Effects of whole rat embryos cultured on serum from zinc- and copper-deficient rats.

Whole rat embryos of 9.5 gestational days were cultured for 2 d on sera taken from rats fed diets deficient in zinc (0.5 micrograms Zn/g diet) or copper (0.6 micrograms Cu/g diet), or fed a control diet (100 micrograms Zn and 10 micrograms Cu per g diet). Head malformations were observed in embryos cultured on 12 of 16 zinc-deficient and 11 of 12 copper-deficient serum samples. The protein contents, crown-rump lengths (CRL) and percentages of head to CRL in these embryos were significantly smaller than those of embryos cultured on control serum. Copper and zinc were then added directly to 8 zinc- and 7 copper-deficient serum samples that had grown abnormal embryos. All subsequent cultured embryos had a normal appearance and protein content, CRL and head-to-CRL percentages comparable to controls, except one zinc embryo. These findings suggest that zinc and copper can act directly on embryonic development, and that whole rat embryo cultures can be used to detect deficiencies of these elements.