Heretofore the vitamin K-deficient Diet E of Almquist and Stokstad,1 Ration K-1 of Ansbacher,2 Diet 508 of Dam and co-workers,3 or modifications thereof, have been used by the majority of investigators1-7 in assays, in which chicks served as test animals. Since putrified fish meal is an excellent source of one of the natural antihemorrhagic vitamins, obstacles are frequently encountered in the employ of fish meal diets even under conditions tending to minimize bacterial action.Recently we found that the difficulties arising from K-vitamin synthesis are not experienced when diets are used which contain neither fish meal nor yeast, and in which vitamin K had been destroyed by prolonged heat treatment. We are now making vitamin K assays with Ration K-7 outlined in the accompanying table.It is similar to the Ansbacher et al.8 modification of the 240-H ration of Kline et al.,9 the outstanding difference being the heat treatment of the grain mixture which is prolonged from 36 to about 168 hours.When baby chicks...
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