Blood glutathione status and activity of glutathione-metabolizing antioxidant enzymes in erythrocytes of young trotters in basic training.
Authors: Janiak M, Suska M, Dudzińska W, Skotnicka E
Journal: Journal of animal physiology and animal nutrition
Summary
# Editorial Summary Young trotters undergoing basic training experience oxidative stress that may outpace their natural antioxidant defences, according to research by Janiak and colleagues examining the blood glutathione system in nine 16–20-month-old horses during a progressive 4-month conditioning programme. Nine untrained trotters were subjected to gradually intensified low-to-moderate exercise (4–40 km weekly over 12 weeks), with blood samples collected at rest before training, after the conditioning period, and immediately and 60 minutes following a routine workout on day 112. Immediately post-exercise, glutathione peroxidase activity and the reduced-to-oxidised glutathione ratio (GSH/GSSG) dropped significantly whilst oxidised glutathione accumulated—a pattern persisting an hour later despite compensatory increases in glutathione-disulfide reductase activity—suggesting reactive oxygen species production exceeded the young animals' antioxidative capacity. Although enzyme activities improved over the full training period, the persistent elevation of oxidised glutathione and depressed GSH/GSSG ratio after exertion indicates immature trotters cannot adequately manage exercise-induced oxidative stress, with implications for training load management, nutritional support, and potential supplementation strategies in young performance horses. Practitioners may need to reassess training intensity and duration in young trotters and consider targeted antioxidant nutritional intervention during basic conditioning phases.
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Practical Takeaways
- •Young horses in early training may be at risk of oxidative stress exceeding their antioxidant capacity; consider dietary antioxidant supplementation or modified training protocols for immature trotters
- •Post-exercise glutathione depletion persists for at least 60 minutes in young horses, suggesting recovery time and nutritional support should be prioritized in training schedules
- •Monitor young horses carefully during basic training as their antioxidant defenses appear insufficient to cope with current training intensities, even at low-to-moderate levels
Key Findings
- •Post-exercise glutathione peroxidase (GPX) activity and NADP+ were significantly lower (p<0.05 and p<0.01 respectively) while oxidized glutathione (GSSG) was markedly higher than at rest
- •The reduced/oxidized glutathione ratio (GSH/GSSG) remained significantly depleted 60 minutes post-exercise despite increased enzyme activities
- •Young trotters in basic training showed evidence that reactive oxygen species production exceeded antioxidative defense capacity, sustained at 60 minutes post-exercise
- •All investigated parameters except NAD+ and GSH/GSSG ratio changed significantly during the 4-month low-to-moderate intensity training period