Astaxanthin is the dominant carotenoid pigment found in the marine copepod, Tigriopus

10 Astaxanthin is the dominant carotenoid pigment found in the marine copepod, Tigriopus 11 californicus (Baker), giving these animals orange-red coloration. Like all metazoans, T. 12 californicus must convert carotene or hydroxy-carotenoids present in their algal diet to 13 astaxanthin. Other astaxanthin-pigmented crustaceans have been shown to use a precursor14 specific bioconversion pathway to astaxanthin. The aims of this study were to demonstrate that 15 T. californicus bioconverts dietary carotenoids to astaxanthin. Prior to the experiments copepods 16 were maintained on a carotenoid-free diet on which they lost all carotenoid coloration. Copepods 17 were then fed one of four dietary carotenoids (β-carotene, lutein, zeaxanthin, or canthaxathin) 18 that are precursors to specific astaxanthin bioconversion pathways. We found that copepods from 19 each precursor pigment group produced astaxanthin, and that the amount produced depended on 20 . CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/174300 doi: bioRxiv preprint first posted online Aug. 15, 2017;