乳牛のルーメン発酵とメタン生成に対する金属マグネシウム由来の分子状水素の影響
A crossover experiment using four non-lactating Holstein dairy cows examined how elevated dissolved H2, generated by dietary elemental magnesium supplementation, influences rumen fermentation and enteric methane production. Compared with Mg(OH)2 supplementation, elemental Mg increased rumen dissolved H2 and methane concentrations at 2.5 hours post-feeding. Feed digestibility and volatile fatty acid concentrations declined, while the acetate-to-propionate ratio and succinate concentration rose. Microbial community analysis revealed reduced abundance of carbohydrate-degrading bacteria (Ruminococcaceae_UCG-014, Bifidobacterium, Mollicutes_RF9) and increased Christensenellaceae and Bacteroidales_BS11. Methanogen populations shifted, with greater abundance of Methanomassiliicoccales and Methanobacteriales and higher 16S rRNA gene copy numbers. These findings indicate that a pulse of dissolved H2 suppresses fermentative bacteria, redirects H2 toward succinate synthesis, and ultimately promotes methanogenesis.
Dissolved H2 generated from elemental Mg suppresses carbohydrate-degrading rumen bacteria, reducing fermentation efficiency. Concurrently, enrichment of Christensenellaceae and Bacteroidales_BS11 channels H2 into succinate production, while expanded methanogen populations (Methanomassiliicoccales, Methanobacteriales) increase H2 utilization for methane synthesis.
This study is at the animal-experiment stage. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).
See also:
https://h2-papers.org/en/papers/30981486