The present experiment was aimed to investigate the effects of dietary different levels of quercetin on growth performance, nutrient apparent digestibility, serum biochemical indices, fecal microorganisms and their metabolites of weaned piglets. A total of 144 healthy 21-day-old " Duroc×Landrace×Large White" crossbred weaned piglets with similar body weight [ (7.45±0.09) kg] were randomly divided into 3 groups with 8 replicates per group and 6 piglets per replicate. Piglets in three groups were fed the basal diet (control group), basal diet+...