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The effects of exogenous nutrients on growth of chick embryo brain
Insights
Early nutrient addition can manipulate chick embryo brain growth. Specific amino acids like L-tryptophan inhibited growth, while glycine stimulated it, impacting neuronal proliferation.
Area of Science:
- Developmental biology
- Neuroscience
- Biochemistry
Background:
- Early brain development is crucial and sensitive to environmental factors.
- Nutrient availability significantly influences embryonic growth and cellular proliferation.
Purpose of the Study:
- To investigate the impact of exogenous nutrient administration on embryonic chick brain growth.
- To identify specific nutrients that can inhibit or stimulate brain development during neuronal proliferation.
Main Methods:
- Chick embryos at days 6-7 were administered exogenous nutrients (L-tryptophan, D-tryptophan, 5-Methyltryptophan, Glycine) via the chorioallantoic membrane.
- Cerebral hemispheres were analyzed for weight, DNA content (cell number), and protein content post-neuronal proliferation.
- Correlation between brain parameters and blood glucose levels was assessed.
Main Results:
- L-Tryptophan and 5-Methyltryptophan significantly inhibited brain weight and DNA content, likely due to amino acid imbalance and altered serotonin production.
- D-Tryptophan showed no significant effect.
- Glycine significantly stimulated brain growth, potentially via conversion to glucose, correlating with increased blood glucose levels.
- Brain weight and DNA content showed a significant positive correlation with blood glucose levels.
Conclusions:
- Early embryonic brain growth can be modulated (inhibited or stimulated) by specific nutrient additions during the critical period of neuronal proliferation.
- Nutrient interventions offer a potential strategy to influence early brain development within genetic constraints.
- Understanding nutrient-brain interactions is key for developmental interventions.
Abstract:
The effect of an early addition of exogenous nutrients on brain growth has been investigated in chick embryo. The nutrients were introduced onto chorioallantoic membrane at day 6 or 7 of embryonal life, and the cerebral hemispheres examined at the end of neuronal proliferation for the following parameters: weight, DNA content (index of cell number) and protein content. L-Tryptophan produced significant inhibition, probably by creating amino acid imbalance and interference with the transport of other amino acids. D-Tryptophan (slower transport) was inactive. 5-Methyltryptophan produced significant inhibition, probably by causing deficiency of tryptophan utilization and of production of serotonin, which is a growth factor for early brain. Glycine stimulated brain growth, probably by conversion to glucose which is the main energy source for the embryo in this period. Brain weight and DNA were found to be significantly correlated with blood glucose level. It is concluded that, within genetic limits, early brain growth might be manipulated in both directions (inhibition or stimulation) by addition of proper nutrients during sensitive period of neuronal proliferation.