Effect of dietary protein, zinc, and carbon monoxide on fetal zinc concentration in mice.

Dietary protein and zinc deficiencies known to be detrimental to the developing fetus are common in pregnant women in developing countries. Everyone in modern society is at risk of exposure to carbon monoxide (CO). This study was conducted to observe the effect of dietary protein, zinc, and exposure to CO on the fetal zinc concentrations by factorial experimentation. Pregnant mice of CD-1 strain were maintained on 17% (control) or 9% (deficient) protein diets mixed with deficient, normal (control), or supplemental zinc throughout gestation. The dams in each dietary group were exposed to air (control) or 500 ppm CO in air in environmental chambers from gestation day 8 to gestational day 18. The dams were sacrificed on d 18 and fetal zinc levels were measured by atomic absorption spectrophotometry. Carbon monoxide levels used in this study had no significant effect on fetal zinc concentration in any treatment group. When both dietary protein and zinc levels were normal, the mean fetal zinc concentrations were higher than all other dietary protein/zinc combinations (15.2 +/-6.0 and 14.2 +/- 4.1 microg Zn/g of tissue for 0 and 500 ppm CO levels). However, when dietary protein levels were deficient, supplemental zinc increased the fetal zinc concentrations significantly (12.7+/-3.8 and 13.1+/-0.3.6 microg Zn/g of tissue, in 0 and 500 ppm CO groups) as compared to zinc-deficient groups (8.7 +/- 3.0 and 10.0 +/- 3.3 microg Zn/g of tissue in 0 and 500 ppm CO groups). The results of this study may be relevant to populations that experience both marginal zinc and protein diets during gestation.