Pesq. Vet. Bras. 33(11):1385-1389, novembro 2013 1385 RESUMO.-O presente estudo teve por objetivo avaliar a influência do exercício físico de intensidade submáxima sobre as concentrações séricas de aspartato aminotransferase (AST), creatinoquinase (CK) e lactato-desidrogenase (LDH) em muares durante prova de enduro de 100 km realizada no estado do Espírito Santo. Para tal foram obtidas amostras de soro de 20 muares em três momentos assim definidos: no repouso (T0); após 54 km de percurso (T1); após 80 km de percurso (T2); e após 100 km de percurso (T3). As referidas amostras foram encaminhadas ao Laboratório Clínico Veterinário (CEMEVES) para processamento. Na avaliação da atividade sérica de AST, os valores médios registrados nos momentos T0, T1, T2 e T3 foram, respectivamente, de 341,7±73,9 UI/L, 403,1±78,4 UI/L, 410,5±70,5 UI/L e 426,5±66,7 UI/L. Na avaliação da atividade sérica da LDH, os valores médios registrados foram de 423,1±101,8 UI/L, 534,4±131,8 UI/L, 628,5±100,6 UI/L e 823,4±273,2 UI/L, respectivamente, nos momentos T0, T1, T2 e T3. Por fim, na avaliação da atividade sérica da CK os valores de mediana foram de 231,3 UI/L, 310,6 UI/L, 253,2 UI/L e 476,0 UI/L, respectivamente nos momentos T0, T1, T2 e T3. A análise dos resultados demonstrou que o exercí-cio físico imposto levou ao aumento significativo das atividades séricas de AST e LDH e não alterou as concentrações séricas de CK. The aim of this study was to evaluate the influence of an exercise of submaximal intensity on serum concentrations of aspartate aminotransferase (AST), creatine kinase (CK) and lactate dehydrogenase (LDH) in mules during endurance exercise in Espirito Santo, Brazil. Serum samples were obtained from 20 mules in four different moments: at rest (T0); after 54 km (T1); after 80 km (T2); and after 100 km (T3). Samples were analyzed at Laboratório Clínico Veterinário (CEMEVES). Serum AST analysis revealed mean values of 341.7±73.9 UI/L, 403.1±78.4 UI/L, 410.5±70.5 UI/L and 426.5±66.7 UI/L, respectively at moments T0, T1, T2 and T3. LDH mean values recorded in T0, T1, T2 and T3 were, respectively, 423.1±101.8 UI/L, 534.4±131.8 UI/L, 628.5±100.6 UI/L and 823.4±273.2 UI/L. Finally, when evaluating CK, median values recorded were 231.3 UI/L, 310.6 UI/L, 253.2 UI/L and 476.0 UI/L, respectively on the moments T0, T1, T2 and T3. Results showed that the physical exercise imposed leaded to significantly increase in serum AST and LDH and did not change serum CK.

The purpose of this study was to examine the development pattern of Mangalarga-Marchador foals by determination of muscle development and deposition of adipose tissue associated with the evaluation of blood-based biomarkers. Thus, 72 Mangalarga Marchador foals (ages ranged from 1-12 mo) were randomly selected and divided into 12 age groups (n=6 per group), evaluated monthly. The thickness of the Longissimus dorsi (LD) and rump fat (RF) were determined through an ultrasound performed on each foal’s left side. Such parameters were used to calculate the percentage of body fat (BF), fat mass (FM), and fat-free mass (FFM). Morphometric measurements were taken on the foal’s right side using a tape measure and a hypsometer. Blood samples were collected for determinations of total proteins, albumin, triglycerides, cholesterol, urea, creatinine, and glucose. Morphometric measurements,  the thickness of the LD and RF, weight, BF, FM, and FFM showed differences between age groups (P<0.001). Muscle development and fat deposition in subcutaneous tissue were greater between six and 12 months and average weight gain and FFM were proportionally greater between one and six months. We concluded that morphometric measurements increase steadily and linearly during the first 12 months of life, indicating that it is feasible to use the linear regression formula. Moreover, significant differences between age and biochemical biomarkers may be attributed to nutritional and digestive physiology adaptations during these periods.