Inhibition of growth of methane-producing bacteria of the ruminant forestomach by hydroxymethylglutaryl-SCoA reductase inhibitors.

Two hydroxymethylglutaryl-SCoA (HMG-CoA) reductase inhibitors, mevastatin and lovastatin, inhibited the in vitro growth and production of CH4 of strains of Methanobrevibacter isolated from the rumen. Mevastatin or lovastatin did not inhibit growth of species of rumen bacteria that are essential for fermenting cellulose, starch and other plant polysaccharides to acetate, propionate, and butyrate. Approximately 4 nmol of lovastatin per milliliter resulted in 50% growth inhibition of Methanobrevibacter strain ZA10 and concentrations > or =10 nmol per milliliter completely inhibited growth and CH4 formation. Results of in vitro growth studies suggest that supplementation of ruminant feeds with HMG-CoA inhibitors could decrease ruminant methane production and increase the efficiency of feed utilization by domestic ruminants.