Evidence for differential absorption of zeacarotene, cryptoxanthin, and lutein in young broiler chickens.

The intestinal tracts of young chicks, fed a yellow corn-soy-based diet from hatching until 3-weeks-old, were excised and divided into five segments equal in length. The contents of the segments were removed and analyzed for content of zeacarotene, cryptoxanthin (monohydroxycarotenoid), and lutein (dihydroxycarotenoid) by high pressure liquid chromatography. Cryptoxanthin, which is poorly absorbed by young chickens, served as a nonabsorbed reference material. The ratios of zeacarotene to cryptoxanthin were not reduced significantly (P less than .05) from that in the ingested feed until the ileal region was reached. The ratios of lutein to cryptoxanthin were reduced significantly (P less than .05) in the duodenal and upper jejunal region. The finding of different sites of absorption for zeacarotene and lutein, combined with the poor absorption of cryptoxanthin, suggests the existence in chickens of regulatory mechanisms for carotenoids.