Phytochemistry and in vitro effects on methane production from ruminants

The current work examined determinants of enteric CH4 production from cattle native to Benin according to the 2006 Intergovernmental Panel on Climate Change Guidelines for National Greenhouse Gas Inventories and screened the potential of some essential oils (EO) from medicinal plants native to Benin to reduce enteric CH4 production with beneficial effects on ruminal fermentation in vitro. Effects of EO (Zingiber officinalis, Lippia multiflora, Mentha piperita, Eucalyptus citriodora, Ocimum basilicum, Cymbopogon citratus, Laurus nobilis, Citrus aurantifolia, Ocimum gratissimum) on enteric CH4 production were evaluated in in vitro batch cultures and Rumen Simulation Technique (RUSITEC) experiments using Andropogon gayanus grass as substrate. Methane emission factors estimated using data specific to Benin cattle population varied among cattle breeds and subcategory owing to differences in proportions of gross energy intake expended to meet maintenance, production and activity with a national value of 39.5 kg CH4/head per year. Essential oils show promise as a means of reducing enteric CH4 from ruminants at different dosages, but they could have negative side-effects on rumen function.