508 IX. CAROTENOIDS AND VITAMINS A 



concentrations of vitamin A occur in the liver. Appreciable amounts are 

 also found in the body fat of chickens, and, in the case of hens, in the 

 ovaries and in the eggs.^"" Bieri^^^ observed that aqueous ^^-carotene sus- 

 pensions injected intravenously into chicks deficient in vitamin A was con- 

 verted to the vitamin, and appeared as such in the liver and serum, whereas 

 injected cryptoxanthin did not result in significant amounts of vitamin A. 

 No vitamin A was found in the liver of the cormorant {Phalacrocorax carbo) . 



The vitamin A content of the liver oil of chickens which have been fed a 

 normal diet is given as 20,000 I.U./g., while that of the liver oil from the 

 goose on a normal dietary regimen is 14,000 I.U./g.^^^ These values com- 

 pare with those of Mattson and Deuel,^"^ who cited liver contents of 7.9 

 ± 0.9 I.U./g. (carotene-free, vitamin A-low diet), 117.0 I.U./g. (high caro- 

 tene-free, vitamin A-low diet), 117.0 I.U./g. (high carotene, vitamin A-low 

 diet), 5327 ± 630 and 4660 ± 1025 I.U./g. (high vitamin A with carotene- 

 free or carotene-high diet, respectively). In later tests^"*^ on chickens, the 

 liver contained the following amounts of vitamin A (I.U./g.) corresponding 

 to the various levels of vitamin A in the diet (I.U./lb. of food): (diet), 

 370 (liver); 1,000,665; 30,000,4092; 60,000,6940; 100,000,4654; and 

 200,000, 4626. It is evident that up to a certain point there is a propor- 

 tionahty between the vitamin A intake and the amount stored in the liver; 

 however, when the optimum level is reached (60,000 I.U./lb.), further in- 

 creases in vitamin A in the food do not result in further increase in liver 

 vitamin A, but actually in a decrease. Ganguly and co-workers^^ re- 

 corded average figures for liver vitamin A of 136 to 348 I.U./g. in chickens 

 fed on experimental diets low in carotenoids; in one group a valvie as low 

 as 14.0 I.U./g. was recorded. 



The amount of vitamin A stored in the body fat of chickens continued to 

 increase progressively to the highest levels of vitamin A intake, in the tests 

 of Deuel et al^^^ cited above. The chicken body fat had the following vita- 

 min A content (I.U./g.) at different levels of intake (I.U./lb. food) : 

 (diet), 32.3 (fat); 1,000,23.4; 30,000, 42.2; 60,000, 59.3; 100,000, 92.7; 

 and 200,000, 222.6. Thus, the concentration of \atamin A in the body fat 

 of the birds receiving the food containing 200,000 I.U. of vitamin A per 

 pound was more than twice that observed in chickens which received the 

 diet containing 100,000 I.U. of vitamin A/lb. of food. These values are 

 much higher than those recorded by Ganguly et al.,^^ which varied between 

 1.8 and 11.0 I.U./g. for the experimental diets without an especially high 



"1 J. G. Bieri, Arch. Biochem. Biophys., 56, 90-96 (1955). 



^^2 H. Vogel and H. Knobloch, Chemie und Technik der Vitarnine, 3rd ed., F. Enke, 

 Stuttgart, 1950, p. 41; cited by H. H. Inhoffen and H. Pommer in W. H. Sebrell, Jr. 

 and R. S. Harris, The Vitamins, Vol. I, Academic Press, New York, 1954, pp. 100-106. 



