The association between depot fat mobilization and the presence of xanthophyll in the plasma of normal sheep

Abstract

1. Blood plasma of normal fed sheep is not pigmented but on starvation the plasma assumes a yellow to green colour. Unlike the pigments of the so-called yellow fatted sheep, the pigmentation disappears on refeeding.2. Using spectrophotometric and chromatographic methods, this pigment has been identified as xanthophyll (lutein).3. The xanthophyll content of plasma is related to the plasma non-esterified fatty acid (N.E.F.A.) concentration and it therefore appears that the pigment is mobilized from the fat depots together with the free fatty acids. Maximum levels of about 60μg./100 ml. xanthophyll are observed in sheep plasma after 4 days starvation.