Effects Of Different Levels Of Eucalyptus Oil On Methane Production Under In Vitro Conditions

Livestock animals are seriously contributing to global warming as methane producers. Six levels (0, 2, 4, 6, 8, and 10 ml.kg(-1) DM) of eucalyptus oil (EuO) were investigated under in vitro conditions to study the mitigation ability for methane production, using two rations: R1 (70% forage: 30% concentrates) and R2 (60% forage: 40% concentrates). Two cannulated sheep were used as donor animals to obtain the rumen liquid. The results showed that CH 4 production levels were significantly (P <= 0.05) lower in all treated groups with EuO than the control group (0 ml.kg(-1) DM) in both rations. The retreating for CH 4 of R1 was 32%, adding of 2 mL.kg(-1) DM, and was 38% in10 ml.kg(-1) DM. Regarding R2, the decrease ratio of methane production was 42% in 2.0 mL addition, whereas it was 46% in 10 mL of addition rate. In R2, protozoa count was significantly (P <= 0.05) lower by adding the eucalyptus oil compared with the control. In conclusion, using EuO and a high-protein diet could decrease both total gas volume and methane production even with minimal oil levels (2.0 mL EuO.kg(-1)DM). It is recommended to carry out an in vivo experiment to emphasize the effects of EuO on the ruminant.