Zinc deficiency and behavior: a development perspective

Zinc deficiency was induced in 35 and 300 day-old male Holtzman rats. Group ZDA was fed ad lib a diet deficient in zinc (1 ppm), ZSP controls were pair-fed a diet supplemented with zinc (50 ppm) and ZSA controls were fed ad lib a diet supplemented with zinc (50 ppm). Physical status and six open-field behaviors were evaluated. Food intake, body weight and plasma zinc concentrations were significantly reduced in both age groups. Expanded use of the open-field revealed significantly lower latencies to explore the novel environment and significantly lower ambulation scores in the young and older zinc deficient rats. Older rats spent significantly less time grooming than their controls. Rearing was significantly less in young zinc deficient rats and "kangaroo-like" posture was evident. Young rats made deficient during critical periods of growth and development, were at greater risk for most parameters tested, compared to the older deficient rats. These rats do demonstrate, however, that feeding low-zinc diets to older, fully developed animals results in significant physical and behavioral impairment.