Search

Crystalline vitamin B12, isolated from liver by Rickes et al. (1948) was shown by Ott et al. (1948) to give response similar to the animal protein factor (APF ) required for chick growth. Preparations of a microbiologically produced material by Stokstad et al. (1948) have also been shown to be highly active as a source of APF, when measured by chick assay. A vitamin B12 ** concentrate (4.4 ug. of B12 per gram) was fed at a 1% level to APF depleted chicks to determine its effect upon chick growth and to APF depleted laying hens to determine the effect upon hatchability. The concentrate was used to supplement both a synthetic and a natural type chick diet. The synthetic diet contained alpha soybean protein, cerelose, soybean oil, salts, amino acids, and vitamins A, D, and B-complex supplements. The natural type diet contained wheat bran, ground corn, oats and wheat, soybean oil . . .