The profile of urinary lipid metabolites in cats

Polyunsaturated fatty acids including arachidonic acid (AA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are converted to lipid mediators by oxidation. Unlike other mammals, cats cannot synthesize AA. Since their lipid metabolic features remain unknown, we qualitatively analyzed 118 types of urinary lipid metabolites in healthy neutered cats. Using LC-MS, we found 26 lipid metabolites in urines of all individuals. In detail, 20 AA-, 5 EPA- and 1 DHA-derived lipid mediators were detected. Focusing on oxidative pathway, 17 cyclooxygenase-metabolites and 5 metabolites produced by non-enzymatic pathway were detected. Of interest, few lipoxygenase- or cytochrome P450-metabolites were excreted. Thus, AA-derived cyclooxygenase-metabolites mainly composed the urinary lipid metabolites in cats.