Background: It is imperative to possess a profound comprehension of the physiological and metabolic responses exhibited by equines when subjected to physical exertion. Objectives: To ascertain the correlation between the fatty acid profile and the activity of muscle enzymes in the blood serum of equines and analyse the impact of strenuous physical exertion on these parameters. Study design: Randomised, blinded cross-over in vivo experiments. Methods: The study was conducted on 15 pure-bred Arabian horses divided into groups: -experimental group (GE) (n=7) trained horses, participating in a 40-kilometre sport horse endurance event. -control group (GC) (n=8) neither competing nor trained. Peripheral blood were collected from the GE: three days prior to the commencement of the equestrian event (rest test), one hour and 24 hours after the conclusion of the event; from the GC: was administered rest test. The serum concentrations of CK, AST, LDH were assessed by the Roche Cobas Mira S clinical chemistry analyser. The composition of plasma fatty acids was determined using gas chromatography. Results: Higher AST and CK levels were noted in resting samples from horses undergoing regular training compared to horses that were not trained. Increases in AST and CK levels were also seen immediately after exercise.The demonstrated a positive correlation between regular training of the horses and increased levels of 14;1 and 18;1n-7 fatty acids, while decreased levels were observed for 14;0, 15;0, 16;0, 16;1n-7 and 16;1n-7 fatty acids. Intense exercise influenced the fatty acid profile by raising the proportion of 12;0, 14;0, 15;0, 16;0, 16;1n-7, 17;1, 18;1n-9 and 18;3n-3 fatty acids, and lowering 17;0, 18;2n-6, 18;3n-6 and 22;6n-3 fatty acids. The observed changes were found to be statistically significant or highly significant. Main limitations: Number of animals among groups. Conclusions: Horses used in endurance sports should receive feed supplements rich in omega 6 fatty acids.
