STORAGE OF CAROTENOIDS AND OF VITAMINS A 505 



turkeys, while Loniiberg^^e reported their occurrence in the skin, fat, face, 

 and bill of fifteen species of wild fowl. 



Xanthophyllic pigments occur extensively in the eyes of birds. Lonn- 

 berg"^ noted the presence of carotenoids in some species of wild birds, 

 while Hollander and Owen"^ found both carotene and xanthophyll in the 

 iris of numerous species of domestic chickens, but they were not present 

 in this tissue in the case of pigeons. Nelson^^^ states that the carotenoids 

 in the iris are so labile that the color of the eyes can be changed by an al- 

 teration in diet. 



Considerable work has been completed on the nature of the carotenoid 

 in the retinas of birds. As early as 1877, Capranica^^^ reported that three 

 types of oil droplets could be obtained from hens' retinas. These w^ere 

 characterized by Kiihne and Ayres,"^ in 1878, as three differently colored 

 pigments which they called " chlorophane" (greenish), " xanthophane" 

 (yellowish) and ''rhodophane" (reddish). Sixty years later, Wald and 

 Zussman^^^'"^ found that the greenish pigment resembled the bacterial ca- 

 rotenoid sarcinene, in a micrococcus from human skin (Sarcina lutea) . The 

 yellowish substance consisted of a mixture of lutein and zeaxanthin in the 

 same ratio as they occur in egg, and the reddish pigment was found to be 

 astaxanthin. Von Studnitz et aL^^^'^^° are of the opinion that the greenish 

 .yellow pigment is lacertofulvin, the red substance is astaxanthin, and the 

 bright yellow pigment is lutein. Galloxanthin is another carotenoid which 

 Wald^^^ isolated from chicken retina; the composition is not known, but 

 Goodwin^^^ suggests that it may be an epoxide. 



Feathers constitute a unique site in which carotenoids may be deposited; 

 the feather carotenoids can be considered in the same category as those 

 stored in the skin and external structures of bright-colored sea animals. 

 The component carotenoids are xanthophylls, which may be synthesized 

 from the alimentary carotenoids, and are characteristic of the species. The 

 early work on plumage carotenoids was summarized by Palmer-^ and by 

 Karrer and Jucker.^^ Lonnberg"* reported the presence of carotenoids 

 in the feathers of a wide variety of birds. Brockmann and Volker''^ dis- 

 covered a pigment in the feathers of the wild canary (Serinus canarius) 



"^ E. Lonnberg, Arkiv Zool, A 21,^o. 11, 1-12 (1930). 

 "5 W. F. Hollander and R. D. Owen, Poultry Sci., 18, 385-387 (1939). 

 "•5 N. M. Nelson, Poultry Sci., 23, 541-542 (1944). 

 5" S. Capranica, Arch. Physiol, 1877, 283-295. 



"8 W. Kuhue and W. C. Ayres, /. Physiol, 1, 109-130 (1878-1879). 

 "9 G. Wald and H. Zussman, Nature, I40, 197 (1937). 



^^ G. von Studnitz, H. J. Neumann, and H. K. Loevenich, Arch. ges. Physiol. (Pflii- 

 ger's), 246, 652-663 (1943). 



581 G. Wald, /. Gen. Physiol, 31, 377-383 (1948). 



