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Developmental delays in offspring of rats undernourished or zinc deprived during lactation
1United States Department of Agriculture, Grand Forks Human Nutrition Research Center, ND 58202.
Insights
Zinc or calorie deprivation in lactating rats caused developmental delays in offspring reflexes. These delays persisted, but motor impairments resolved after rehabilitation, though growth retardation continued.
Area of Science:
- Developmental neuroscience
- Nutritional science
- Animal models
Background:
- Maternal nutrition during lactation significantly impacts offspring development.
- Zinc and calorie availability are critical for neurodevelopment and overall growth.
- Understanding specific nutritional deficiencies is key to addressing developmental deficits.
Purpose of the Study:
- To investigate the effects of zinc and calorie deprivation during lactation on offspring reflex and motor development.
- To compare the impact of isolated zinc deficiency versus calorie restriction.
- To assess the long-term effects of these deficiencies and subsequent rehabilitation on motor function and growth.
Main Methods:
- Offspring from zinc- or calorie-deprived lactating rats were tested for reflexes and motor skills from postnatal Day 4 to 21.
- A battery of reflex and motor tests were administered.
- Motor function and growth were reassessed at 45 and 60 days after a rehabilitation period.
Main Results:
- Both zinc-deprived and undernourished offspring showed delayed development of certain reflexes (auditory startle, air righting, rope descent) after the first week.
- Zinc deficiency did not exacerbate deficits seen with calorie restriction alone, except for eye opening.
- No significant motor impairments were observed at 45 and 60 days post-rehabilitation.
- Persistent growth retardation was evident in both deficient groups long after rehabilitation.
Conclusions:
- Preweaning zinc and calorie deficiencies cause significant, but potentially reversible, delays in specific reflex development.
- While motor function may recover, persistent growth retardation highlights the long-lasting impact of early-life nutritional stress.
- This study underscores the critical role of adequate maternal nutrition during lactation for optimal offspring neurodevelopment and growth.
Abstract:
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.
