XIU. ItlUjllUKMENTS 517 



l)atii'ut with ponik'ioiis anemia, whose needs appear to be satislied by I to 

 2 7 injected daily. The requirements of chicks are similarly high (p. 511). 



The oral administration of vitamin B12 at low dosage levels produces 

 excellent responses in deficient rats. However, just as in the case; of human 

 subjects, the ingested vitamin was found not to i)e e.xcreted in the urine 

 of rats^' unless it was giv(Mi at such unusually high levels as 0.9 mg. per 

 kilogram of body weight, in which case only a fraction of a per cent of the 

 dose was present in the urine. 



The relation between various alterations in dietary composition and vi- 

 tamin B12 deficiency in tlie mouse was studied by Bosshardt and coworkers. ■*- 

 The addition of fat to vitamin Bi2-deficient diets containing 20 % or more 

 protein elimmated fatalities and resulted in an increase in growth. The 

 best growth was obtained when a fairly high level of fat was supplied in 

 the diet together with vitamin B12. 



C. OF PIGS 



THOMAS H. JUKES and WILLIAiM L. WILLI.IMS 



The early approaches to the experimental production of vitamin B12 

 deficiency in pigs, just as with chicks, were made difficult by the presence 

 of the vitamin in casein used in "purified" diets,^^ and again, as in the 

 case of chicks, the use of crude all-vegetable diets often gave better ex- 

 perimental results than did the employment of "purified" diets. It soon 

 became evident that pigs, like chicks, needed an animal protein factor. 



A growth response of pigs on purified or all-vegetable diets to supple- 

 ments of liver extract, fish meal, or fish solubles was noted by various 

 investigators.^*-^^ The diet used l)y McRoberts and Hogan contained acid- 

 washed casein, sucrose, lard, corn starch, minerals, and \itamins and was 

 homogenized into an "artificial milk" before feeding. Responses \\ere ob- 

 tained to extracts of yeast or liver. 



Ferrin""^ stated that fish meal appeared to contain some dietary factors 

 which were water-soluble, and he found that choline or methionine would 

 not replace the growth-promoting effects of fish meal for pigs when added 

 to a corn-soybean meal diet. 



" B. F. Chow, L. Barrows, and C. Lang, J. Nutriiion 42, 405 (1950). 



" D. K. Bosshardt, W. J. Paul, and R. H. Barnes, ,/. Nutrition 40, 595 (1950). 



" R. W. Colby and M. E. Ensminger, ./. Animal Sci. 9, 90 (1950). 



** N. R. Ellis and J. H. Zeller, ./. Animal Sci. 2, .374 (194.3). 



« V. F. McRol)erts and A. G. Hogan, ./. Nvtrition 28, 165 (1944). 



" B. W. Fairl)anlvs, J. E. Krider, and D. V. Catron, North Ain. Veterinarian 24, 



351 (1944). 

 " E. F. Ferrin, J. Animal Sci. 5, 42 (1946). 

 ■•8 D. V. Catron and C. C. Culbertson, lova Farm Sci. 3, 3 (1949). 



