Vitamin K Activity in Vitamin B12-Antibiotic Supplements

Prolonged blood clotting times have been consistently obtained in this laboratory with chicks fed a corn-soya type diet described by Griminger et al. (1953) or a purified diet containing all known nutrients required by the chick except vitamin K. It appears, however, that some investigators have not been able to detect prolonged clotting times although their basal diets were alleged to be identical to the corn-soya ration described by Griminger and co-workers. It became apparent however that identical rations had not been used since Griminger et al. used crystalline vitamin B12 and in many instances other investigators have used B12-antibiotic supplements as a source of this vitamin. Since many of these supplements are fermentation residues it is not unlikely that they would contribute sufficient vitamin K to a corn-soya basal to promote normal clotting time. To examine this possibility six vitamin B12-antibiotic supplements commonly used in chick rations were obtained …