Exercise-induced alterations in plasma concentrations of ghrelin, adiponectin, leptin, glucose, insulin, and cortisol in horses.

This research examined if short-term, high-intensity exercise changes the plasma concentrations of several key hormones involved in regulating energy balance in horses. The results showed that cortisol and insulin levels changed during exercise, while the levels of leptin and ghrelin, which can influence energy intake, altered after the exercise.

Study Design and Participants

• The study involved six Standardbred mares with an average age of 11 years and average weight of 521 kg.
• The horses went through an exercise trial (EX) consisting of an incremental exercise test (GXT) and a control trial, where they maintained their regular standing (CON).
• Multiple plasma samples were collected at various intervals before, during, and after the exercise to assess hormonal changes.
• A separate set of samples was also collected around mealtime to measure any food-induced changes.
• Data analysis involved ANOVA for repeated measures and Tukey’s test.

Exercise Findings

• No significant changes were found in the levels of glucose, leptin, adiponectin, or ghrelin during the exercise.
• However, cortisol levels in plasma increased by 29%, and insulin decreased by 35% during the exercise.

Post-Exercise Findings

• In the initial 60 minutes after exercise, plasma concentrations of glucose and cortisol increased notably, 36% and 102% respectively, compared to rest conditions.
• Leptin levels were found to be 20% lower 24 hours after exercise in comparison to the control trial.
• Ghrelin levels were 37% lower in the EX trial as against the CON trial before and after the meal, but spiked 43% higher 12 hours post-exercise.
• No significant changes were noticed in the plasma concentrations of insulin or adiponectin during the recovery phase after exercise.

Conclusion

• The researchers concluded that short-term high-intensity exercise changes the plasma concentrations of leptin and ghrelin after exercise in Standardbred mares. These changes could trigger the horse’s body to alter energy intake.
• While cortisol and insulin levels change during the exercise, other hormones like ghrelin and leptin undergo changes post-exercise. This dichotomy could be of importance in understanding the overall energy balance in exercising horses and the subsequent impact on their performance and recovery.