Fig. 6

A Classification of measured metabolites according to chemical class in rumen fluid. B partial least square discriminant analysis (PLS-DA) score plot of rumen fluid. C abundance of carbohydrates, D abundance of propionate precursors and propionate, E abundance of choline, trimethylamine, and formate, I concentration of total VFA, molar proportions of individual VFAs, and AP ratio. H metabolic pathway mapping of common quantified metabolites in the rumen fluid. Selected metabolites met the criteria of P < 0.1 and VIP score ≥ 1.5. CON, without PEO; PEO, Pinus koraiensis cone essential oil; VFA, volatile fatty acid; Others, sum of valerate, isovalerate and isobutyrate; AP, acetate to propionate; VIP, variable importance in projection. *P < 0.1, **P < 0.05