Time course evaluation of carotenoid and retinol concentrations in posthatch chick tissue.

Carotenoid and retinol concentrations were determined in chicks hatched from carotenoid-enriched eggs while being fed a carotenoid free starter diet. Single Comb White Leghorn (SCWL) hatching eggs were obtained from breeder hens fed diets enriched with either 0.2% beta-carotene, canthaxanthin, lutein, or basal control. Twenty-five day-old chicks hatched from each treatment group were placed in a battery and fed a carotenoid-free basal diet. At 1, 4, 7, 10, and 13 d, five chicks per treatment were randomly selected, and blood serum, liver, and unabsorbed yolk sac were collected for carotenoid and retinol analysis. There were no significant differences in retinol concentrations in the serum, liver, and unabsorbed yolk sac of the chickens. Only small amounts of beta-carotene were detected in the chick tissues. Concentration of all three carotenoids and retinol were greater in the liver and unabsorbed yolk sac than in serum. In the serum and liver, respective carotenoid concentrations decreased and retinol concentration increased with increasing age, whereas respective carotenoid and retinol concentrations in the unabsorbed yolk sac increased over time. It may be concluded that yolk sac carotenoids are not absorbed well, as unabsorbed yolk sac concentrations increased over time, and that carotenoid in serum and liver decrease linearly with increasing age.