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Updated: Aug 18, 2026
Neurodevelopmental Reflex Testing in Neonatal Rat Pups
Published on: April 24, 2017
Effects of undernutrition on development of far-field auditory brain stem responses in rat pups
Insights
Maternal protein deficiency in rats significantly delays auditory brain stem response (ABR) maturation in pups. While undernourishment impacts early ABR development, differences lessen with age, suggesting resilience.
Area of Science:
- Neuroscience
- Developmental Biology
- Nutritional Science
Background:
- Auditory brain stem response (ABR) maturation is a critical indicator of auditory pathway development.
- Nutritional status during gestation and early life can significantly impact neurodevelopmental trajectories.
Purpose of the Study:
- To investigate the impact of maternal and early postnatal protein deficiency on the maturation rate of the auditory brain stem response (ABR) in Sprague-Dawley rats.
- To determine if reduced body temperature in undernourished pups contributes to observed ABR delays.
Main Methods:
- Timed-pregnant Sprague-Dawley rats were fed either a normal (24% protein) or deficient (8% protein) diet from day 15 of gestation.
- Postnatally, litters were cross-fostered and maintained on their respective diets, with pup numbers thinned to 8.
- Auditory brain stem response (ABR) was recorded repeatedly from postnatal day 16 to day 43.
- A separate experiment controlled for body temperature differences between nutritional groups.
Main Results:
- Undernourished rat pups exhibited significantly lower body weights compared to well-nourished controls.
- Early ABR development was significantly delayed in the protein-deficient group compared to controls.
- The developmental delay in ABR between groups decreased over time, even with continued dietary deficiency.
- Body temperature differences did not solely account for the observed ABR delays.
Conclusions:
- Maternal and early postnatal protein deficiency negatively impacts the rate of auditory brain stem response (ABR) maturation in developing rats.
- While undernourishment causes initial delays, some recovery or compensatory mechanisms may occur during development.
- Nutritional factors are crucial determinants of auditory system maturation rate.
Abstract:
Timed-pregnancy Sprague-Dawley rats were placed on special diets on day 15 of their pregnancy. One group received a normal, 24% protein diet, and the second a deficient, 8% protein diet. After birth the litters within each group were cross-fostered, thinned to 8 pups each, and maintained on their respective diets. Beginning with postnatal day 16 the ABR (auditory brain stem response) was repeatedly recorded from the pups until day 43. Undernourished rat pup body weights were less than one-third of those of the well-nourished litters at the conclusion of testing. ABRs taken from the undernourished group were significantly delayed in early development compared with the controls, but the differences decreased with age despite continuation of a deficient diet. A second experiment was run to rule out body temperature differences between the two groups and showed that the ABR effect was not solely due to this variable. These results indicate that undernourishment is one of the factors that can affect the rate of maturation of the ABR.
