Effect of seaweed-based trace mineral block supplementation on methane emission in ruminants

초록

Enteric methane production in ruminants contributes significantly to greenhouse gas (GHG) emissions and represents a loss of dietary energy. In this study, we investigated the effects of trace mineral supplementation, derived from sea staghorn (Codium fragile) which is rich in essential trace elements (Fe, Mn, Co, Zn, etc.), on rumen microbial community structure and methanogenesis in vitro fermentation conditions. 1% of the trace mineral block (TMB) supplementation resulted in a slight improvement (77.4%) in dry matter digestibility and significantly reduced methane production by 24%, along with a lower acetate-to-propionate ratio and decreased CO₂ and total gas production. In contrast, 2% TMB further reduced methane but significantly reduced digestibility, suggesting microbial stress at higher supplementation levels. In 16S rRNA gene sequencing analysis, archaeal communities showed an overall reduction under TMB supplementation, with enrichment of Methanobrevibacter thaueri and suppression of Methanobrevibacter millerae. Bacterial shifts included increased abundance of hydrogen-utilizing and propionate-associated taxa (Ruminobacter, Succinivibrio, and Selenomonas), particularly at 1% TMB. These findings indicated that 1% TMB had potential positive effect on fermentation efficiency and methane mitigation, whereas higher supplementation impairs methanogenic archaea and bacterial communities, reduces digestibility and makes methane mitigation less efficient. © The Korean Society for Applied Biological Chemistry 2026.

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