Endogenous free diOH BAs and liberated free diOH BAs in urine of breast-fed female piglets by different enzymatic deconjugations. Control, urine sample without enzymatic treatment; CGH, urine sample after CGH treatment; GUS, urine sample after GUS treatment; S&GI, urine sample after sulfatase with glucuronidase inhibitor treatment; CH&S, after choloylglycine hydrolase and sulfatase treatment. Free triOH BAs (A), Free tetraOH BAs (B), Free diOH BAs (C), Free monoOH BAs (D).