Effective reduction of enteric methane production with extracts of Perilla seeds by changing the bacterial 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 microbiome (i.e., diversity, composition, and structure). For the microbiome analysis, one amplicon library was prepared for bacteria from the DNA samples (only the samples from three doses: 0%, 2%, and 4%). Briefly, the V4 hypervariable region of bacterial 16S rRNA gene was amplifies using domain-specific primer set 515F/806R.