ZINC-DEFICIENCY AND DIETARY-FOLATE METABOLISM IN PREGNANT RATS

Five groups of pregnant Wistar rats (zinc-deficient diet without folat e supplementation; folinic acid, folate monoglutamate, folate polyglut amate-supplemented groups receiving zinc-deficient diet; pair-fed grou p as controls) were fed from day one of fertilization with a semisynth etic zinc-deficient diet containing 0.2 mg/kg of Zn in the diet for th e 4 deficient groups and 100 mg/kg for the pair-fed group. After 20 da ys, the zinc status (plasma, liver, femoral bone) was significantly de creased in the zinc-deficient groups. The liver and plasma folate leve ls were lower in the zinc-deficient groups compared to the pair-fed gr oup. Moreover, the folinic acid and the polyglutamate folate supplemen tations (100 mg/kg diet) did not normalize the folate status of the an imals. Only the supplementation with folate monoglutamate led to corre ct folate levels in the pregnant rats. Nevertheless, no form of folate supplementation prevented fetal growth retardation in any of the zinc -deficient groups.These results indicate that zinc deficiency in pregn ant rats decreases folate bioavailability of folinic acid, folate poly glutamates and, to a lesser extent, that of folate monoglutamate. Howe ver, no form of folate supplementation (i.e., folate monoglutamate) pr events fetal growth defect and the incidence of malformation in zinc-d eficient rats.