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.
Publication Date: 2025-12-12 PubMed ID: 41463865PubMed Central: PMC12729770DOI: 10.3390/ani15243580Google Scholar: Lookup
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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
Researcher Affiliations
- OxiDx Pty Ltd., Nedlands, WA 6009, Australia.
- Proteomics International, Nedlands, WA 6009, Australia.
- 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.
References
This article includes 37 references
- Stallones L., McManus P., McGreevy P. Sustainability and the Thoroughbred Breeding and Racing Industries: An Enhanced One Welfare Perspective. Animals. 2023;13:490. doi: 10.3390/ani13030490.
- Schrurs C., Dubois G., Van Erck-Westergren E., Gardner D.S. Cardiovascular Fitness and Stride Acceleration in Race-Pace Workouts for the Prediction of Performance in Thoroughbreds. Animals. 2024;14:1342. doi: 10.3390/ani14091342.
- Paksoy Y., Ünal N. Multivariate analysis of morphometry effect on race performance in Thoroughbred horses. Rev. Bras. Zootec. 2019;48:e20180030. doi: 10.1590/rbz4820180030.
- Hall C., Huws N., White C., Taylor E., Owen H., McGreevy P. Assessment of ridden horse behavior. J. Vet. Behav. 2013;8:62–73. doi: 10.1016/j.jveb.2012.05.005.
- Morrice-West A.V., Hitchens P.L., Walmsley E.A., Wong A.S.M., Whitton R.C. Association of Thoroughbred Racehorse Workloads and Rest Practices with Trainer Success. Animals. 2021;11:3130. doi: 10.3390/ani11113130.
- Crawford K.L., Finnane A., Greer R.M., Barnes T.S., Phillips C.J.C., Woldeyohannes S.M., Bishop E.L., Perkins N.R., Ahern B.J. Survival Analysis of Training Methodologies and Other Risk Factors for Musculoskeletal Injury in 2-Year-Old Thoroughbred Racehorses in Queensland, Australia. Front. Vet. Sci. 2021;8:698298. doi: 10.3389/fvets.2021.698298.
- Wong A.S.M., Morrice-West A.V., Hitchens P.L., Whitton R.C. The association between Thoroughbred racehorse training practices and musculoskeletal injuries in Victoria, Australia. Front. Vet. Sci. 2023;10:1260554. doi: 10.3389/fvets.2023.1260554.
- Verheyen K.L., Price J.S., Wood J.L. Exercise during training is associated with racing performance in Thoroughbreds. Vet. J. 2009;181:43–47. doi: 10.1016/j.tvjl.2009.03.008.
- Wong A.S.M., Morrice-West A.V., Whitton R.C., Hitchens P.L. Changes in Thoroughbred speed and stride characteristics over successive race starts and their association with musculoskeletal injury. Equine Vet. J. 2023;55:194–204. doi: 10.1111/evj.13581.
- Morrice-West A.V., Hitchens P.L., Walmsley E.A., Stevenson M.A., Whitton R.C. Training practices, speed and distances undertaken by Thoroughbred racehorses in Victoria, Australia. Equine Vet. J. 2020;52:273–280. doi: 10.1111/evj.13156.
- McGowan C.M., Hyytiäinen H.K. Muscular and neuromotor control and learning in the athletic horse. Comp. Exerc. Physiol. 2017;13:185–194. doi: 10.3920/CEP170001.
- Logan A.A., Nielsen B.D. Training Young Horses: The Science behind the Benefits. Animals. 2021;11:463. doi: 10.3390/ani11020463.
- McGowan C.M., Whitworth D.J. Overtraining syndrome in horses. Comp. Exerc. Physiol. 2008;5:57–65. doi: 10.1017/S1478061508979202.
- Padalino B., Rubino G., Centoducati P., Petazzi F. Training versus Overtraining: Evaluation of Two Protocols. J. Equine Vet. Sci. 2007;27:28–31. doi: 10.1016/j.jevs.2006.11.013.
- James C., Dugan C.W., Boyd C., Fournier P.A., Arthur P.G. Temporal tracking of cysteine 34 oxidation of plasma albumin as a biomarker of muscle damage following a bout of eccentric exercise. Eur. J. Appl. Physiol. 2024;124:2639–2650. doi: 10.1007/s00421-024-05488-1.
- Lim Z.X., Duong M.N., Boyatzis A.E., Golden E., Vrielink A., Fournier P.A., Arthur P.G. Oxidation of cysteine 34 of plasma albumin as a biomarker of oxidative stress. Free Radic. Res. 2020;54:91–103. doi: 10.1080/10715762.2019.1708347.
- Lim Z.X., Peos J., Ostojic S., Arthur P.G., Fournier P.A. Recovery from Resistance Exercise with or Without Blood Flow Restriction Results in an Early Biphasic Pattern of Change in Albumin Cys34 Oxidation in Untrained Males. Antioxidants. 2025;14:667. doi: 10.3390/antiox14060667.
- James C., Lloyd E.M., Arthur P.G. Temporal changes in thiol-oxidized plasma albumin are associated with recovery from exercise-induced muscle damage after a marathon. Physiol. Rep. 2024;12:e70155. doi: 10.14814/phy2.70155.
- James C., Lloyd E.M., Arthur P.G. The Level of Thiol-Oxidised Plasma Albumin Is Elevated Following a Race in Australian Thoroughbred Horses. Vet. Med. Sci. 2025;11:e70487. doi: 10.1002/vms3.70487.
- Fraser C.G. Reference change values. Clin. Chem. Lab. Med. 2011;50:807–812. doi: 10.1515/cclm.2011.733.
- Buckley P., Buckley D.J., Freire R., Hughes K.J. Pre-race and race management impacts serum muscle enzyme activity in Australian endurance horses. Equine Vet. J. 2022;54:895–904. doi: 10.1111/evj.13519.
- Frankiewicz-Jóźko A., Szarska E. Anti-oxidant level to exercise in the blood of endurance horses. Biol. Sport. 2000;17:217–227.
- Arfuso F., Rizzo M., Giannetto C., Giudice E., Cirincione R., Cassata G., Cicero L., Piccione G. Oxidant and Antioxidant Parameters’ Assessment Together with Homocysteine and Muscle Enzymes in Racehorses: Evaluation of Positive Effects of Exercise. Antioxidants. 2022;11:1176. doi: 10.3390/antiox11061176.
- Yamazaki M., Kusano K., Ishibashi T., Kiuchi M., Koyama K. Intravenous infusion of H2-saline suppresses oxidative stress and elevates antioxidant potential in Thoroughbred horses after racing exercise. Sci. Rep. 2015;5:15514. doi: 10.1038/srep15514.
- Williams C.A., Kronfeld D.S., Hess T.M., Saker K.E., Waldron J.E., Crandell K.M., Harris P.A. Comparison of oxidative stress and antioxidant status in endurance horses in three 80-km races. Equine Comp. Exerc. Physiol. 2005;2:153–157. doi: 10.1079/ECP200562.
- Abate M., Pellegrino R., Di Iorio A., Salini V. Oxidative Stress and Performance after Training in Professional Soccer (European Football) Players. Antioxidants. 2023;12:1470. doi: 10.3390/antiox12071470.
- Powers S.K., Deminice R., Ozdemir M., Yoshihara T., Bomkamp M.P., Hyatt H. Exercise-induced oxidative stress: Friend or foe? J. Sport Health Sci. 2020;9:415–425. doi: 10.1016/j.jshs.2020.04.001.
- Clemente-Suarez V.J., Bustamante-Sanchez A., Mielgo-Ayuso J., Martinez-Guardado I., Martin-Rodriguez A., Tornero-Aguilera J.F. Antioxidants and Sports Performance. Nutrients. 2023;15:2371. doi: 10.3390/nu15102371.
- Steinbacher P., Eckl P. Impact of oxidative stress on exercising skeletal muscle. Biomolecules. 2015;5:356–377. doi: 10.3390/biom5020356.
- Meng Q., Su C.H. Antioxidant Defense and Redox Signaling in Elite Soccer Players: Insights into Muscle Function, Recovery, and Training Adaptations. Antioxidants. 2025;14:815. doi: 10.3390/antiox14070815.
- Schrurs C., Blott S., Dubois G., Van Erck-Westergren E., Gardner D.S. Locomotory Profiles in Thoroughbreds: Peak Stride Length and Frequency in Training and Association with Race Outcomes. Animals. 2022;12:3269. doi: 10.3390/ani12233269.
- Lindner A.E. Relationships between racing times of Standardbreds and v4 and v200. J. Anim. Sci. 2010;88:950–954. doi: 10.2527/jas.2009-2241.
- Evans D.L., Harris R.C., Snow D.H. Correlation of racing performance with blood lactate and heart rate after exercise in thoroughbred horses. Equine Vet. J. 1993;25:441–445. doi: 10.1111/j.2042-3306.1993.tb02987.x.
- Evans D.L., Priddle T.L., Davie A.J. Plasma lactate and uric acid responses to racing in pacing Standardbreds and relationships with performance. Equine Vet. J. Suppl. 2002;34:131–134. doi: 10.1111/j.2042-3306.2002.tb05405.x.
- Harkins J.D., Beadle R.E., Kamerling S.G. The correlation of running ability and physiological variables in thoroughbred racehorses. Equine Vet. J. 1993;25:53–60. doi: 10.1111/j.2042-3306.1993.tb02902.x.
- Lee Y.-W., Shim S.-T., Song H.-E., Hwang H.-S., Seo J.-P., Lee K.-K. The Correlation of Racing Performance with Pre-Race Blood Values in Thoroughbred Horses. J. Vet. Clin. 2018;35:190–194. doi: 10.17555/jvc.2018.10.35.5.190.
- James C., Weber J., Boyde C., Fournier P., Arthur P.G. The thiol oxidation state of albumin is associated with training load across an Australian football pre-season. Oxidative Med. Cell. Longev. 2025. accepted .
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