Standardized exercise tests in horses : current situation and future perspectives

The purpose of this literature review is to clarify how exercise capacity can be measured in horses and which standardized exercise tests (SETs) exist. In this review, the measurement of the exercise capacity of horses is discussed and the standardized exercise tests (SET) are described. Two main types of SETs are used. Laboratory or treadmill tests are easy to standardize and provide more options to use all kinds of measuring devices, since the horse stays on the treadmill. On the other hand, field tests are conducted under the natural conditions associated with the specific sports discipline, and are easier to implement in the training schedule. However, field tests encompass interfering variables, such as weather conditions, ground surface conditions and the rider or jockey. Several variables are measured in order to calculate the fitness level which may be expressed by different parameters, such as V200 (speed at a heart rate of 200 beats per minute), V1a4 (speed at a blood lactic acid level of 4 mmol/L) and VO2max (maximum oxygen uptake)

Substrate use in horses during exercise : the 'fasted' compared to the postprandial state

Training in the fasted state has beneficial effects on performance in the human athlete. In the horse, training in the fasted state is associated with an increased mobilization of non-esterified fatty acids (NEFA) as an energy source. This is in contrast with postprandial (grain-fed) training, during which lipolysis is suppressed. A higher NEFA availability is thought to reduce muscle glycogen depletion and muscle acidification. This could aid in delaying muscle fatigue. The equine gastrointestinal tract and roughage rich diet do not allow a real 'fasted' state. Luckily, roughage does not induce high plasma insulin peaks, and therefore does not have the same negative effects as grain feeding. Furthermore, the roughage-containing hindgut serves as a fluid and electrolyte buffer and continuously provides the liver with propionic acid, a precursor used in gluconeogenesis. In horses, unlike in human athletes, there is still a lot to discover when it comes to optimal pre-exercise feeding management throughout competition and training. However, whatever approach is chosen, high quality roughage needs to be the key ingredient of the equine diet. In sport horses with high energy demands, feeding good quality roughage may be combined with fibre rich concentrates, pelleted roughages sources or vegetal oil instead of starch rich concentrates to reach the energy requirements for intensive work. Last but not least, feeding multiple small meals throughout the day is preferred over feeding a larger meal twice a day

Effects of training on equine muscle physiology and muscle adaptations in response to different training approaches

It is well known that exercise induces chemical, metabolic and structural changes in muscles. However, the effect of the type of exercise on these changes has not been thoroughly studied in horses yet, because of a lack of standardized study methods. In this review, the effect of three different types of exercise on muscle adaptation and metabolic responses is investigated. The requirements for power exercise are not the same as for low intensity exercise. Each type of training induces its own shift in muscle fiber typing, as well as in enzyme concentrations and (an) aerobic capacity. These physiological adaptations in response to training facilitate more efficient exercise and therefore increase performance. Hence, it is important to know the adaptations that muscles undergo in response to each type of exercise to optimize training management of sport horses in function of the needs of the discipline in which they compete

Flexibility of equine bioenergetics and muscle plasticity in response to different types of training : an integrative approach, questioning existing paradigms

Equine bioenergetics have predominantly been studied focusing on glycogen and fatty acids. Combining omics with conventional techniques allows for an integrative approach to broadly explore and identify important biomolecules. Friesian horses were aquatrained (n = 5) or dry treadmill trained (n = 7) (8 weeks) and monitored for: evolution of muscle diameter in response to aquatraining and dry treadmill training, fiber type composition and fiber cross-sectional area of the M. pectoralis, M. vastus lateralis and M. semitendinosus and untargeted metabolomics of the M. pectoralis and M. vastus lateralis in response to dry treadmill training. Aquatraining was superior to dry treadmill training to increase muscle diameter in the hindquarters, with maximum effect after 4 weeks. After dry treadmill training, the M. pectoralis showed increased muscle diameter, more type I fibers, decreased fiber mean cross sectional area, and an upregulated oxidative metabolic profile: increased β-oxidation (key metabolites: decreased long chain fatty acids and increased long chain acylcarnitines), TCA activity (intermediates including succinyl-carnitine and 2-methylcitrate), amino acid metabolism (glutamine, aromatic amino acids, serine, urea cycle metabolites such as proline, arginine and ornithine) and xenobiotic metabolism (especially p-cresol glucuronide). The M. vastus lateralis expanded its fast twitch profile, with decreased muscle diameter, type I fibers and an upregulation of glycolytic and pentose phosphate pathway activity, and increased branched-chain and aromatic amino acid metabolism (cis-urocanate, carnosine, homocarnosine, tyrosine, tryptophan, p-cresol-glucuronide, serine, methionine, cysteine, proline and ornithine). Trained Friesians showed increased collagen and elastin turn-over. Results show that branched-chain amino acids, aromatic amino acids and microbiome-derived xenobiotics need further study in horses. They feed the TCA cycle at steps further downstream from acetyl CoA and most likely, they are oxidized in type IIA fibers, the predominant fiber type of the horse. These study results underline the importance of reviewing existing paradigms on equine bioenergetics

Retrospective analysis of soft tissue injuries treated with allogenic bone marrow derived mesenchymal stem cells

Objectives: Tendon and ligament pathology has been managed successfully with mesenchymal stem cells from various biological sources. This retrospective study aims to evaluate the re-injury rate of the treatment of tendon and ligament lesions with allogenic bone marrow derived mesenchymal stem cells (BM-MSCs). Methods: Data from horses treated with allogenic BM- MSCs was recovered retrospectively from hospital records. Horses were included if they were solely treated with BM- MSCs, received only one treatment, had no other concur- rent lesion at the time of treatment, and had sufficient information about lameness and ultrasound evaluations. Outcome was evaluated in terms of re-injury within 12 months after treatment. Frequency counts were calcu- lated, and a chi-square test of homogeneity was used to determine whether distribution was identical across differ- ent disciplines and different anatomic structures. Results: Forty-two horses were included: 8 show jum- pers, 15 dressage horses, 15 Standardbreds and 7 leisure horses. There were 22 digital flexor tendons and 20 liga- ment injuries. The overall re-injury rate was 33%. No sta- tistical evidence was found to conclude that re-injury rate was influenced by discipline (p-value = 0.987) or ana- tomic structure (p-value = 0.592). No adverse reactions were observed on the treated horses. Conclusions: The treatment was safe, and re-injury rate was lower than reported when using conventional thera- pies. Our sample suggests that re-injury rate is the same across the different disciplines and anatomic structures. Further studies should be conducted, imposing a larger sample size and a control group

Effects of aleurone supplementation on glucose-insulin metabolism and gut microbiome in untrained healthy horses

Aleurone, a layer of the bran fraction, is deemed to be responsible for the positive health effects associated with the consumption of whole-grain products. Studies on rodents, pigs, and humans report beneficial effects of aleurone in five main areas: the reduction of oxidative stress, immunomodulatory effects, modulation of energy management, digestive health, and the storage of vitamins and minerals. Our study is the first aleurone supplementation study performed in horses. The aim of this study was to investigate the effect of an increase in the dose levels of aleurone on the postprandial glucose-insulin metabolism and the gut microbiome in untrained healthy horses. Seven adult Standardbred horses were supplemented with four different dose levels of aleurone (50, 100, 200, and 400 g/day for 1 week) by using a Latin square model with a 1-week wash out in between doses. On day 7 of each supplementation week, postprandial blood glucose-insulin was measured and fecal samples were collected. 16S ribosomal RNA (rRNA) gene sequencing was performed and QIIME2 software was used for microbiome analysis. Microbial community function was assessed by using the predictive metagenome analysis tool Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) and using the Metacyc database of metabolic pathways. The relative abundancies of a pathway were analyzed by using analysis of composition of microbiomes (ANCOM) in R. There was a significant dose-dependent increase in the postprandial time to peak of glucose (p = 0.030), a significant delay in the time to peak of insulin (p = 0.025), and a significant decrease in both the insulin peak level (p = 0.049) and insulin area under the curve (AUC) (p = 0.019) with increasing dose levels of aleurone, with a consideration of 200 g being the lowest significant dose. Alpha diversity and beta diversity of the fecal microbiome showed no significant changes. Aleurone significantly decreased the relative abundance of the genera Roseburia, Shuttleworthia, Anaerostipes, Faecalibacter, and Succinovibrionaceae. The most pronounced changes in the relative abundance at phyla level were seen in Firmicutes and Verrucomicrobia (downregulation) and Bacteroidetes and Spirochaetes (upregulation). The PICRUSt analysis shows that aleurone induces a downregulation of the degradation of L-glutamate and taurine and an upregulation of the three consecutive pathways of the phospholipid membrane synthesis of the Archaea domain. The results of this study suggest a multimodal effect of aleurone on glucose-insulin metabolism, which is most likely to be caused by its effect on feed texture and subsequent digestive processing; and a synergistic effect of individual aleurone components on the glucose-insulin metabolism and microbiome composition and function

The Other Press, October 28, 1982

Detailed overview of the classification of the study population by OGTT results, and for enteral biopsy and rectal palpation findings. (PDF 250 kb

Sport horses with inflammatory airway disease (IAD) with predominantly eosinophils or mast cells are more predisposed to poor performance, exercise induced pulmonary haemorrhage (EIPH) and have shorter careers when compared to horses with neutrophilic IAD

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