Effect of Zinc Supplementation on the Spatial Learning and Memory of Rats at Pre- and Postnatal Age

Abstract

Background and Objectives: It is known that zinc supplementation influences the function of nervous system; however, its role on the learning and memory is unknown. Here, we investigated the effect of zinc supplementation on spatial learning and memory at prenatal and early postnatal age. Materials and Methods: In this experimental study 3 groups of male Wistar rats at 45 days of postnatal age and 10 in each group were tested in the Morris Water Maze for spatial learning and memory in 5 consecutive days. The control group received normal diet and water. The second group was received 227 mg/L zinc sulfate added in to their drinking water from 21 days of postnatal age until the end of experiments. Another group was offspring of mothers fed with zinc supplement during both pregnancy and lactation. Results: Our results showed that, in spite of increased serum zinc levels in both supplemented groups, only the group administered by the zinc supplement during postnatal age displayed failures in spatial learning and memory. They were significantly slower in either the acquisition test or the probe trial when compared to the other groups. Conclusion: These data suggest that postnatal zinc supplementation can lead to impairment of the spatial learning and memory. However, zinc supplementation at prenatal and early postnatal age not considerably affects the spatial learning and memory.