Differential evaluation of oregano extracts in the production of volatile fatty acids and methane during ruminal fermentation in vitro

The objective was to evaluate the effect of oregano extracts on ruminal fermentation in vitro in the production of gas, volatile fatty acids (VFA) and methane. Four preparations of oregano (Lippia graveolens) were obtained with different methodology; for an aqueous medium, were obtained two extracts (cooking and infusion), which were prepared with triple-destilled water. The alcoholic extract was prepared in ethanol: water (80:20, v/v) and finally the oily extract was obtained by hydrodistillation for one hour in a modified Clevenger equipment. The oregano extract with the best mitigation of methane was the oil extract by reducing the concentration of this gas three times with respect to the control 160.27 mM/L and 463.73 mM/L respectively. It can be concluded that according to the methodology used in the preparation of oregano extracts, it is the type of chemical structure and concentration of active ingredients that were found in each extract, so these differences are what marked the effects during the in vitro ruminal fermentation on the activity of ruminal microorganisms in the production of gas, VFA and methane.