Modelling of amino acid turnover in the horse during training and racing: A basis for developing a novel supplementation strategy

PLoS One. 2020 Jan 3;15(1):e0226988. doi: 10.1371/journal.pone.0226988. eCollection 2020.

Abstract

Horses in heavy training in preparation for racing and competition have increased metabolic demands to support the more intensive levels of exercise and recovery. However, little is known at the metabolic level about amino acid turnover and the specific alterations of demand caused by high intensity exercise. During exercise, certain amino acids are required in greater quantities due to disproportionate losses via excretory systems and usage in biosynthetic pathways. This investigation has built a theoretical computer model in an attempt to bring together the published rates of protein intake and utilisation to try to understand how some amino acids might be in higher demand than others. The model indicated that after evaluation of the daily amino acid turnover, glutamine/glutamic acid (Glx), serine and ornithine were in negative nitrogen balance which identified these amino acids as critical limiting factors for anabolism. Adjustment of the modelling conditions to cater for high intensity training indicated that an additional demand was placed on eight amino acids, including GLx, valine, lysine, histidine and phenylalanine which could thus become limiting under these conditions. The modelling results indicated that an amino acid supplement with the correct amino acids to match demand could theoretically be beneficial to a 500Kg horse in quantities of 20-80g/day. These results open new avenues of research for specifically tailoring amino acid supplementation to meet demands for sports horses in heavy training and improving general well-being, especially in hotter climates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / metabolism*
  • Animals
  • Computer Simulation
  • Dietary Supplements*
  • Homeostasis
  • Horses
  • Models, Theoretical
  • Nitrogen / metabolism
  • Physical Conditioning, Animal*

Substances

  • Amino Acids
  • Nitrogen

Grants and funding

The work was supported by the Gideon Lang Research Foundation. Dr David Wood works as a veterinarian consultant to Horsepower Pty Ltd to provide independent advice. Horsepower Pty Ltd provided support in the form of salary for author DW, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific role of this author is articulated in the ‘author contributions’ section. Dr David Wood works as a veterinarian consultant to Horsepower to provide independent advice. Dr Wood assisted us in the final stages of preparation of the manuscript and provided valuable insight for checking the protein model and clinical interpretation of the data.474 The university authors have not been paid as consultants and have not received any direct grant funding from Horsepower Pty Ltd. This does not alter our adherence to PLOS ONE policies on sharing data and materials. The work was supported by the Gideon Lang Research Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.