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Age-Dependent Amino Acid Metabolism.
Caiyun You1, Xiaoyi Long1, Haiyang Wei1
1Research Center for Bio-feed and Molecular Nutrition, College of Animal Science and Technology, Southwest University, Chongqing, People's Republic of China.
The Journal of Nutrition
|August 25, 2025
Summary
Pig liver and intestinal amino acid metabolism changes with age. Jejunal enzyme activity increases, while liver ornithine cycle enzymes and mTORC1 signaling decrease, with gut microbes linked to metabolites.
Area of Science:
- Animal Physiology
- Nutritional Biochemistry
- Gastrointestinal Metabolism
Background:
- Understanding pig amino acid metabolism in the liver and intestines is crucial for improving nitrogen utilization efficiency through nutritional strategies.
- Age-dependent metabolic shifts significantly impact nutrient processing and overall animal health.
Purpose of the Study:
- To investigate age-related changes in amino acid metabolism within the liver and intestinal tissues of growing-finishing pigs.
- To identify key metabolic pathways and microbial associations influenced by age in pigs.
Main Methods:
- Fifty growing-finishing pigs were fed a standard diet and euthanized at five different ages (90, 120, 150, 180, 210 days).
- Analysis included metabolic enzyme activity, gene and protein expression, microbiota composition, and metabolomics in liver, jejunal mucosa, and intestinal contents.
- Statistical analysis utilized SAS 9.2 linear/quadratic models to determine age-dependent effects.
Main Results:
- Liver ornithine cycle enzyme activities (carbamoyl-phosphate synthase-Ⅰ, ornithine transcarbamylase) and target of rapamycin complex 1 (mTORC1) signaling decreased with age, particularly at day 210.
- Jejunal mucosa enzyme activities (glutamate dehydrogenase, alanine aminotransferase, aspartate aminotransferase) increased with age, showing higher levels at day 210 compared to day 90.
- Liver metabolomics revealed 31 differentially abundant metabolites, enriched in tryptophan/glutamate metabolism, with correlations found between specific glutamate/tryptophan metabolites and colonic microbes like Temporobacter.
Conclusions:
- Jejunal glutamine-cycle enzyme activities increase with age, contrasting with a decline in liver ornithine-cycle enzyme activity and mTORC1 expression.
- Specific colonic bacteria, such as Temporobacter, are significantly associated with host glutamate and tryptophan metabolites, indicating a gut-microbiota-metabolite axis.
- These age-dependent metabolic shifts in pigs highlight important physiological changes relevant to nutrition and gut health.
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