SOURCES OF FAT IN ANIMAL BODY 531 



This fatty acid has been reported to be widely distributed in the fat of 

 various species of animals. Cruickshank 54 alone, and with associates, 55 

 proved that linolenic acid is readily deposited in egg yolk. Reiser 56 also 

 noted the presence of this trienoic acid in the neutral fat of the carcass of 

 growing chicks after isomerized linolenate and fats containing linolenic 

 acid had been fed. However, Chu and Kummerow 57 reported that lino- 

 lenic acid was present only in skin lipids, and not in liver lipids, after 6, 

 12, or 25% of linseed oil had been included in the diets. Skin lipids con- 

 tained 25-29% of linolenic acid, irrespective of the level of linseed oil fed. 

 These findings are not in accordance with those of Matsubara, 58 who ob- 

 served that both linoleic and linolenic acids were present in liver and also 

 in muscle lipids of pigeons after the feeding of linseed oil. They were 

 largely present in the phospholipid fraction. 



Linolenate may occur in the depot fat of the mammals, as well as in the 

 fowl. Beadle and associates 59 demonstrated that, after a diet of highly 

 unsaturated fats has been fed, as much as 27.6% of the fatty acids present 

 in rats, and 11.4% of those composing pig fat, may consist of trienoic acids, 

 of which linolenic acid is the principal acid. This compound has likewise 

 been reported in the abdominal fat 60 of the horse to the extent of 4.48%, 

 as well as in the body fat of this animal, 61 in a 1.69% concentration. Gupta 

 and Hilditch 10 confirmed the positive findings of Brooker and Shorland, 9 ' 62 

 and of Crowell, 63 who found linolenic acid present in the mesenteric fat of 

 the horse. On the other hand, Holmberg and Rosenqvist 64 reported 

 contradictory results so far as linolenate is concerned ; they noted a higher 

 proportion of linoleic acid. These differences are probably to be ascribed 

 to the diet of the horses previous to slaughtering. Eckstein 65 found that 

 linolenic acid is a normal constituent of human fat; on the other hand, 



54 E. M. Cruickshank, Biochem. J., 28, 965-977 (1934). 



65 E. M. Cruickshank, J. Houston, and T. Moore, Biochem. J., 33, 1630-1634 (1939). 



65 R. Reiser, J. Nutrition, 42, 325-336 (1950). 



57 T. K. Chu and F. A. Kummerow, Poultry Sci., 29, 846-851 (1950). 

 68 K. Matsubara, J. Biochem. (Japan), 36, 17-41 (1944). 



59 B. W. Beadle, O. H. M. Wilder, and H. R. Kraybill, /. Biol. Chem., 175, 221-229 

 (1948). 



60 H. A. Schuette, T. M. Garvin, and E. J. Schwoegler, J. Biol. Chem., 107, 635-639 

 (1934). 



81 A. Heiduschka and A. Steinruck, /. prakt. Chem., 102, 241-266 (1921). 



62 F. B. Shorland, J". New Zealandlnst. Chem., 13, 5-20 (1949); cited by E. G. Brooker 

 and F. B. Shorland, Biochem. J., 46, 80-85 (1950). 



63 G. K. Crowell, J. Assoc. Offic. Agr. Chemists, 27, 448-451 (1944). 



64 J. Holmberg and U. Rosenqvist, Svensk. Kern. Tid., 61, 89-97 (1949); Chem. Abst., 

 43, 6839 (1949). 



66 H. C. Eckstein, /. Biol. Chem., 64, 797-806 (1925). 



