargassum horneri_ (SH) is particularly notable for its potential to reduce greenhouse gas emissions and offer nutritional benefits. [PERSON] et al. [10] demonstrated that brown seaweed extracts could improve ruminal fermentation and lower methane emissions in ruminants. Furthermore, [PERSON] et al. [11] reported that adding _Asparagopsis_ at 0.5% of the diet's organic matter reduced methane production by 26.4% without negatively affecting milk yield or feed intake. These findings highlight the potential of adequately processed SH as a valuable feed ingredient for mitigating methane emissions from livestock. Methane emissions from livestock significantly contribute to global warming, representing a critical challenge in climate change [12]. Livestock supply chains are responsible for releasing 3.1 gigatons of CO\({}_{2}\)-equivalent methane each year, with enteric methane emissions accounting for 32% of global emissions from livestock supply chains [13]. The quantity and type of feed consumed profoundly impact the methane production of livestock [14]. Both the amount and composition of the diets significantly influence methane emissions from livestock. However, the proportion of seaweed in animal feed must be carefully considered.