Effects of the Prevention of Coprophagy in the Rat

Abstract

When rats are prevented from eating their feces and are fed a vitamin K-free diet, vitamin K deficiency uniformly develops. The extent of the vitamin deficiency as measured by prolongation of the prothrombin time is variable, but it does appear to pass through one and possibly two peaks during the first 12 weeks after weaning. Menadione added to an otherwise vitamin K-free diet prevents the development of vitamin K deficiency in the rat that cannot practice coprophagy. In a single-dose 18-hour test, menadione and vitamin K₁ are both active in returning the prothrombin time to normal at a level of 1.0 µg per 100 gm body weight. It has been confirmed that a small but extremely variable number of conventional rats develop vitamin K deficiency when fed a vitamin K-free diet.