An open-source, lockable mouse wheel for the accessible implementation of time- and distance-limited elective exercise.

Current methods of small animal exercise involve either voluntary (wheel running) or forced (treadmill running) protocols. Although commonly used, each have several drawbacks which cause hesitancy to adopt these methods. While mice will instinctively run on a wheel, the distance and time spent running can vary widely. Forced exercise, while controllable, puts animals in stressful environments in which they are confined and often shocked for "encouragement." Additionally, both methods require expensive equipment and software, which limit these experiments to well-funded laboratories. To counter these issues, we developed a non-invasive mouse running device aimed to reduce handler-induced stress, provide time- and distance-based stopping conditions, and enable investigators with limited resources to easily produce and use the device. The Lockable Open-Source Training-Wheel (LOST-Wheel) was designed to be 3D printed on any standard entry-level printer and assembled using a few common tools for around 20 USD. It features an on-board screen and is capable of tracking distances, running time, and velocities of mice. The LOST-Wheel overcomes the largest drawback to voluntary exercise, which is the inability to control when and how long mice run, using a servo driven mechanism that locks and unlocks the running surface according to the protocol of the investigator. While the LOST-Wheel can be used without a computer connection, we designed an accompanying application to provide scientists with additional analyses. The LOST-Wheel Logger, an R-based application, displays milestones and plots on a user-friendly dashboard. Using the LOST-Wheel, we implemented a timed running experiment that showed distance-dependent decreases in serum myostatin as well as IL-6 gene upregulation in muscle. To make this device accessible, we are releasing the designs, application, and manual in an open-source format. The implementation of the LOST-Wheel and future iterations will improve upon existing murine exercise equipment and research.

Changes in microarchitecture of atherosclerotic calcification assessed by 18F-NaF PET and CT after a progressive exercise regimen in hyperlipidemic mice.

BACKGROUND: Despite the association of physical activity with improved cardiovascular outcomes and the association of high coronary artery calcification (CAC) scores with poor prognosis, elite endurance athletes have increased CAC. Yet, they nevertheless have better cardiovascular survival. We hypothesized that exercise may transform vascular calcium deposits to a more stable morphology. METHODS: To test this, hyperlipidemic mice (Apoe-/-) with baseline aortic calcification were separated into 2 groups (n = 9/group) with control mice allowed to move ad-lib while the exercise group underwent a progressive treadmill regimen for 9 weeks. All mice underwent blood collections and in vivo 18F-NaF µPET/µCT imaging both at the start and end of the exercise regimen. At euthanasia, aortic root specimens were obtained for histomorphometry. RESULTS: Results showed that, while aortic calcification progressed similarly in both groups based on µCT, the fold change in 18F-NaF density was significantly less in the exercise group. Histomorphometric analysis of the aortic root calcium deposits showed that the exercised mice had a lower mineral surface area index than the control group. The exercise regimen also raised serum PTH levels twofold. CONCLUSION: These findings suggest that weeks-long progressive exercise alters the microarchitecture of atherosclerotic calcium deposits by reducing mineral surface growth, potentially favoring plaque stability.

What do Brazilian owners know about canine obesity and what risks does this knowledge generate?

Canine obesity is associated with genetic, environmental, and behavioural factors, with the latter including both the behaviour of the dog and the owner. Knowledge about owner perception of canine obesity and its treatment can inform the development of new strategies to help prevent and manage this disease. Therefore, the aim of this study was to evaluate the opinions of dog owners regarding canine obesity and weight management. Dog owners residing in the city of Sao Paulo (Brazil) completed a questionnaire, either at home or in the waiting rooms of 3 veterinary hospitals. Owners determined their dog's body condition score (BCS), and this was compared with BCS determined by a veterinarian. Questionnaire findings from dogs that were in overweight (BCS 6-7/9) or obese (BCS (8-9/9) condition were compared with those in ideal weight (4-5/9) using chi-square tests and odds ratios. A total of 926 dogs were included, of which 480 (52%), 317 (34%) and 129 (14%) were in ideal, overweight and obese condition, respectively. Many owners under-estimated their dog's weight status, with the proportion increasing as the dog's weight status increased (ideal 60/480, 13%; overweight 174/317, 55%; obese 88/129, 68%; P<0.001). Although most owners (890/926, 96%) believed that canine obesity could pose health risks, the proportion that disagreed increased as weight status increased (ideal 12/480, 2%; overweight 14/317, 4%; 10/129, 8%; P = 0.006). Finally, although most owners (880/926, 95%) stated that they would let their dog undergo weight management, only a minority (182/926; 20%) believed that a trained professional was needed, and they had various misperceptions including potential cost and what the strategies that would be effective. Based on the findings of this study, it would be advisable for veterinarians to spend time addressing these misperceptions, in the hope of both improving awareness of obesity and the outcomes of weight management.

Barriers to entering race training before 4 years of age for Thoroughbred horses born in the 2014 Australian foal crop.

Currently, there is a paucity of data on the barriers for Australian Thoroughbred horses transitioning from stud farm to racetrack. This paper reports the reasons why horses failed to enter race training and documents their exit destinations. Biographical records of Australian Thoroughbred horses born in 2014 were investigated to determine the number of horses that had not officially entered race training by the start of the 4-year old racing season (1 August 2018). Of the 13,677 foals born in 2014, 66% had commenced training and 51% had raced before the beginning of their 4-year-old season in Australia. A sampling frame based on the post code of the premises where foals were born and records from Racing Australia were used to select a geographically representative sample of the 2014 Australian Thoroughbred foal crop (n = 4,124). From the population eligible for sampling 1,275 horses that had not entered training were enrolled in the survey and their breeders were sent an online questionnaire with follow-up phone calls for those who had not responded. Of the 633 responses (50% of 1275) the most frequent outcomes for horses were: death (38%, n = 239), participation in the racing industry in their 4-year old racing season (24%, n = 154) and retirement (16%, n = 100) either as Australian Stud Book (ASB) bloodstock (n = 17), or as horses rehomed outside the Thoroughbred industry (n = 83). Illness or injury was the most frequent reason for horses not entering race training that were ASB bloodstock, rehomed or deceased. There was a loss of traceability at the point of sale with most horses sold at 1 year of age. This study provides important information on the reasons, alternative outcomes and gaps in traceability for horses not entering training prior to the 4-year-old racing season.

Maternal exercise before and during pregnancy alleviates metabolic dysfunction associated with high-fat diet in pregnant mice, without significant changes in gut microbiota.

Although maternal exercise before and during pregnancy is beneficial, the effects of exercise on microbiota changes during pregnancy are unknown. Here we tested the hypothesis that maternal exercise before and during pregnancy would positively affect glucose homeostasis, pancreatic cell function, and gut microbiota dysbiosis in high-fat diet (HFD) fed dams. Female C57BL/6 mice were fed either a HFD or a low-fat diet (LFD) for 12 weeks. The HFD mice were split into two groups for 4 weeks prior to pregnancy initiation and throughout the pregnancy: sedentary (HFD) or exercised (HFD + Ex). Food intake, body weight, body composition, and glucose and insulin tolerance were measured. At gestation day 19, blood, pancreas, gonadal visceral and subcutaneous fat, plantaris muscle, and cecum were collected for analysis. Both HFD and HFD + Ex mice had impaired glucose clearance compared to LFD mice at 15 days of gestation. No changes were found in pancreatic α- or ß-cell health. HFD + Ex mice had significantly reduced visceral fat mass, serum insulin, and leptin levels and increased high-density lipoprotein levels, compared to HFD-fed mice. In contrast to our hypothesis, microbiota diversity and composition were not different among groups. The relative abundance of five bacterial phyla, such as Firmicutes, Bacteroidetes, Verrucomicrobia, Deferribacteres, and Actinobacteria, were not significantly altered with diet or exercise during pregnancy. Our findings suggest that maternal exercise prevents excess visceral fat accumulation, hyperinsulinemia, and hyperleptinemia associated with a HFD, but not through the alterations of gut microbiota composition or diversity during pregnancy.

Epidemiology and risk factors for eliminations from Fédération Equestre Internationale endurance rides between 2004-2015 in Italy.

There is limited information on risk factors for elimination from endurance rides and changes over the years. The objectives of this study were to describe elimination for irregular gait and metabolic reasons from Fédération Equestre Internationale (FEI) endurance rides in Italy (2004-2015) and to assess risk factors and to investigate changes in elimination rates and speed over the long term. Data for FEI endurance rides were collected from three websites. Year, month, day, location, class (Concours de Raid d'Endurance International [CEI]*/**/***), restriction to young riders, distance (km), number of starters, horses' age and breed, and average finish speed for each horse were recorded. Horses were classified as completed, retired or eliminated for irregular gait, metabolic or other reasons. Environment data were obtained from the Il Meteo website. Descriptive data were summarized, and univariable analyses and multivariable logistic regression analyses were performed to investigate risk factors. The chi-squared test and one-way or Friedman analysis of variance (ANOVA) were used to assess differences between years. Variables associated with elimination for irregular gait were the number of starters, age of the horse, classes, minimum temperature and presence of rain; those associated with elimination for metabolic reasons were the number of starters, classes, horse breed and minimum temperature. Average finish speed increased over the years but the elimination frequency changed only for metabolic reasons, with a higher percentage at the beginning of the study period. This study was conducted in Italy and the results may not be applicable globally; speed was available only for horses that completed the competition. Average finish speed increased over the years but the percentage of eliminations remained stable after 2007. Training, nutrition, previous injuries and treatments are likely to contribute to problems occurring during the ride, and investigation of these factors would be desirable.

A three-criteria performance score for rats exercising on a running treadmill.

In this study, we propose a novel three-criteria performance score to semiquantitatively classify the running style, the degree of involvement and compliance and the validity of electric shock count for rats exercising on a treadmill. Each score criterion has several style-marks that are based on the observational registry of male Sprague-Dawley rats running for 4-7 weeks. Each mark was given a score value that was averaged throughout a session-registry and resulting in a session score for each criterion, ranging from "0" score for a hypothetical "worst runner", to score "1" for a hypothetical "perfect runner" rat. We found significant differences throughout a training program, thus providing evidence of sufficient sensitivity of this score to reflect the individual evolution of performance improvement in exercise capacity due to training. We hypothesize that this score could be correlated with other physiological or metabolic parameters, thus refining research results and further helping researchers to reduce the number of experimental subjects.

Survey of trainers on the use of swimming exercise for Standardbred racehorses in Australia.

OBJECTIVES: To determine swimming training practices in Australian harness racing horses and potential targets for future research. METHODS: An online survey of Australian Standardbred trainers and telephone interviews with 20 leading trainers were conducted. Questions relating to swimming facility and protocol, perceived benefits and contraindications were included. Descriptive data analysis was performed. RESULTS: Data were collected from 270 trainers: 250 by online survey (250/1770, response rate 14.1%) and 20 by interview. Of these, 103 trainers (38.1%), including 91 surveyed trainers (91/250, 36.4%) and 12 interviewed trainers (12/20, 60.0%), used swimming exercise. The most popular reasons for swimming were to replace trackwork for horses with limb injuries (79.4%), improve or maintain fitness (62.7%) and provide mental stimulation through variety in training (40.0%). Free swimming (78.4%) was more common than tethered, but the frequency and duration for horses in full training varied widely between trainers, with a median of four swim sessions per horse each week (range 0.5-12) for a median of 7 min (range 1.5-30 min) per session, mostly as a continuous swim, but sometimes as intervals. The main reasons given by those not swimming horses were lack of an adequate facility (60.5%) and lack of perceived benefit (16.2%). Reasons for not swimming individual horses varied widely. CONCLUSIONS: Trainer opinions and protocols varied widely with respect to swimming exercise for Standardbred race horses. The role of swimming exercise requires further study so that evidence-based recommendations can be made.

Prevalence of and risk factors for equine glandular and squamous gastric disease in polo horses.

The objectives of this study were to determine the prevalence rates and risk factors for equine glandular gastric disease (EGGD) and equine squamous gastric disease (ESGD) in a population of 63 polo horses in competition. The prevalence of EGGD grade ≥ 1 was 69% and EGGD ≥ 2 was 31%. The prevalence of ESGD grade ≥ 1 was 54% and grade ≥ 2 was 37%. The risk factors retained in the final multivariable models were years of experience in polo competition for EGGD grade ≥ 1 and for grade ≥ 2, with decreased experience being associated with EGGD and weekly exercise duration and non-steroidal anti-inflammatory drug (NSAID) use being associated with ESGD grade ≥ 1. Decreasing weekly exercise duration was the only risk factor associated with ESGD grade ≥ 2. Equine gastric disease was common in this population of polo horses and the amount of experience and weekly exercise duration were related to the risk of disease.

Prévalence de la maladie gastrique glandulaire et squameuse des équidés et facteurs de risque chez les chevaux de polo. Les objectifs de cette étude consistaient à déterminer les taux de prévalence et les facteurs de risque pour la maladie gastrique glandulaire équine (MGGE) et la maladie gastrique squameuse équine (MGSE) dans une population de 63 chevaux de polo de compétition. La prévalence de la MGGE de grade ≥ 1 était de 69 % et de la MGGE ≥ 2 était de 31 %. La prévalence de la MGSE de grade ≥ 1 était de 54 % et de grade ≥ 2 était de 37 %. Les facteurs de risque conservés dans les modèles multivariables finaux étaient des années d'expérience dans les compétitions de polo pour la MGGE de grade ≥ 1 et de grade ≥ 2, et une expérience réduite était associée à la MGGE et la durée de l'exercice hebdomadaire et l'usage d'anti-inflammatoires non stéroïdiens (AINS) étaient associés à la MGSE de grade ≥ 1. La réduction de l'exercice hebdomadaire était le seul facteur de risque associé à la MGSE de grade ≥ 2. La maladie gastrique équine est commune dans cette population de chevaux de polo et la quantité d'expérience et la durée de l'exercice hebdomadaire étaient associées au risque de maladie.(Traduit par Isabelle Vallières).

Risk factors for equine glandular and squamous gastric disease in show jumping Warmbloods.

BACKGROUND: Prevalence of, and risk factors for, equine squamous gastric disease (ESGD) are well established. Limited data exists on risk factors for equine glandular gastric disease (EGGD). OBJECTIVES: To identify management factors associated with EGGD in show jumping Warmbloods in training. A secondary objective was to identify management factors associated with ESGD. STUDY DESIGN: Cross-sectional. METHODS: Gastroscopies were performed in horses following a 12-16 h fast. Management questionnaires were collected for each horse. Risk factors were determined using multivariable logistic regression modelling. RESULTS: Eighty-three horses were included in the final analysis. Exercising ≥6 days per week increased the odds of EGGD grade ≥1/4 (odds ratio [OR] = 3.5; 95% confidence interval [CI] 1.2-10.7) compared to less frequent exercise. Currently showing increased the risk of EGGD grade ≥2/4 (OR = 10.2; 95% CI, 1.04-100), while competing at the international level decreased the odds of EGGD grade ≥2/4 (OR = 0.11; 95% CI, 0.01-0.97). Exercise intensity increased the odds of grade ≥1/4 ESGD (OR = 2.8; 95% CI, 1.03-7.8) and feeding beet pulp decreased odds (OR = 0.22; 95% CI, 0.07-0.7). Exercise intensity (OR = 3.8; 95% CI, 1.1-12.8) increased the likelihood of grade ≥2/4 ESGD and feeding beet pulp decreased the odds of grade ≥2/4 ESGD (OR = 0.1; 0.02-0.64) respectively. MAIN LIMITATIONS: This study used a convenience sample of horses within a relatively small (approximately 200 km) geographic radius. The sample size was relatively small, particularly within the international competition level group. CONCLUSIONS: Training and feeding strategies and competition level appear to influence the occurrence of EGGD and ESGD. Prospective studies evaluating the impact of training frequency, duration, and intensity on gastric physiology may clarify the role of exercise in gastric disease.

Effects of a Lifestyle-Based Physical Activity Intervention on Medical Expenditure in Japanese Adults: A Community-Based Retrospective Study.

Background. This study aimed to investigate whether a lifestyle-based physical activity program could contribute to reduced medical expenditure. Methods. The study participants were 60 adults aged 63.1 (standard deviation, 4.4) years in the intervention group; the case-control group consisted of 300 adults who were randomly selected from Japan's national health insurance system. This community-based retrospective study incorporated a 3-year follow-up. Results. The total and outpatient medical expenditure in the intervention group were significantly lower than in the control group: total expenditure, $US640.4/year; outpatient expenditure, $369.1/year. The odds ratio for outpatient visiting was 6.47-fold higher in the control than in the intervention group. Conclusion. Our study suggests that a health program to promote physical activity can result in reduced total medical expenditure, outpatient medical expenditure, and possibly also inpatient medical expenditure.

Exercise during early, but not late abstinence, attenuates subsequent relapse vulnerability in a rat model.

Exercise has shown promise as a nonpharmacological intervention for addiction, with evidence suggesting a potential utility for relapse prevention. In humans, exercise as an intervention is typically introduced well after the initiation of abstinence, yet neurobiological data from preclinical studies suggest that it may be more effective if initiated during early abstinence. Here, using rat models, we determined whether the beneficial effects of exercise on relapse vulnerability depends on when exercise is first initiated, during early versus late abstinence. Once rats (n=47) acquired cocaine self-administration, they were given 24-h access to cocaine (1.5 mg/kg per infusion) under a discrete trial procedure (four infusions per hour) for 10 days. The rats then began a 14-day abstinence period in which they had access (2 h per day) to a locked wheel throughout abstinence (sedentary) or an unlocked wheel during early (days 1-7), late (days 8-14) or throughout (days 1-14) abstinence (n=10-14 per group). Cocaine seeking, as assessed under an extinction/cued-induced reinstatement procedure, was examined on day 15 of abstinence. Exercise beginning during early abstinence robustly attenuated subsequent cocaine seeking, and this effect persisted even when exercise ended on the seventh day of abstinence. In contrast, exercise during late abstinence was not effective and these animals displayed high levels of cocaine seeking similar to those observed in sedentary animals. These results indicate that the timing of exercise availability differentially impacts cocaine seeking with results suggesting that exercise during early, but not late, abstinence may provide long-term protection against cocaine relapse.

Short-term follow-up of exercise training program and beta-blocker treatment on quality of life in dogs with naturally acquired chronic mitral valve disease.

This study aimed to evaluate the effects of carvedilol treatment and a regimen of supervised aerobic exercise training on quality of life and other clinical, echocardiographic, and biochemical variables in a group of client-owned dogs with chronic mitral valve disease (CMVD). Ten healthy dogs (control) and 36 CMVD dogs were studied, with the latter group divided into 3 subgroups. In addition to conventional treatment (benazepril, 0.3-0.5 mg/kg once a day, and digoxin, 0.0055 mg/kg twice daily), 13 dogs received exercise training (subgroup I; 10.3 ± 2.1 years), 10 dogs received carvedilol (0.3 mg/kg twice daily) and exercise training (subgroup II; 10.8 ± 1.7 years), and 13 dogs received only carvedilol (subgroup III; 10.9 ± 2.1 years). All drugs were administered orally. Clinical, laboratory, and Doppler echocardiographic variables were evaluated at baseline and after 3 and 6 months. Exercise training was conducted from months 3-6. The mean speed rate during training increased for both subgroups I and II (ANOVA, P>0.001), indicating improvement in physical conditioning at the end of the exercise period. Quality of life and functional class was improved for all subgroups at the end of the study. The N-terminal pro-brain natriuretic peptide (NT-proBNP) level increased in subgroup I from baseline to 3 months, but remained stable after training introduction (from 3 to 6 months). For subgroups II and III, NT-proBNP levels remained stable during the entire study. No difference was observed for the other variables between the three evaluation periods. The combination of carvedilol or exercise training with conventional treatment in CMVD dogs led to improvements in quality of life and functional class. Therefore, light walking in CMVD dogs must be encouraged.

Short-term follow-up of exercise training program and beta-blocker treatment on quality of life in dogs with naturally acquired chronic mitral valve disease

This study aimed to evaluate the effects of carvedilol treatment and a regimen of supervised aerobic exercise training on quality of life and other clinical, echocardiographic, and biochemical variables in a group of client-owned dogs with chronic mitral valve disease (CMVD). Ten healthy dogs (control) and 36 CMVD dogs were studied, with the latter group divided into 3 subgroups. In addition to conventional treatment (benazepril, 0.3-0.5 mg/kg once a day, and digoxin, 0.0055 mg/kg twice daily), 13 dogs received exercise training (subgroup I; 10.3±2.1 years), 10 dogs received carvedilol (0.3 mg/kg twice daily) and exercise training (subgroup II; 10.8±1.7 years), and 13 dogs received only carvedilol (subgroup III; 10.9±2.1 years). All drugs were administered orally. Clinical, laboratory, and Doppler echocardiographic variables were evaluated at baseline and after 3 and 6 months. Exercise training was conducted from months 3-6. The mean speed rate during training increased for both subgroups I and II (ANOVA, P>0.001), indicating improvement in physical conditioning at the end of the exercise period. Quality of life and functional class was improved for all subgroups at the end of the study. The N-terminal pro-brain natriuretic peptide (NT-proBNP) level increased in subgroup I from baseline to 3 months, but remained stable after training introduction (from 3 to 6 months). For subgroups II and III, NT-proBNP levels remained stable during the entire study. No difference was observed for the other variables between the three evaluation periods. The combination of carvedilol or exercise training with conventional treatment in CMVD dogs led to improvements in quality of life and functional class. Therefore, light walking in CMVD dogs must be encouraged.

Exercise training modifies gut microbiota in normal and diabetic mice.

Cecal microbiota from type 2 diabetic (db/db) and control (db/(+)) mice was obtained following 6 weeks of sedentary or exercise activity. qPCR analysis revealed a main effect of exercise, with greater abundance of select Firmicutes species and lower Bacteroides/Prevotella spp. in both normal and diabetic exercised mice compared with sedentary counterparts. Conversely, Bifidobacterium spp. was greater in exercised normal but not diabetic mice (exercise × diabetes interaction). How exercise influences gut microbiota requires further investigation.

Wide housing space and chronic exercise enhance physical fitness and adipose tissue morphology in rats.

The current cages commonly used in animal experiments can prevent rats from engaging in most forms of natural locomotion behaviors. These animals tend to exhibit sedentary habits. Here, we show that a combination of wide housing space and training exercise helps to reduce white adipose mass and to increase brown adipose mass. Thus, this combination is a useful strategy for truly enhancing the physical fitness of captive rats commonly used in exercise-related interventional studies and to maximize their welfare.

Number, causes and destinations of horses leaving the Australian Thoroughbred and Standardbred racing industries.

OBJECTIVE: Significant proportions of horses leave the Australian Thoroughbred and Standardbred racing industries, which has ramifications for both the economic sustainability and the public perception of racing. The aim of this study was to quantify potential horse wastage, describe the destinations of exiting horses and identify risk factors for horses going to these destinations. METHODS: Questionnaires were sent to 1258 selected Thoroughbred and 981 Standardbred trainers, with response rates of 30% and 32%, respectively. The survey investigated the role of various risk factors for wastage, including horse age, sex and number of years in training. The destination of departing horses was also examined in relation to these risk factors. RESULTS: Total horse exit rates for the 2002-03 official race year were 39.7% and 38.7% for the Thoroughbred and Standardbred racing industries, respectively. Reasons for leaving included 'poor performance/slow' (36.5% Thoroughbreds, 35.2% Standardbreds), 'illness/injury' (31.0%, 27.1%), 'to breed' (9.4%, 10.1%), 'unsuitable temperament/behaviour' (6.4%, 6.4%) and 'other' (16.8%, 21.2%). Statistically significant (P < 0.001) risk factors influencing the destinations of both Thoroughbred and Standardbred racing horses included whether the trainer owned the horses, sex, age and reasons for leaving. In addition, some factors were specific to one breed or the other. CONCLUSIONS: Improved behaviour training and early identification of the causes of poor performance could assist in reducing wastage.

Elevations in serum muscle enzyme activities in racehorses due to unaccustomed exercise and training.

Hereditary muscular disease is well described in racehorses, yet little is known about traumatic muscle disease associated with unaccustomed exercise or training. The objective of the study was to compare sedentary horses, racehorses undergoing training for the first time (unaccustomed exercise), and experienced racehorses during a training season (accustomed exercise) to investigate the effect of exercise and training on serum muscle enzyme activities and other variables. Horses were sampled prior to exercise for serum activities of aspartate amino transferase (AST), creatine kinase and other variables γ glutamyl transferase (GGT) and serum amyloid A (SAA) in a three-part study. Serum activities of AST and GGT were higher in fit racehorses (n=47) compared with sedentary horses (n=57) at a single time point (P<0.05). The monthly serum activity of AST in two-year-old racehorses (n=10) increased from month 1 to 4 of unaccustomed training (P<0.05). The serum activities of AST and GGT in three-year-old racehorses (n=12) previously accustomed to exercise sampled fortnightly to monthly showed a linear increase (P<0.05) with cumulative training days over the seven months of training, but showed minimal increase during the first four months of accustomed training. SAA was weakly correlated to cumulative training days. In conclusion, AST activity was increased by unaccustomed exercise and cumulative training stress in the racehorse. GGT appeared to be correlated to cumulative training load. Mild to moderate elevations in serum AST in racehorses may be associated with cumulative muscle damage from training or trauma associated with unaccustomed exercise.

Deletion of frizzled-related protein reduces voluntary running exercise performance in mice.

OBJECTIVE: To study the effect of frizzled-related protein (Frzb) deletion in mice on voluntary running wheel exercise performance and osteoarthritis. METHODS: At the age of 7 weeks, Frzb(-/-) and wild-type mice were grouped and a running wheel was introduced into the cage. At week 8, all mice were caged solitarily with a running wheel available. Mice were allowed free exercise for 6-12 months and distances run were recorded daily. Non-running mice were used as additional control group. X-rays of knees and hips were taken at different time points. At the end of the experiment, mice were sacrificed and joints were processed for histological evaluation. Cartilage damage, synovitis and osteophyte formation were scored. Muscle fiber composition of the soleus and extensor digitorum longus was studied by immunofluorescence. RESULTS: At the age of 6 months, both female and male wild-type mice showed a significantly greater exercise performance than the Frzb(-/-) mice (P<0.05). At 1 year, the difference was still significant for male mice, but not for females. Running exercise did not significantly affect severity of osteoarthritis. No statistical differences in osteoarthritis severity were seen between Frzb(-/-) mice and wild-type mice. No differences were seen in muscle composition between Frzb(-/-) mice and wild-type mice. CONCLUSION: Absence of Frzb in mice reduced voluntary exercise performance in running wheels. These experiments demonstrate that the effects of genes in mice can also be evaluated using functional outcomes such as running wheel exercise performance, similar to evolving practice in human clinical trials.