Effect of rosemary extracts on rumen microflora of Sanhe dairy cattle

Rosemary extract (RE) is safe and efficient as a plant-derived feed additive. The aim of this study was to evaluate the effect of dietary addition of crude extract of rosemary on the rumen microbiome of Sanhe cattle.The RE group (N = 8) was fed the basal diet + 20g/per-day of RE and the CON group (N = 8) was fed the basal diet only and the experiment was conducted for 57 days. On the last day of the trial period, rumen fluid was collected using an oral stomach tube hose 2 h prior to morning feeding, rumen fluid genomic DNA was extracted, and macrogenomic sequencing was performed. Macro-genome sequencing of rumen fluid was performed based on second-generation sequencing technology and commissioned to Novogene Co., Ltd. (Beijing, China)