Equine metabolism encompasses the biochemical processes that occur within horses to maintain life, including the conversion of food into energy, the synthesis of necessary compounds, and the elimination of waste products. These processes are essential for supporting various physiological functions such as growth, reproduction, and physical performance. Key components of equine metabolism include carbohydrate, fat, and protein metabolism, each of which contributes to the overall energy balance and health of the horse. Factors influencing metabolic rate and efficiency in horses include age, breed, diet, exercise, and health status. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, regulation, and implications of metabolic processes in equine physiology.
Jarvis N, McKenzie HC.Weight loss occurs when the supply of energy is insufficient to meet the energy needs of an individual. The energy supply may be reduced by inadequate provision of feed, inadequate consumption, reduced digestion and absorption, or disruption in metabolic processing. Increased energy expenditure occurs with exercise and during cold temperatures, pregnancy, and lactation. Underlying clinical disease, particularly chronic inflammation, neoplasia, and protein-losing conditions, can cause weight loss or exacerbate existing weight loss. A methodical approach to weight-loss investigation and treatmen...
Ericsson AC, Johnson PJ, Gieche LM, Zobrist C, Bucy K, Townsend KS, Martin LM, LaCarrubba AM.Common treatments for Equine Metabolic Syndrome (EMS) and associated conditions include removal from pasture and adoption of an all-hay diet. Pharmacological treatments for EMS include metformin, a biguanide antihyperglycemic agent also administered to people to help improve glucose tolerance and insulin sensitivity. Both treatments may work, at least partially, through the gut microbiota, yet little is known regarding these effects in the equine host. To determine the influence on the fecal microbiota of this diet change and administration of metformin, six healthy horses were removed from pa...
Graham-Thiers PM, Bowen LK.Feeding management in horses suggests feeding horses in advance of exercise, particularly the grain portion of the diet. Plasma amino acids () peak at 3 to 6 h postfeeding depending on the AA. The timeframe between feeding and exercise may affect the availability of AA during and after exercise. The purpose of this study was to observe the differences in plasma AA in horses fed prior to exercise or after exercise. Eight light type horses were fed a diet with adequate protein and AA for horses in light to moderate exercise. After an adjustment period, horses completed a standardized exercise te...
Noordwijk KJ, Qin R, Diaz-Rubio ME, Zhang S, Su J, Mahal LK, Reesink HL.Carpal osteochondral fragmentation and subsequent post-traumatic osteoarthritis (PTOA) are leading causes of wastage in the equine athlete. Identification of synovial fluid biomarkers could contribute to the diagnosis and understanding of osteoarthritis (OA) pathophysiology. Objective: The aim of this study was to identify differentially expressed metabolic and glycosylation pathways in synovial fluid from healthy horses and horses with naturally occurring carpal OA. Methods: Cross-sectional, in vivo metabolomics and glycomics study. Methods: In cohort 1, carpal synovial fluid (n = 12 horses...
Glycogen in skeletal muscle is a major source of energy during exercise and an important determinant of endurance capacity, so that its measurement may provide a meaningful marker of athletes' preparation and a possible predictor of performance, both in humans and in equines. Gold standard of glycogen concentration measurement is the histochemical and biochemical analysis of biopsy-derived muscle tissue, an invasive and potentially injuring procedure. Recently, high-frequency ultrasound (US) technology is being exploited in human sports medicine to estimate muscle glycogen content. Therefore, ...
Freeman DE.Maintenance fluid therapy is challenging in horses that cannot drink or are denied feed and water because of concerns about gastrointestinal tract function and patency. Intravenous fluid delivery to meet water needs based on current recommendations for maintenance requirements were obtained in fed horses and therefore might not apply to horses that are not being fed. This is a critical flaw because of the interdependence between intestinal tract water and extracellular water to support digestion while preserving water balance, a concept explained by the enterosystemic cycle. Because horses dri...
Boakari YL, Alonso MA, Riccio AV, Affonso FJ, Losano JDA, Nichi M, Belli CB, Fernandes CB.Information about mule physiology is scarce. Glucose and lactate serve as prognostic tools in neonates; thus, real-time evaluations would be beneficial. Our main objective was to measure glucose and lactate concentrations from healthy mule and equine foals from birth to 720 hours. Glucose and lactate concentrations were evaluated with a benchtop Randox Daytona analyzer (LAB) using plasma and with an Accutrend Plus system (ACP) using whole blood. Data were analyzed using PROC MIXED (P < .05), intraclass coefficient correlation and Bland-Altman analysis. Glucose and lactate concentrations fro...
Mukai K, Ohmura H, Takahashi Y, Kitaoka Y, Takahashi T.We investigated whether horses trained in moderate and mild hypoxia demonstrate greater improvement in performance and aerobic capacity compared to horses trained in normoxia and whether the acquired training effects are maintained after 2 weeks of post-hypoxic training in normoxia. Seven untrained Thoroughbred horses completed 4 weeks (3 sessions/week) of three training protocols, consisting of 2-min cantering at 95% maximal oxygen consumption under two hypoxic conditions (H16, F O = 16%; H18, F O = 18%) and in normoxia (N21, F O = 21%), followed by 2 weeks of post-hypoxic traini...
Kramer KJ, Kagan IA, Lawrence LM, Smith SR.Ethanol-soluble carbohydrates (ESCs) of cool-season grasses include mono- and disaccharides and sometimes short-chain fructans, which may exacerbate the risk of pasture-associated laminitis. A calibration for prediction of ESC concentrations by near-infrared reflectance spectroscopy (NIRS) was developed from 323 samples of four cool-season grass species (orchardgrass, Kentucky bluegrass, tall fescue, and perennial ryegrass) across 10 cultivars collected in central Kentucky in the morning and afternoon over two growing seasons. The calibration, which had accuracy above 95%, was used to predict ...
Yu X, Fang C, Liu L, Zhao X, Liu W, Cao H, Lv S.This study was designed to provide a basis for further understanding of the mechanism of lactation based on mRNA expression differences in milk fat between different milk yields in Kazakh horses. Total RNA was extracted from the milk fat during the peak of lactation period. A total of 310 differentially expressed genes (DEGs) were identified by comparative transcriptome analysis of the high-yield and low-yield group. These DEGs regulate lactation by participated in AMPK signaling pathway, FoxO signaling pathway, ErbB signaling pathway, VEGF signaling pathway. In addition, we performed quantita...
Lindinger MI, Waller AP.What is the central question of this study? What are the mechanisms by which equine sweat glands transport sodium, potassium and water into sweat? What is the main finding and its importance? The flux of sodium into sweat does not have an active transport component, the flux of potassium into sweat is partially dependent on an active transport mechanism, and there is no evidence for paracellular transport. In two series of experiments, this study used radioactive sodium (Na ) and potassium (K ) to trace the net flux, and calculate the unidirectional fluxes, of these ions from extracellular flu...
Lindåse S, Nostell K, Bergsten P, Forslund A, Bröjer J.Proxies are mathematical calculations based on fasting glucose and/or insulin concentrations developed to allow prediction of insulin sensitivity (IS) and β-cell response. These proxies have not been evaluated in horses with insulin dysregulation. The first objective of this study was to evaluate how fasting insulin (FI) and proxies for IS (1/Insulin, reciprocal of the square root of insulin (RISQI) and the quantitative insulin sensitivity check index (QUICKI)) and β-cell response (the modified insulin-to-glucose ratio (MIRG) and the homeostatic model assessment of β-cell function (HOMA-β)...
Wimmer-Scherr C, Taminiau B, Renaud B, van Loon G, Palmers K, Votion D, Amory H, Daube G, Cesarini C.Equine atypical myopathy (AM) is caused by hypoglycin A (HGA) and methylenecyclopropylglycine (MCPG) intoxication resulting from the ingestion of seeds or seedlings of some Acer tree species. Interestingly, not all horses pasturing in the same toxic environment develop signs of the disease. In other species, it has been shown that the intestinal microbiota has an impact on digestion, metabolism, immune stimulation and protection from disease. The objective of this study was to characterize and compare fecal microbiota of horses suffering from AM and healthy co-grazers. Furthermore, potential d...
Gretler SR, Finno CJ, Kass PH, Knych HK.In humans, the drug metabolizing enzyme CYP2D6 is highly polymorphic resulting in substantial differences in the metabolism of drugs including anti-arrhythmics, neuroleptics, and opioids. The objective of this study was to phenotype a population of 100 horses from five different breeds and assess differences in the metabolic activity of the equine CYP2D6 homolog using codeine as a probe drug. Administration of a probe drug is a common method used for patient phenotyping in human medicine, whereby the ratio of parent drug to metabolite (metabolic ratio, MR) can be used to compare relative enzym...
Bradbery AN, Coverdale JA, Hartz CJ, Millican AA, Goehring MS, Fikes KK, Picking E, Hammer CJ, Dunlap KA, Cardoso RC, Wickersham TA, Leatherwood JL....Results from previous studies indicate that maternal overnutrition during late gestation predisposes foals to metabolic disease, however, specific mechanisms resulting in disease remain unknown. Quarter Horse mares (n = 16), were randomly assigned to dietary treatments, beginning on gestational day 235, and consisted of a control group (CON- diet meeting nutrient requirement; n = 8) or an overfed diet (HIGH; n = 8) where mares received an additional 40 % above CON. On gestational days 285 and 315, an intravenous glucose tolerance test (FSIGTT) was conducted. Following parturition, foals were s...
Trevisiol S, Moulard Y, Delcourt V, Jaubert M, Boyer S, Tendon S, Haryouli H, Taleb W, Caroff M, Chabot B, Drif L, André F, Garcia P, Loup B....According to international sport institutions, the use of peroxisome proliferator activated receptor (PPAR)-δ agonists is forbidden at any time in athlete career due to their capabilities to increase physical and endurance performances. The (PPAR)-δ agonist GW501516 is prohibited for sale but is easily available on internet and can be used by cheaters. In the context of doping control, urine is the preferred matrix because of the non-invasive nature of sampling and providing broader exposure detection times to forbidden molecules but often not detected under its native form due to the organi...
Mrugala D, Leatherwood JL, Morris EF, Dickson EC, Latham CM, Owen RN, Beverly MM, Kelley SF, White-Springer SH.Conjugated linoleic acid (CLA) improves oxidative stress and mitochondrial biogenesis in various species but has not been thoroughly investigated in horses. We collected blood and muscle samples from lightly exercising horses before and 6 and 12 wk after receiving either soybean oil (CON; n = 5) or CLA (CLA; n = 5) supplementation. Samples were analyzed for markers of mitochondrial characteristics, antioxidant status, oxidative stress, and muscle damage. Data were analyzed using a linear model with repeated measures. In the triceps brachii (TB), citrate synthase (CS) activity was higher in CON...
Catandi GD, Obeidat YM, Broeckling CD, Chen TW, Chicco AJ, Carnevale EM.Advanced maternal age is associated with a decline in fertility and oocyte quality. We used novel metabolic microsensors to assess effects of mare age on single oocyte and embryo metabolic function, which has not yet been similarly investigated in mammalian species. We hypothesized that equine maternal aging affects the metabolic function of oocytes and in vitro-produced early embryos, oocyte mitochondrial DNA (mtDNA) copy number, and relative abundance of metabolites involved in energy metabolism in oocytes and cumulus cells. Samples were collected from preovulatory follicles from young (≤1...
Ribeiro RM, Ribeiro DS, Cota LO, Leme FO, M Carvalho A, Faleiros RR.This study aimed to characterize and correlate physiological and metabolic changes in horses fed a hypercaloric diet (HD). Nine mature horses with a mean initial body condition score of 2.9 ± 1 (scale, 1-9) were fed a high-calorie diet for 5 months. Fasting blood samples were collected before the study and biweekly for the duration of the project to determine the concentrations of cholesterol (CHOL), very low (VLDL), low (LDL) and high-density (HDL) lipoproteins, triglycerides, non-esterified fatty acids, and fructosamine. A low-dose oral glucose tolerance test (LGTT) was conducted before, 75...
Bourebaba L, Kornicka-Garbowska K, Al Naem M, Röcken M, Łyczko J, Marycz K.Protein tyrosine phosphatase 1B (PTP1B) is one of the major negative regulators of leptin and insulin signaling, and has been strongly implicated in insulin resistance development in the course of obesity and metabolic syndrome conditions; however, its exact role in controlling adipose tissue biogenesis is still poorly understood. This investigation aimed to elucidate whether selective inhibition of PTP1B using MSI-1436 compound may improve and restore the defective adipogenicity of ASCs isolated from EMS-affected horses. Equine ASC EMS cells were cultured under adipogenic conditions in the pr...
Delarocque J, Frers F, Huber K, Jung K, Feige K, Warnken T.Insulin dysregulation (ID) is an equine endocrine disorder, which is often accompanied by obesity and various metabolic perturbations. The relationship between weight variations and fluctuations of the insulin response to oral glucose tests (OGT) as well as the metabolic impact of ID have been described previously. The present study seeks to characterize the concomitant metabolic impact of variations in the insulin response and bodyweight during repeated OGTs using a metabolomics approach. Methods: Nineteen Icelandic horses were subjected to five OGTs over one year and their bodyweight, insuli...
Sullivan SN, Cole SL, Stewart MC, Brokken MT, Durgam S.To investigate the effects of triamcinolone acetonide (TA) and methylprednisolone acetate (MPA) on the viability of resident cells within the fibrocartilage on the dorsal surface of the deep digital flexor tendon (FC-DDFT) and fibrocartilage on the flexor surface of the navicular bone (FC-NB) of horses. Methods: 12 to 14 explants of FC-DDFT and of FC-NB from grossly normal forelimbs of 5 cadavers of horses aged 9 to 15 years without evidence of musculoskeletal disease. Methods: Explants were incubated with culture medium (control) or TA-supplemented (0.6 or 6 mg/mL) or MPA-supplemented (0.5 or...
Direkvandi E, Rouzbehan Y, Fazaeli H.To determine the effects of feeding frequency on nutrient digestibility and blood metabolites in horse, 16 Turkmen horses were used with weight of 430 ± 46 kg and age of 7 ± 1.8 years. Four feeding frequencies with 2 (M2), 4 (M4), 6 (M6), and 8 (M8) meals per day were used for a period of 28 days. The ratio of hay to concentrate was 70:30 in the experimental diet. Acid insoluble ash was used as internal marker to determine digestibility. On the 27th day of experiment, the blood was collected on 13 time points throughout the day. The results of this experiment showed that feed intake was not ...
Dockalova H, Zeman L, Horky P.Veterinarians can recommend milk thistle for the treatment of equine liver disease and laminitis. Milk thistle seed cakes were fed in the range of normal feed doses in this study. The milk thistle seed cakes were fed (twice a day) to the experimental group of the horses ( = 5) and biochemical blood markers (TP, Albumin, ALT (alanine transaminase), AST (aspartate transaminase), ALP (alkaline phosphatase), GGT (gamma-glutamyltransferase), Bilirubin, Cholesterol, HDL (high-density lipoprotein), LDL (low-density lipoprotein), TAG (triacylglycerol), BHB (beta-hydroxybutyric acid), NEFA (non-esterif...
Bourdon B, Contentin R, Cassé F, Maspimby C, Oddoux S, Noël A, Legendre F, Gruchy N, Galéra P.Articular cartilage experiences mechanical constraints leading to chondral defects that inevitably evolve into osteoarthritis (OA), because cartilage has poor intrinsic repair capacity. Although OA is an incurable degenerative disease, several dietary supplements may help improve OA outcomes. In this study, we investigated the effects of Dielen® hydrolyzed fish collagens from skin (Promerim®30 and Promerim®60) and cartilage (Promerim®40) to analyze the phenotype and metabolism of equine articular chondrocytes (eACs) cultured as organoids. Here, our findings demonstrated the absence of cyto...
Kinsella HM, Hostnik LD, Rings LM, Swink JM, Burns TA, Toribio RE.The endocrine pancreas and hypothalamic-pituitary-adrenal axis (HPAA) are central to energy homeostasis, but information on their dynamics in response to energy challenges in healthy newborn foals is lacking. Objective: To evaluate glucagon, insulin, ACTH, and cortisol response to fasting and carbohydrate administration in healthy foals. Methods: Twenty-two healthy Standardbred foals ≤4 days of age. Methods: Foals were assigned to fasted (n = 6), IV glucose (IVGT; n = 5), PO glucose (OGT; n = 5), and PO lactose (OLT; n = 6) test groups. Blood samples were collected frequently for 210 min...
Ishii H, Shibuya M, Leung GN, Yamashita S, Yamada M, Kushiro A, Kasashima Y, Okada J, Kawasaki K, Kijima-Suda I.The use of GW1516, a peroxisome proliferator-activated receptor δ (PPAR δ) agonist, is strictly prohibited in both horseracing and equestrian competitions. However, little is known about its metabolic fate in horses. To the best of our knowledge, this is the first reported metabolic study of GW1516 in equine urine. Methods: Urine samples obtained from a thoroughbred after nasoesophageal administration with GW1516 were protein-precipitated and the supernatants were subsequently analyzed by liquid chromatography/electrospray ionization high-resolution mass spectrometry (LC/ESI-HRMS) with a Q-E...
Herbert E, Ouerdane H, Lecoeur P, Bels V, Goupil C.Muscles are biological actuators extensively studied in the frame of Hill's classic empirical model as isolated biomechanical entities, which hardly applies to a living organism subjected to physiological and environmental constraints. Here we elucidate the overarching principle of a living muscle action for locomotion, considering it from the thermodynamic viewpoint as an assembly of actuators (muscle units) connected in parallel, operating via chemical-to-mechanical energy conversion under mixed (potential and flux) boundary conditions. Introducing the energy cost of effort as the generaliza...
Martin-Rosset W, Andueza D, Vermorel M.The metabolisable energy (ME) content of feeds is a better estimate of their 'true' energy value than their digestible energy (DE) content, because ME takes account of the gross energy of methane (GEgas) and the gross energy of urine (GEurine) losses. The accuracy and precision of the Gesellschaft für Ernährungsphysiologie (GfE) and Institut National de la Recherche Agronomique (INRA) systems for predicting the DE and ME contents of diets for horses were compared using the results of a study comprising 15 mixed diets. The INRA system was more accurate than the GfE system for predicting DE, G...
Robinson MA, Stefanovski D, You Y, Boston RC, Soma LR.Capsaicinoids deter horses from chewing on bandages and are applied topically to provide analgesia to musculoskeletal injuries. They are banned during competition due to their nerve blocking properties. The pharmacokinetics of oral (PO) and direct gastric administration via nasogastric tube (NG), or topical (TOP) administration of two capsaicinoid-containing products were investigated, and the withdrawal times required prior to competition were estimated. Capsaicin (CAP) and dihydrocapsaicin (DCAP) were quantified in plasma, and both compounds were best described by a delayed absorption two co...
Kinnunen S, Oksala N, Hyyppä S, Sen CK, Radak Z, Laaksonen DE, Szabó B, Jakus J, Atalay M.Several micronutrient supplementation strategies are used to cope with oxidative stress, although their benefits have recently been questioned. The aim of the present study was to examine the effects of DL-alpha-lipoic acid (LA) in response to acute exercise and during recovery in horses. Six standardbred trotters were tested on the treadmill before and after 5-week LA supplementation (25 mg/kg body weight/day). According to electron paramagnetic resonance measurements, strenuous aerobic exercise increased significantly free radical formation in the gluteus medius muscle, which was prevented b...
Brinkmann L, Gerken M, Hambly C, Speakman JR, Riek A.During winter, free-living herbivores are often exposed to reduced energy supply at the same time that energy needs for thermoregulation increase. Several wild herbivores as well as robust horse breeds reduce their metabolism during times of low ambient temperature and food shortage. Thyroid hormones (THs) affect metabolic intensity and a positive effect of THs on basal metabolic rate (BMR) has been demonstrated in mammals and birds. As BMR and field metabolic rate (FMR) are often assumed to be intrinsically linked, THs may represent a reliable indicator for FMR. To test this hypothesis, 10 Sh...
Davie AL, Evans DJ.The associations between velocity during a standardized, submaximal 800-m exercise test and blood lactate concentration after exercise were investigated in Thoroughbred racehorses on sand and grass racetracks. Predicted lactate concentrations for each horse's exercise test velocity were calculated from the line of best fit derived from results at each racetrack. The repeatability of the differences between the measured and predicted blood lactate response to exercise was also investigated. Exercise tests were conducted at speeds ranging from 12.8 to 16.6 m/s. The variability of velocity within...
Breidenbach A, Schlumbohm C, Harmeyer J.The aim of the present study was to investigate the importance of putative regulatory factors of the calcium (Ca) and inorganic phosphate (P(i)) homeostatic system in the horse. The concentrations of Ca, P(i), vitamin D metabolites, parathyroid hormone (PTH), the activity of the alkaline phosphatase (AP) and the concentration and binding properties of vitamin D binding protein (DBP) were measured in the plasma. In addition, the ability of the renal cortex to hydroxylate calcidiol into 24,25(OH)2D3 and 1,25(OH)2D3 was evaluated in vitro. The plasma concentration of Ca (3.2 +/- 0.15 mmol.L-1, N ...
Qureshi SH, Moza B, Yadav S, Ahmad F.The denaturation of bovine and horse cytochromes-c by weak salt denaturants (LiCl and CaCl(2)) was measured at 25 degrees C by observing changes in molar absorbance at 400 nm (Delta epsilon(400)) and circular dichroism (CD) at 222 and 409 nm. Measurements of Delta epsilon(400) and mean residue ellipticity at 409 nm ([theta](409)) gave a biphasic transition for both modes of denaturation of cytochromes-c. It has been observed that the first denaturation phase, N (native) conformation X (intermediate) conformation and the second denaturation phase, X conformation D (denatured) conformation are...
Tait AD, Hodge LC, Allen WR.Horse fetal gonadal tissue was incubated with 3 beta-hydroxy-5,7-pregnadien-20-one and 5,7-cholestadien-3 beta-ol and it was shown that both substrates were converted to 3 beta-hydroxy-5,7-androstadien-17-one. These findings support the proposal that in this tissue there is a 5,7-diene pathway producing 3 beta-hydroxy-5,7-androstadien-17-one, the putative precursor of equilin in the placenta.
Lepage OM, Marcoux M, Tremblay A.Levels of alkaline phosphatase and osteocalcin or bone Gla-protein, a new marker of bone metabolism, were analyzed in blood samples of 50 clinically normal female Standardbred horses between four months and twenty years of age. Samples were collected in the morning before exercise. Serum osteocalcin was measured by radioimmunoassay using bovine antibodies. There was a significant inverse correlation between alkaline phosphatase, osteocalcin and the age of the animals up to 48 months. The decrease in osteocalcin levels in serum was very marked during the first 30 months of life. The mean osteoc...
Piscator M.Cadmium exposure, metabolism, and effects are described especially in relation to dietary intakes. Data on dietary intakes in several countries have been complied from studies using the duplicate diet method or fecal analysis. These two methods seem to give more accurate data than estimates based on cadmium concentrations in food classes and food consumption (composite method). The present data on absorption and retention of ingested cadmium indicate that normally less than 5% is ingested, but absorption may increase in women who have iron deficiency. Earlier estimates of the critical concentr...
McKeever KH, Schurg WA, Jarrett SH, Convertino VA.The purpose of this study was to determine if a chronic hypervolemia would accompany endurance exercise training in the horse. Six mature previously inactive horses were utilized for this study. During the 5-wk experiment, five of the horses were trained for 14 d on a treadmill ergometer at a constant treadmill speed of 5.6 km X hr-1 and a constant grade of 12.5% for graduated lengths of time. One horse was trained by lunging at a trotting pace in a round pen. Following training, plasma volume increased by 4.7 1 (29.1%, P less than 0.05). Although the rate of daily water intake did not change ...
Bourebaba L, Michalak I, Röcken M, Marycz K.Reactive oxygen species (ROS) are key mediators of several cellular damage and thus associated with equine diseases such as inflammation and metabolic syndrome. This study aimed to evaluate the protective and antioxidant activities of methanolic extract prepared from Cladophora glomerata (C. glomerata) biomass, on equine adipose derived mesenchymal stem cells (EqASCs), under experimental oxidative stress induced by HO. Pre-treatment of EqASCs cells with different concentrations of C. glomerata methanolic extract (1% and 5%) provided a clear protection against cellular damage triggered by HO. T...
Le Goff D.Using a density gradient ultracentrifugal procedure, we have separated equine plasma and follicular fluid high-density lipoproteins (HDL). The density distribution of the follicular fluid HDL was clearly displaced towards the highest densities in comparison with that of plasma HDL. Similarly, an analysis of size distributions showed a decrease in follicular fluid HDL diameters (4.2 to 9.2 nm) compared to plasma HDL (5.5 to 9.5 nm). HDL were isolated into three subfractions on the basis of the disposition of the Sudan Black stained bands in the centrifuge tubes. Concentrations of each subfracti...
Selim S, Elo K, Jaakkola S, Karikoski N, Boston R, Reilas T, Särkijärvi S, Saastamoinen M, Kokkonen T.Obesity and insulin resistance have been shown to be risk factors for laminitis in horses. The objective of the study was to determine the effect of changes in body condition during the grazing season on insulin resistance and the expression of genes associated with obesity and insulin resistance in subcutaneous adipose tissue (SAT). Sixteen Finnhorse mares were grazing either on cultivated high-yielding pasture (CG) or semi-natural grassland (NG) from the end of May to the beginning of September. Body measurements, intravenous glucose tolerance test (IVGTT), and neck and tailhead SAT gene exp...
Gokbulut C, Nolan AM, McKellar QA.The present study was carried out to investigate whether the pharmacokinetics of avermectins or a milbemycin could explain their known or predicted efficacy in the horse. The avermectins, ivermectin (IVM) and doramectin (DRM), and the milbemycin, moxidectin (MXD), were each administered orally to horses at 200 microg/kg bwt. Blood and faecal samples were collected at predetermined times over 80 days (197 days for MXD) and 30 days, respectively, and plasma pharmacokinetics and faecal excretion determined. Maximum plasma concentrations (Cmax) (IVM: 21.4 ng/ml; DRM: 21.3 ng/ml; MXD: 30.1 ng/ml) w...
Borgia L, Valberg S, McCue M, Watts K, Pagan J.The aim of this study was to determine whether the glycaemic/insulinaemic responses to hay with non-structural carbohydrate (NSC, soluble carbohydrate) of 17% (HC), 10% (MC) or 4% (LC) differs in control horses and whether these responses differ between control and horses with polysaccharide storage myopathy (PSSM). Five clinically normal control horses and seven PSSM horses, all unfit and of Quarter Horse breeding (age 9.4 ± 3.4 years, body condition score range: 4.5-6). A crossover design compared the HC and LC hay, with horses randomly assigned to hay type for 5 days, and all horses fed th...
McGowan CM, Golland LC, Evans DL, Hodgson DR, Rose RJ.Thirteen Standardbred horses trained intensively for 34 weeks and detrained for 12 weeks to investigate the effects of training, overtraining and detraining on muscle metabolites, buffering capacity and enzyme activities (CS, HAD and LDH). After a standardised exercise test to fatigue at 10 m/s (approximately 100% VO2max), there was significant depletion of [ATP], [PCr] and muscle [glycogen] and accumulation of muscle and plasma [lactate], [NH3] and elevated muscle temperature. After training, associated with increased run time to fatigue (148%), there was reduced depletion of muscle [glycogen...
Holt C, Jenness R.Skim-milk samples from rat, rabbit, pig, sheep, goat, horse and man were analysed for lactose, casein and the total and ultrafilterable concentrations of the main salts. Results are compared with data for the cow. The ultrafiltrate concentrations of Ca and Mg were positively correlated with that of citrate and the colloidal concentrations of Ca, Mg and citrate were positively correlated with that of Pi, suggesting that common, general, principles determine the partition of salts in milks. Casein concentration in the skim-milks was inversely related to that of lactose in accordance with a recen...
Lacombe VA, Hinchcliff KW, Devor ST.To characterize insulin-sensitive glucose-transporter (GLUT-4) protein in equine tissues and determine effects of exercise and glucose administration on content of GLUT-4 protein in equine skeletal muscle. Methods: Tissue samples from 9 horses. Methods: Western blot analyses were performed on crude membrane preparations of equine tissues to characterize GLUT-4. In a crossover, randomized study, horses were strenuously exercised for 3 consecutive days and then administered 13.5% glucose or isotonic saline (0.9% NaCl; control) solution, i.v., at similar infusion rates for 12.1 hours. Samples wer...
Delarocque J, Frers F, Feige K, Huber K, Jung K, Warnken T.Little is known about the implications of hyperinsulinemia on energy metabolism, and such knowledge might help understand the pathophysiology of insulin dysregulation. Objective: Describe differences in the metabolic response to an oral glucose test, depending on the magnitude of the insulin response. Methods: Twelve Icelandic horses in various metabolic states. Methods: Horses were subjected to 3 oral glucose tests (OGT; 0.5 g/kg body weight glucose). Basal, 120 and 180 minutes samples were analyzed using a combined liquid chromatography tandem mass spectrometry and flow injection analysis ...
Knych HK, Baden RW, Gretler SR, McKemie DS.Despite their widespread popularity as sport and companion animals and published and anecdotal reports of vast difference in drug disposition and pharmacokinetics between individuals, studies describing equine drug metabolism are limited. It has been theorized that similar to humans, members of the CYP2D family in horses may be polymorphic in nature leading to differences in metabolism of substrates. This study aims to build on the limited current knowledge regarding P450 mediated metabolism in horses by describing the metabolism of the polymorphic CYP2D6 probe drug codeine in vitro. Codeine, ...
Rose RJ, Hodgson DR, Kelso TB, McCutcheon LJ, Reid TA, Bayly WM, Gollnick PD.This study determined maximal O2 uptake (VO2max), maximal O2 deficit, and O2 debt in the Thoroughbred racehorse exercising on an inclined treadmill. In eight horses the O2 uptake (VO2) vs. speed relationship was linear until 10 m/s and VO2max values ranged from 131 to 153 ml.kg-1.min-1. Six of these horses then exercised at 120% of their VO2max until exhaustion. VO2, CO2 production (VCO2), and plasma lactate (La) were measured before and during exercise and through 60 min of recovery. Muscle biopsies were collected before and at 0.25, 0.5, 1, 1.5, 2, 5, 10, 15, 20, 40, and 60 min after exercis...
Mendoza FJ, Estepa JC, Gonzalez-De Cara CA, Aguilera-Aguilera R, Toribio RE, Perez-Ecija A.Donkeys are commonly afflicted by endocrine and metabolic disturbances but few studies have investigated endocrine variables involved in energy regulation and their association with morphometric indices, age or gender in this species. Hemostatic and clinical differences have been demonstrated between horses and donkeys, so to consider both species as metabolically and endocrinologically similar could lead to misdiagnosis. In this study, plasma concentrations of glucose, triglycerides and endocrine factors involved in energy homeostasis (insulin, glucagon, leptin, adiponectin, ghrelin and insul...
Lauková A, Styková E, Kubašová I, Gancarčíková S, Plachá I, Mudroňová D, Kandričáková A, Miltko R, Belzecki G, Valocký I, Strompfová V.Probiotic bacteria or their antimicrobial proteinaceous substances called bacteriocins (enterocins) hold promising prophylactic potential for animal breeding. This study present the results achieved after application of Enterocin M in horses. Enterocin M has never been applied to horses before. Clinically healthy horses (10) were involved in this pilot experiment. They were placed in the stables of the University of Veterinary Medicine and Pharmacy, Košice, Slovakia, with the approval of the University Ethics Committee. The animals were fed twice a day with hay and oats, or alternatively graz...
Freestone JF, Beadle R, Shoemaker K, Bessin RT, Wolfsheimer KJ, Church C.Ten hyperinsulinaemic ponies divided into conditioned (N = 5) and rested (N = 5) groups were evaluated for their insulin and glucose response following oral glucose administration at Weeks 0, 2, 4, and 6. All ponies received a controlled intake of a pelleted ration during the study. In both groups body weight had decreased from baseline by Week 4 and remained low. After 2 weeks of exercise, ponies in the conditioned group had significantly decreased insulin and glucose indices, including peak insulin response, area under the insulin curve from 0 to 210 min (TIS), and the TIS value: area under ...
Eaton MD, Hodgson DR, Evans DL, Rose RJ.This experiment was undertaken to determine whether there were differences in cardiorespiratory, haematological and muscular responses in horses trained at either low or moderate intensities. Ten Thoroughbred horses previously rested in paddocks for 4 months were trained 5 days/week for 9 weeks. Horses were allocated randomly into fast or slow groups and exercised the same distance each day. Training distances were 1600 m in Weeks 0 and 1 up to 4000 m in Week 9. The fast group were trained at an intensity inducing a post training blood lactate of 4-8 mmol/l. This intensity was determined for e...
Medica P, Giunta RP, Bruschetta G, Ferlazzo AM.Exercise represents a physical stress that challenges homeostasis affecting central and peripheral serotoninergic systems. The influence of the exercise on circulating serotonin (5-hydroxytryptamine [5-HT]) levels depends on training state as well as the exercise protocol. The purpose of the present research was to determine changes of plasma 5-HT in sport horses in response to training (T) and simulated race (SR) and in addition to assess the possible presence of significant differences on circulating 5-HT between two different sessions of exercise. In particular, the research was carried out...
Paßlack N, Vahjen W, Zentek J.Cellobiose is a disaccharide with potential prebiotic effects, as demonstrated in different animal species, but not yet in horses. It was, therefore, the aim of the present study to evaluate the impact of dietary cellobiose on the fecal microbiota of horses. Eight healthy adult horses and two ponies were included in this study. The animals received a diet without or with 10 g and 20 g cellobiose per day for 14 days each. At the end of the feeding periods, fresh fecal samples were collected to measure bacterial metabolites and the microbial composition. For the microbiota analysis, 16S rRNA ...
Ortiz-Rodriguez JM, Balao da Silva C, Masot J, Redondo E, Gazquez A, Tapia JA, Gil C, Ortega-Ferrusola C, Peña FJ.The population of stallion spermatozoa that survive thawing experience compromised mitochondrial functionality and accelerated senescence, among other changes. It is known that stallion spermatozoa show very active oxidative phosphorylation that may accelerate sperm senescence through increased production of reactive oxygen species. Rosiglitazone has been proven to enhance the glycolytic capability of stallion spermatozoa maintained at ambient temperature. Thus, we hypothesized that thawed sperm may also benefit from rosiglitazone supplementation. Thawed sperm were washed and resuspended in Ty...
Irvine CH, Evans MJ.Total tyhroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3) and free triiodothyronine (FT3) concentrations in foal umbilical cord blood were respectively 14, 5 7 and 3 times the concentrations of these hormones in adult horse blood. The TT4 levels in foals declined rapidly to reach adult concentrations by Day 16 and FT4 levels declined steadily during the first 3 months of life. Foal TT3 levels rose during the first 10 hr after birth and thereafter declined, although they were still X2-5 higher than adult levels at 3 months of age. Levels of FT3 similarly increased after birth be...
Lacombe VA, Hinchcliff KW, Kohn CW, Devor ST, Taylor LE.To determine effects of feeding diets with various soluble-carbohydrate (CHO) content on rates of muscle glycogen synthesis after exercise in horses. Methods: 7 fit horses. Methods: In a 3-way crossover study, horses received each of 3 isocaloric diets (a high soluble CHO [HC] diet, a low soluble CHO [LC] diet, or a mixed soluble CHO [MC] diet). For each diet, horses were subjected to glycogen-depleting exercise, followed by feeding of the HC, LC, or MC diet at 8-hour intervals for 72 hours. Results: Feeding the HC diet resulted in a significantly higher glycemic response for 72 hours and sign...
