HOUSING OF PREGNANT RATS IN METABOLISM CAGES - MATERNAL AND DEVELOPMENTAL EFFECTS

The influence of the caging conditions on maternal and gestational var iables was assessed for pregnant rats housed individually in two cage types. Plug positive Sprague-Dawley females were caged either in Makro lon or in metabolism (Tecniplast) cages, and were not disturbed throug hout all the gestational period. Cesarean sections were performed on g estation day 20. All live fetuses were examined for external, internal , and skeletal malformations and variations. Pregnant rats were affect ed by the housing system, as evidenced by a significant weight loss an d reduced food consumption in the animals housed in metabolism cages. A moderate increase in the number of total skeletal defects was also o bserved in the fetuses of dams housed in metabolism cages. An importan t implication of these results would be that in maternal and developme ntal toxicity studies of xenobiotics, pregnant animals should not be h oused in metabolism cages.