Ruminal Methane Production on Simple Phenolic Acids Addition in in Vitro Gas Production Method

Abstract

Methane production from ruminants contributes to total global methane production, which is an important contributor to global warming. In this experiment, six sources of simple phenolic acids (benzoic, cinnamic, phenylacetic, caffeic, p-coumaric and ferulic acids) at two different levels (2 and 5 mM) added to hay diet were evaluated for their potential to reduce enteric methane production using in vitro Hohenheim gas production method. The measured variables were gas production, methane, organic matter digestibility (OMD), and short chain fatty acids (SCFA). The results showed that addition of cinnamic, caffeic, p-coumaric and ferulic acids at 5 mM significantly (P<0.05) decreased methane production. Caffeic acid at 5 mM was the most effective out of the simple phenols tested and it decreased methane by 6.3% from the control. The order of simple phenols to decrease methane was: caffeic acid > p-coumaric > ferulic > cinnamic. The addition of simple phenols did not significantly decrease OMD. Addition of simple phenols tends to decrease total SCFA production. It was concluded that methane decrease by addition of phenolic acids was relatively small, and the effect of phenolic acids on methane decrease depended on the source and concentration applied.

Key words: methane, phenolic acids, in vitro, rumen