Reducing methane emissions and the methanogen population in the rumen of Tibetan sheep by dietary supplementation with coconut oil

The objective was to evaluate the effect of dietary coconut oil on methane (CH4) emissions and the microbial community in Tibetan sheep. Twelve animals were assigned to receive either a control diet (oaten hay) or a mixture diet containing concentrate (maize meal), in which coconut oil was supplemented at 12 g/day or not for a period of 4 weeks. CH4 emissions were measured by using the 'tunnel' technique, and microbial communities were examined using quantitative real-time PCR. Daily CH4 production for the control and forage-to-concentrate ratio of 6:4 was 17.8 and 15.3 g, respectively. Coconut oil was particularly effective at reducing CH4 emissions from Tibetan sheep. The inclusion of coconut oil for the control decreased CH4 production (in grams per day) by 61.2%. In addition, there was a positive correlation between the number of methanogens and the daily CH4 production (R = 0.95, P < 0.001). Oaten hay diet containing maize meal (6:4) plus coconut oil supplemented at 12 g/day decreases the number of methanogens by 77% and a decreases in the ruminal fungal population (85-95%) and Fibrobacter succinogenes (50-98%) but an increase in Ruminococcus flavefaciens (25-70%). The results from our experiment suggest that adding coconut oil to the diet can reduce CH4 emissions in Tibetan sheep and that these reductions persist for at least the 4-week feeding period.