Fecal bile acid patterns in some Xenarthra species from argentina as determined by HPLC

ARAUJO, M. SOLEDAD; LÓPEZ, GUSTAVO H.; CASANAVE, EMMA B.

Mendoza, Argentina, 9-14/8

Congreso; X-IMC; 2009

IFM, SAREM

Determination of fecal bile acid patterns is a useful tool to identify the presence of certain species in an area. In this work, a method for HPLC determination of bile acids in Xenarthra feces is described. Feces from individuals of Zaedyus pichiy, Chaetophractus vellerosus, C. villosus, Tamandua tetradactyla and Myrmecophaga tridactyla were analyzed. Bile acids were extracted from feces with benzene:methanol. A Thermo-Finnigan HPLC equipped with an UV-visible detector set at 200 and 210 nm was used. The separation was achieved using a C-18 reverse phase column. Mobile phase consisted of ammonium carbonate 0.3%:acetonitrile (73:27) 10 min; (68:32) 10 min; (50:50) 10 min, at a constant flow of 0.8 ml/min. Bile acids were identified by comparison with 16 standard retention times (Rt), and quantified by the area under peaks. All the species were differentiated by their bile acid patterns, having lithocholic acid (Rt 29,6 min), glicochenodeoxycholic acid (Rt 23,3 min), cholic acid (Rt 9,5 min) and 1 unidentified peak (Rt 5,3 min). C. villosus, C. vellerosus and Z. pichiy have taurodeoxycholic acid (Rt 26,8 min) and dehydrocholic acid (Rt 4,7 min), while M. tridactyla and T. tetradactyla lack these compounds. C. villosus glycochenodeoxycholic acid’s peak is smaller than taurodeoxycholic acid, being this relation opposite in Z. pichiy and C. vellerosus. In C. vellerosus there is an unidentified peak at Rt 14,2 min, absent in C. villosus and Z. pichiy; the relation between ursodeoxycholic acid and cholic acid is smaller in C. vellerosus than in Z. pichiy; in M. tridactyla cholic acid’s peak is bigger than in T. tetradactyla. We were able to differentiate the feces of all the studied Xenarthra species; thus, demonstrating that HPLC is a useful tool to identify feces from unknown origin in ecological studies.