bluuebunny/crossref_metadata_2025 huggingface dataset:
Chuckwagon Field Study on 148 Horses: Racing Consecutive Days Affects Baseline Blood Electrolytes, pH and Lactate But Does Not Increase the Prevalence of Cardiac Arrhythmias
Authors: Massie S , Leguillette R
Published: June 2014

Introduction

Chuckwagon racing involves 4 Thoroughbred horses pulling a 600 kg wagon through a figure‐8 pattern and running a 1000 m dash. Horses can race four days in a row and there are concerns regarding the contribution of cumulative racing to electrolyte imbalances, arrhythmias, and sudden death, and its impact on recovery. The objective was to investigate the effects of cumulative racing on plasma electrolytes, lactate and prevalence of cardiac arrhythmias.

Methods

148 horses (9.0 ± 2.7 years) from 13 teams were monitored for heart rate and ECG activity on racing days 1 and 2. Differences in plasma electrolytes, pH and lactate (pre‐vs. post‐exercise and between days) were analysed (paired t‐test). Associations between electrolytes and the presence of arrhythmias during racing and recovery (Pearson correlation) were examined.

Results

377 ECGs (82 incomplete due to lost electrode) and 750 plasma samples (374 pre, 376 post) were analysed. 4235 arrhythmic events (21.6% warm‐up, 37.6% racing, 20.4% recovery) were recorded and were not different between days 1 and 2. They mainly comprised supraventricular premature contractions during warm‐up and racing (48% and 81.4% respectively) and ventricular premature contractions during recovery (29.2%). A significant association was found between post‐exercise electrolytes and the presence of arrhythmias during racing (P<0.001, r = 0.17). Consecutive racing significantly increased post‐exercise lactate on day 2 (P<0.001). Pre‐exercise pH and electrolytes were significantly different on day 2.

Conclusions

An association exists between post‐exercise electrolytes and occurrence of arrhythmias during consecutive racing, however it is of little clinical significance. Ventricular arrhythmias are as prevalent in chuckwagon horses as in other disciplines. Overall, repetitive racing is well tolerated.

Ethical Animal Research

The study was approved by the Veterinary Sciences Animal Care Committee of the University of Calgary (AC120049) and owner informed consent was obtained. Sources of funding: Clinical Research Fund from the University of Calgary's Faculty of Veterinary Medicine. Summer Studentships were funded by NSERC. Competing interests: none.
Effects of Aerobic Training on Systolic, Diastolic and Mean Blood Pressure in Arabian Horses
Authors: Mirian M , Piffer ML , Bogossian PM , Fernandes WR
Published: June 2014

Introduction

Exercise causes several physiological changes resulting from autonomic and hemodynamic adaptations, but there are few reports about the behaviour of blood pressure (BP) during physical activity in horses, as well as the effect of training on BP.

Methods

9 untrained Arabian horses underwent two treadmill evaluations (before and after 90 days of aerobic training at 60% HRmax) at 6% incline with incremental speed increases every 3 minutes (commencing at 2.5 m/s and reaching 12.5 m/s). The facial artery was cannulated with a 20 G catheter and systolic blood pressure (SBP), mean (MAP) and diastolic (DBP) blood pressures were recorded with a multiparameter monitor (GE Dash 3000 model). Data were evaluated by two‐way ANOVA for repeated measures and Bonferroni multiple comparison (P<0.05).

Results

During initial evaluation SBP increased in a gradual and uniform manner as speed increased, reaching a maximum of 208 mmHg at a speed of 10 m/s. After training, SBP behaved similarly during treadmill evaluation, however values were lower until 10 m/s (P<0.001), and the maximum value of SBP obtained was 218 mmHg at 12.5 m/s. DPB was not significantly different (P = 0.124). MAP emulated the behaviour of SBP (P = 0.012).

Conclusions

A decrease in SBP and MAP during identical treadmill evaluations before and after 90 days of aerobic exercise (60% HR max) indicated that training decreased cardiac effort required for the maintenance of physical activity.

Ethical Animal Research

procedures were approved by the University of São Paulo. Sources of funding: none declared. Competing interests: none.
Cardiopulmonary Function in Thoroughbred Horses Running Uphill and Downhill on an Inclined Treadmill
Authors: Ohmura H , Mukai K , Takahashi T , Aida H , Jones J
Published: June 2014

Introduction

Eccentric muscle contractions (“negative” work, e.g., downhill running) affect human skeletal muscle differently than concentric contractions, increasing muscle size and strength more than concentric exercise training with reduced oxygen consumption (VO2). Better understanding of skeletal muscle and cardiopulmonary responses to downhill training may indicate a role for this in Thoroughbred training. We hypothesised that Thoroughbreds would reduce metabolic energy cost and cardiopulmonary function when they ran at equivalent speed on a declined treadmill compared with running horizontally or uphill.

Methods

Five well‐trained Thoroughbreds ran for 2‐min incremental exercise intervals on a treadmill at 1.7, 3.5, 6.0, 8.0 and 10.0 m/s on a +4% incline, 0% incline (horizontal) and −4% decline in random order on different days. Cardiopulmonary and O2‐transport variables were measured and analysed with two‐way repeated‐measures ANOVA and Holm‐Šidák pairwise‐comparisons.

Results

Horses ran at all inclines with identical stride frequency and length. At identical uphill speeds they had significantly higher (vs. horizontal) mass‐specific VO2 (43% mean increase) and CO2 production (VCO2/Mb), cardiac output (Q/Mb), heart rate, arterial CO2 tension (PaCO2), and reduced arterial O2 tension and saturation; tidal volume tended to be higher (P = 0.060). Downhill running reduced (vs. horizontal) VO2/Mb (19% mean decrease), VCO2/Mb, Q/Mb and PaCO2. Fractional energy cost increase (incline) and reduction (decline) decreased linearly with increasing speed.

Conclusions

Thoroughbreds run downhill with lower energy cost than on the level or uphill and the cost changes with speed. It remains to be determined if eccentric training induces skeletal muscle changes in horses.

Ethical Animal Research

The study was approved by the Animal Welfare and Ethics Committee of the Equine Research Institute, Japan Racing Association. Sources of funding: none. Competing interests: none.
Validation of a Novel High‐Sensitivity Cardiac Troponin‐T Assay in Horses
Authors: Shields E , Passante S , Massie S , Seiden‐Long I , Leguillette R
Published: June 2014

Introduction

Cardiac troponin‐I (cTn‐I) has been previously validated in horses. Newer high sensitivity troponin assays have recently become available that are now the standard in human cardiology. The objective was to validate the high‐sensitivity cardiac troponin‐T (hscTn‐T) assay for use in horses and to determine the biological variation within and between horse breeds.

Methods

Samples were analysed using the hscTn‐T assay reagent (Roche,Cobas c501). Method validation included linearity, lower limit of quantitation (LLQ), freeze‐thaw stability, within‐and between‐run precision, and comparison with cTn‐I (Abbott iSTAT, Deming regression). Normal range and biological variation included healthy horses (n = 120; age = 7.2 ± 0.5 years (SE)) representing 5 breeds.

Results

Assay was linear from 3–391 ng/L. The LLQ was validated at 3 ng/L. Stability of samples was unaffected by 3 freeze‐thaw cycles. Within‐run mean (±SD) was L1 = 6.50 (±0.97), L2 = 10.1 (±0.88), L3 = 15.3 (±0.82) ng/L and between‐run mean (±SD) was L1 = 12.2 (±1.03), L2 = 57.0 (±4.82), L3 = 256 (±23.1) ng/L. Comparison with cTn‐I assay showed excellent correlation (range: 8–3535 ng/L, r = 0.9998). Bias was evident in the regression results [hscTnT = (0.6153 ± 0.002809)*(cTnI*1000) − (11.53 ± 5.462)]. The 95th and 99th percentile of the normal distribution in healthy horses was 4 and 6 ng/L. Between breed, diurnal effect and between day variation was not detectable due to low concentrations of hscTnT.

Conclusions

This study established reference intervals for hscTn‐T assay in healthy horses and the performance characteristics of hsTn‐T assay in horse samples. Normal population distribution was mostly below the detection limit of the assay. The hscTn‐T assay will likely establish the standard in early detection of cardiac pathologies in horses.

Ethical Animal Research

This study was approved by the Veterinary Sciences Animal Care Committee (protocol number AC12‐0049). Sources of funding: UCVM internship fund. Competing interests: none.
Description of a Field Exercise Test in Cross‐Bred Quarter Horses in Venezuela: Preliminary V200 and V170 Values
Authors: Zerpa H , Chacon T , Campos G
Published: June 2014

Introduction

Field exercise tests (FET) can assist design of individualized training programs. Although FETs have been used in other breeds, there are limited reports for Quarter horses (QH) and cross‐bred QH which are widely used in traditional Venezuelan equestrian activities. The aim of this study was to describe the implementation of an FET in cross‐bred Quarter horses in Venezuela.

Methods

Six horses (3 stallions and 3 mares) performed a FET consisting of a four‐step incremental increase in speed (91 ± 10; 136 ± 3; 271 ± 20; 439 ± 43 m/min). Each cycle lasted 3 to 5 min with 3 minutes of rest between each. Environmental temperature was 32°C. Heart rate and speed were recorded (Polar Equine RS800CX®) and the speed to reach a heart rate of 200 and 170 beats/min was calculated by linear regression. The rate of heart rate decline was determined 5 minutes after the last step. Linear regression analysis, descriptive statistics and an unpaired t‐ test (Graph Pad Prism 5.0) were utilized to identify gender differences (P<0.05).

Results

Gender did not influence the results. V200 and V170 were slightly higher in stallions (617 ± 98 and 465 ± 66 m/min, respectively) than in mares (511 ± 60 and 387 ± 60 m/min, respectively). The rate of heart rate decline was slightly more rapid in mares (25 ± 7 beats/min) compared to stallions (13 ± 5 beats/min).

Conclusions

Although a low number of horses were evaluated, these preliminary data suggest that gender has limited influence on fitness of cross‐bred Quarter horses used in local Venezuelan equestrian activities under tropical environmental conditions. The mean V200 and V170 values obtained were lower than those reported for Thoroughbreds and Standardbreds, but similar to those reported in young racing Quarter horses.

Ethical Animal Research

The study was approved by the Faculty of Veterinary Science, Central University of Venezuela Ethical Research Committee. Sources of funding: “San Antonio Farm” owned by Perez family and CDCH‐UCV (PG‐11‐8095‐2011). Competing interests: none.
Determination of Myofiber Types of Mangalarga Mares and Their Hybrids
Authors: D′angelis FHF , Santos EB , Ferraz GC , Andrade JM , Queiroz‐Neto A
Published: June 2014

Introduction

There are no published studies that characterize the different myofiber types of Mangalarga (ML) horses and hybrids. This study aimed to characterize and compare muscle fibers of the gluteus medius of ML mares and young and inactive mules resulting from the breeding of these mares with a Brazilian donkey.

Methods

Percutaneous biopsies were performed in 11 mares and their foals (10 mules), at a depth of 60 mm. Fiber types were determined by comparing identical images using both the staining techniques of myofibrillar adenosine triphosphatase (mATPase) and nicotinamide adenine dinucleotide‐tetrazolium reductase (NADH‐TR). Stains for mATPase were pre‐incubated in acid medium followed by alkaline incubation. The frequency (F%) and relative total area (RTA%) of fiber types I, IIA and IIX were analysed. The cross‐sectional area (CSA, μm2) was quantified by the NADH‐TR technique. The means were compared using ANOVA followed by Tukey test (P<0.05).

Results

The frequency of type IIA fibers was greater than types I and IIX. Type IIX fibers had higher CSA than I and IIA. The RTA of type IIX fibers was greater than type IIA fibers followed by type I. The higher RTA value of IIX fibers resulted from higher CSA. There was no difference between the variables for mares compared to the mules.

Conclusions

ML mares and mules that resulted from breeding with the Brazilian donkey have a high prevalence of type IIA fibers in the gluteus medius. This fatigue‐resistant fiber uses both metabolic pathways, glycolytic and oxidative, to obtain energy during muscle contraction, thus giving the ML mares and mules good performance in horseback riding, marching contests and endurance rides.

Ethical Animal Research

All procedures were approved by the institutional animal care and use committee of the university (CEUA, Process: 01370/12). Sources of funding: Fundação de Amparo a Pesquisa do Estado de São Paulo. Process: 04655‐9/2012. Competing interests: none.
High‐Resolution Respirometry May Identify Early Indicators for Exertional Rhabdomyolysis in Standardbred Racehorses
Authors: Houben R , Leleu C , Fraipont A , Serteyn D , Votion D
Published: June 2014

Introduction

During racing, mitochondrial oxidative phosphorylation (OXPHOS) is a major source of energy for muscle contraction. Assessment of muscle OXPHOS capacity by high‐resolution respirometry (HRR) might identify animals with altered energy metabolism and consequently increased risk of exertional rhabdomyolysis (ER).

Methods

Prospective cohort study. Ten healthy French Standardbreds in active training, aged 4–7 years, recruited at the start of a competitive racing season, underwent a standardised field exercise test with determination of speed at onset of lactate accumulation (VLa4) and measurement of serum creatine kinase activity (CK) two hours post‐exercise. Triceps brachii muscle microbiopsies were obtained for determination of OXPHOS and electron transfer system (ETS) capacities with HRR. Associations between HRR variables and occurrence of ER over the following four months of racing were analysed using univariate logistic regression.

Results

Two horses developed ER during the study period: one within one month of recruitment, another presented multiple minor episodes over the season. For these ER horses OXPHOS/ETS ratio was lower, and Complex I/Complex I + II ratio and Complex I /Complex II ratio were higher than non‐affected horses in the study (perfect prediction of occurrence of ER with ratio of ≤0.74, ≥0.60 and ≥0.715 respectively). VLa4 for ER horses was within the range of non‐affected horses. Post‐exercise CK was within normal limits for all horses in the study.

Conclusions

OXPHOS and ETS capacities and their derived ratios indicate dysfunctional muscle energy metabolism whereas VLa4 and CK were unremarkable in horses subsequently affected by ER.

Ethical Animal Research

The study was approved by Liège University's Animal Ethics Committee (agreement N° 07‐629); owner informed consent was obtained. Sources of funding: Part of the study protocol was funded by Les Haras Nationaux (France). Competing interests: The Oxygraph‐2k HRR apparatus was provided on loan by OROBOROS Instruments (Innsbruck, Austria); there are no patents, products in development or marketed products to declare.
Expression and Regulation of Glycogen Synthase in Equine Type 1 Polysaccharide Storage Myopathy
Authors: Maile C , Hingst J , Wojtaszewski J , Piercy R
Published: June 2014

Introduction

Equine Type 1 polysaccharide storage myopathy (PSSM1) is associated with a missense, gain‐of‐function mutation in the equine skeletal muscle glycogen synthase gene (GYS1). Affected horses have excessive glycogen storage, amylopectate‐like inclusions in their muscle and higher muscle glycogen synthase activities (GS) than controls. GS is normally allosterically‐regulated by glucose‐6‐phosphate and enzyme activity is reduced by phosphorylation. We hypothesised that the higher GS activity in PSSM1‐affected horses might be due either to 1) increased expression or reduced degradation of the mutant enzyme or 2) due to reduced phosphorylation.

Methods

Semimembranosus muscle samples were biopsied from 4 homozygotes (HH), 13 heterozygotes (RH) and 12 control (RR) Belgian Draught horses. Samples were analysed for glycogen content and GS activity. Western immunoblotting was used to examine expression of total and phosphorylated forms of GS, GSK3β and GLUT4. Data was analysed using non‐parametric ANOVA statistical tests with post‐hoc Dunn's multiple comparison tests.

Results

PSSM1 affected heterozygotes and homozygotes had significantly higher muscle glycogen contents than controls (RR vs. RH P = 0.005, RR vs. HH P = 0.041) and GS activity was significantly higher in PSSM1‐affected homozygotes than in heterozygotes and control horses (P = 0.03). Although there was no difference in total GS expression between groups, there was significantly more expression of GS phosphorylated at site 2 + 2a in PSSM1‐affected horses in comparison with controls (P = 0.009).

Conclusions

Our data suggest that increased GS activity in PSSM1‐affected horses is not associated with increased expression or degradation of the mutant enzyme and occurs despite increased phosphorylation of GS at site 2 + 2a. Alternative mechanisms, including aberrant ligand binding might account for the increased GS activity in PSSM1‐affected muscle.

Ethical Animal Research

Muscle biopsy samples were collected according to ethical approval from the local Institutional Animal Care and Use Committee. Explicit owner informed consent for participation in this study is not stated. Sources of funding: Petplan Charitable Trust and The Royal Veterinary College. Competing interests: none.
In Silico Three Dimensional Modelling of Mutant Glycogen Synthase Associated with Equine Type 1 Polysaccharide Storage Myopathy
Authors: Maile C , O′Reilly A , Wallace B , Piercy R
Published: June 2014

Introduction

Equine Type 1 polysaccharide storage myopathy (PSSM1) is associated with a dominant, missense mutation in the equine glycogen synthase gene (GYS1) that increases the enzyme's activity. The amino acid sequence surrounding the PSSM1 mutation is highly conserved amongst species from yeast to horses suggesting that this region plays an important role, but its functional significance has yet to be determined.

Methods

Computer modelling can predict three dimensional (3D) protein structures using related proteins as templates. Yeast glycogen synthase (GS) has high sequence homology (73%) to the equine enzyme and since the yeast enzyme's structure has been solved, we hypothesised that in silico modelling based on the yeast protein using MODELLER and SwissPDBViewer software would predict the enzyme's structure and explain the mutant enzyme's increased activity.

Results

Homology‐modelling revealed that, like the yeast enzyme, equine GS likely forms a tetramer surrounding a catalytic cleft and undergoes large structural rearrangements upon G6P binding to highly‐conserved binding sites. The enzyme's glycogen binding sites are located on the extremities of the enzyme and are also conserved in the equine protein. The PSSM1 mutation lay close to the G6P binding site, but did not confer any clear structural rearrangement on the protein's 3D configuration. The mutation was distant from the known phosphorylation sites and the glycogen binding sites.

Conclusions

The close proximity of the mutation to the G6P binding site suggests that it might influence substrate interaction or allosteric regulation. Further studies evaluating G6P ligand binding and enzyme activation are warranted and might best be made following purification of the mutant and wild type proteins.

Ethical Animal Research

No animals were used in the study. Sources of funding: Petplan Charitable Trust and The Royal Veterinary College. Competing interests: none.
Mitochondrial Respirometry in Skeletal Muscle of Exercising Eventing Horses Run to Exhaustion
Authors: Miranda ACT , Ramos D , Chicaybam G , Almeida F , Galina A
Published: June 2014

Introduction

Mitochondria play a central role in energy metabolism during muscle contraction and in the balance of anaerobic and aerobic energy production. This study evaluated mitochondrial respirometry in skeletal muscle of eventing horses before and after an intense effort.

Methods

Fourteen Brazilian Sport Horses 4 to 6 years old performed an incremental velocity test on a high speed treadmill inclined to 3% and galloped at speeds up to 8 m/s until exhaustion. Biopsies from the gluteus medius muscle were obtained before and immediately after the end of the test. Mitochondrial respiration was assessed by O2K oxygraph of high resolution (Oroboros). The results were standardized by minute and per gram of wet weight of muscle and expressed as mean ± SD. Plasma lactate was measured using a spectrophotometer. Results were compared by paired t–test (P<0.05).

Results

The maximal respiration value of mitochondria did not change in gluteus medius muscle of horses at exhaustion. However, there was an increase in stage 3 mitochondrial respiration with pyruvate/malate substrate, and also an increase of non‐mitochondrial respiration after exercise. Lactate values before and after exercise were 0.4 ± 0.1 mmol/L and 12.1 ± 4.6 mmol/L, respectively.

Conclusions

There is little change in mitochondrial respirometry in the gluteus medius muscle after intense exercise indicating predominantly anaerobic metabolism in the muscle of the eventing horses, as supported by the high plasma lactate concentrations after the test. The increase of oxidase reactions after intense exercise is related to an increase in non‐mitochondrial respiration.

Ethical Animal Research

All procedures were approved by the Board of Ethical Research of Universidade Federal Rural do Rio de Janeiro: number 264/2012. Sources of funding: Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq; PRONEX and Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro – FAPERJ. Competing interests: none.
Effect of Sedation and Exercise on Phenylalanine Pharmacokinetics in Horses
Authors: Naylor R , Smith K , Rankin D , Blake V , Atherton P , Piercy R
Published: June 2014

Introduction

Measurement of incorporation of stable isotope‐containing amino acids into muscle is the gold‐standard technique for measuring muscle protein synthesis (MPS), but its use in assessing MPS in horses has not been evaluated. Determination of MPS requires steady‐state tracer plasma enrichment and serial muscle biopsy. Given that MPS is often assessed in response to exercise and that muscle biopsy in the standing horse typically requires sedation, the influence of exercise and sedation on tracer kinetics was determined.

Methods

Three mature Thoroughbred geldings received 0.1 mg/kg D5‐phenylalanine (D5‐Phe) IV and plasma D5‐Phe enrichment was measured over 3 hrs. Pharmacokinetic modeling determined the rate of appearance and phenylalanine pool size, from which a loading dose and infusion rate that would achieve a steady 5–10% enrichment were calculated. Subsequently, steady‐state was confirmed by measuring plasma enrichment during 6 hours of infusion after loading. Horses then received the same dose and completed a 12‐minute exercise test and were sedated with xylazine 0.4 mg/kg IV. Plasma D5‐Phe enrichment was determined every 5–15 minutes for 2 hours after both exercise and sedation.

Results

The mean rate of phenylalanine appearance in the horse was 56 umol/kg/hr (SD 24) and mean phenylalanine pool size 41 umol/kg (SD 8.8). A loading dose of 3.3 umol/kg and an infusion rate of 4.5 umol/kg/hr D5‐phenylalanine was calculated and subsequently, confirmed to achieve steady state tracer concentration at 5.6–9.1% APE in sedentary horses. Exercise caused a transitory, and sedation a more prolonged reduction in plasma enrichment (up to 20%).

Conclusions

D5‐phenylalanine is a suitable metabolic tracer in the horse as a steady‐state can be achieved, however interventions should be taken into account.

Ethical Animal Research

The study was performed in in accordance with the local Ethics Committee approval and Home office project license (PPL 70/7523) under the UK A(SP)A Act 1986. Sources of funding: Boehringer Ingelheim. Competing interests: R Naylor is completing a PhD studentship sponsored by Boehringer Ingelheim.
Influence of Weight Loss on Skeletal Muscle Mitochondrial Function in the Mature Horse
Authors: Zambito J , Nichols C , Barnes K , Spooner H , Hollander J
Published: June 2014

Introduction

Obesity creates many metabolic issues in horses, yet stepwise alterations in mitochondrial capacity and oxidant status during weight loss have not been assessed. Skeletal muscle contains subsarcolemmal (SSM) and interfibrillar (IFM) mitochondria, which respond differently to physiological stimuli, impacting tissue and systemic oxidant status. It was hypothesised that horses would display improved muscle mitochondrial subpopulation function in middle gluteal muscle, and decreases in circulating oxidant status markers during weight loss from an obese (7 to 8) to moderate (5) body condition score (BCS).

Methods

8 light‐type horses were studied. Mitochondrial subpopulations were isolated through differential centrifugation and all enzymatic activity through colorimetric kinematic assays. Effects of BCS reduction or percent weight loss were evaluated using SAS (mixed procedure with repeated measures).

Results

Plasma nitrate decreased in response to BCS reduction (P = 0.06) and percent weight loss (P = 0.06), whereas erythrocyte total glutathione (P = 0.06) concentration increased with decreasing BCS. Mitochondrial electron transport chain complexes I and IV displayed greater activity in SSM than IFM (P≤0.03), while all complexes in IFM had decreased activity due to both weight parameters (P≤0.01). Interactions between subpopulation complex IV activity and weight loss markers (P<0.05) were displayed. Citrate synthase activity, indicating mitochondrial number, was greater in SSM than IFM (P<0.0001) but was unaffected with weight loss. Lipid peroxidation was decreased with BCS change (P = 0.01) and weight loss (P = 0.02), displaying greater amounts in SSM than IFM (P≤0.02).

Conclusions

Alterations in complex activities and lipid peroxidation suggest IFM are more affected by weight loss, with large contributions from complex IV by‐products. Mitochondrial component flexibility may contribute individually to disease development and performance of equine athletes.

Ethical Animal Research

The study was approved by the Middle Tennessee State University Institutional Animal Care and Use Committee. Sources of funding: West Virginia University Summer Undergraduate Research Experience Program and Middle Tennessee State University. Competing interests: none.
The Use of Nutritional Supplements in Dressage and Eventing Horses
Authors: Agar C , Gemmill R , Hollands T , Freeman S
Published: June 2014

Introduction

Selecting the appropriate nutritional supplements for performance horses is difficult, due to significant gaps in the current scientific evidence. Our hypothesis was that nutritional supplements are chosen based on owner's perception of discipline specific health and performance problems.

Methods

A mixed methods (open and closed questions) online questionnaire was distributed through British Eventing and Dressage websites, to collect data on demographics of owners and their horses, supplements used, and their opinion on health and performance problems in their discipline, and in their own horses. Data was evaluated using descriptive analysis and Sign and Fisher's exact tests for quantitative data, and thematic analysis for qualitative data.

Results

599 responses met the inclusion criteria, of which 441 were or had competed in dressage, and 158 in eventing (unaffiliated novice to affiliated advanced levels). Participants had been riding for 26.4 (3–60) (mean (range)) years, currently competed 1.2 (0–10) horses, and used 2 (0–12) supplements in their top horse. Participants ranked the most important health and performance issues as (1) Energy and behaviour, (2) Lameness, (3) Back and muscle problems for dressage, and (1) Lameness, (2) Energy and behaviour, (3) Stamina and fitness for eventing horses. The most common reason supplements were used in individual horses were (1) Joints and mobility, (2) Behavioural problems for dressage, and (1) Electrolytes, (2) Joints and mobility for eventing.

Conclusions

There was discrepancy between participants' opinions of the main health and performance problems within their discipline, and their reasons for using supplements.

Ethical Animal Research

The study was approved by the School of Veterinary Medicine and Science Ethics Committee at University of Nottingham. Sources of funding: School of Veterinary Medicine and Science, University of Nottingham. Competing interests: Teresa Hollands is employed by Dodson and Horrell Ltd.
Effect of Chelated Chromium and L‐carnitine on Subcutaneous Fat Deposition in the Mangalarga Marchador Breed after Training
Authors: Barcelos K , Jordão L , Ferraz G , Lana A , Rezende A
Published: June 2014

Introduction

The Brazilian Mangalarga Marchador breed is valued for its gait. However few studies have assessed the use of nutritional additives on this breed's performance. This study was designed to test the hypothesis that chelated trivalent chromium and L‐carnitine feed supplementation may reduce subcutaneous fat deposition after training.

Methods

13 mares (2.5 to 3 years old) were assigned to one of three treatments (T1, 10 mg Cr/day; T2, 10 g LCN/day; T3, control) according to a completely randomized design, with split‐plot arrangement. The diet was Panicum maximum cv. Massai and concentrate (50:50 ratio and 2.5% BWT). During 42 days the mares received supplementation and exercised for 50 min on a treadmill and 60 min on an automatic walker every other day, resting on Sundays. Subcutaneous fat was measured with ultrasound before and after training in the back‐loin(GDL), croup(GG), and base of the tail(GBC). Results were compared by Tukey test (P<0.05).

Results

Before training, the variables were similar across the groups (P>0.05). After training, in GDL, T2 (1.76 mm) was 37.37% lower (P<0.05) than control (2.81 mm), while T1 (2.22 mm) was similar to T2 and control. There was no difference between treatments (P>0.05) in GG. In GBC, there was a 24.45% increase from pre (8.59 mm) to post‐treatment (10.69 mm) evaluations, regardless of the treatment.

Conclusions

Supplementation with L‐carnitine reduces subcutaneous fat deposition in the lumbar region of Mangalarga Marchador mares after training, which may be indicative of increased use of subcutaneous fat in this region as a substrate for exercise.

Ethical Animal Research

Procedures were approved research by the University (no. 237 / 2012 protocol). Sources of funding: CNPq, CAPES, FAPEMIG, ABCCMM, Lab TORTUGA, Haras Esperança e Grande Sertão. Competing interests: none.
Effect of Diet and Road Transport on Post‐Exercise Plasma Lactate Concentration
Authors: Connysson M , Jansson A
Published: June 2014

Introduction

Horses are usually transported before competitions. The aim of this study was to compare the lactate response in horses on two diets that were transported or not transported before exercise.

Methods

Six trained and raced Standardbred trotter mares, all accustomed to transportation, were used. Two diets were fed in two periods of 29 days in a crossover design; one forage‐only diet (F) and one diet with 50% of DM intake from forage and 50% from oats (FO). The horses had slow exercise 1–3 times/week (approximately 1 h walk and slow trot [6–7 m/s]) and intensive exercise1–2 times/week (4000 m slow trot warm‐up, 2000 m at 10–11 m/s on a race track or five 500 m intervals at 9 m/s on a slope, slow trot downhill). At day 21, horses were subjected to transport for 100 kilometres before they performed an exercise test (TT) (4000 meter warm‐up [6.3–10 m/s] and 2140 m “race” [11.6–12.7 m/s]). At day 26, the horses performed a control test (CT) where they were kept in their stall before the exercise test was performed. Blood samples were collected after the finish line and 10 and 30 min post‐exercise. Plasma lactate (Lac) was analysed using a spectrophometric method. ANOVA was performed using PROC MIXED (significant difference P<0.05).

Results

There was no difference in Lac (after finish and 10 and 30 min post‐exercise) between diets (F: 14.9 vs. FO: 17.1 mmol/l SEM: 2.1) or exercise tests (TT: 15.9 vs. CT: 16.1 mmol/l SEM 2.0).

Conclusions

Diet and transport seem not to affect post‐exercise plasma lactate in experienced competition horses transported 100 km.

Ethical Animal Research

The Umeå local ethics committee approved this study. Sources of funding: KSLA (The Royal Swedish Academy of Agriculture and Forestry). Competing interests: none.
Effect of Non‐Structural Carbohydrate, Fat and Fiber Intake on Glycogen Repletion Following Intense Exercise
Authors: Mesquita VS , Pagan JD , Valberg SJ , Waldridge BM , Whitehouse C
Published: June 2014

Introduction

Muscle glycogen is a potentially limiting substrate for horses during intense exercise. Low‐starch, high‐fat concentrates have become popular for performance horses, but their effect on muscle glycogen usage and repletion is unclear.

Methods

Six Thoroughbred horses were studied in a 3 x 3 Latin Square design to measure the effect of non‐structural carbohydrate (NSC), fat and fiber intake on glycogen repletion following intense exercise. Horses were fed isocaloric, isonitrogenous rations that supplied high (HS), medium (MS) or low (LS) NSC intake. The horses were fed 1.25% BW/d grass‐hay and 1.0% BW/d concentrate. These rations provided 45%, 36% and 18% of total digestible energy (DE) from NSC, 11%, 15% and 23% of total DE from fat, and 30%, 33% and 45% of total DE from fiber. During each 1‐month period horses were trained for three weeks on a high‐speed treadmill followed by a three‐day glycogen‐depletion period comprising multiple bouts of intense exercise. Muscle biopsies were taken before and 0, 24, 48 and 72 hours post‐depletion. A standardized exercise test (SET) was performed on day 1 of the depletion period.

Results

During the SET, lactate was lower in LS compared to MS or HS (P<0.05). Heart rate, plasma glucose, VO2, VCO2 were unaffected by treatment. Muscle glycogen depletion averaged 33%, 30%, and 36% in the HS, MS and LS treatments. Muscle glycogen repletion was significantly lower in the LS group 72 hours post exercise (P<0.05).

Conclusions

Low NSC concentrates may not provide enough substrate for glycogen repletion following multiple bouts of intense exercise.

Ethical Animal Research

Approved by Kentucky Equine Research animal use committee. Sources of funding: Kentucky Equine Research and Cargill. Competing interests: Some of the concentrates tested are owned by the funding sources. Dr Pagan is president of Kentucky Equine Research.
The yeast protein interaction network has a capacity for self‐organization
Authors: Dhroso Andi , Korkin Dmitry , Conant Gavin C.
Published: June 2014

The organization of the cellular interior gives rise to properties including metabolic channeling and micro‐compartmentalization of signaling. Here, we use a lattice model of molecular crowding, together with literature‐derived protein interactions and abundances, to describe the molecular organization and stoichiometry of local cellular regions, showing that physical protein–protein interactions induce emergent structures not seen when random interaction networks are modeled. Specifically, we find that the lattices give rise to micro‐groups of enzymes on the surfaces of protein clusters. These arrangements of proteins are also robust to protein overexpression, while still showing evidence for expression tuning. Our results indicate that some of the complex organization of the cell may derive from simple rules of molecular aggregation and interaction.
The Kv1.3 potassium channel is localized to the cis‐Golgi and Kv1.6 is localized to the endoplasmic reticulum in rat astrocytes
Authors: Zhu Jing , Yan Jenny , Thornhill William B.
Published: June 2014

The functions of voltage‐gated potassium (Kv) channels in neurons have been well defined, whereas their roles in glial cells are not fully understood. Kv1.1, Kv1.3 and Kv1.6 are endogenously expressed in C6 astrocytoma cells, but their trafficking and subcellular localization have not been well studied. In C6 cells, Kv1.1 was localized to the cell surface, Kv1.3 was predominantly localized in the cis‐Golgi, and Kv1.6 was enriched in the endoplasmic reticulum. Disruption of the Golgi stacks with brefeldin A treatment redirected Kv1.3 to the endoplasmic reticulum, further confirming that Kv1.3 was localized in the Golgi. Denaturing and reducing immunoblot analysis identified an expected Kv1.3 monomer and an unexpected Kv1.3 dimer/aggregate. These two forms had different protein half‐lives: that of the monomer form T1/2 was 5.1 h, whereas the dimer/aggregate form was stable over the 8‐h measurement period. The Kv1.3 dimer/aggregate form on immunoblots appeared to be correlated with its Golgi retention, based on examination with several cell types that expressed Kv1.3. Glycosidase treatment showed that Kv1.3 contained complex‐type N‐glycans terminated with sialic acids, suggesting that Kv1.3 had traveled to the trans‐Golgi network for sialylation before it was recycled to the cis‐Golgi for retention. Inhibition of N‐glycosylation did not affect Kv1.3 localization, indicating that N‐glycans did not play a role in its Golgi retention. Thus, Kv1.3 appears to be distributed to the cis‐Golgi membrane of rat astrocytes in a similar way as a Golgi resident protein, and this unusual distribution appears to be correlated with its SDS/2‐mercaptoethanol‐resistant dimer/aggregate forms on immunoblots.
The association of −330 interleukin‐2 gene polymorphism and HLA‐DR15 allele in Iranian patients with multiple sclerosis
Authors: Sayad A.
Published: June 2014

The purpose of this case–control study was to evaluate the frequencies and potential genetic susceptibility of the −330 IL2 T and G alleles and HLA‐DRB1*1501 allele in Iranian patients with multiple sclerosis (MS) compared to healthy controls. Two hundred and sixty Iranian patients with MS from medical genetics department of Sarem Women hospital were selected. Besides, 450 ethnically age‐ and sex‐matched healthy individuals without personal or family backgrounds of autoimmune disorders were enrolled as a control group. All polymorphisms were analysed using RFLP‐PCR technique. HLA‐DRB1 genotyping was carried out by HISTO TYPE SSP high‐resolution Kits according to the manufacturer's suggestions. The frequency of the T allele at the −330 IL2 polymorphism was significantly higher in patients with MS than controls (OR: 2.45, 95 CI: 1.9–3, P = 4 × 10−14). Moreover, the T/T genotype was more frequent in patients than in controls (51% vs. 30%). This study indicated that the −330 T IL2 allele and the T/T genotype were related to increased plasma concentration of IL2 and a higher risk of developing MS among Iranian patients. Carrying both the −330 T IL2 and the HLA, DRB1* 1501 alleles showed the most susceptibly effect to MS. Our data demonstrated −330 T IL2 allele provided major susceptibility to MS and HLA‐DRB1* 1501 allele had an additive effect. In addition, it seems that studies with larger sample size are required to bring about more authentic results. Our findings suggest that IL2 gene polymorphisms influence the susceptibility to MS in Iranian patients.
Two novel alleles HLA‐DRB1*11:150 and HLA‐DRB1*14:145 identified in Saudi individuals
Authors: Fakhoury H. A. , Cereb N. , Jawdat D. , Al Jumah M. , Alaskar A. S. , Hajeer A. H.
Published: June 2014

Two new HLA‐ DRB1 alleles were identified by sequence‐based typing method (SBT) in 1100 participants in the Saudi Stem Cell Donor Registry. HLA‐DRB1*11:150 differs from HLA‐DRB1*11:01:01G by a single C to A substitution at nucleotide position 5580 in exon 2, resulting in an amino acid change from alanine to glutamic acid at position 74. HLA‐DRB1*14:145 differs from HLA‐DRB1*14:04 by a C to G substitution at nucleotide position 5511 in exon 2, resulting in an amino acid change from threonine to arginine at position 51.
Sleep timing and longitudinal weight gain in 4‐ and 5‐year‐old children
Authors: Scharf R. J. , DeBoer M. D.
Published: June 2014

Background and Objective

Short night‐time sleep duration is a possible factor contributing to childhood obesity. Our objective was to evaluate associations between sleep timing (including bedtime and waketime) and weight gain in 4‐ to 5‐year‐old children.

Methods

We used cross‐sectional and longitudinal regression analyses of a large, nationally representative sample of children from the Early Childhood Longitudinal Study–Birth Cohort. Data regarding the timing and duration of weekday sleep were assessed via parent questionnaire. Short sleep duration, late bedtime and early waketime were defined as those greater than one standard deviation from the mean for the group.

Results

Using linear regression adjusted for confounders, sleep duration at 4 and 5 years and bedtime at 5 years were linked to body mass index (BMI) z‐score (P < 0.001). Odds of obesity were higher at 4 years for children sleeping <9.44 h nightly (adjusted odds ratio 1.35, confidence interval 1.02–1.78, P < 0.05) and at 5 years for children going to bed at 9:00 pm or later (1.49, 1.16–1.45, P < 0.01) or waking before 6:30 am (1.23, 1.01–15.51, P < 0.05). Assessed longitudinally, both short sleep duration (P < 0.05) and later bedtime at 4 years (P < 0.01) were associated with increases in BMI z‐score between 4 and 5 years.

Conclusions

Children with shorter night‐time sleep durations and later bedtimes were more likely to be obese and to gain weight over time. Pediatricians should encourage families to place children to bed at earlier times to promote longer sleep duration as a potential means of controlling weight gain.
Relationship Between Elevated Morning Blood Pressure Surge, Uric Acid, and Cardiovascular Outcomes in Hypertensive Patients
Authors: Turak Osman , Afsar Baris , Ozcan Firat , Canpolat Ugur , Grbovic Enis , Mendi Mehmet Ali , Oksuz Fatih , Siriopol Dimitrie , Covic Adrian , Caliskan Mustafa , McFann Kim , Johnson Richard J. , Kanbay Mehmet
Published: June 2014

Early morning blood pressure surge (MBPS) is a risk factor for cardiovascular events (CVEs), but the relationship with uric acid is not well understood. The authors aimed to determine the association between MBPS and increased uric acid and the effect of elevated MBPS and uric acid combination on CVEs. A total of 921 patients underwent 24‐hour ambulatory blood pressure monitoring and were followed for a median of 40 months. During this period, 103 (11.2%) CVEs occurred. There was a significant relationship between increasing quartiles of serum uric acid level and increasing values of MBPS (P<.0001). Patients in the highest quartile stratified by elevated MBPS and serum uric acid level had a 3.55 odds of major CVE compared with patients in the lowest quartile. Serum uric acid is associated with MBPS and development of new CVEs.
Grazing behaviour of a non‐herbivorous characin: revisiting plasticity
Authors: Marques P. S. , Costa M. F. , Corrêa C. C. D. , Marinho M. M. , Mazzoni R.
Published: June 2014

Feeding behaviour and diet of Bryconamericus microcephalus differed between canopy conditions. At the open canopy site, a behavioural modification, grazing on algae, was observed. This was also reflected in gut content analysis and suggests behavioural plasticity in response to resource availability.
First case of synophthalmia and albinism in the Pacific angel shark Squatina californica
Authors: Escobar‐Sánchez O. , Moreno‐Sánchez X. G. , Aguilar‐Cruz C. A. , Abitia‐Cárdenas L. A.
Published: June 2014

The first record in Mexican waters of albinism and synophthalmia (partial cyclopia) in the Pacific angel shark, Squatina californica is presented. Albinism is not lethal, but synophthalmia may cause the death of the individual immediately after birth.
The effects of a diet rich in inulin or wheat fibre on markers of cardiovascular disease in overweight male subjects
Authors: Tripkovic L. , Muirhead N. C. , Hart K. H. , Frost G. S. , Lodge J. K.
Published: June 2014

Background

Previous studies suggest that the beneficial health effects of a diet rich in whole grains could be a result of the individual fibres found in the grain. The present study aimed to investigate the influence of a diet high in either wheat fibre (as an example of an insoluble fibre) or inulin (a nondigestible carbohydrate) on markers of cardiovascular disease.

Methods

Ten male participants classified as at higher risk of cardiovascular disease [mean (SD) body mass index 30.2 (3) kg m−2, mean (SD) waist circumference 106.4 (7) cm, mean (SD) age 39.8 (9) years] were recruited to a randomised, controlled, cross‐over study comparing the consumption of bespoke bread rolls containing either inulin, wheat germ or refined grain (control) (15 g day−1) for 4 weeks with a 4‐week washout period between each regime. At the end of each regime, participants underwent an oral glucose tolerance test (OGTT), measures of pulse wave velocity (PWV), 24‐h ambulatory blood pressure (AMBP), plasma lipid status and markers of glucose control.

Results

There was no difference in measures of glucose control, lipid status, 24‐h AMBP or PWV after the intervention periods and no changes compared to baseline. There was no significant difference between OGTT glucose and insulin time profiles; however, there was a significant difference in area under the curves between the wheat fibre and control interventions when comparing change from baseline (control +10.2%, inulin +4.3%, wheat fibre −2.5%; P = 0.03).

Conclusions

Only limited differences between the interventions were identified, perhaps as a consequence of the amount of fibre used and intervention length. The wheat germ intervention resulted in a significant reduction in glucose area under the curve, suggesting that this fibre may aid glucose control.
The effects of brand popularity as an advertising cue on perceived quality in the context of internet shopping
Authors: Kim Ji‐Hern , Min Dongwon
Published: June 2014

Brand popularity as a descriptive norm has been used as an advertising cue by internet malls. It is based on the assumption that consumers prefer brands with popularity claims because they perceive the popularity claim results from superior quality. However, little research has been done on how popularity cues affect perceived quality in internet shopping contexts. Particularly, the interaction effect between brand popularity and price on the quality perception has never been investigated. This research presents the results of two experiments showing that brand popularity and price have an interaction effect on the estimation of sales, which in turn influences perceived quality. Only when consumers believe that the sales volume is high would the perceived quality increase. This research also analyzes the manner in which brand popularity reduces consumers' perceived risk in purchase decision‐making.
The phonological planning in Mandarin spoken production of mono‐ and bimorphemic words
Authors: Chen Train‐Min , Chen Jenn‐Yeu
Published: June 2014

A spoken word is a linearized sequence of sounds; therefore, speakers must always start with the beginning portion of a word when preparing to speak it. This is not only true for producing a simplex word like “bandit,” but has been shown to be true for producing a compound word such as “weekday.” We investigated whether this word‐onset‐first planning strategy was also observed in Mandarin Chinese. The form preparation paradigm was used. The first morpheme of a disyllabic compound word served as the prompt to cue the participants to produce the second morpheme. The second morphemes of the compound words shared the same segmental syllables or did not. A significant preparation effect was observed in Experiment 1 and replicated in Experiment 2. Experiment 3 using the first character to cue the second character of a monomorpheme two‐character word also found a significant preparation effect. The results indicated that compound words are not processed in the same way in English and Mandarin Chinese. Potential accounts are discussed of the cross‐language difference.