Oxidative and cardiac metabolism of horses subjected to low intensity exercise before and after antioxidant supplementation/Metabolismo oxidativo e cardiaco de equinos submetidos a exercicio de baixa intensidade antes e apos suplementacao com antioxidante

• Published in: Ciência rural Vol. 44; no. 6; p. 1060
• Main Authors: Yonezawa, Leticia Andreza, Barbosa, Tatiana de Sousa, Watanabe, Marcos Jun, Knaut, Jhonatas Luiz, Marinho, Camila Luz, Michima, Lilian Emy dos Santos, Kohayagawa, Aguemi
• Format: Journal Article
• Language: Spanish
• Published: Universidade Federal de Santa Maria 01.06.2014
• Subjects: Antioxidants; Enzymes; Physiological aspects
• ISSN: 0103-8478

The present study aimed to evaluate cardiac and lipoperoxidation markers in horses subjected to low intensity and long duration (TLD) exercise test, before and after vitamin E supplementation. For this purpose, 10 horses were used, subjecting them to the first TLD with a workload based on individual maximal oxygen uptake (V[O.sub.2max]). Then, horses received vitamin E (dl- alphatocopherol) during 59 days at a daily oral dose of 1,000IU, and thereafter they performed a second TLD with the same protocol as the first. Blood samples were collected to determine plasma malondialdehyde (MDA) as an index of lipoperoxidation, serum cardiac troponin I (cTnl) and creatine kinase MB isoenzyme (CK-MB) as cardiac markers. As a result of the exercise, there was no significant increase in MDA or cTnI, but serum CK-MB increased suggesting myocardial stress. The supplementation was able to minimize reactive oxygen species production, as evidenced by lower concentrations of MDA at all times evaluated, but it didn't cause protective effect on the myocardium. It was concluded that the low intensity and long duration exercise promoted light myocardial stress in horses and vitamin E supplementation reduced lipoperoxidation. Key words: malondialdehyde, cardiac troponin I, CK-MB, vitamin E, exercise physiology, equine. O presente estudo objetivou avaliar os marcadores cardiacos e de lipoperoxidacao em equinos no teste de exercicio de baixa intensidade e longa duracao (TLD), antes e apos a suplementacao com vitamina E. Para tanto, foram utilizados 10 equinos, submetendo-os ao primeiro TLD, com carga de trabalho fundamentada no consumo maximo de oxigenio individual (V[O.sub.2max]). Em seguida, durante 59 dias, os equinos receberam vitamina E (dl-alfa-tocoferol) na dose diaria de 1.000UI por via oral e, posteriormente, realizaram um segundo TLD com o mesmo protocolo do primeiro. As amostras de sangue foram colhidas para determinacao do malondialdeido (MDA) plasmatico, como indice de lipoperoxidacao, da concentracao serica de troponina I cardiaca (cTnl) e da isoenzima MB da creatinoquinase (CK-MB) como marcadores cardiacos. Como efeito do exercicio, nao se observou aumento significativo de MDA nem de cTnl, mas sim da concentracao serica de CK-MB, sugerindo-se o estresse miocardico. A suplementacao foi capaz de amenizar a producao de especies reativas de oxigenio, evidenciada pela menor concentracao de MDA em todos os momentos avaliados, porem nao causou efeito protetor no miocardio. Concluiu-se que o exercicio de baixa intensidade e longa duracao promoveu estresse miocardico em equinos de forma leve e a suplementacao com vitamina E reduziu a lipoperoxidacao. Palavras-chave: malondialdeido, troponina I cardiaca, CK-MB, vitamina E, fisiologia do exercicio, cavalo.