PSXIV-13 Effect of phytochemicals on in vitro rumen fermentation and methane production

Abstract

Abstract The objective of this study was to evaluate the effects of eight phytochemicals from four plant species, in two presentations, essential oils (EO) and aqueous extracts (AE) of garlic (GEO, GAE), cinnamon (CEO, CAE), eucalyptus (EEO, EAE) and rosemary (REO, RAE) on rumen fermentation, using the in vitro gas production technique. The experiment was set up as a completely randomized block design in a 2 × 4 factorial arrangement of treatments. All treatments were incubated with 0.5 g of a basal diet (BD; 50% concentrate, 20% alfalfa and 30% corn silage, dry matter basis). Additionally, BD and BD with 30 ppm of sodium monensin (MON) were used as controls. Phytochemicals were evaluated at a single dose of 900 mg/L of inoculum. In vitro dry matter digestibility (IVDMD), maximum volume of gas (Vmax), gas production rate (S) and lag phase (L) were evaluated. Methane (CH4) was determined indirectly, by fixation of CO2present in gas samples with 1M KOH solution, Non-fixed gas was assumed to be CH4. Methane production was correlated with organic matter fermented in the rumen (mL CH4/g OMFR). Data were analyzed using PROC MIXED of SAS ©. The effects of treatments were tested for the following contrasts: EO Vs AE, W Vs EO, W Vs AE. Some essential oils (GEO, CEO, REO) decreased CH4 production (mL CH4/g OMFR) and IVDMD by 20.4% and 17.8% compared to control treatments (BD and MON) (P < 0.05). Aqueous extracts showed a similar response (P < 0.05) to control treatments. In conclusion the use of essential oils negatively affected rumen fermentation and the production of CH4 in P cinnamon essential oil.