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Plasma beta-endorphin, cortisol and immune responses to acute exercise are altered by age and exercise training in horses.
Abstract: Ageing appears to affect immune and neuroendocirne function in horses and response to acute exercise. No studies have examined the combined effects of training and ageing on immune and neuroendocirne function in horses. Objective: To ascertain whether training and age would affect the plasma beta-endorphin (BE) and cortisol (C) as well as immune function responses to acute exercise in Standardbred mares. Methods: Graded exercise tests (GXT) and simulated race tests (SRT) were performed before and after 12 weeks training at 60 % HRmax. BE and C were measured at rest and at 5, 10, 20, 40, 60 and 120 min post GXT. Leucocyte cell number, CD4+ and CD8+ lymphocyte subsets, and mitogen stimulated lymphoproliferative response (LPR), were measured in jugular blood before and after the SRTs. Results: Cortisol rose by 5 min post GXT in young (Y) and middle-age (MA) mares (P<0.05) and remained elevated until 40 and 60 min post GXT, respectively during both pre- and post training GXT. There was no rise in C in old (0) mares after either GXT (P>0.05). Pretraining BE rose (P<0.05) by 5 min post GXT in all mares. After training, BE was higher in Y and O vs. MA (P<0.05) at 5 min post GXT. Post training BE was higher at 5 min post GXT in Y and O vs. pretraining (P<0.05). After SRT, lymphocyte number rose in all mares (P<0.05); however, lower lymphocyte numbers (P<0.05) were seen in MA vs. Y and O vs. MA (P<0.05). The O had reduced LPR to Con A and PHA stimulation (P<0.05) compared to Y and MA after the SRT after both pre- and post training SRT. LPR to PWM was lower (P<0.05) in O vs. Y and MA after the pretraining SRT. Training caused an increase in resting LPR to PWM in MA only (P<0.05). Conclusions: Both age and training altered the plasma beta-endorphin and cortisol responses as well as and immune responses to acute exercise. Conclusions: This study provides important information on the effects of ageing and training that will aid in the management and care of an increasing number of active older horses.
Publication Date: 2007-04-04 PubMed ID: 17402430DOI: 10.1111/j.2042-3306.2006.tb05551.xGoogle Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research paper evaluates how age and physical training alter horses’ immune and neuroendocrine responses to acute exercise by examining changes in the plasma beta-endorphin, cortisol, and immune function.
Objective and Methodology
- The study’s key aim was to understand the collective influence of training and age on plasma beta-endorphin (BE), cortisol (C), and immune responses to sudden exercise in Standardbred mares.
- The researchers employed Graded Exercise Tests (GXT) and Simulated Race Tests (SRT) before and after 12 weeks of training at 60% HRmax.
- They studied the horses’ BE and C levels at rest and at specific time frames post-GXT. Additionally, they evaluated leucocyte cell count, CD4+ and CD8+ lymphocyte subgroups, and lymphoproliferative response (LPR), in the horses’ jugular blood before and after the SRTs.
Results
- Researchers found that cortisol levels increased 5 minutes post-GXT in young (Y) and middle-aged (MA) mares and continued to stay high until 40 and 60 minutes post-GXT, respectively, both before and after training.
- There was no increase in cortisol in older (O) mares after GXT.
- Pre-training, beta-endorphin increased in all mares by 5 minutes post-GXT. After training, beta-endorphin was higher in young and old mares compared to middle-aged mares at 5 min post-GXT. Moreover, post-training, beta-endorphin was higher in Y and O compared to pre-training.
- After the SRT, lymphocyte counts increased in all mares; however, lower counts were seen in middle-aged mares compared to young and old versus middle-aged mares after SRT.
- Older horses displayed reduced lymphoproliferative response to Concanavalin A (Con A) and Phytohemagglutinin (PHA) stimulation compared to young and middle-aged horses after the SRT, both pre- and post-training.
- Training led to an increase in resting lymphoproliferative response to Pokeweed Mitogens (PWM) in middle-aged horses.
Conclusions
- Both age and training notably altered the plasma beta-endorphin, cortisol and immune responses to acute exercise in horses.
- This study offers valuable insights into the impacts of ageing and training on horses, supporting the management and care of an increasing number of active older horses.
Cite This Article
APA
Malinowski K, Shock EJ, Rochelle P, Kearns CF, Guirnalda PD, McKeever KH.
(2007).
Plasma beta-endorphin, cortisol and immune responses to acute exercise are altered by age and exercise training in horses.
Equine Vet J Suppl(36), 267-273.
https://doi.org/10.1111/j.2042-3306.2006.tb05551.x Publication
Researcher Affiliations
- Equine Science Center, Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, USA.
MeSH Terms
- Age Factors
- Aging / immunology
- Aging / physiology
- Animals
- Area Under Curve
- CD4 Lymphocyte Count / veterinary
- CD4-CD8 Ratio / veterinary
- Exercise Test / veterinary
- Horses / blood
- Horses / immunology
- Horses / physiology
- Hydrocortisone / blood
- Leukocyte Count / veterinary
- Mitogens / pharmacology
- Physical Conditioning, Animal / methods
- Physical Conditioning, Animal / physiology
- beta-Endorphin / blood
Citations
This article has been cited 8 times.- Pilozzi A, Carro C, Huang X. Roles of β-Endorphin in Stress, Behavior, Neuroinflammation, and Brain Energy Metabolism. Int J Mol Sci 2020 Dec 30;22(1).
- Ferlazzo A, Cravana C, Fazio E, Medica P. The different hormonal system during exercise stress coping in horses. Vet World 2020 May;13(5):847-859.
- Husain S. Delta Opioids: Neuroprotective Roles in Preclinical Studies. J Ocul Pharmacol Ther 2018 Jan Feb;34(1-2):119-128.
- Cravana C, Medica P, Ragonese G, Fazio E. Influence of training and competitive sessions on peripheral β-endorphin levels in training show jumping horses. Vet World 2017 Jan;10(1):67-73.
- Kang OD, Lee WS. Changes in Salivary Cortisol Concentration in Horses during Different Types of Exercise. Asian-Australas J Anim Sci 2016 May;29(5):747-52.
- Hulmi JJ, Myllymäki T, Tenhumäki M, Mutanen N, Puurtinen R, Paulsen G, Mero AA. Effects of resistance exercise and protein ingestion on blood leukocytes and platelets in young and older men. Eur J Appl Physiol 2010 May;109(2):343-53.
- Bodnar RJ. Endogenous opiates and behavior: 2006. Peptides 2007 Dec;28(12):2435-513.
- Cravana C, Medica P, Fazio E, Satué K, Brancato G, La Fauci D, Bruschetta G. Circulating ACTH and Cortisol Investigations in Standardbred Racehorses Under Training and Racing Sessions. Vet Sci 2025 May 19;12(5).
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