In vitro EVALUATION OF THE EFFECT OF 2-NITROETHANOL AND NITROETHANE ON METHANOGENESIS AND RUMINAL FERMENTATION

Abstract

Rumen methanogenesis is considered an inefficient process, as it can lead to the loss of up to 12% of the total energy consumed by the ruminant. Recent studies have demonstrated the antimethanogenic capacity of nitrocompounds such as 2-nitro-1-propanol and 3-nitro-1-propionic acid under in vitro conditions. However, the effects of 2-nitroethanol and nitroethane have not yet been evaluated. The objective of this study was to determine the capacity of these nitrocompounds to reduce methane production in an in vitro system using three consecutive 24-hour incubation periods. The results showed that all nitrocompounds significantly reduced methane production, achieving reductions of up to 98%. However, changes in volatile fatty acid production were also observed. Total gas production was not affected, whereas hydrogen accumulation increased, suggesting a metabolic redirection toward alternative pathways such as the fumarate pathway. In addition, changes in microbial diversity were observed with nitroethane, which caused notable initial reductions in the ruminal microbiota. Overall, discontinuous serial supplementation with 2-nitroethanol and nitroethane exerts a significant effect on methane reduction in vitro, maintaining its efficacy despite the adaptive capacity of the rumen ecosystem. Nevertheless, further studies are required to evaluate the final products of derived from their reduction.