Effects of duodenal infusion of sunflower oil on β-glucuronidase activity and enterolactone concentration in dairy cows fed flax meal

•Microbial β-glucuronidase increases absorption of mammalian lignans.•Abomasal infusion of sunflower oil has no effect on β-glucuronidase activity.•Dietary flax meal decreases fecal β-glucuronidase activity.•Flax lignans metabolism is not affected by sunflower oil in the small intestine.