Developmental delays in offspring of rats undernourished or zinc deprived during lactation.

Offspring of rats who were zinc or calorie deprived during lactation were administered a battery of reflex and motor tests from postnatal Day 4 to Day 21. Compared to offspring of ad lib-fed control rats, both zinc deprived and undernourished offspring exhibited developmental delays in reflexes which appeared after the first postnatal week (auditory startle, air righting, and rope descent). As the deficiencies continued the delays appeared to be more pronounced. The zinc deficiency did not add to the deficits associated with calorie restriction alone because there were no significant differences between the zinc deficient and undernourished pups on any of the measures except eye opening. When rehabilitated offspring were tested at 45 and 60 days of age for motor deficits there were no significant impairments resulting from preweaning dietary conditions. However, the growth retardation of zinc deprived and undernourished rats persisted long after dietary rehabilitation was implemented.