Zinc deficiency in pregnant Long-Evans hooded rats: teratogenicity and tissue trace elements

The Long-Evans hooded rat is widely used in experimental teratology. This study determines the teratogenicity of maternal Zn deficiency in the Long-Evans hooded rat, and examines the effects of Zn deficiency on Zn, Fe, and Cu concentrations in maternal and fetal tissues. Dams were fed an egg white-based diet containing 100 micrograms/g Zn for 1 week prior to mating. At mating rats were fed diets with 0.5, 4.5, 9.0, or 100 micrograms/g Zn ad lib, or 100 micrograms/g Zn pair-fed to 0.5 micrograms/g Zn dams. Laparotomies were performed on day 21 of gestation. Live fetuses and resorptions were counted. Fetuses were weighed and examined for external malformations. Some fetuses were used for Zn, Fe, and Cu determinations, others for internal or skeletal examination. Zn, Fe, and Cu levels were determined in maternal liver, kidney, and plasma. The 0.5 micrograms/g Zn dams lost weight during pregnancy; 27% of implantation sites were resorbed, 91.7% of live fetuses were malformed, and fetal weight was low. There were no malformed fetuses in the 4.5 micrograms/g Zn or 9.0 micrograms/g Zn groups; litter weights were low in the 4.5 micrograms/g Zn group. Tissue Zn was correlated with dietary Zn. Increased Fe concentration occurred in all maternal and fetal tissues in the 0.5 micrograms/g Zn group. The teratogenicity of Zn deficiency in the Long-Evans rat appears similar to that previously reported in the Sprague-Dawley strain.