MODULATION OF BEHAVIORAL PERFORMANCE OF PREPUBERTAL MONKEYS BY MODERATE DIETARY ZINC DEPRIVATION

Young rhesus monkeys (Macaca mulatta, n = 14) 25-30 mo of age were fed a zinc-deficient (ZD) diet (2 mu g Zn/g diet) (moderate zinc deprivat ion) over 15 week. The ZD diet period was compared with a zinc-adequat e (ZA) diet period (50 mu g Zn/g diet) of the same duration, which eit her 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 sig ns of zinc deficiency or effects on growth rate. Spontaneous motor act ivity was lower and performance of a visual-attention task and short-t erm-memory task were poorer during the ZD period than during the ZA pe riod. Behavioral effects were detected as changes from individual base line values, and often represented a failure to improve. The results s uggests that dietary zinc deprivation can modulate behavior in prepube rtal monkeys without affecting growth.