Use of the β‐carotene rich alga Dunaliella Bardawil as a source of retinol

Abstract

1. Dunaliella bardawil, a β‐carotene accumulating halo‐tolerant alga, has been tested as a source of retinol in a chick diet. 2. Chicks were fed diets deficient in retinol or supplemented with retinol, synthetic β‐carotene or dry algae. 3. After an initial lag, chicks grew equally well on diets supplemented with algae, retinol or β‐carotene. 4. Serum and liver analyses revealed a normal content of retinol in all chicks except those grown on the retinol‐deficient diet. Chicks fed the algae‐supplemented diet contained lutein but no β‐carotene in their serum, even though the ratio of β‐carotene to lutein in the algae was over 15:1. 5. Laying hens fed with an algae‐supplemented diet showed enhanced egg yolk colour attributable to a higher lutein content. No β‐carotene was present in the egg‐yolk. 6. These studies demonstrate the possibility of using dried Dunaliella bardawil as a dietary supplement which can fully satisfy the retinol requirement and also serve as a yolk‐colour enhancing agent.