Influences of Portulaca oleracea extracts on in vitro methane emissions and rumen fermentation of forage

This paper was conducted to study the influences of Portulaca oleracea extract with high flavonoid content in different solvents (water and 80% ethanol) on in vitro methane emission and rumen fermentation of forage for 24 h. Four treatments were control without additive, monensin (6 mg), water extract (40 mg) and ethanol extract (40 mg), respectively. Gas productions of ethanol extract (65.32 ml/g DM) and water extract (66.97 ml/g DM) were significantly higher than that of control (61.24 ml/g DM) and monensin (51.11 ml/g DM). Comparing with control (21.02%), methane emissions of ethanol extract (9.44%) and monensin (12.27%) were reduced significantly. The pH value of ethanol extract (6.47) declined significantly compared to control (6.79). Comparing with MCP of control (6.71 mg/ml), there was significant increase by ethanol extract (7.21 mg/ml) and water extract (7.18 mg/ml) but no significant change by monensin. NH3-N by ethanol extract (4.59 mg/100 ml) and water extract (4.75 mg/100 ml) was decreased significantly in contrast to control (8.39 mg/100 ml). VFA of ethanol extract (36.89 mM) and water extract (35.19 mM) was increased significantly as compared to control (31.79 mM) and monensin (31.40 mM). There was a significant decrease in acetate to propionate ratio to ethanol extracts (4.61) and monensin (4.66) compared with control (5.30). Water and ethanol extracts increased total bacteria count by 7.48% and 6.66%, respectively. Monensin and ethanol extract significantly reduced methanogens by 39% and 58%, while water extract did not affect the methanogens count. Furthermore, protozoa numbers of monensin and ethanol extract were significantly reduced by 44% and 38%, and protozoa were not affected by water extract. In addition, ruminal fungi were not influenced by addition of water extract and ethanol extract. In conclusion, P. oleracea ethanol extract can promote the extent of fermentation and effectively inhibit methane production.