Aerobic exercise produces changes in plasma IL-6 but not IL-1b in four-beat gaited horses

Exercise is an important stressor and is correlated with cytokine production in several tissues. There is little information about changes in interleukin (IL)-6 and IL-1b in four-beat gaited horses during a typical aerobic exercise challenge. The objective of this research was to characterise changes in plasma IL-6, IL-1b, cortisol and other blood biomarkers in four-beat gaited horses after a marcha simulation test. We subjected 12 fit horses (approximately 5 years old and 390 kg) to the marcha simulation test (MST) (i.e. a 10 min warm-up, 30 min at marcha and 15 min cool down). Blood samples were collected before the MST, immediately after the MST and 15 and 120 min after the MST (i.e. recovery). Results were analysed with One Way Repeated Measures ANOVA and a Tukey tests with P≤0.05 and Pearson correlation test. The highest value of plasma IL-6 was observed immediately after MST (6.85 pg/ml) (P≥0.05). IL-1 and cortisol did not change (P≥0.05). However, creatine kinase (CK) and aspartate aminotransferase...