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.
National Institute of Oceanography, Israel Oceanographic & Limnological Research, Tel-Shikmona, Haifa.
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Ben-Amotz
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Mokady
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Edelstein
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M
Avron
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