Journal of Tekirdag Agricultural Faculty, vol.18, no.1, pp.138-145, 2021 (Scopus)
The digestibility of feed in ruminants and the volatile fatty acids (VFA) resulting from digestion directly affect
animal performance. It has long been studied on the use of essential oils as an alternative to antibiotics to ensure
optimum conditions for the rumen environment. Cyclotrichium niveum (mountain mint) essential oil is rich in
antimicrobial agents. In this study different doses (0, 50, 100 and 150 mg/L of culture fluid) of Cyclotrichium
niveum essential oil was incubated 24 hours with barley in diluted ruminal fluid takes from fistulated cows fed
with a 40:60 concentrate:forage diet in order to assess the effects on rumen microbial fermentation and in vitro
true digestibility of barley. True digestibility of barley was determined in ANKOM Daisy Incubator. All doses of
Cyclotrichium niveum significantly (P<0.001) decreased the in vitro dry matter (DM), organic matter (OM),
neutral detergent fiber (NDF) digestibility of barley. Cyclotrichium niveum essential oil negatively affected endproducts
of rumen fermentation; the value of the measured rumen volatile fatty acids (VFA: acetate, propionate,
butyrate, isobutyric acid, valerate and isovalerate) significantly decreased compared to the control group (P<0.001).
Carbon dioxide and methane gases created as a result of incubation in rumen fluid were calculated using volatile
fatty acid values formed in rumen fluid. The addition of Cyclotrichium niveum essential oil significantly reduces
the CO2 in rumen fluid (P<0.001). Methane (CH4) gas from rumen fluid was significantly decreased in treatment
groups compared the control group (P <0.001) While end-products of rumen fermentation parameters significantly
decreased with all doses of Cyclotrichium niveum essential oil, rumen pH has increased (P<0.05). The results show
that when the Cyclotrichium niveum essential oil incubated with barley significantly inhibited the rumen microbial
activity and overall fermentation process of rumen.