IV. BIOCHEMICAL SYSTEMS 437 



that methionine could replace the vitamin Bi2 requirement of their chicks. 

 However, this does not apply to depleted chicks fed high soybean-meal 

 diets, for an acute deficiency was observed in 1949 by Stokstad and co- 

 workers'"^ in chicks receiving a diet containing 70% soybean meal with 

 the addition of 0.3 % methionine and 0.2 % choline chloride. Similar results 

 were reported by Ott,'"* who used a diet containing 70% soybean meal 

 with 0.9% methionine and 0.2% choline chloride and found the require- 

 ment of vitamin Bi-. for chicks to be 27 y per kilogram of diet. 



TABLE V 



Diets Used in the Study of the Growth of Chicks as Affected by 



"Methylating Agents""" 



" Inositol 100 mg., niacinamide 5 mg., calcium pantothenate 5 mg., thiamine HCl 1 mg., riboflavin 1 

 mg., pyridoxine HCl 1 mg., vitamin K compound 0.5 mg., biotin 0.02 mg. 



The effects of various combinations of vitamin B^, folic acid, homo- 

 cystine, choline, betaine, and methionine were studied in vitamin B12- 

 depleted chicks on deficient diets by Jukes and Stokstad."" The basal diets 

 used are sho\\Ti in Table \. With diet 1, it was found that any of the follow- 

 ing substances would produce a growth response: folic acid, vitamin B12, 

 betaine, choline, or methionine. Some typical results are shown in Table 

 \T . The data show that the response to methionine was affected very little 



108 E. L. R. Stokstad, T. H. Jukes, J. V. Pierce, A. C. Page, Jr., and A. L. Franklin, 



/. Biol. Chem. 180, 647 (1949). 

 »o3 W. H. Ott, Poultry Set. 30, 86 (1951). 

 "0 T. H. Jukes and E. L. R. Stokstad, J. Nutritio7i (In press.) 



