Effects of Prevention of Coprophagy on Pregnant Mice

Abstract

The effects of prevention of coprophagy on reproductive performance were examined in ICR mice. Females were treated with restrainers in order to prevent them from ingesting their feces from day 1 through day 17 of pregnancy. The restrained animals fed a commercial diet did not show any clear adverse effects. In contrast, restrained dams fed a purified diet deficient in vitamin B12 exhibited stillbirths (14%) and abortions (7%). Restrained dams fed a diet lacking in vitamin B12 and folic acid also experienced frequent abortions (27%). In addition, six out of 14 restrained dams (43%) aborted when fed a vitamin B complex-deficient diet. Sham-restrained animals, fed the vitamin B complex deficient-diet, but able to ingest their feces trapped by smaller-mesh floors, escaped these adverse effects. Sham-restrained animals fed the commercial diet, however, showed only a slight improvement in their reproductive performance. In conclusion, coprophagy has nutritional significance as long as the diet is lacking at least B vitamins, especially vitamin B12 and folic acid, whereas it almost entirely loses its nutritional significance when the mouse has access to a balanced diet such as the one made available to the laboratory mice in the present study.