Vitamin K deficiency in rederived SPF rodents. Case reports

The main physiological function of vitamin K is the contribution in the blood clotting by helping the synthesis of prothrombin and other blood clotting compounds in the liver. Formerly all mouse stocks of the Imperial Cancer Research Fund in London were cleared from pathogens by sterile hysterectomies and cross-fostering. The imported SPF freshly littered mice were fed on diet sterilized with 2.5 Mrad gamma irradiation. The new immunodeficient stocks were affected with a high incidence of haemothorax and haemopericardium fatalities. This was remedied by raising the standard supplementation of the diet with 2.5 mg/kg menadione (Vitamin K(3)) to 5 mg/kg by the manufacturer. After the gradual recontamination of these stocks by the successive re-entry of some pathogens during the ensuing years a fresh rederivation programme were carried out. This time to the originally germfree foster mothers a minimal basic intestinal flora (Streptococcus faecalis var. liquefaciens, Streptococcus faecium and Lactobacillus plantarum) were added. The drinking water of this poliassociated foster colony was supplemented by menadion. Fatal hemorrhagic diathesis cases reappeared but could again be eliminated by raising the menadion supplementation of the diet up to 20 mg/kg. However, occasional cases or uterine and cardiac haemorrhages still occurred, especially in some newly established transgenic mice, which had an impaired blood clotting cascade. Diet analyses revealed a great fluctuation in the menadione contents between batches of diet with deficiencies aggravated by irradiation. Instead of the declared 20 mg/kg menadion, as low as 1.1 mg/kg could be detected by chemical analyses. The NRC (1995) prescribes only 1 mg phylloquinone/kg diet as minimum requirement for healthy mice with normal gut flora. On the contrary, after their several years experiences, especially for immunodeficient mice, the optimum supplementation may be set up to 150 to 200 mg/kg before pelleting or gamma irradiation.