Relative tissue uptake of all-trans and 9-cis β-Carotene from Dunaliella bardawil or D. salina algal extracts by ferrets

The algae Dunaliella bardawil (Db) and D. salina (Ds) contain large concentrations of all-trans β-carotene (a-t βC) and 9-cis βC (9-c). Seven week old male ferrets were fed carotene-free pelleted diets for 27 days. Beginning on day 18, groups of ferrets (n=6 or 7) received daily one of six oral supplements varying in ratios of 9-c and a-t βC mixed with ∼ 1 ml of Ensure™. Supplements contained: (A) 3.0 mg a-t & 1,4 mg 9-c, (B) 1.1 mg a-t & 1.7 mg 9-c, (C) 1.0 mg a-t & 2.9 mg 9-c, (D) 2.0 mg a-t & 1.3 mg 9c, (E) 0.4 mg a-t from βC beadlets (Hoffmann-LaRoche Inc.), or (F) 3.1 mg a-t from βC beadlets. Supplement A was derived directly from a 20% Betateneβ preparation (Ds extract) while B and C were enriched in 9-c by selective removal of a-t βC. Supplement D utilized the spray dried alga Db (NET, Eilat, Israel). On day 27, blood and tissues were obtained for HPLC analysis of βC and its isomers. Analyses of livers showed that a-t βC was the primary isomer, but 9-c and other isomers were also detected in all groups. The hepatic a-t:9-c ratios were 6.1, 2.5, 1.4, 4.8, 45.0 and 51.6 for groups A-F, respectively which were substantially higher than dietary ratios. Lower amounts of a-t and 9-c βC were found in kidneys but ratios of a-t:9-c were not different between groups (9.2 to 16.8). Only trace amounts of 9-c were found in serum. These results demonstrate that the algae Db and Ds provide bioavailable sources of βC isomers, but as in the human, absorotion of 9-c βC is poor and any 9-c βC absorbed is quickly cleard by the liver.