Bioavailability of a natural isomer mixture as compared with synthetic all-trans-beta-carotene in rats and chicks.
The unicellular halotolerant alga Dunaliella bardawil was previously shown to contain high concentrations of beta-carotene composed of about equal amounts of the all-trans and 9-cis isomers. One-d-old chicks and 7-wk-old male rats were fed diets supplemented with synthetic all-trans-beta-carotene or dry D. bardawil at equivalent levels of beta-carotene. The chicks were fed diets containing up to 0.025% beta-carotene for 2 mo, and the rats up to 0.1% beta-carotene for 2 wk. Liver analyses at the end of these periods indicated that both species showed at least a tenfold higher accumulation of the algal beta-carotene isomer mixture than of the synthetic all-trans-beta-carotene. The ratio of 9-cis-beta-carotene to the all-trans isomer in the livers of the algae-fed rats and chicks was similar to or higher, respectively, than that present in the algae. Retinol plus retinyl ester accumulated to a similar extent in the rats and chicks fed diets supplemented with synthetic all-trans or the natural isomer mixture of beta-carotene. The preferable accumulation of the natural isomer mixture of beta-carotene suggests that attention should be paid to the different sources of beta-carotene when testing their efficacy in effects other than providing retinol, such as in their possible role in the prevention of some types of cancer.
Ben-Amotz
A
A
National Institute of Oceanography, Israel Oceanographic & Limnological Research, Tel-Shikmona, Haifa.
Mokady
S
S
Edelstein
S
S
Avron
M
M
D000284:Administration, Oral; D000818:Animals; D002338:Carotenoids / Q000008:administration & dosage*; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D056890:Eukaryota; D007408:Intestinal Absorption; D008099:Liver / Q000378:metabolism; D008297:Male; D009753:Nutritive Value; D051381:Rats; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D019207:beta Carotene
D019207:beta Carotene; D002338:Carotenoids