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Neurodevelopmental Reflex Testing in Neonatal Rat Pups
Published on: April 24, 2017
Growth and development of brain of artificially reared hypoketonemic rat pups
N Auestad1, R Fisher, F Chiappelli
1Division of Nutritional Sciences, University of California, Los Angeles School of Public Health.
Insights
Artificial rearing (AR) in rats showed that medium chain fatty acids are not essential for brain development or growth, as alternative substrates compensate for their absence. This study highlights adaptive mechanisms in early life nutrition.
Area of Science:
- Neuroscience
- Developmental Biology
- Nutritional Science
Background:
- Artificial rearing (AR) models are crucial for studying nutritional impacts on development.
- Understanding the role of specific milk fat components, like medium chain fatty acids, is vital for infant nutrition and brain development.
Purpose of the Study:
- To investigate the necessity of medium chain fatty acids (MCFAs) and ketone bodies for brain development and growth in artificially reared rat pups.
- To compare the effects of a standard artificial milk formula versus a medium chain triglyceride-deficient formula on growth and brain morphology.
Main Methods:
- Three groups of rat pups were studied: mother-reared controls, artificially reared controls (AR-c) with standard milk substitute, and artificially reared (AR-h) pups with a medium chain triglyceride-deficient milk substitute.
- Artificial rearing involved gastric infusion from postnatal Day 5 to 17.
- Morphological and biochemical markers were used to assess growth and brain integrity.
Main Results:
- Artificially reared pups (AR-h) exhibited hypoketonemia.
- All groups achieved similar body weights by Day 17.
- While overall brain weight was similar between AR and mother-reared groups, AR brains weighed less.
- A reduction in the size of vibrissal barrel fields in the somatosensory cortex was observed in both AR groups compared to mother-reared controls.
Conclusions:
- Medium chain fatty acids and ketone bodies are not mandatory for rat pup growth and brain development.
- The developing brain can utilize alternative substrates to compensate for the absence of medium chain fatty acids and ketone bodies.
- Distinct differences exist between artificially reared and mother-reared rat pups, emphasizing the complexity of nutritional influences on development.
Abstract:
Three groups of rats were reared: mother-reared controls; artificially reared controls (AR-c), which were fed a milk substitute with the same composition of macro-nutrients as natural rat's milk; and an artificially reared test group (AR-h), which was fed a milk substitute identical to that fed AR-c pups except that the component of fat containing medium chain length fatty acids was omitted (medium chain triglyceride deficient) and replaced on an isocaloric basis with carbohydrate. The AR rats were fed the milk substitute from postnatal Day 5 until Day 17 by fitting them with gastric cannulas through which the milk could be infused automatically. The nutritional impact of the milk substitutes on growth and the integrity of the brain was assessed by a comparison of morphologic and biochemical markers. Pups in the AR-h group were hypoketonemic. Animals in all groups attained the same body weight by Day 17 and there was no difference in the morphologic markers among the groups with one exception: the vibrissal "barrel fields" of the somatosensory cortex of rat pups in both AR groups were reduced in size but not in number of distribution from those of the mother-reared groups. Furthermore, the brains of the rat pups in the AR groups were not different in weight, but they weighed less than brains of mother-reared controls. Our data show that although there are many similarities in the status of AR rat pups when compared with mother-reared controls, distinctive differences associated with artificial rearing are evident. We conclude that medium chain fatty acids in milk fat and the circulating ketone bodies are not mandatory substrates for growth and the development of the brain. Mechanisms must exist whereby alternative substrates are used to compensate when these metabolites are diminished in supply.
