水素水400ppbが反芻動物の栄養改善とメタン排出抑制に与える影響：in vitroルーメン発酵および細菌叢の解析
This in vitro study examined how hydrogen-rich water (HRW) at three concentrations (200, 400, and 800 ppb) influences rumen fermentation and bacterial community dynamics, using 40 samples across 12-hour and 48-hour fermentation periods. Among the tested concentrations, 400 ppb HRW produced the most notable reduction in methane levels at both time points (P < 0.05) while achieving the highest microbial crude protein content after 48 hours. Ammonia nitrogen and microbial crude protein were elevated at 12 hours, though dry matter degradation was reduced. Total volatile fatty acid synthesis was not significantly altered, but the acetate-to-propionate ratio increased. Bacterial community profiling at 400 ppb revealed enrichment of Firmicutes, Streptococcus, Schwartzia, and Oribacterium, alongside reductions in Prevotella, Ruminobacter, and Succinivibrio. A negative correlation between Streptococcus abundance and methane output, and a positive correlation between Rikenellaceae_RC9_gut_group and methane, were identified. These findings suggest that 400 ppb HRW can reshape rumen microbial structure to suppress methane production without compromising fermentation efficiency, indicating potential utility as drinking water in livestock management.
At 400 ppb, hydrogen-rich water reshapes rumen microbial composition by enriching Streptococcus and Oribacterium while suppressing Prevotella and Ruminobacter, thereby reducing methanogenic activity without impairing volatile fatty acid production.
Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).
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https://h2-papers.org/en/papers/39528942