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Animals : an open access journal from MDPI2025; 15(24); 3580; doi: 10.3390/ani15243580

Stable Levels of Thiol-Oxidised Plasma Albumin, a Biomarker of Oxidative Stress, Is Correlated with Enhanced Performance in Australian Thoroughbred Racehorses.

Abstract: Thoroughbred race performance is influenced by genetics, training, recovery, and management, but decisions about race readiness are often subjective and lack validated physiological markers. This study evaluated thiol-oxidised albumin, a blood-based indicator of oxidative stress, as a potential biomarker of pre-race fitness in Australian Thoroughbreds. Seventy-five clinically healthy racehorses from seven stables were monitored across 216 competitive events (150 races, 66 trials). Blood samples were collected from the jugular at baseline, 48 h pre-race, and for each day up to 8 days post-race to examine levels of thiol-oxidised using the OxiDx test. At baseline, thiol-oxidised albumin levels were stable, but 24% of horses exhibited oxidative stress before racing, rising to 53% after three consecutive races. Thiol-oxidised albumin levels also remained increased for at least 8 days post-race. Statistical analyses were conducted in GraphPad Prism 10.6 using paired t-tests or repeated-measures one-way ANOVA with Dunnett's post hoc test, alongside a generalised estimating equation model to assess associations with ordinal variables; significance was set at < 0.05. Reference change values were calculated to determine thresholds for biologically meaningful changes in thiol-oxidised albumin levels. Increased pre-race oxidative stress was significantly associated with poorer finishing positions and lower trainer-perceived performance but was unrelated to horse age or sex. Horses without oxidative stress were more likely to finish in the top three. These findings demonstrate that oxidative stress prior to racing is common and adversely affects performance. Thiol-oxidised albumin represents a promising objective biomarker to guide training and racing strategies, with implications for both performance and equine welfare.
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Publication Date: 2025-12-12 PubMed ID: 41463865PubMed Central: PMC12729770DOI: 10.3390/ani15243580Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This study investigated whether levels of thiol-oxidised plasma albumin, a biomarker of oxidative stress, can predict racing performance in Australian Thoroughbred racehorses.
  • The research found that higher oxidative stress before racing was linked to poorer race outcomes, suggesting that thiol-oxidised albumin could be used as an objective tool to assess race readiness and manage training strategies.

Background and Rationale

  • Performance in Thoroughbred racehorses depends on multiple factors including genetics, training regimen, recovery, and management.
  • Currently, decisions regarding a horse’s race readiness are largely subjective and lack validated physiological markers.
  • Oxidative stress refers to an imbalance between free radicals and antioxidants in the body, which can negatively impact cellular function and recovery.
  • Thiol-oxidised albumin is a blood-based marker that indicates oxidative stress by measuring modifications to plasma albumin, a major blood protein sensitive to oxidative changes.

Study Design and Methods

  • The study involved 75 clinically healthy Australian Thoroughbred racehorses from seven different stables.
  • A total of 216 competitive events were monitored, including 150 official races and 66 trial runs.
  • Blood samples were collected from the jugular vein at multiple time points:
    • Baseline (resting, before the racing schedule)
    • 48 hours pre-race
    • Daily for up to 8 days following each race
  • The OxiDx test was used to quantify thiol-oxidised albumin levels in the plasma samples.
  • Statistical analyses involved:
    • Paired t-tests and repeated-measures one-way ANOVA with Dunnett’s post hoc tests to compare changes over time.
    • A generalised estimating equation model to explore associations between biomarker levels and ordinal variables such as finishing position and trainer ratings.
    • Reference change values were calculated to identify biologically meaningful changes in albumin oxidation for individual horses.
    • A significance threshold of p < 0.05 was applied.

Key Findings

  • At baseline, thiol-oxidised albumin levels were generally stable across horses.
  • However, 24% of horses already showed signs of oxidative stress 48 hours before racing.
  • This proportion increased to 53% after three consecutive races, indicating cumulative oxidative stress through repeated exertion.
  • Thiol-oxidised albumin levels remained elevated for at least 8 days post-race, showing prolonged oxidative stress following competition.
  • Horses that exhibited increased oxidative stress before racing tended to have:
    • Significantly poorer finishing positions
    • Lower performance scores as perceived by trainers
  • There was no significant correlation between oxidative stress levels and the horse’s age or sex.
  • Horses without evidence of oxidative stress prior to racing had a greater chance of finishing in the top three positions.

Implications and Conclusions

  • This study highlights the prevalence of oxidative stress in racehorses, particularly before and after races.
  • Pre-race oxidative stress adversely affects race performance, supporting the idea that managing oxidative balance could enhance outcomes.
  • Thiol-oxidised albumin can serve as a reliable, objective biomarker for assessing physiological readiness and recovery in racehorses.
  • Use of this biomarker could guide trainers in optimizing training intensity, scheduling races more effectively, and improving overall equine welfare by preventing overexertion.
  • Future work may focus on refining the biomarker’s predictive power and integrating it into regular veterinary and training assessments.

Cite This Article

APA
James C, Sheahan J, Arthur P. (2025). Stable Levels of Thiol-Oxidised Plasma Albumin, a Biomarker of Oxidative Stress, Is Correlated with Enhanced Performance in Australian Thoroughbred Racehorses. Animals (Basel), 15(24), 3580. https://doi.org/10.3390/ani15243580

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 15
Issue: 24
PII: 3580

Researcher Affiliations

James, Christopher
  • OxiDx Pty Ltd., Nedlands, WA 6009, Australia.
Sheahan, Jordana
  • Proteomics International, Nedlands, WA 6009, Australia.
Arthur, Peter
  • School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia.

Grant Funding

  • N/A / Proteomics International

Conflict of Interest Statement

Christopher James is affiliated with OxiDx Pty Ltd. and Jordana Sheahan is affiliated with Proteomics International. OxiDx Pty Ltd. is jointly owned by Proteomics International and the University of Western Australia and is responsible for conducting research and development activities related to developing the OxiDx test. The funder (Proteomics International) had no influence on the study design, data collection, analysis, interpretation, or the preparation of this manuscript. Peter Arthur is a co-author of issued patents covering the blood test technology used in this study. The efficacy of this patented approach has not been demonstrated, nor do the authors believe the patent or any future benefits they may receive because of it inappropriately influence any work described in this manuscript.

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