design: DNA from rumen fluid from sheep supplemented (or not) with an herbal compound was extracted with the ZymoBIOMICS DNA miniprep kit; Bacterial 16S ribosomal RNA genes targeted sequencing was performed using the Quick-16S NGS Library Prep Kit (Zymo Research, Irvine, CA). The bacterial and archaeal  V3-V4 region of 16S gene were amplified using Zymo's specific primers. The final library was sequenced on Illumina MiSeq with a v3 reagent kit (600 cycles). The sequencing was performed with 10% PhiX spike-in.