444 VITAMIN Bi2 



of vitamin B12 on egg production and hatchability in the domestic fowl. 

 With a sucrose-soybean protein diet low in vitamin B12, hens showed a 

 decrease in egg production. Hatchability of the eggs from hens fed this 

 vitamin Bi2-deficient diet also decreased to zero in 3 to 6 weeks. ^ Addition 

 of APF concentrates to the diet improved the egg production and hatch- 

 ability but failed to produce the normal hatchability of hens on a practical 

 all-mash diet. Incubation of eggs from hens on a vitamin B^-deficient diet 

 resulted in embryonic mortality reaching a peak at the seventeenth day,'* 

 The most characteristic symptoms of the deficiency present in the embryos 

 was myoatrophy of the leg and a malposition, "head between thighs." 

 Other anomalies included hemorrhages of the embryo, allantois, and perosis. 

 Injection of vitamin B12 into eggs laid by hens on a vitamin Bi2-deficient 

 diet improved the hatchability and lowered mortality among the chicks 

 which hatched.^ 



The effect of vitamin B12 on the anemia produced in chicks by injection 

 of phenylhydrazine hydrochloride has been studied.^ Neither liver extract 

 nor vitamm B12 alone influenced the rate of hemoglobin formation, but in 

 combination with folic acid both showed activity in bringing about a more 

 rapid regeneration of hemoglobin. A deficiency of vitamin Bi2 and lysine 

 in the diet of cockerels resulted in failure of morphological differentiation 

 of testicular tissue accompanied by a decrease in comb growth.^ Supple- 

 mentation with vitamin B12 and lysine produced greater testicular growth 

 and differentiation over that of the normal controls. 



Hyperthyroid rats require a growth factor present in liver, fish solubles, 

 and tomatoes.^ Vitamin B12 is a growth factor in this deficiency, but folic 

 acid is not effective in growth promotion of such animals. 



Vitamin B12 has been found to have an effect on the metabolism of amino 

 acids, enhancing their utilization for building fixed tissues.^ It plays a 

 fundamental role, affecting the capacity of the normal mammal to utilize 

 protein;^'' animal deficiencies in vitamin B12 may even be fatal in the pres- 

 ence of high levels of protein. 



3 O. Olcese, J. R. Couch, and C. M. Lyman, J. Nutrition 41, 73 (1950). 



^ O. Olcese, J. R. Couch, J. H. Quisenberry, and P. B. Pearson, ./. Nutrition 41, 



423 (1950), 

 sR. J. Lillie, M. W. Olson, and H. R. Bird, Froc. Soc. Exptl. Biol. Med. 72, 598 



(1949). 

 8 C. A. Nichol, A. E. Harper, and C. A. Elvehjem, Froc. Soc. Exptl. Biol. Med. 71, 



34 (1949). 



7 F. X. Gassner, A. R. Patten, H. S. Wilgus, and L. W. Charkey, Froc. Soc. Exptl. 

 Biol. Med. 75,630 (1950). 



8 J. J. Betheil and H. A. Lardy, J. Nutrition 37, 495 (1949). 



» L. W. Charkey, H. S. Wilgus, A. R. Patton, and F. X. Gassner, Froc. Soc. Exptl. 



Biol. Med. 73, 21 (1950). 

 10 A. M. Hartman, L. P. Dryden, and C. A. Gary, Arch. Biochem. 23, 165 (1949). 



