Protein or Indispensable Amino Acid Supplementation After Deficiency Partially Restored Growth and Did Not Induce...

Area of Science:

• Nutritional biochemistry
• Metabolic regulation
• Animal models in nutrition research

Background:

• Inadequate protein intake during early development is linked to impaired growth and increased metabolic syndrome risk later in life.
• Understanding the specific roles of protein and indispensable amino acids (IAAs) is crucial for addressing these nutritional challenges.

Purpose of the Study:

• To investigate the impact of protein or specific indispensable amino acid (lysine, threonine, methionine) deficiency and subsequent supplementation on energy metabolism in growing rats.
• To evaluate the recovery of growth parameters and metabolic markers following nutritional interventions.

Main Methods:

• Growing rats were fed diets deficient in protein or specific IAAs (lysine, threonine, methionine) for 3 weeks.
• Following deficiency, rats were supplemented with either protein or the deficient IAA to meet requirements for another 3 weeks.
• Measurements included body weight, food intake, body composition, energy expenditure, and plasma fibroblast growth factor 21 levels.

Main Results:

• All deficiencies caused significant growth retardation, with threonine deficiency being most severe.
• Supplementation partially restored growth, but body weight and lean body mass remained significantly lower than controls.
• Increased energy expenditure compensated for increased food intake in protein-supplemented and threonine-supplemented groups, preventing adiposity.
• Lysine and methionine supplementation increased food intake without a corresponding rise in energy expenditure.
• Plasma fibroblast growth factor 21 levels were inversely correlated with protein and IAA status.

Conclusions:

• Individual indispensable amino acids play distinct roles in growth and metabolic adaptation.
• Targeted supplementation of specific IAAs shows potential for improving nutritional interventions and mitigating adverse metabolic consequences of early-life deficiencies.