ANIMAL CAROTENOIDS 



fasting and this may be taken to indicate that carotenoids play some 

 part in gametogenesis and/or the gonads act as a reserve store of 

 carotenoids. Contrary to a suggestion of Zechmeister « » it was found 

 that the pigment concentrations of normal and fasted mussel tissue are 

 independent of lipid concentrations. Mussels, kept in a similar environ- 

 ment to that of the fasted animals, were divided into two groups, one of 

 which was fed a carotenoid-free diet and the other a diet of Nitzschia 

 closterium. The animals fed on A^. closterium increased their concentra- 

 tions of zeaxanthin and mytiloxanthin, the latter being formed probably 



Qlycymerin in CSj 



Mytiloxanchin in C52 



• Hopkinsaxanthin in i-ghc 

 I oecroleum \ 



440 



4ZU 44'J ^50 



Wuve length (m^) 



520 



Fig 25— The absorption spectra of Pectenoxanthin {from Lederer, E. {1938) 

 Bull. Soc. Chim. Biol.. 20, 611), Glvcymerin {from Fabre, R., and Lederer, 

 E {1934) Bull. Soc. Chim. Biol.. 16, 105), Mytiloxanthin {from Scheer, 

 6 T {1940) J. biol. Chem., 136, 275), and Hopkinsiaxanthin (from Strain, 

 H. H. {1949) Biol. Bull. Woods. Hole, 97, 206). 



by oxidation of alimentary carotenoids, but which of these were involved 

 could not be determined. The mussels on the carotenoid-free diet lost 

 much more pigment than did those that were merely fasted. This in- 

 teresting resuh may be due to the utilization of stored carotenoids by the 

 activities of feeding in a condition of virtual starvation, for body weight 

 data indicated that the carotenoid-free diet was not well absorbed. In the 

 fasted animals no useless energy was expended in " feeding " and the 



177 



