Secondary plant compounds such as catechin and resveratrol, and those pigments and antioxidants present in extracts of grape seed (Vitis vinifera L.) and bilberry (Vaccinium myrtillus L.) were shown to reduce methane production in rumen fluid. The plant substances were tested in a simplified model of ruminal methane production, using glycerol tripolylactate (Hydrogen Release Compound) as maintenance substrate for rumen bacteria. Fumarate, a known inhibitor of methane production, served as a reference compound in the in vitro tests. The methane-mitigating efficiencies of the plant extracts and compounds were calculated by subtraction of the methane quantity produced in flasks with the interfering additives from the one in blank flasks without additives. Then, the volume of the methane drop was translated into mmole by means of the Ideal Gas Law. Extracts of grape seed and bilberry and the pure compounds catechin and resveratrol had higher methanemitigating efficiencies than did fumarate at comparable concentrations. Although the mode of action of the plant compounds is largely unclear, chemical extraction of putative active compounds from the assays followed by HPLC analysis showed a drastic decrease of the plant compounds in question, such as anthocyanins and procyanidins. In the case of resveratrol, only 0.14% of the initial amount was recovered at the end of incubation. Hence, it can be concluded that the phenolic compounds were altered and degraded in the experimental model of ruminal methane production. Therefore, the methane-mitigating plant substances do not seem to imply the risk of bioaccumulation or persistence, but even offer the possibility of functioning as alternative electron sinks to methane precursors.
|Title of host publication||Proceedings of the 4th Greenhouse Gases and Animal Agriculture Conference, Banff, Canada, 3 - 8 October, 2010|
|Place of Publication||Banff|
|Publication status||Published - 2010|
|Event||The 4th Greenhouse Gases and Animal Agriculture Conference, Banff, Canada - |
Duration: 3 Oct 2010 → 8 Oct 2010
|Conference||The 4th Greenhouse Gases and Animal Agriculture Conference, Banff, Canada|
|Period||3/10/10 → 8/10/10|