Effective reduction of enteric methane production with extracts of Perilla seeds by changing the archaeal phenotype in rumen cultures

The ethanol extracts from Perilla frutescens seeds was evaluated at five doses (0, 1, 2, 3, 4, and 5% of the fermentation substrate added, on dry matter basis) for its dose effects on pH, methane production, ammonia concentration, VFA, dry matter degradation (DMD), activity of glycose hydrolases (i.e., cellulase, carboxymethyl cellulase, and xylanase), populations of select rumen microbes, and archaea (i.e., diversity, composition, and structure). For archaeal community analysis, one amplicon library was prepared for archaea from the DNA samples (only the samples from three doses: 0%, 2%, and 4%). Briefly, the V1-V3 region of the archaeal 16S rRNA gene was amplified using archaea-specific domain primer set M86F/M448R.