Peripheral Modulators of the Central Fatigue Development and Their Relationship with Athletic Performance in Jumper Horses.
Authors: Arfuso Francesca, Giannetto Claudia, Giudice Elisabetta, Fazio Francesco, Panzera Michele, Piccione Giuseppe
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Researchers investigated whether changes in serotonergic markers and neurohumoral factors during competitive jumping could explain fatigue development in performance horses, monitoring seven Italian Saddle mares across a standardized competition course with blood sampling before exercise, immediately post-competition, and 30 minutes into recovery. The exercise induced predictable metabolic responses—elevated heart rate, lactate, and rectal temperature—alongside significant alterations in amino acid profiles, with tryptophan levels and the tryptophan-to-branched-chain amino acid ratio rising whilst leucine and valine decreased; concurrent hormonal shifts included elevated prolactin and suppressed dopamine, with increased non-esterified fatty acids indicating mobilisation of energy reserves. Strong correlations emerged between these peripheral serotonergic indices and both physical performance measures and fatigue indicators, suggesting the serotonergic system may modulate fatigue perception during high-stress competitive situations rather than physical effort alone. The findings carry practical significance for equine professionals managing competition-related fatigue, as nutritional interventions targeting branched-chain amino acid supplementation, careful warm-up protocols, and stress-reduction strategies could theoretically attenuate the biochemical cascade associated with central fatigue. Further investigation in larger populations and across different disciplines is warranted to translate these mechanistic insights into evidence-based management protocols.
Read the full abstract on PubMed
Practical Takeaways
- •Competition stress in jumping horses activates the serotoninergic system beyond physical exertion alone, potentially contributing to behavioral changes (passivity) observed during competitive events
- •Monitoring tryptophan/BCAA ratios and prolactin levels may help identify fatigue development and recovery status in competition horses
- •Training and competition management should account for neurohumoral fatigue factors, not just physical conditioning, particularly in high-stress competitive environments
Key Findings
- •Heart rate peaked during jumping course and outbound phases (p < 0.0001)
- •Tryptophan and tryptophan/BCAA ratio increased significantly post-exercise (p < 0.0001), suggesting enhanced serotoninergic function linked to fatigue
- •Prolactin increased post-exercise (p < 0.0001) while dopamine decreased (p < 0.0001), indicating neuroendocrine shift during competition stress
- •Significant correlations found between peripheral serotoninergic indices, neurohumoral factors, and athletic performance parameters