Activity of Vitamin B 12 in the Growth of Chicks. *

Summary

Vitamin B₁₂ administered orally or parenterally completely counteracted a thyrotoxic condition in chicks produced by feeding a basal ration containing 0.05% iodinated casein. A level of 0.75 γ vitamin B₁₂ per 100 g of ration resulted in a half maximal growth response. At a level of 1.5 γ vitamin B₁₂ per 100 g of ration the growth response after a two week test period was 88 g compared to 86 g for a group supplemented with 3% condensed fish solubles. A response of 72 g resulted from the intramuscular injection of 0.1 γ vitamin B₁₂ per bird per day.

Pure vitamin B₁₂ can replace the animal protein factor activity of condensed fish Solubles and injectable liver preparations.