On the Cause of Vitamin K Deficiency in Male Rats Fed Irradiated Beef and the Production of Vitamin K Deficiency Using an Amino Acid Synthetic Diet

Abstract

Vitamin K deficiency, as seen by a hemorrhagic syndrome, developed in rats fed a diet consisting entirely of ground beef irradiated at 2.79 or 5.58 Mrad. Addition of soybean protein and corn oil to the diet prevented the deficiency. Or, addition of 0.1 mu g vitamin K/sub 1//g of dry irradiated beef diet maintained normal plasma prothrombin levels. There was no evidence that irradiation caused the formation of vitamin K antagonists in ground beef. If coprophagy is prevented, deficiency develops more rapidly in rats on the irradiated beef diet. Assay of the vitamin K activity in the diet indicated that after irradiation of ground beef its menadione-equivalent vitamin K activity falls to 14 to 16 mu g/100 g dry wt compared with 35 in nonirradiated beef. It was estimated that the irradiated beef contains approximates one-half of the vitamin K required to maintain a normal prothrombin level. Fecal synthesis of vitamin K was not diminished by feeding the irradiated beef. (H.H.D.)