Determination of speed and assessment of conditioning in horses submitted to a lactate minimum test-alternative approaches.

The maximal lactate steady state (MLSS) is a well-known gold standard method for determining the aerobic capacity of athletic horses. Owing to its high cost and complex execution, there is a search for standardized exercise tests that can predict this value in a single session. One of the methods described for this purpose is the lactate minimum test (LMT), which could be more accurate despite being adequate to predict MLSS. This study aimed to examine the impact of training on the speed corresponding to lactate minimum speed (LMS) and to apply new mathematical methods to evaluate the fitness level of horses based on the curve obtained by the LMT. Ten Arabian horses underwent a 6-week training program based on LMS calculated by second-degree polynomial regression (LMSP). In addition, the LMS was also determined by visual inspection (LMSV), bi-segmented linear regression (LMSBI) and spline regression (LMSS). From the curve obtained during the LMT, it was possible to calculate angles α, ß and ω, as well as the total area under the curve (AUCTOTAL) before (AUCPRELMS) and after (AUCPOSLMS) the LMS. The methods for determining the LMS were evaluated by ANOVA, intraclass correlation coefficient (ICC) and effect size (ES) by Cohen's d test. The Pearson correlation coefficient (r) between the proposed LMS determination methods and other mathematical methods was also calculated. Despite showing a good correlation (ICC >0.7), the LMS determination methods differed from each other (p < 0.05), albeit without a significant difference resulting from conditioning. There were reductions in α:ß ratio, angle α, and AUCPOSTLMS, with the latter indicating lower lactate accumulation in the incremental phase of LMT after conditioning, in addition to an improvement in the animals' aerobic capacity. Considering that the most common methods for determining the LMS are applicable yet with low sensitivity for conditioning assessment, the approaches proposed herein can aid in analyzing the aerobic capacity of horses subjected to LMT. The mathematical models presented in this paper have the potential to be applied in human lactate-guided training program trials with a comparable study basis.

Immediate Effect of Hoof Trimming on Hoof and Thoracic Joint Angles in Mangalarga Mares.

It is important to understand the effects of hoof trimming on hoof and limb conformation to maximize its benefits on the health of the appendicular skeleton of horses, thus promoting improvements in athletic performance and sporting longevity with regard to athletic horses. There is little information on possible changes in the angulation of the thoracic limb joints after hoof trimming and correlations between the angulation of the thoracic limb joints with hoof measurements. To that purpose, nineteen Mangalarga mares received routine hoof trimming. Visual recordings (photographs) were taken before and after the procedure. Differences (p < 0.05) were found in hoof length, toe angle, heel angle, medial heel height, and metacarpophalangeal angle. Before trimming, correlations were found between frog length and scapulohumeral angle (SH) (r = -0.457; p = 0.049), and between toe length and shoulder-ground angle (SG) (r = -0.553; p = 0.049). A correlation was also seen between the distance from the frog to the lateral wall and the SH angle (r = 0.690; p = 0.001). After trimming, there was a correlation between humeroradial (HR) and SH joint angles (r = 0.669; p = 0.002), and the SG and SH angles (r = 0.488; p = 0.034). This study showed an immediate effect of trimming on the toe angle and heel angle and on the metacarpophalangeal joint angle, in addition to correlations between the hoof and proximal joint angles, following trimming, thus evidencing the relevance of trimming not only in hoof morphology, but also in the conformation of the appendicular skeleton of horses.

In vivobiocompatibility and biodegradability of poly(lactic acid)/poly(ε-caprolactone) blend compatibilized with poly(ε-caprolactone-b-tetrahydrofuran) in Wistar rats.

Poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) are two important aliphatic esters known for their biodegradability and bioresorbability properties; the former is stiffer and brittle while the smaller modulus of the latter allows a suitable elongation. The new biomaterials being developed from the blend of these two polymers (PLA and PCL) is opportune due to the reducing interfacial tension between their immiscible phases. In a previous study, PLA/PCL immiscible blend when compatibilized with poly(ε-caprolactone-b-tetrahydrofuran) resulted in enhanced ductility and toughness no cytotoxic effect invitrotests. There is little published data on the effect of poly(ε-caprolactone-b-tetrahydrofuran) on PLA and PCL biocompatibility and biodegradabilityin vivotests. This study focuses on evaluating the behavioral response and polymer-tissue interaction of compatibilized PLA/PCL blend compared to neat PLA implanted via intraperitoneal (IP) and subcutaneous (SC) in male Wistar rats, distributed in four experimental groups: neat PLA, PLA/PCL blend, sham, and control at 2-, 8- and 24-weeks post-implantation (WPI). An open-field test was performed to appraise emotionality and spontaneous locomotor activity. Histopathological investigation using hematoxylin-eosin (H&E) and picrosirius-hematoxylin (PSH) was used to assess polymer-tissue interaction. Modifications in PLA and the PLA/PCL blend's surface morphology were determined by scanning electron microscopy (SEM). PLA group defecated more often than PLA/PCL rats 2 and 8 WPI. Conjunctive capsule development around implants, cell adhesion, angiogenesis, and giant cells of a foreign body to the biomaterial was observed in light microscopy. Both groups displayed a fibrous reaction along with collagen deposition around the biomaterials. In the SEM, the images showed a higher degradation rate for the PLA/PCL blend in both implantation routes. The polymers implanted via IP exhibited a higher degradation rate compared to SC. These findings emphasize the biocompatibility of the PLA/PCL blend compatibilized with poly(ε-caprolactone-b-tetrahydrofuran), making this biopolymer an acceptable alternative in a variety of biomedical applications.

Effect of work on body language of ranch horses in Brazil.

The horses' responses to exercise are commonly monitored using physiological variables, nonetheless physical and mental states can also be expressed through body language. The aims of this study were: (i) to identify how facial expressions and other behavioural variables change in ranch horses after a routine workday, and (ii) to investigate if these changes can be used as indicators of physical tiredness by relating them to known variables of physical fitness and workload. Fourteen crossbred ranch horses were assessed pre- and post-workday on two farms, recording the body language, physiological and workload variables. Statistical analysis consisted of four stages: (i) comparisons between the sampling times (pre- vs post-workday) using linear mixed-effects models with repeated measures and a paired Wilcoxon test; (ii) selection of the most powerful variables by applying Kaiser-Meyer-Olkin test and principal components analyses (PCA); (iii) evaluations of the relationships within these selected variables utilizing PCA and Spearman rank coefficients; and (iv) identifying a critical level of the most robust behavioural indicators using a non-hierarchical cluster analysis. Results showed that after a workday the horses increased the frequency/duration of body language indicative of resting. They also decreased the frequency/duration of body language indicative of attention and movements to avoid flies. However, some of these behaviours are also shown when horses are in pain, leading us to suggest that some ranch horses were probably experiencing a combination of of tiredness and slight soreness. Of particular interest, because of the ease with which it can be assessed on the farm and generalized to other situations, we suggest that the frequency of shifting weight between the forelegs has potential to be used as an indicator of physical tiredness in horses. The results can also be used in the development of tools to improve the welfare of ranch horses as well as horses used in other activities, although more research is needed to validate this assumption.

Candidate genes for performance in horses, including monocarboxylate transporters / Genes candidatos para desempenho em equinos, incluindo transportadores de monocarboxilatos

Some horse breeds are highly selected for athletic activities. The athletic potential of each animal can be measured by its performance in sports. High athletic performance depends on the animal capacity to produce energy through aerobic and anaerobic metabolic pathways, among other factors. Transmembrane proteins called monocarboxylate transporters, mainly the isoform 1 (MCT1) and its ancillary protein CD147, can help the organism to adapt to physiological stress caused by physical exercise, transporting lactate and H+ ions. Horse breeds are selected for different purposes so we might expect differences in the amount of those proteins and in the genotypic frequencies for genes that play a significant role in the performance of the animals. The study of MCT1 and CD147 gene polymorphisms, which can affect the formation of the proteins and transport of lactate and H+, can provide enough information to be used for selection of athletic horses increasingly resistant to intense exercise. Two other candidate genes, the PDK4 and DMRT3, have been associated with athletic potential and indicated as possible markers for performance in horses. The oxidation of fatty acids is highly effective in generating ATP and is controlled by the expression of PDK4 (pyruvate dehydrogenase kinase, isozyme 4) in skeletal muscle during and after exercise. The doublesex and mab-3 related transcription factor 3 (DMRT3) gene encodes an important transcription factor in the setting of spinal cord circuits controlling movement in vertebrates and may be associated with gait performance in horses. This review describes how the monocarboxylate transporters work during physical exercise in athletic horses and the influence of polymorphisms in candidate genes for athletic performance in horses.(AU)

Algumas raças de equinos são altamente selecionadas para atividades desportivas. O potencial atlético de cada animal pode ser medido pelo seu desempenho nas competições equestres. Um alto potencial atlético depende, entre outros fatores, da capacidade do animal de produzir energia através dos metabolismos aeróbio e anaeróbio. As proteínas transmembrana chamadas transportadores de monoxarboxilato, principalmente a isoforma 1 (MCT1) e sua proteína auxiliar CD147, podem ajudam o organismo a se adaptar ao estresse fisiológico causado pelo exercício físico, transportando íons lactato e H+. Algumas raças de equinos são selecionadas para diferentes objetivos, portanto é provável que existam diferenças nas quantidades de transportadores monocarboxilatos e na frequência genotípica dos seus respectivos genes. O estudo de polimorfismos nos genes das proteínas MCT1 e CD147, afetando a sua formação e o transporte dos íons lactato e H+, podem fornecer informações suficientes para a seleção de equinos com capacidade de serem altamente treinados e resistentes a intensos exercícios. Dois outros genes candidatos que têm sido relacionados com potencial atlético e utilizados como possíveis marcadores para desempenho em equinos são o PDK4 e o DMRT3. A oxidação de ácidos graxos é altamente efetiva para produção de ATP e é controlada pela expressão do gene PDK4 (pyruvate dehydrogenase kinase, isozyme 4) no musculo esquelético durante e após do exercício físico. O gene DMRT3 (doublesex and mab-3 related transcription factor 3) codifica um importante fator de transcrição no controle dos movimentos em vertebrados e pode ser associado com a marcha em algumas raças de equinos. Esta revisão descreve como agem os transportadores de monocarboxilatos durante o exercício físico em equinos atletas e qual a influência de alguns polimorfismos em genes candidatos para o desempenho atlético em equinos.(AU)

Intense Exercise and Aerobic Conditioning Associated with Chromium or L-Carnitine Supplementation Modified the Fecal Microbiota of Fillies.

Recent studies performed in humans and rats have reported that exercise can alter the intestinal microbiota. Athletic horses perform intense exercise regularly, but studies characterizing horse microbiome during aerobic conditioning programs are still limited. Evidence has indicated that this microbial community is involved in the metabolic homeostasis of the host. Research on ergogenic substances using new sequencing technologies have been limited to the intestinal microbiota and there is a considerable demand for scientific studies that verify the effectiveness of these supplements in horses. L-carnitine and chromium are potentially ergogenic substances for athletic humans and horses since they are possibly able to modify the metabolism of carbohydrates and lipids. This study aimed to assess the impact of acute exercise and aerobic conditioning, associated either with L-carnitine or chromium supplementation, on the intestinal microbiota of fillies. Twelve "Mangalarga Marchador" fillies in the incipient fitness stage were distributed into four groups: control (no exercise), exercise, L-carnitine (10g/day) and chelated chromium (10mg/day). In order to investigate the impact of acute exercise or aerobic conditioning on fecal microbiota all fillies undergoing the conditioning program were analyzed as a separate treatment. The fillies underwent two incremental exercise tests before and after training on a treadmill for 42 days at 70-80% of the lactate threshold intensity. Fecal samples were obtained before and 48 h after acute exercise (incremental exercise test). Bacterial populations were characterized by sequencing the V4 region of the 16S rRNA gene using the MiSeq Illumina platform, and 5,224,389 sequences were obtained from 48 samples. The results showed that, overall, the two most abundant phyla were Firmicutes (50.22%) followed by Verrucomicrobia (15.13%). The taxa with the highest relative abundances were unclassified Clostridiales (17.06%) and "5 genus incertae sedis" from the phylum Verrucomicrobia (12.98%). There was a decrease in the phylum Chlamydiae and in the genus Mycobacterium after the second incremental exercise test. Intense exercise changed the community's structure and aerobic conditioning was associated with changes in the composition and structure of the intestinal bacterial population of fillies. The intra-group comparison showed that chromium or L-carnitine induced moderate changes in the fecal microbiota of fillies, but the microbiota did not differ from the control group, which was exercised with no supplementation. Fecal pH correlated positively with Simpson's index, while plasma pH correlated negatively. Our results show that exercise and aerobic conditioning can change in the microbiota and provide a basis for further studies enrolling a larger number of horses at different fitness levels to better understand the effects of exercise and training on the intestinal microbiota of horses.

Distance exercised during submaximal training on race winnings for Thoroughbred racehorses / Distância percorrida durante treinamento submáximo sobre rendimentos de cavalos de corrida da raça Puro Sangue Inglês

Evaluations of the physical fitness of Thoroughbred racehorses have been correlated with race earnings, but few reports exist about the influence of the distance exercised during training on both physical conditioning indices and financial productivity. During one training season sixteen claiming Thoroughbred horses were subjected to submaximal training and monitored by a global positioning system (GPS) coupled to a heart rate monitor. After initial and single monitoring, the horses were distributed into two groups of eight individuals each; one group exercised short distances (SD) between 1600 and 1900m, while the other exercised long distances (LD) between 2000 and 2350m. The duration (min) and mean and maximal velocities (ms-1)attained during each session were determined, as well as the difference in distances exercised (m) between official races and each training session. Blood lactate concentration ([LA]) during recovery was also determined. Student's t-test was used for a non-paired analysis, with P≤0.05 considered significant. The winnings (USD) of each horse were correlated with the peak heart rate (HRpeak) attained during the training session. The distances exercised in the training sessions were greater in relation to the official races distances by 24.7% and 40% for SD and LD, respectively. Lactatemia did not differ between the groups. The HRpeak obtained during the training session was lower in LD group. The velocity at which the heart rate reached 200 bpm (V200) was higher in LD group. There was a moderate correlation (r= 0.42) between the highest winnings and lowest HRpeak. The horses that ran longer distances during their submaximal training session had better cardiac conditioning and tendency to increase financial productivity.

Avaliações da aptidão física de cavalos Puro Sangue Inglês (PSI) têm sido correlacionadas com o ganho financeiro, mas a influência da distância percorrida durante o treinamento, tanto sobre índices de condicionamento físico como na produtividade financeira tem sido pouco relatada. Monitoraram-se, por meio de global positioning system (GPS) acoplado a frequencímetro, numa temporada de treinamento, dezesseis equinos da raça PSI, de uma mesma categoria, submetidos a treinamento submáximo. Após o monitoramento inicial e único de uma sessão de treino, os equinos foram distribuídos em dois grupos de oito componentes (DC e DL) diferenciados de acordo com a distância percorrida durante cada sessão de treino, sendo DC para distância curta e DL para distância longa. Dessa maneira, DC e DL percorreram distâncias entre 1600-1900 e 2000-2350 metros, respectivamente. Determinaram-se o tempo e as velocidades médias e máximas atingidas (m s-1), bem como a diferença entre as distâncias percorridas (m) entre as corridas oficiais e as sessões. A produção de lactato sanguíneo durante a recuperação foi quantificada. Empregou-se teste t de student para análise não pareada, sendo P≤0,05. Correlacionaram-se os ganhos financeiros (USD) de cada cavalo com afrequência cardíaca de pico (FCpico) atingidas durante as sessões. As distâncias percorridas nos treinos foram maiores em relação às corridas oficiais em 24,7% e 40% para DC e DL, respectivamente. A lactatemia não diferiu entre os grupos. A frequência cardíaca de pico (FCpico) obtida durante as sessões foi menor para o grupo DL. A velocidade que a frequência cardíaca atingiu 200 bpm (V200) foi maior para DL. Houve correlação moderada entre os maiores ganhos financeiros e menores FCpico. Os cavalos que treinaram maiores distâncias durante sessões de treinamento submáximo tiveram melhor condicionamento cardíaco e maior produtividade financeira.

Relationship between Brazilian Thoroughbred race horses performance and lay-up period after osseous thoracic limb diseases / Relação entre o desempenho e período de recuperação após enfermidades ósseas do membro torácico distal de cavalos Puro Sangue Inglês

It is well established in the literature that musculoskeletal injuries are important compromising agents in the performance of Thoroughbred horses. In Brazil, there are no studies on the interrelation between lay-up period post-injury and retirement of racehorses due to musculoskeletal injures. The aim of this study is to determine the relationship between rehabilitation times of track injures and variables of prior race performance and later return to competitions. The radiographic reports and athletic history of 416 thoroughbreds during the period between 2003 and 2006 were examined; they were selected based on continued presentations after injury diagnosis. The temporal variables (post-injury rehabilitation time) and performance variables (race score before and after injury) were evaluated by multivariate correspondence analysis of the data and represented in perceptual maps. Correspondence was observed between most of the animals that had a short lay-up post-injury and variables that denote decline in subsequent performance. Considering the integrity of the bone healing process as crucial for the horse to be able to handle later training routines and competitions, shortening this period could lead to an imbalance of the bone repair metabolism, thus resulting in performance decline and compromise of the horse athletic career.

Está bem estabelecido na literatura que as lesões músculo-esqueléticas são importantes agentes comprometedores do desempenho em cavalos PSI de corrida. No Brasil, não existem estudos sobre a relação entre o período de reabilitação pós-lesional e o afastamento de cavalos de corridas devido a lesões músculo-esqueléticas. O objetivo deste estudo foi determinar se existe relação entre o tempo de reabilitação de injúrias adquiridas na pista e os resultados obtidos em corridas, antes e depois de retornar às competições. Entre 2003-2006, foram examinados os relatórios radiológicos e história atlética de 416 PSI, selecionados com base em apresentações continuadas após o diagnóstico das lesões. As variáveis temporais (tempo de reabilitação pós-lesão-RT) e variáveis de desempenho (pontuação corrida antes e depois da injúria-SB/SA) foram avaliadas por análise de correspondência multivariada dos dados e representado em mapas de percepção. Correspondência foi observada entre a maioria dos animais que tiveram uma recuperação pós-lesão curta e variáveis que denotam o declínio no desempenho subsequente. Considerando a integridade do processo de cicatrização óssea como crucial para o cavalo a ser capaz de lidar com rotinas de treinamento e competições, o encurtamento deste período poderia levar a um desequilíbrio no metabolismo de reparação óssea, resultando em comprometimento do desempenho e da carreira atlética.

Exercício em esteira não elevou a temperatura do casco de equinos / Exercise on treadmill did not enhance the temperature of the equine hoof

Objetivou-se avaliar em equino a influência do exercício progressivo e intenso realizado em esteira de alta velocidade sobre a temperatura de regiões da pele, incluindo face, pescoço e quartela, e do casco, incluindo coroa, parede e sola. Utilizaram-se cinco equinos Puro Sangue Árabes, desferrados, com idade média de 8±0,7 anos, sendo duas fêmeas e três machos, com peso corpóreo médio de 420±10kg. A intensidade de esforço foi determinada por meio da quantificação do lactato sanguíneo. As temperaturas foram determinadas com o auxílio de termógrafo, antes, durante e após o exercício. Realizou-se análise de variância seguida pelo teste de Tukey, sendo P≤0,05. A lactacidemia aumentou, principalmente nas velocidades intensas. Houve redução das temperaturas das regiões da face, pescoço e quartela após o exercício e diminuição das temperaturas da parede, coroa e sola do casco durante o exercício, enquanto a temperatura da manta de rolamento da esteira não se alterou em nenhum momento. Constatou-se indiretamente que a perfusão sanguínea do casco diminuiu durante o teste de esforço tanto em sua fase aeróbia como na anaeróbia. Nenhuma das intensidades de esforço foi capaz de alterar a temperatura da manta de rolamento da esteira. A temperatura do casco diminuída como decorrência fisiológica do esforço físico imposto, retornou aos valores normais após o término do exercício.

The objective of the study was to evaluate the influence of intense and progressive exercise performed on a high speed treadmill on the temperature of the skin of the face, neck, pastern, and hoof, including the crown, sole and wall. Five unshod Arabian horses were used, with a mean age of 8±0.7 years, two females and three males, average body weight of 420±10kg. The exercise intensity was determined by quantification of blood lactate concentrations. Temperatures were determined with thermography before, during and after exercise. The effect of exercise on the temperature of the anatomic structures studied was evaluated by ANOVA for repeated measures followed by Tukey test, with P≤0.05. Blood lactate increased, especially at more intense speeds. There were decreases in temperature of the regions of the face, neck and pastern after the exercise, of the wall, crown and sole of the hoof during the effort. The temperature of the moving belt blanket bearing did not change at any time throughout the test exercise. It was found, indirectly, that the blood perfusion in the hoof decreased both during the aerobic and anaerobic phase of the exercise test. None of the effort intensities was able to change the temperature of treadmill moving belt. The temperature of the hoof reduced as a physiologic consequence of the exercise and returned to normal values after the end of the test.

Alterações hematológicas e cardíacas em cavalos Árabes submetidos ao teste de esforço crescente em esteira rolante / Hematological and cardiac alterations in Arabian horses submitted to incremental effort test in treadmill

Estudaram-se alterações na freqüência cardíaca e variáveis hematológicas de eqüinos Puro Sangue Árabe (PSA), submetidos a exercício intenso em esteira rolante sob condições tropicais. Para tanto, 24 eqüinos, treinados, realizaram exercício teste de intensidade crescente e amostras de sangue foram obtidas durante as etapas de esforço 4; 5; 6; 7; 8; 9 e10 m.s-1, com 10% de inclinação. As colheitas de sangue foram realizadas 15 segundos antes do término de cada etapa. A freqüência cardíaca foi obtida em cada etapa do exercício teste. Com as amostras de sangue foram obtidos, hematócrito, hemácias, hemoglobina e leucócitos totais. Foram calculados índices hematimétricos absolutos, volume corpuscular médio (VCM), hemoglobina corpuscular média(HCM) e a concentração de hemoglobina corpuscular média (CHCM).Os resultados mostram que houve variação significativa (p≤ 0,05), a partir do repouso, entre os valores médios da freqüência cardíaca e das variáveis hematimétricas. Destaque para o VCM e HCM que aumentaram significativamente (p≤ 0,05) na etapa de esforço máximo(10m/s) demonstrando haver anisocitose durante o exercício intenso. Desta forma, o grau das alterações destas variáveis fisiológicas está relacionado com a intensidade e duração do exercício teste.

Alterations in heart rate and hematological variables of Arabian horses submitted to intense exercise in treadmill under tropical conditions were studied. Twenty four trained horses were adapted to exercise ona high performance treadmill and then submitted to an incremental(4; 5; 6; 7; 8; 9 and 10 m.s-1) exercise test. Heart rate was verified andblood samples were taken 15 seconds before the end of each exercise step to determine the hematocrit, concentration of leucocytes, erythrocytes and hemoglobin. From these data the mean corpuscular volume (MCV), the mean corpuscular hemoglobin (MCH) and the mean corpuscular hemoglobin concentration (MCHC) were calculated.The results show that there were significant variations in heart rateand hematimetric variables from the rest when compared to the values after the exercise. The hematological indexes MCV and MCH had also increased significantly in the stage of maximum effort (10m/s)demonstrating the occurrence of anisocytosis during the intense exercise. In such a way, the degree of the alterations of these physiological variables is related with the intensity and duration of the effort.

Light exercise causes adaptive changes in muscles of young Brasileiro de Hipismo horses / Atividade física leve causa mudanças adaptativas musculares em eqüinos jovens da raça Brasileiro de Hipismo

This study aimed to determine the changes in the Gluteus medius of 4 year-old Brasileiro de Hipismo (BH) horses submitted to light physical activity for 10 months. The study involved 11 horses from the "Nove de Julho" Battalion of the Military Police of São Paulo State (PM-SP). Percutaneous muscle biopsy was performed in horses at maintenance and in those that had participated in routine police work for 10 months with the PM-SP. Fragments of the left Gluteus medius muscle was removed at depths of 20mm and 60mm. To determine the fiber types, the histochemical analyses were performed for myofibrillar adenosine triphosphatase (mATPase) and nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR). The morphometry of the fibers was performed by calculating the cross sectional area (CSA), relative frequency distribution (F) and relative cross-sectional area (RCSA). After the period of physical activity, type IIA fibers showed an increase in F and RCSA at both depths. The type I fibers showed a decrease in F at a depth of 60mm and the type IIX fibers showed no change in F at the two depths. With regard to the results for RCSA, type I and IIX fibers also did not show alterations after 10 months of light physical activity. Low intensity physical activity produced significant adaptations in the Gluteus medius muscle of horses of the BH breed, including changes in metabolic and contractile properties as evidenced by the increase in the area occupied by type IIA fibers at both depths of the biopsy.

Este estudo objetivou determinar as adaptações do músculo Gluteus medius de cavalos da raça Brasileiro de Hipismo (BH), que participaram de atividades físicas leves por 10 meses. Foram utilizados 11 eqüinos, machos, da raça BH e com idade de 4 anos, provenientes do "Batalhão Nove de Julho" da Polícia Militar do Estado de São (PM-SP). Realizou-se a biópsia muscular percutânea nos animais inativos e, após participarem das atividades de ronda e policiamento desenvolvido pela PM-SP por 10 meses, foram retirados fragmentos do músculo Gluteus medius nas profundidades de 20mm e 60mm. Para a determinação dos tipos de fibra muscular, foram feitas análises histoquímicas por meio das técnicas de adenosina trifosfatase miofibrilar (mATPase) e nicotinamida adenina dinucleotídeo tetrazólio redutase (NADH-TR). Na análise morfométrica das fibras, calculou-se a área de secção transversal (AST), a freqüência média (F) e a área de secção transversal relativa (ASTR). Após o período de atividade física, as fibras tipo IIA apresentaram aumento da F e da ASTR nas duas profundidades. As fibras tipo I apresentaram diminuição da F na profundidade de 60mm e as fibras tipo IIX não sofreram alteração da F nas duas profundidades. A ASTR das fibras tipo I e IIX não apresentaram alteração após os 10 meses. A atividade física de baixa intensidade produziu adaptações significativas no músculo Gluteus medius de cavalos da raça BH, incluindo mudança nas propriedades metabólicas e contráteis evidenciadas pelo aumento da área ocupada pelas fibras tipo IIA, nas duas profundidades de biópsia.

Exercise intensity, but not electrolyte reposition, alters plasmatic cortisol and glucose levels of horses submitted to 30 and 60km distance endurance rides

This study was aimed at comparing cortisol and glucose plasmatic levels in a group of trained horses submitted to 30 and 60km endurance exercises, at the average speed of 10 and 15km h-1, respectively. The horses were randomly divided in two groups, one treated, orally, with a hypertonic electrolyte paste before, during and after the tasks and the other used as control. Cortisol data revealed significant increase in the first moment when the intensity of the exercise was higher (15km/h) or with the prolongation of it (30km long), in the second moment to all groups. Glucose data remained constant during 30km ride; however after 20km distance, in 60km ride, it revealed a significant increase in control group, returning to basal levels in the subsequent moment. Electrolyte replenishment has its importance in the maintenance of the hidroelectrolyte and acid-base status and, in this study, may have contributed to the homeostasis of glucose levels.

O presente estudo teve como objetivo comparar os níveis plasmáticos de glicose e cortisol de um grupo de eqüinos atletas submetidos ao esforço de longa duração (enduro eqüestre) em distâncias de 30 e 60km, com velocidades médias de 10 e 15km h-1, respectivamente. Os animais foram aleatoriamente separados em dois grupos, sendo que a um deles foi administrada, por via oral, uma pasta eletrolítica hipertônica antes, durante e após as referidas provas. O outro grupo foi usado como controle. Os resultados das concentrações de cortisol revelaram um aumento significativo, no primeiro momento, em que a intensidade do esforço era maior (15km/h), ou com a continuação deste (30km de distância), no segundo momento, para todos os grupos. Os resultados referentes à concentração de glicose permaneceram constantes durante a prova de 30km; entretanto, nos primeiros 20km da prova de 60km, tais resultados revelaram um aumento significativo no grupo controle, retornando a valores basais no momento subseqüente. A reposição eletrolítica tem a sua importância na manutenção do equilíbrio hidroeletrolítico e ácido básico e, no presente estudo, pode ter contribuído para a manutenção da concentração média de glicose plasmática.

Long-term creatine supplementation improves the aerobic capacity of horses

O objetivo do presente estudo foi investigar os efeitos da suplementação oral com creatina sobre respostas fisiológicas ao treinamento aeróbico. Doze cavalos da raça Puro Sangue Arabe foram submetidos a treinamento aeróbico por 90 dias, com ou sem suplementação com creatina, que consistia da administração diária de 75g de monoidrato de creatina misturada à ração durante os 90 dias de treinamento. O treinamento físico foi conduzido exclusivamente em esteira rolante de alto desempenho sendo a intensidade do treinamento estabelecida em 80% da velocidade obtida através da V4 (velocidade na qual a concentração sangüínea de lactato atinge 4mmol L-1) determinada mensalmente para cada animal. Para o estabelecimento da V4 individual foi empregado um teste físico de esforço crescente em que, após um período de aquecimento de 4min a 4m s-1, a velocidade era aumentada à cada intervalo de dois minutos, para 6, 8 e 10m s-1. As amostras sangüíneas foram coletadas 15s antes do témino de cada intervalo para a determinação do lactato, hematócrito, hemoglobina e eritrócitos. Os resultados demonstraram um aumento significativo (P<0,05) da V4 dos animais que receberam creatina por 60 e 90 dias quando comparados, no mesmo período, com os animais que não receberam a suplementação. As outras variáveis hematológicas não apresentaram alterações. É possível sugerir que a suplementação prolongada com creatina pode promover efeitos benéficos no desempenho atlético de eqüinos.

Reposição eletrolítica sobre variáveis fisiológicas de cavalos em provas de enduro de 30 e 60km / Electrolyte reposition on physiologic variables of horses submitted to 30 and 60km endurance rides

O presente estudo teve como objetivo a comparação de variáveis fisiológicas (freqüência cardíaca, peso corporal, hematócrito, proteínas totais) entre um grupo de eqüinos atletas submetidos a provas de enduro eqüestre nas distâncias de 30 e 60km com velocidade média de 10 e 15km h-1, respectivamente. Em ambas as provas, os animais foram divididos em dois grupos experimentais que receberam, ou não, reposição eletrolítica por via oral, na forma de pasta, antes, durante e após as referidas provas. Os resultados obtidos revelaram que a administração da pasta eletrolítica não apresentou nenhum efeito colateral aos animais, nas distâncias em que foi avaliada, e sugerem que um suplemento à base de eletrólitos pode contribuir para o desempenho de cavalos submetidos a esforços prolongados.