Effect of Various Levels of Vitamin B12 Upon Growth Response Produced by Aureomycin in Chicks

Summary 1. The vit. B12 requirement for growth of chicks was studied on a deficient diet with and without the addition of aureomycin. In some experiments, a “sparing effect” of aureomycin upon vit. B12 requirement was noted but in others no effect was observed. A growth-promoting effect for aureomycin was noted both in the presence and absence of added vit. B12. 2. The mortality of deficient chicks on the diet containing no added vit. B12 was markedly reduced by aureomycin. 3. The addition of sulfamethazine to the diet did not appear to effect the quantitative requirement of chicks for vit. B12.