Influence of Dietary Lipids on Pigmentation of Young Chickens

Abstract

Supplementation of a basal casein-dextrose diet (40 μg added lutein/g) with 2% coconut or olive oil increased serum lutein significantly (P<.05) when fed to broiler chicks depleted of their oxycarotenoid stores. The influence of chain length, saturation, and concentration of dietary lipids on the absorption of lutein was investigated.Coconut oil, which contains primarily short chain, saturated fatty acids, gave higher (P<.05) serum lutein values than olive oil, which contains primarily long chain, unsaturated fatty acids. Diets supplemented with 5% capric, lauric, myristic, palmitic, stearic, oleic, or linoleic acids or tristearin, triolein, or trilaurin could be divided into three groups based on the ability of the lipids to promote lutein absorption into serum when they were fed. The long chain, saturated fatty acids (myristic, palmitic, and stearic) and triglyceride, tristearin, promoted minimal absorption, whereas the short chain, saturated lauric acid promoted the highest absorption. The short chain, saturated triglycerides and fatty acids and long chain, unsaturated fatty acids and triglycerides promoted intermediate absorption of lutein. Lutein absorption from a white corn-soybean-starch diet depended on concentration of dietary lipid (0, 2, 4, 6, 8, and 10%) when cottonseed oil was substituted isocalorically for starch. Serum and toeweb lutein increased linearly up to four-fold and three-fold, respectively, as the dietary fat increased up to 6%, where a break-point occurred. Additional fat caused smaller increases of lutein. Graded levels of dietary lauric or oleic acid gave similar results, whereas stearic acid (up to 10%) did not support a significant (P<.05) absorption. The absorption of lutein promoted by mixtures of oleic and stearic acids correlated positively with the amount of oleic acid but not stearic acid. The results can be explained on the basis of the micellar theory of digestion and on the basis of oxycarotenoids being nonpolar, nonamphiphilic lipids.