Seaweed supplementation to mitigate methane (CH4) emissions by cattle (SeaCH4NGE-PLUS)

This report contains the main experimental results of the SeaCH4NGE-PLUS project. In short, screening of the chemical content showed approx. 20 algae species collected in Iceland in 2020 and 2021, not bromoform-rich seaweed, but bromoform-rich seaweed can have a methane-reducing effect when given to cattle. Samples of brown algae were often high in phenol content, indicating a high fluorotannin content that has been linked to moderate methane reduction. Studies on Asparagopsis algae. indicated that these samples could have a short shelf life, but the effect was smaller than expected. Fermentation can have a small positive effect on methane production (ie slightly reduce production), but the extraction of the florotannin did not have a decisive effect on methane production. This report is closed until 31.12.2023.
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This report contains the main experimental results from the project SeaCH4NGE-PLUS. Briefly, the screening of chemical content of a range of seaweeds collected in Iceland in 2020 and 2021 did not identify a bromoform rich seaweed that had high promise as a methane reducing feed component for cattle. Certain samples of brown macroalgae were high in total phenolic content, indicating a high phlorotannin content that has been associated with a moderate methane reduction. That is consistent with the findings of this research. Samples of Asparagopsis sp. indicated that they may have a short shelf life to preserve the bromoform content. Fermentation may increase slightly the methane reduction potential of seaweed, but extracting phlorotannins did not yield a much higher reduction of methane as hypothesized. This report is closed until 31.12.2023.