Distribution of dietary palm carotenes and their metabolites in the rabbit

Abstract

The distributions of dietary palm carotenes and their metabolites in rabbit's plasma and organs were determined using non-aqueous reversed-phase high performance liquid chromatography and a photodiode array detector. Rabbits fed with diets enriched with palm carotenes 309 mg/kg diet were found to have the different various carotenes in varying amounts in their plasma and organ tissues, mainly in the liver and adrenal glands. Most of the supplemented α- and β-carotenes were metabolized to retinol and retinyl esters, which were mainly stored in the liver and to a lesser extent, the pancreas. Small amounts of other carotenes such as phytoene, phytofluene and ζ-carotene, were present in the rabbit's plasma and organ tissues. The contents of retinol and retinyl esters in the liver of rabbits fed diets supplemented with palm carotenes were respectively 3 and 30 times higher than that in the rabbit groups fed diets without palm carotenes. The major retinyl esters present in the organ tissues were retinyl palmitate, oleate and linoleate, whereas only retinyl palmitate and stearate were found to be in predominant in the plasma. ϵ-Retinyl esters, which are metabolites from α-carotene, were also found to be present in the liver and pancreas. For rabbits fed with diets enriched with palm carotenes but depleted of palm vitamin E, relatively small amounts of carotenes and retinyl esters were detected (only in the plasma and liver), indicating that vitamin E substantially affects the disposition of dietary carotenes and their metabolites in plasma and tissues of rabbits.