Comparative metabolic fractionation of carotenoids in three flamingo species

1. 1. Three flamingo species, Phoenicoparrus andinus, Php. jamesi and Phoenicopterus ruber, subsisting chiefly upon plant food, elaborate major proportions of ketocarotenoids from dietary carotenes, storing principally canthaxanthin in plasma, as well as in feathers, wherein secondary concentrations of astaxanthin and a newly described ketocarotenoid, phoenicoxanthin, also occur. 2. 2. Canthaxanthin, predominant in tarsal skin of both Andean and Jame's species, is replaced by esterified astaxanthin in that of Pht. ruber. 3. 3. The principal liver carotenoid in andinus and in jamesi is β-carotene; in ruber, it is 4-keto-α-carotene. 4. 4. Echinenone occurs in several tissues of both andinus and jamesi; esterified fucoxanthin in tarsal skin of both; and ϵ-carotene in andinus liver.