Comparative absorption and transport of five common carotenoids in preruminant calves.

Preruminant calves, maintained in a monogastric state by feeding an all-liquid diet, were used to compare the serum appearance and lipoprotein transport of five different carotenoids over 144 h. Thirty newborn calves were fed milk replacer for 1 wk and then randomly assigned to six groups (n = 5), with each group receiving a single 20-mg oral dose of beta-carotene in water-soluble beadlets, canthaxanthin in water-soluble beadlets, lutein in oil, lycopene in oil, crystalline alpha-carotene in 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 post-dosing. Lipoprotein separation and analysis were completed with selected animals. All carotenoids were absorbed, but in variable amounts. At peak serum carotenoids levels, HDL contained 70-90% of the carotenoids. Canthaxanthin and lutein peaked earlier in serum (8 and 12 h) than 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 alpha-carotene and lycopene displayed slower disappearance rates than did beta-carotene. The peak serum level (nmol/L +/- SEM) of canthaxanthin (392 +/- 136) was lower than that of beta-carotene (1245 +/- 425), and carotenoids levels of calves receiving these commercial beadlet sources were higher than the serum levels of calves receiving beta-carotene (45 +/- 17.5), alpha-carotene (42 +/- 18.0), lutein (51 +/- 9.5) and lycopene (18 +/- 4.6), which were fed in oil.(ABSTRACT TRUNCATED AT 250 WORDS)