Comparison of enantiomers of organic acids for their effects on methane production in vitro
2014
Reis, L. G. | Chaves, A. V. | Williams, S. R. O. | Moate, P. J.
This study aimed to evaluate the effect of organic acids on in vitro fermentation characteristics. Four organic acids (tartaric, malic, fumaric and citric) and their enantiomers (L-tartaric, D-tartaric, DL-tartaric, L-malic and DL-malic) were analysed using in vitro batch culture incubations, at four concentrations (0, 5, 10 and 15 mM). Cumulative total gas and methane (CH4) production (mL/g DM) were measured at 6, 12 and 24 h; ammonia, pH, volatile fatty acids (VFA) and in vitro dry matter digestibility (IVDMD) were determined after 24 h of fermentation. Overall, addition of acids at 5 to 15 mM increased (P < 0.0001) cumulative gas and CH4 production. No effect (P > 0.10) of enantiomers, individual acid or interaction acid × concentration was detected at 12 and 24 h for cumulative gas or CH4 production. Addition of DL-malic, L-malic and fumaric acids increased (P < 0.0001) the percentage of propionic acid in the ruminal fluid total VFA compared with all concentrations of the other organic acids or their enantiomers. Ammonia concentration was not affected (P ≥ 0.28) by the addition of organic acids, concentrations or interactions. These findings are evidence that ruminal microorganisms can metabolise both D- and L-enantiomers of organic acids. None of the organic acids and their enantiomers at four different concentrations demonstrated potential as CH4 mitigation agents.
显示更多 [+] 显示较少 [-]