520 VITAMIN Bi2 



The effect of a "crude vitamin-Bio concentrate" on the growth of wean- 

 ling pigs fed a corn-soybean diet was studied by Luecke and coworkers.^* 

 Six 6-week-old pigs were used in each group, and the pigs grew at about 

 1 .4 times the rate of the control group during a period of 7 weeks ; however, 

 the authors noted that the supplementary preparation was impure so that 

 it could not be definitely stated that its growth-promoting activity was due 

 to its vitamin B12 content. 



Further studies by the Illinois group^^ placed the vitamin Bi2 requirement 

 of young pigs on the purified a-protein diet at about 20 7 per kilogram of 

 dry diet or 0.6 7 per kilogram of body weight w'hen injected daily; the 

 latter figure was approximatel}^ half of the oral requirement. 



In experiments with pigs on a corn-peanut meal basal diet, Cunha and 

 associates"" found that a vitamin B12 concentrate prepared from the strep- 

 tomycin fermentation was ineffective in promoting growth while an animal 

 protein factor supplement from the aureomycin fermentation produced a 

 remarkable increase in growth. It was later shown by Jukes and coworkers^^ 

 that vitamin B12 was ineffective under these conditions and that small 

 amounts of aureomycin Mere responsible for the growth produced by the 

 animal protein factor supplement. 



The requirement of male pigs on wire floors for vitamin B12 on a corn- 

 soybean meal diet was studied by Richardson and coworkers"^ in the pres- 

 ence and absence of 40 mg. of supplementary antibiotics per pound of diet. 

 The following results were obtained: 



Gain in pounds per day from weaning to 75 lb. 

 Level of added vitamin B12, 



7 per pound diet Without antibiotics With antibiotics 



1.19 0.91 



6 1.22 1.54 



10 1.25 1.58 



20 1.29 1.53 



Pigs receiving the basal diet and antibiotics without additional vitamm Bio 

 showed an extremely rough hair coat, dermatitis, an exudate around the 

 eyes, nervousness, and irritability. The authors concluded that the sup- 

 plementary vitamin B12 requirement of weanling pigs was 5 7 or less per 

 pound of corn-soybean meal diet containing antibiotics. 



S8 R. W. Luecke, W. N. IVIcMillen, F. Thorp, Jr., and J. R. Boniece, Science 110, 



139 (1949). 

 68 R. O. Nesheim, J. L. Krider, and B. C. Johnson, Arch. Biochem. 27, 240 (1950). 

 SOT. J. Cunha, J. E. Burnside, D. M. Buschman, R. S. Ghisscock, A. M. Pearson 



and A. L. Shealy, Arch. Biochem. 23, 324 (1949). 



61 T. H. Jukes, E. L. R. Stokstad, R. R. Taylor, T. J. Cunha, H. M. Edwards, and 

 G. B. Meadows, Arch. Biochem. 26, 324 (1950). 



62 D. Richardson, D. V. Catron, L. A. Underkofler, H. M. Maddock, and W. C. 

 Friedland, ./. Nutrition 44, 371 (1951). 



