COMPARATIVE ABSORPTION AND TRANSPORT OF 5 COMMON CAROTENOIDS IN PRERUMINANT CALVES

Preruminant calves, maintained in a monogastric state by feeding an al l-liquid diet, were used to compare the serum appearance and lipoprote in transport of five different carotenoids over 144 h. Thirty newborn calves were fed milk replacer for 1 wk and then randomly assigned to s ix groups (n = 5), with each group receiving a single 20-mg oral dose of beta-carotene in water-soluble beadlets, canthaxanthin in water-sol uble beadlets, lutein in oil, lycopene in oil, crystalline alpha-carot ene oil or crystalline beta-carotene in oil as part of a morning meal. Serial blood samples were taken by jugular puncture for up to 1 wk po st-dosing. Lipoprotein separation and analysis were completed with sel ected animals. All carotenoids were absorbed, but in variable amounts. At peak serum carotenoids levels, HDL contained 70-90% of the caroten oids. Canthaxanthin and lutein peaked earlier in serum (8 and 12 h) th an did the less polar lycopene, alpha-carotene, and beta-carotene (16, 24 and 24 h). Canthaxanthin and lutein were also cleared more quickly from the serum. Serum concentrations of cu-carotene and lycopene disp layed slower disappearance rates than did beta-carotene. The peak seru m level (nmol/L +/- SEM) of canthaxanthin (392 +/- 136) was lower than that of beta-carotene (1245 +/- 425), and carotenoids levels of calve s receiving these commercial beadlet sources were higher than the seru m levels of calves receiving beta-carotene (45 +/- 17.5), alpha-carote ne (42 +/- 18.0), lutein (51 +/- 9.5) and lycopene (18 +/- 4.6), which were fed in oil. The results show differential uptake and clearance o f various carotenoids and enhanced uptake of beadlet forms of two caro tenoids. We suggest that the preruminant calf is an excellent model in which to evaluate uptake and transport of carotenoids, especially for those carotenoids that are not approved for human feeding studies.