Modelling of amino acid turnover in the horse during training and racing: A basis for developing a novel supplementation strategy.
Authors: Dunstan R Hugh, Macdonald Margaret M, Thorn Brittany, Wood David, Roberts Timothy K
Journal: PloS one
Summary
# Editorial Summary Horses undertaking intensive training and racing experience elevated metabolic demands that current feeding strategies may not fully address, particularly regarding amino acid availability during recovery and high-intensity effort. Dunstan and colleagues developed a computational model integrating published data on equine protein metabolism to identify which amino acids become disproportionately depleted during exercise and training, revealing that glutamine/glutamic acid, serine and ornithine exist in negative nitrogen balance under standard training conditions, with an additional eight amino acids—including valine, lysine, histidine and phenylalanine—becoming limiting during high-intensity work. The modelling suggests that targeted amino acid supplementation at 20–80g daily could theoretically restore balance in a 500kg horse, though the specific ratios and timing would require empirical validation through performance or recovery trials. This theoretical framework challenges the assumption that conventional protein supplementation adequately addresses the selective amino acid losses incurred through sweat, urine and increased biosynthetic demand, and provides a quantitative basis for developing bespoke supplementation protocols—particularly valuable for competition horses or those training in hot climates where excretory losses are magnified. Further research translating these computational predictions into practical supplementation interventions could refine nutrient strategies and potentially enhance recovery, muscle adaptation and overall welfare in performance horses.
Read the full abstract on PubMed
Practical Takeaways
- •Current protein supplementation for racing/competition horses may not adequately address specific amino acid demands, particularly for high-intensity work
- •Targeted amino acid supplementation tailored to training intensity could theoretically improve recovery and well-being, with specific benefit in hot climates where losses are higher
- •This is early-stage theoretical modelling—actual efficacy requires validation through feeding trials before changing supplementation protocols
Key Findings
- •Computer modelling identified glutamine/glutamic acid, serine, and ornithine as amino acids in negative nitrogen balance during standard training in horses
- •High-intensity training modelling indicated 8 amino acids become limiting, including valine, lysine, histidine, and phenylalanine in addition to glutamine/glutamic acid
- •Theoretical supplementation strategy suggests 20-80g/day of targeted amino acids may benefit 500kg horses in heavy training