Modulation of behavioral performance of prepubertal monkeys by moderate dietary zinc deprivation

Young rhesus monkeys (Macaca mulatto, n = 14) 25-30 mo of age were fed a zinc-deficient (ZD) diet (2 μg Zn/g diet) (moderate zinc deprivation) over 15 week. The ZD diet period was compared with a zinc-adequate (ZA) diet period (50 μg Zn/g diet) of the same duration, which either preceded or followed it (crossover design). Plasma zinc was lower at the end of the ZD than after the ZA period. There were no overt signs of zinc deficiency or effects on growth rate. Spontaneous motor activity was lower and performance of a visual-attention task and short-term-memory task were poorer during the ZD period than during the ZA period. Behavioral effects were detected as changes from individual baseline values, and often represented a failure to improve. The results suggests that dietary zinc deprivation can modulate behavior in prepubertal monkeys without affecting growth.