512 VITAMIN Bi2 



injected vitamin B12. The requirement of rats on a diet containing thyroid 

 powder is even higher than that of the chick. Ruminants also have com- 

 paratively high requirements. This was not realized at first, and cobalt- 

 deficient ruminants were dosed with amounts of vitamin Bio based on the 

 levels used in patients with pernicious anemia; these amounts were in- 

 sufficient for the animals (p. 521). 



Vitamin B12 was found to improve the hatchability of eggs when injected 

 into hens-*^ which were kept on all- vegetable diets. The amount needed for 

 good results, including sufficient carry-over to permit good growth of the 

 chicks, was about 4 7 per week. 



In a search for new sources of the vitamin for use in poultry feeds, it was 

 found that cultures of Streptomijces aureofaciens supplied not only vitamin 

 B12 but also a new growth factor which was not identical with any of the 

 known vitamins. This factor was identified as aureomycin, and other anti- 

 biotics were shown to produce similar effects in increasing the growth rate 

 of chicks fed supposedly adequate diets.^^ 



TABLE XXI 



Pantothenic Acid Content of Chick Livers as Affected 

 BY Dietary Vitamin B12** 



Thiamine, calcium pantothenate, pyridoxine, folic acid, and biotin. 



1. Relationships between Pantothenic Acid and Vitamin B12 in 



Chicks 



Evans and coworkers-^ found that when chicks were fed vitamin B12 the 

 apparent pantothenic acid content of their liver tissue uas much lower 

 than that of the liver tissue of chicks fed the iinsupplemented vitamin B12- 

 deficient diet. Pantothenic acid was assayed with L. arahinosus after di- 

 gestion with either Mylase-P or intestinal phosphatase and chicken liver 



2« C. F. Petersen, A. C. Wiese, C. E. Lampman, and P. V. Dahlstrom, PouUry Set. 



29, 618 (1950). 

 " E. L. K. Stokstad, nnd T. H. Jukes, Proc. Soc. Expll. Biol. Mai. 73, ;')23 UOSOj. 

 28 R. J. Evans, A. C. Groschkc, and H. A. Butts, Arch. Biochem. 31, 454 (1951). 



