Effects of the addition of essential oils cumimaldehyde, eugenol, and thymol on the in vitro gas production and digestibility of alfalfa (Medicago sativa L.) silage

Abstract

The aim of this study was to investigate the in vitro effects of the addition of three essential oils, mainly cuminaldehyde,eugenol, and thymol to alfalfa (Medicago sativa L.) silage on gas production, digestibility, and metabolic energy. The essential oils wereadded at 0 ppm (controls) and 100 ppm (group 1), 200 ppm (group 2), and 300 ppm (group 3) with three replications. The cumulativeamount of gas resulting from the addition of the three essential oils at the 96th h of incubation was significantly lower than that of thecontrol group (P < 0.05). The cumulative amount of gas production at the 96th h of incubation with thymol ranged from 184.63 mL/g to217.38 mL/g. In conclusion, this study showed that the addition of different amounts of cuminaldehyde, eugenol, and thymol to alfalfasilage reduced the amount of in vitro gas production. Therefore, these treatments can potentially reduce environmental pollution fromruminal digestion. However, the use of increasing levels of essential oils reduced the amounts of digestible organic matter and metabolicenergy. Additional studies are necessary to reveal the effects of these essential oils on in vivo ruminal fermentation by measuringchanges in feed consumption and productivity