Learning and memory disabilities in young adult rats from mildly zinc deficient dams

Abstract

Three experiments were conducted to test the behavior of the offspring of rat dams (ZD) fed a mildly zinc deficient diet (10.0 micrograms Zn/g) during pregnancy and lactation. Since zinc deficiency causes anorexia, a second group of rat dams (PF) was fed the same quantity of the diet during gestation and lactation as was consumed by their ZD mates. A third group of rats (AL) was fed the diet ad lib during gestation and lactation. The PF and AL dams were given zinc supplemented (25.0 micrograms Zn/ml) drinking water whereas the ZD dams were given double distilled, deionized drinking water. After weaning, the offspring of all dams were fed Purina Laboratory Chow ad lib until they were 100 days old. The offspring were then reduced to 85% of their ad lib weight and tested on a 17-arm radial maze for memory and learning. In Experiments 1 and 2, the ZD males suffered a significant learning deficit when compared to the AL males. Whereas the PF males suffered a significant learning impairment in Experiment 1, the learning deficit of the PF group was not as severe as the deficit of the ZD group. There was no impairment in reference (long-term) memory for any of the groups. In Experiment 3, significant differences in working (short-term) memory were found among the three groups of females. The ZD group was significantly inferior in working memory when compared to the PF and AL groups. No significant differences in working memory were found between the PF and AL groups.