Vitamin A (Retinol and Retinyl Esters), α‐Tocopherol and Lipid Levels in Plasma of Captive Wild Mammals and Birds1

Summary Vitamin A (retinol and retinyl esters), vitamin E and lipids were determined in a wide variety of wild mammals and birds held in captivity. In mammals plasma levels of vitamin A were generally below 500ng/ml and those of vitamin E were highly variable (0.1–2μg/ml). In primates, vitamin E levels were 3 to 8 μg/ml. Whereas in Marsupalia, Chioptera, primates, Rodentia, Proboscidea, Sirenia, Perissodactyla and Artiodactyla only retinol was found, retinyl esters (basically retinol palmitate/oleate) represented 10 to 50% of the total plasma vitamin A in some birds of the order Ciconiiformes and Falconiformes. Retinol levels in birds were higher compared to mammals (500-2,000 ng/ml). The same was true for lipids as well as for vitamin E levels (1–26 μg/ml) in the plasma of birds.