AUTHOR=Krizsan Sophie J. , Hayes Maria , Gröndahl Fredrik , Ramin Mohammad , O’Hara Peter , Kenny Owen 

TITLE=Characterization and in vitro assessment of seaweed bioactives with potential to reduce methane production

JOURNAL=Frontiers in Animal Science

VOLUME=3

YEAR=2022

URL=https://www.frontiersin.org/journals/animal-science/articles/10.3389/fanim.2022.1062324

DOI=10.3389/fanim.2022.1062324

ISSN=2673-6225

ABSTRACT=<p>This study collates compositional analysis of seaweeds data with information generated from <italic>in vitro</italic> gas production assays in the presence and absence of seaweeds. The aim was to assess and rank 27 native northern European seaweeds as potential feed ingredients for use to reduce methane emissions from ruminants. It provides information for use in future <italic>in vivo</italic> dietary trials concerning feed manipulation strategies to reduce CH<sub>4</sub> emissions efficiently from domestic ruminants based on dietary seaweed supplementation. The seaweeds <italic>H. siliquosa</italic> and <italic>A. nodosum</italic> belonging to phylum <italic>Phaeophyta</italic> displayed the highest concentration of phlorotannins and antioxidant activity among the macroalgae giving anti-methanogenic effect <italic>in vitro</italic>, while this explanation was not valid for the observed reduction in methane when supplementing with <italic>C. filum</italic> and <italic>L. digitata</italic> in this study. <italic>D. carnosa</italic> and <italic>C. tenuicorne</italic> belonging to phylum <italic>Rhodophyta</italic> had the highest protein content among the macroalgae that reduced methane production <italic>in vitro</italic>. There were no obvious explanation from the compositional analysis conducted in this study to the reduced methane production <italic>in vitro</italic> when supplementing with <italic>U. lactuca</italic> belonging to phylum <italic>Chlorophyta</italic>. The strongest and most complete methane inhibition <italic>in vitro</italic> was observed when supplementing with <italic>Asparagopsis taxiformis</italic> that was used as a positive control in this study.</p>