94 CHOLINE 



by glycine,^"^' ^"^ and by gelatin. ^"^^ ^°^* ^°* Briggs showed that 10% gelatin 

 in chick diets increased the need of niacin and might cause niacin defi- 

 ciency.^^° This effect was counteracted by either niacin or tryptophan. Per- 

 osis caused by egg white injury^" was prevented by biotin.^^- In so far as 

 choline is concerned, its antiperotic effect does not necessarily depend on 

 the same deficiency state in which its growth-stimulating action is evident. 

 In choline-deficient chicks neither methionine^°^ • ^°'' nor betaine^"^ • ^"^ was 

 antiperotic unless the diet contained mono- or dimethylaminoethanol. This 

 is due to the fact that the chick is practically unable to convert 

 aminoethanol into monomethylaminoethanol.^^*- ^^^ On the other hand, ar- 

 senocholine is strongly antiperotic and growth-promoting,^"^- ^^* even 

 though it does not cause the methylation of homocysteine. ^^^ This analog 

 of choline is known to be incorporated into the lecithin molecule,^" and 

 it is a fair assumption that this occurs in the chick also. From the data in 

 Tables III to VI it is evident that antiperosis in choline-deficient chicks is 

 a function of choline, possibly in phospholipid form, and not a general func- 

 tion of sources of labile methyl. In this connection it should be noted that 

 4 and 9 %, respectively, of the tagged methyl of C ^^-methyl-labeled methio- 

 nine were found in tissue choline isolated from 2 chicks 48 hours after the 

 feeding of amino acid.^^^ This is not conclusive evidence of transmethyla- 

 tion, even at a relatively slow rate, because the labeled choline may have 

 resulted from the methylation of dietary dimethylaminoethanol through 

 C^^-formate resulting from the partial oxidation of the labeled methionine 

 methyl. 



For normal growth chick rations must contain 1.1 % of methionine, one- 

 half of which may be replaced by cystine. ^^^ Homocystine can be substituted 

 for cystine and for methionine also if the supply of methyl donors is ade- 

 quate. Choline and betaine are suitable donors. 



The requirement of chicks for choline has been reported as 150 and 100 

 mg. %, respectively, for a diet of natural foodstuff s^"^ and for a purified 

 diet.^°'* The allowance reconomended by the Committee on Animal Nutri- 



307 T. H. Jukes, J. Nutrition 22, 315 (1941). 



3«8 T. H. Jukes, and E. L. R. Stokstad, J. Nutrition 43, 459 (1951); 48, 209 (1952). 



309 H. L. Lucas, L. C. Norris, and G. F. Heuser, Poultry Sci. 25, 93 (1946). 



"0 G. M. Briggs, /. Biol. Chem. 161, 749 (1945). 



311 L. W. McElroy and T. H. Jukes, Proc. Soc. Exptl. Biol. Med. 45, 296 (1940). 



312 T. H. Jukes and F. H. Bird, Proc. Soc. Exptl. Biol. Med. 49, 231 (1942). 



313 A. E. Schaefer, W. D. Salmon, and D. R. Strength, J. Nutrition 44, 305 (1951). 

 31* T. H. Jukes, J. J. Oleson, and A. C. Dornbush, J. Nutrition 30, 219 (1945). 



315 T. H. Jukes and A. D. Welch, /. Biol. Chem. 146, 19 (1942). 



316 H. J. Almquist and T. H. Jukes, Proc. Soc. Exptl. Biol. Med. 51, 243 (1942). 



317 A. D. Welch and R. L. Landau, /. Biol. Chem. 144, 581 (1942). 



318 K. A. Burke, R. F. Nystrom, and B. C. Johnson, J. Biol. Chem. 188, 723 (1951). 



319 C. R. Grau and H. J. Almquist, J. Nutrition 26, 631 (1943). 



