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Growth and activity but not maturation are affected by perinatal diet
J C Martin1, D C Martin, P Shores
1Department of Psychiatry, University of Washington, Seattle 98105.
Insights
Diet composition significantly impacts maternal and neonatal weight gain in Sprague-Dawley rats, but shows minimal effects on offspring development and activity. Sex differences were observed in weight and activity levels.
Area of Science:
- Reproductive biology
- Developmental toxicology
- Animal nutrition
Background:
- Dietary interventions are crucial for understanding reproductive and developmental outcomes.
- Evaluating the impact of different diets, including liquid formulations, is essential in toxicological studies.
- Sprague-Dawley rats are a common model for studying growth, maturation, and activity.
Purpose of the Study:
- To investigate the effects of two distinct diets (Purina chow and a liquid Ensure diet) on Sprague-Dawley rat offspring.
- To assess the impact of pre- and postnatal dietary exposures on maternal weight gain, neonatal growth, and developmental milestones.
- To examine sex-specific differences in growth and activity patterns in response to dietary variations.
Main Methods:
- Gravid Sprague-Dawley rats were fed either Purina chow or Ensure diet from gestation day 1.
- Dietary switching occurred on gestation day 21 for half of each group, continuing through weaning.
- Offspring were maintained on their respective diets until postnatal day 60, with daily assessments of seven developmental measures.
Main Results:
- Diet significantly affected maternal weight gain during the second trimester and neonatal weight gain through postnatal day 45.
- Females exhibited greater sensitivity to dietary changes than males.
- Males were consistently heavier than females across all postnatal weighings, and sex-specific differences were noted in wheel activity.
Conclusions:
- While diet influences maternal and neonatal weight gain, it has limited impact on the developmental measures and activity levels in Sprague-Dawley rat offspring.
- Sex-specific growth and activity patterns are evident, independent of the tested dietary regimens.
- The study discusses the utility of liquid diets in behavioral teratology and the potential of growth measurements as alternatives to developmental testing.
Abstract:
Growth, maturation and activity in Sprague-Dawley rat offspring were studied as a function of two diets which were offered both pre- and postnatally. Day 1 gravid rats were placed ad lib on either Purina chow or Ensure, a total liquid diet. Half of each group was switched to the other diet on day 21 of gestation and maintained on it through weaning. Offspring remained on the same diet until sacrificed on postnatal day 60. Seven developmental measures were assessed daily until all of the animals reached criterion. The type of diet significantly affected maternal weight gain during the second third of gestation, and neonatal weight gain as measured on days 7, 14, 21, 28 and 45. Females were affected more than were male littermates. Males were significantly heavier than female littermates at all postnatal weighings. Diet had little or no effect on the developmental measures. Male/female differences were found for voluntary activity in the wheel which was measured on day 45. The use of liquid diets in behavioral teratology studies and the wisdom of using pellet diets as a control are discussed. The possibility of substituting careful measures of growth as an alternative to developmental testing is discussed.