Effect of nitroethane, dimethyl-2-nitroglutarate and 2-nitro-methyl-propionate on ruminal methane production and hydrogen balance in vitro.

Ruminal methanogenesis is considered a digestive inefficiency that results in the loss of 2-12% of the host's gross energy intake and contributes nearly 20% to the United States annual CH(4) emissions. Presently, the effects of the known CH(4) inhibitor, nitroethane, and two synthetic nitrocompounds, dimethyl-2-nitroglutarate and 2-nitro-methyl-propionate, on ruminal CH(4) production and fermentation were evaluated in vitro. After 24 h incubation at 39 degrees C under 100% CO(2), ruminal fluid cultures treated with 2.97 or 11.88 mumol ml(-1) of the respective nitrocompounds produced > 92% less CH(4) (P < 0.05) than non-treated controls. Quantification of fermentation end-products produced and H(2) balance estimates indicate that fermentation efficiencies were not compromised by the nitro-treatments.