title: Metabolism of canthaxanthin, a red diketocarotenoid, by chickens.
abstract: Canthaxanthin, (4,4'-diketo-beta,beta-carotene), a red carotenoid used to extend the dominant wavelength of the yellow pigments in the skin and egg yolk of chickens, was fed (70 micrograms/g diet) to chicks depleted of normal tissue oxycarotenoids. High performance liquid chromatography analysis of tissues from such chicks revealed that a portion of canthaxanthin was reduced to 4-hydroxyechinenone (4-hydroxy-4'-keto-beta,beta-carotene) that in turn was reduced in part to isozeaxanthin (4,4'-dihydroxy-beta,beta-carotene). The alcohols thus formed were acylated in part to 4-hydroxyechinenone monoester and isozeaxanthin monoester and diester. Individual metabolites were identified by retention times, ratios A470/A430, and stopped-flow spectral analyses, which were identical in each case to authentic standards. Ratios of canthaxanthin to metabolites varied with the tissue, but in general metabolites were concentrated in the integument.
mesh_terms: D000818:Animals; D016644:Canthaxanthin; D002338:Carotenoids / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism / Q000493:pharmacokinetics; D002645:Chickens / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D014018:Tissue Distribution
chemical_list: D002338:Carotenoids; D016644:Canthaxanthin