From Chromatography to Climate: Profiling Tropical Seaweeds as Methane-Reducing Ruminant Feed Additives

Lessening enteric methane emissions in ruminant livestock (such as cattle and goats) has become a global challenge in achieving sustainable production. Although the supplementation of seaweed in the diet of ruminants has shown hopeful results, most of the research conducted on this topic has focused on temperate species, leaving tropical species underexplored.

A recent study published in Veterinary World attempted to address this knowledge gap (1). This study, conducted by researchers at Universitas Andalas, IPB University, and the National Research and Innovation Agency (all in Indonesia), investigated the nutritional composition, bioactive compounds, and in vitro rumen fermentation characteristics of two tropical seaweeds, brown seaweed (Sargassum binderi) and green seaweed (Kappaphycus striatum), as potential functional feed additives for ruminant livestock (1). In the study, amino acids and fatty acids were profiled using high-performance liquid chromatography (HPLC) and gas chromatography-flame ionization detection (GC-FID), respectively, while bioactive metabolites were identified through liquid chromatography-high-resolution mass spectrometry (LC–HRMS) metabolomics.

Greenhouse gas (GHG) emissions from the livestock sector are responsible for roughly 24.5–29% of total global emissions, a percentage equivalent to emissions for which the transport industry is responsible (2–4). Methane emissions represent a particular concern, both for their potent greenhouse effect and because they signify a substantial loss of feed energy which could otherwise support animal growth and productivity (5). As climate change increases and the demand for animal-derived food products rises, there is a critical need for sustainable innovations for the reduction of ruminant methane emissions without compromising productivity. One potential approach is the supplementation of seaweed to livestock diet; seaweed offers a robust source of bioactive compounds known to suppress the production of enteric methane (6), boost the utilization of nutrients, and improve general ruminant performance (4, 7–9).

“Despite the growing body of evidence supporting the use of seaweeds as sustainable feed additives for mitigating enteric methane emissions in ruminants,” the authors wrote in their article (1), “most existing research has been restricted to temperate and subtropical species… Consequently, there is a lack of research focusing on tropical seaweed species, which are abundant, locally adaptable, and more environmentally sustainable for integration into regional livestock systems such as those in Indonesia…By bridging the existing knowledge gap, this study provides the first integrated assessment of these two tropical seaweed species as potential ruminant feed additives, contributing to the development of sustainable, regionally sourced strategies for improving animal productivity and reducing environmental impacts in tropical livestock production systems.”

The rumen fluid for study was obtained as a byproduct from goats immediately after their slaughter for human consumption at a licensed abattoir. The investigation revealed that green seaweed exhibited a higher crude protein content (7.52%) and digestibility (with a dry matter digestibility [DMD] percentage of 73.56% and an organic matter digestibility [OMD] percentage of 72.71%) than brown seaweed (with corresponding percentages of 6.84%, 46.38%, and 44.99%, respectively). Volatile fatty acid (VFA) production (136.75–151.75 mM) and ammonia concentrations (22.21–26.78 mM) differed significantly (p < 0.01) between species of seaweed, while the pH remained within the optimal range (7.00–7.21). Both seaweeds contained balanced essential and non-essential amino acid profiles and abundant polyunsaturated fatty acids, notably linoleic, α-linolenic, eicosapentaenoic acid, docosahexaenoic acid, and conjugated linoleic acid. Metabolomic screening identified ~85 bioactive compounds, including lipid-derived metabolites, amino alcohols, vitamins, and osmolytes such as betaine and cholecalciferol, indicating their potential to modulate rumen fermentation and enhance animal resilience (1).

“Both S. binderi and K. striatum demonstrated promising nutritional and bioactive potential as ruminant feed additives,” the authors wrote in their study (1). “Their compositional diversity suggests species-specific applications–S. binderi as an energy-dense supplement and K. striatum as a functional additive for stress adaptation.” (1)

However, the researchers believe that further in vivo trials are warranted for determining optimal inclusion levels, long-term safety, and methane mitigation efficacy under production conditions (1).

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References

1. Sucitra, L. S.; Zain, M.; Agustin, F. et al. Nutritional Composition, Bioactive Potential, and in vitro Rumen Fermentation of Tropical Brown (Sargassum binderi) and Green (Kappaphycus striatum) Seaweeds as Functional Feed Additives for Ruminants. Vet. World 2025, 18 (11), 3335-3351. DOI: 10.14202/vetworld.2025.3335-3351
2. Bačėninaitė, D.; Džermeikaitė, K.; Antanaitis, R. Global Warming and Dairy Cattle: How to Control and Reduce Methane Emission. Animals (Basel) 2022, 12 (19), 2687. DOI: 10.3390/ani12192687
3. Kristiansen, S.; Painter, J.; Shea, M. Animal Agriculture and Climate Change in the US and UK Elite Media: Volume, Responsibilities, Causes and Solutions. Environ. Commun. 2021, 15 (2), 153-172. DOI: 10.1080/17524032.2020.1805344
4. Min, B. R.; Parker, D.; Brauer, D. et al. The Role of Seaweed as a Potential Dietary Supplementation for Enteric Methane Mitigation in Ruminants: Challenges and Opportunities. Anim. Nutr. 2021, 7 (4), 1371–1387. DOI: 10.1016/j.aninu.2021.10.003
5. Huang, H.; Lechniak, D.; Szumacher-Strabel, M. et al. The Effect of Ensiled Paulownia Leaves in a High-Forage Diet on Ruminal Fermentation, Methane Production, Fatty Acid Composition, and Milk Production Performance of Dairy Cows. J. Anim. Sci. Biotechnol. 2022, 13 (1), 104. DOI: 10.1186/s40104-022-00745-9
6. Wanapat, M.; Prachumchai, R.; Dagaew, G. et al. Potential Use of Seaweed as a Dietary Supplement to Mitigate Enteric Methane Emission in Ruminants. Sci. Total Environ. 2024, 931, 173015. DOI: 10.1016/j.scitotenv.2024.173015
7. Costa, M.; Cardoso, C.; Afonso, C. et al. Current Knowledge and Future Perspectives of the Use of Seaweeds for Livestock Production and Meat Quality: A Systematic Review. J. Anim. Physiol. Anim. Nutr. (Berl) 2021, 105 (6), 1075–1102. DOI: 10.1111/jpn.13509
8. Makkar, H. P. S.; Tran, G.; Heuzé, V. et al. Seaweeds for Livestock Diets: A Review. Anim. Feed Sci. Technol. 2016, 212, 1–17. DOI: 10.1016/j.anifeedsci.2015.09.018
9. Corona, G.; Ji, Y.; Anegboonlap, P. et al. Gastrointestinal Modifications and Bioavailability of Brown Seaweed Phlorotannins and Effects on Inflammatory Markers. Br. J. Nutr. 2016, 115 (7), 1240–1253.DOI: 10.1017/S0007114516000210