Serum muscle-derived enzymes response during show jumping competition in horse

AIM: The effect of two jumping competitions, performed in two consecutive weekends, on serum creatine phosphokinase (CPK), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH), urea, creatinine (CREA) concentrations were evaluated in 12 healthy jumper horses. MATERIALS AND METHODS: Blood sampling was performed before the 1(st) day of competition (T(0)), at the end of each show (J(1), J(2)), on the day after the competition (T(1)); the same sampling plan was followed during the second weekend (J(3), J(4) and T(2)). RESULTS: One-way repeated measures analysis of variance showed an increase in CPK at J(1) and J(2) respect to T(0) and at J(3) and J(4) respect to all other time points (p<0.05). LDH activity showed an increase at J(2) respect to T(0), at J(3) respect to T(0), J(1), J(2) and at J(4) respect to all other time points (p<0.05). AST values increased at J(1) and J(2) respect to T(0) (p<0.05). A significant increase of CREA was found at J(3) respect to T(0), T(1) and J(1) and at J(4) respect to all other time points (p<0.05). A decrease in serum urea levels was found at J(1) respect to T(0), at J(2) and J(4) respect to T(0) and T(1); at T(2) respect to T(0) (p<0.05). A positive correlation between urea/CPK (p=0.0042, r(2)=0.030), LDH/CPK (p<0.0001, r(2)=0.535), CREA/LDH (p<0.0001, r(2)=0.263), CREA/CPK (p<0.0001, r(2)=0.496) was observed. CONCLUSION: Our results suggest that 5 days recovery period between the two consecutive competition weekends is insufficient to allow muscle recovery and avoid potential additional stress. The findings obtained in this study improve the knowledge about metabolic changes occurring in athlete horse during the competition to identify muscle alterations following show jumping competitions.