Some dietary carotenoids and blood-carotenoid levels in flamingos—II. γ-carotene and α-carotene consumed by the American flamingo

Abstract

1. 1. American flamingos, Phoenicopterus ruber, when denied dietary carotenoids until their blood-carotenoids had descended to low values, then yielded canthaxanthin as the only such pigment. 2. 2. Supplying γ-carotene as the only added carotenoid failed to supplement the descending cantaxanthin concentrations, or to evoke the presence, in the blood or liver, of γ-carotene itself or any recognized derivative thereof. 3. 3. When β-carotene was added to the γ-carotene supplement, however, this resulted in the elaboration of echinenone and of additional canthaxanthin, both of which were then in the blood, as in earlier studies involving β-carotene as the sole carotenoid. 4. 4. The inclusion of α-carotene (along with lesser concentrations of β-carotene) in the birds' diet was followed by the storage of α-carotene and phoenicopterone, acccompanying the residual, β-carotene-derived canthaxanthin, in the liver, while phoenicopterone and canthaxanthin were the only carotenoids detected in the blood.