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.
Jocelyn NA, Harris PA, Menzies-Gow NJ.The oral sugar test (OST) is used to identify equine insulin dysregulation (ID); however only a dose of 0.15 mL/kg bwt corn syrup has been evaluated. Objective: To determine the effect of varying the dose of corn syrup on insulin and glucose response to the OST and the test's ability to distinguish between ponies with a history of laminitis (PL) and without laminitis (NL). Methods: Randomised crossover experiment. Methods: After an overnight fast, in a three-way randomised crossover study with a 7-day washout, 0.15, 0.3 or 0.45 mL/kg bwt corn syrup was administered orally to eight ponies (5 PL...
Bachmann M, Czetö A, Romanowski K, Vernunft A, Wensch-Dorendorf M, Wolf P, Metges CC, Zeyner A.Postprandial alterations of plasma amino acid (PAA) levels partly reflect a temporal contribution of the feed. How cereal grains affect PAA levels is not known. We hypothesized that a meal of cereal grains causes a temporal increase of PAA, affected by grain species, grain genotype and meal size. Six mares were used in three consecutive trials, receiving four oats, barley and maize genotypes, respectively. Individual grain genotypes were provided as 3 meal sizes corresponding to 1.0, 1.5 or 2.0 g starch/kg body weight. Meadow hay (1.5 kg/100 kg body weight) was offered daily. At the test...
Uhl EW.Although vitamin D is critical to calcium/phosphorus homeostasis, bone formation and remodeling, there is evolution-based variation between species in vitamin D metabolism and susceptibility to rickets and osteomalacia. Most herbivores produce vitamin D3 in response to sunlight, but dogs and cats have generally lost the ability as carnivore diets are rich in vitamin D. Nutritional deficiencies and/or poor exposure to sunlight can induce rickets in birds, swine, cattle and sheep, but horses are less susceptible as they have evolved a calcium homeostasis that is quite different than other animal...
Freeman DE.Colic surgery is one of few treatments in which a veterinarian can use a skill to save an animal's life from a deadly disease within a short timeframe. Unfortunately, such success is not achieved without considerable risk for surgical failure, which is responsible for most complications in the immediate post-operative period. The last 50 years have witnessed considerable improvements in colic surgery, although a ranking of the most important ones might not meet with universal agreement. Teamwork plays a critical role in the final outcome, starting and finishing with the referring veterinarian...
Liu Y, Siard M, Adams A, Keowen ML, Miller TK, Garza F, Andrews FM, Seeram NP.The human health benefits attributed to turmeric/curcumin spice has resulted in its wide utilization as a dietary supplement for companion pets and other animals including horses. While the quantification of free curcuminoids (curcumin, demethoxycurcumin, bisdemethoxycurcumin) and their phase-2 metabolites (curcumin-O-sulfate, curcumin-O-glucuronide) have been extensively investigated in human and rodent biological samples (primarily plasma and serum), there is lack of similar data for horses. Herein, we report a validated LC-ESI-MS/MS method for the simultaneous quantification of the aforemen...
Merlo B, Teti G, Mazzotti E, Ingrà L, Salvatore V, Buzzi M, Cerqueni G, Dicarlo M, Lanci A, Castagnetti C, Iacono E.Wharton's jelly (WJ) is an important source of mesenchymal stem cells (MSCs) both in human and other animals. The aim of this study was to compare human and equine WJMSCs. Human and equine WJMSCs were isolated and cultured using the same protocols and culture media. Cells were characterized by analysing morphology, growth rate, migration and adhesion capability, immunophenotype, differentiation potential and ultrastructure. Results showed that human and equine WJMSCs have similar ultrastructural details connected with intense synthetic and metabolic activity, but differ in growth, migration, a...
Robles M, Peugnet P, Dubois C, Piumi F, Jouneau L, Bouchez O, Aubrière MC, Dahirel M, Aioun J, Wimel L, Couturier-Tarrade A, Chavatte-Palmer P.Feeding pregnant broodmares with cereal concentrates has been shown to increase maternal insulin resistance and affect foal metabolism in the short and long-term. These effects are likely to be mediated by the placenta. Here, we investigated feto-placental biometry and placental structure and function at term in mares fed with or without cereals concentrates. From 7 months of gestation, 22 multiparous mares were fed forage only (group F (n = 12)) or received forage and cracked barley (group B (n = 10)) until foaling. Foals and placentas were weighed and placental samples were collected...
D'Ascola A, Bruschetta G, Zanghì G, Campo S, Medica P, Campana S, Ferlazzo G, Gibbs BF, Ferlazzo AM.Serotonin (5-HT) is a neurohormone transported from plasma into platelets and leukocytes by a specific transporter (SERT). While it is known that the brain 5-HT system is modulated by physical exercise, the peripheral serotoninergic response to exercise is not yet fully elucidated. In particular, this study aimed to evaluate changes in plasma 5-HT levels and equine leukocyte SERT expression in response to treadmill exercise in untrained horses. Analyses were carried out pre- and post-treadmill exercise. 5-HT plasma levels were analysed by HPLC. Leukocytes and platelets were isolated to perform...
Rapson JL, Schott HC, Nielsen BD, McCutcheon LJ, Harris PA, Geor RJ.Age and diet may affect insulin sensitivity (SI) but these factors have received limited investigation in horses. Objective: To measure minimal model parameters during an insulin-modified frequently sampled intravenous glucose tolerance test (FSIGTT) after adaptation to a forage only diet (HAY) or forage supplemented with either starch/sugar-rich (SS) or oil/fibre-rich (FF) concentrate feeds; and to assess glucose and insulin responses to a standardised meal challenge (SMC, 4 g/kg BW of SS) after diet adaptation in adult and aged mares. Methods: Latin square design with eight adult (5-12 yea...
Choi TLS, Wong JKY, Kwok WH, Curl P, Mechie S, Wan TSM.Methylstenbolone (2,17α-dimethyl-5α-androst-1-en-17β-ol-3-one) is a synthetic anabolic and androgenic steroid (AAS) sold as an oral 'nutritional supplement' under the brand names 'Ultradrol', 'M-Sten' and 'Methyl-Sten'. Like other AASs, methylstenbolone is a prohibited substance in both human and equine sports. This paper describes the studies of the in vitro and in vivo metabolism of methylstenbolone in horses using LC/HRMS, GC/MS and GC/MS/MS. Phase I in vitro metabolic study of methylstenbolone was performed using homogenised horse liver. Hydroxylation was the only biotransformation obse...
Knych HK, Seminoff K, McKemie DS, Kass PH.Acepromazine is a tranquilizer used commonly in equine medicine. This study describes serum and urine concentrations and the pharmacokinetics and pharmacodynamics of acepromazine following intravenous, oral, and sublingual (SL) administration. Fifteen exercised adult Thoroughbred horses received a single intravenous, oral, and SL dose of 0.09 mg/kg of acepromazine. Blood and urine samples were collected at time 0 and at various times for up to 72 hr and analyzed for acepromazine and its two major metabolites (2-(1-hydroxyethyl) promazine and 2-(1-hydroxyethyl) promazine sulfoxide) using liqu...
DeBoer ML, Martinson KM, Pampusch MS, Hansen AM, Wells SM, Ward C, Hathaway M.Leucine has been shown to stimulate the mammalian/mechanistic target of rapamycin (mTOR) signaling pathway which plays numerous key regulatory roles in cell growth, survival, and metabolism including protein synthesis in a number of species. However, previous work with equine satellite cells has suggested distinct species differences in regards to physiological effects and the magnitude of responses to growth factors and regulators. Because there is limited research available regarding the role of leucine in regulating equine skeletal muscle protein synthesis, the objective of this study was t...
White SH, Warren LK.Exercise is associated with increased production of reactive oxygen species (ROS) as metabolism is upregulated to fuel muscle activity. If antioxidant systems become overwhelmed, ROS can negatively affect health and performance. Adaptation to exercise through regular training has been shown to improve defense against oxidative insult. Given selenium's role as an antioxidant, we hypothesized that increased Se intake would further enhance skeletal muscle adaptations to training. Quarter Horse yearlings (18 ± 0.2 mo; 402 ± 10 kg) were randomly assigned to receive either 0.1 or 0.3 mg Se/kg DM a...
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...
Waraksa E, Wójtowicz-Zawadka M, Kwiatkowska D, Jarek A, Małkowska A, Wrzesień R, Namieśnik J.A novel assay for the simultaneous determination of ibuprofen (IBU) and its four probable metabolites, 1-hydroxyibuprofen (1-OH IBU), 2-hydroxyibuprofen (2-OH IBU), 3-hydroxyibuprofen (3-OH IBU) and carboxyibuprofen (CBX IBU) in equine urine samples with the application of Gas Chromatography-Electron Ionization-Mass Spectrometry (GC-EI-MS) has been developed and elaborated. The new approach for sample preparation including minimizing matrix effects by the application of weak cation exchange solid-phase extraction together with strong cation exchange solid-phase extraction has been applied. The...
Anderson ST, Kidd LJ, Barton AJ, Greer RM.Breeding mares typically foal yearly. Little is known about the dynamics of maternal bone stores during gestation and lactation, the timing of any maternal bone mobilisation, re-accretion post-foaling, or the dynamics of bone metabolism in foals. We measured serum osteocalcin (OC) and serum pyridinoline (PYD) concentrations in 18 mares monthly from 6months gestation to foaling, and in both mares and foals for 4months after birth. From 6 to 11months of gestation, there was no change in mean monthly OC. Serum PYD increased between 7months gestation and foaling. After foaling, mean serum OC was l...
Marycz K, Michalak I, Kornicka K.Horses metabolic disorders have become an important problem of modern veterinary medicine. Pathological obesity, insulin resistance and predisposition toward laminitis are associated with Equine Metabolic Syndrome (EMS). Based on pathogenesis of EMS, dietary and cell therapy management may significantly reduce development of this disorder. Special attention has been paid to the diet supplementation with highly bioavailable minerals and mesenchymal stem cells (MSC) which increase insulin sensitivity. In nutrition, there is a great interests in natural algae enriched via biosorption process with...
Schwinn AC, Sauer FJ, Gerber V, Bruckmaier RM, Gross JJ.Cortisol levels reflect hypothalamic-pituitary-adrenocortical (HPA) axis activity. While most plasma cortisol is supposed to be bound to the soluble corticosteroid-binding globulin (CBG), only free cortisol (FC) actively regulates metabolic and immunological processes. We aimed to establish a multispecies suitable method to assess FC in cows and horses which in combination with total cortisol (TC) allows interpreting proportional changes of cortisol in saliva as well as in blood in response to a standardized HPA axis activation via ACTH. We further investigated if the ratios of cortisol fracti...
Szydlarska J, Weiss C, Marycz K.Methyl-β-cyclodextrin (MβCD) is a cyclic oligosaccharide, commonly used as a pharmacological agent to deplete membrane cholesterol. In this study, we examined the effect of MβCD on adipose-derived mesenchymal stromal cells (ASCs) isolated form healthy horses (ASC) and from horses suffering from metabolic syndrome (ASC). We investigated the changes in the mRNA levels of the glucose transporter 4 (GLUT4) and found that MβCD application may lead to a significant improvement in glucose transport in ASC. We also showed that MβCD treatment affected GLUT4 upregulation in an insulin-independent m...
Robles M, Nouveau E, Gautier C, Mendoza L, Dubois C, Dahirel M, Lagofun B, Aubrière MC, Lejeune JP, Caudron I, Guenon I, Viguié C, Wimel L....Obesity is a growing concern in horses. The effects of maternal obesity on maternal metabolism and low-grade inflammation during pregnancy, as well as offspring growth, metabolism, low-grade inflammation, testicular maturation and osteochondrotic lesions until 18 months of age were investigated. Twenty-four mares were used and separated into two groups at insemination according to body condition score (BCS): Normal (N, n = 10, BCS ≤4) and Obese (O, n = 14, BCS ≥4.25). BCS and plasma glucose, insulin, triglyceride, urea, non-esterified fatty acid, serum amyloid A (SAA), leptin and adiponect...
Newkirk KM, Ehrensing G, Odoi A, Boston RC, Frank N.OBJECTIVE To assess insulin, glucagon, and somatostatin expression within pancreatic islets of horses with and without insulin resistance. ANIMALS 10 insulin-resistant horses and 13 insulin-sensitive horses. PROCEDURES For each horse, food was withheld for at least 10 hours before a blood sample was collected for determination of serum insulin concentration. Horses with a serum insulin concentration 20 μU/mL underwent a frequently sampled IV glucose tolerance test to determine sensitivity to insulin by minimal model analysis. Horses with a sensitivity to insulin < 1.0 × 10 L•min•mU w...
Warnken T, Delarocque J, Schumacher S, Huber K, Feige K.Insulin dysregulation (ID) with basal or postprandial hyperinsulinemia is one of the key findings in horses and ponies suffering from the equine metabolic syndrome (EMS). Assessment of ID can easily be performed in clinical settings by the use of oral glucose challenge tests. Oral glucose test (OGT) performed with 1 g/kg bodyweight (BW) glucose administered via naso-gastric tube allows the exact administration of a defined glucose dosage in a short time. However, reliable cut-off values have not been available so far. Therefore, the aim of the study was to describe variations in insulin respo...
Wynn MAA, Ball BA, Legacki E, Conley A, Loux S, May J, Esteller-Vico A, Stanley S, Scoggin K, Squires E, Troedsson M.In the latter half of gestation in the mare, progesterone concentrations decline to near undetectable levels while other 5α-reduced pregnanes are elevated. Of these, 5α-dihydroprogesterone and allopregnanolone have been reported to have important roles in either pregnancy maintenance or fetal quiescence. During this time, the placenta is necessary for pregnane metabolism, with the enzyme 5α-reductase being required for the conversion of progesterone to 5α-dihydroprogesterone. The objectives of this study were to assess the effects of a 5α-reductase inhibitor, dutasteride on pregnane metab...
Soma LR, Robinson MA, You Y, Boston RC, Rudy J.Compartmental models were used to investigate the pharmacokinetics of intravenous (i.v.), oral (p.o.), and topical (TOP) administration of dimethyl sulfoxide (DMSO). The plasma concentration-time curve following a 15-min i.v. infusion of DMSO was described by a two-compartment model. Median and range of alpha (t ) and beta (t ) half-lives were 0.029 (0.026-0.093) and 14.1 (6.6-16.4) hr, respectively. Plasma concentration-time curves of DMSO following p.o. and TOP administration were best described by one-compartment absorption and elimination models. Following the p.o. administration, median a...
Berlin S, Wallstabe S, Scheuch E, Oswald S, Hasan M, Wegner D, Grube M, Venner M, Ullrich A, Siegmund W.Standard treatment of foals with severe abscessing lung infection caused by Rhodococcus equi using rifampicin and a macrolide antibiotic can be compromised by extensive inhibition and/or induction of drug metabolising enzymes (e.g. CYP3A4) and transport proteins (e.g. P-glycoprotein), as has been shown for rifampicin and clarithromycin. The combination of rifampicin with the new, poorly metabolised gamithromycin, a long-acting analogue of azithromycin and tulathromycin with lower pharmacokinetic interaction potential, might be a suitable alternative. Objective: To evaluate the pharmacokinetic ...
Ma Y, Ke C, Wan Z, Li Z, Cheng X, Wang X, Zhao J, Ma Y, Ren L, Han H, Zhao Y.The neonatal Fc receptor (FcRn) is involved in IgG metabolism and transport in placental mammals. However, whether FcRn is responsible for IgG transfer from maternal serum to colostrum/milk is controversial. Interestingly, large domestic animals, such as cows, pigs, sheep, and horses, in which passive IgG transfer is exclusively completed via colostrum/milk, all express an FcRn α-chain that is shorter in the cytoplasmic tail (CYT) than its counterparts in humans and rodents. To address whether the length variation has any functional significance, we performed in vitro experiments using the Tr...
Connysson M, Muhonen S, Jansson A.This study investigated the effects of transport and diet on metabolic response during a subsequent race-like test in Standardbred horses in training fed a forage-only diet and a 50:50 forage:oats diet. Six trained and raced Standardbred trotter mares were used. Two diets, 1 forage-only diet (FONLY) and 1 diet with 50% of DM intake from forage and 50% from oats (FOATS), were fed for two 29-d periods in a crossover design. At Day 21, the horses were subjected to transport for 100 km before and after they performed an exercise test (transport test [TT]). At Day 26, the horses performed a control...
Warzecha CM, Coverdale JA, Janecka JE, Leatherwood JL, Pinchak WE, Wickersham TA, McCann JC.The objective of this study was to determine bacterial community profiles of the equine cecum in response to abrupt inclusion of varying levels of dietary starch. Seven cecally cannulated Quarter Horse geldings (497 to 580 kg) were used in a crossover design with two 28-d periods and a 28-d washout between each. Horses were randomly assigned to dietary treatments consisting of a commercial concentrate offered as fed at either 0.6 (low starch [LS]) or 1.2% BW (high starch [HS]) daily that was divided into 2 meals at 12-h intervals. Prior to the start of each period, horses were allowed ad libit...
Yoshida T, Ohta Y.The experiment was conducted to estimate dietary threonine (Thr) requirement using plasma amino acid concentrations as a criterion in mature thoroughbreds. Four adult thoroughbreds were used, and a 4 × 4 Latin square design was used for four dietary Thr levels. Plasma Thr concentration was constant until 0.41%, and then increased rapidly with increasing dietary Thr levels. The Thr requirement was estimated to be 67% of lysine with plasma Thr concentration at four Thr levels.
Robles M, Dubois C, Gautier C, Dahirel M, Guenon I, Bouraima-Lelong H, Viguié C, Wimel L, Couturier-Tarrade A, Chavatte-Palmer P.Primiparous mares are known to produce smaller foals than multiparous mares. This difference seems to be partly explained by the reduced exchange surface and volume of the placental villi in primiparous compared to multiparous placentas. The effect of maternal parity on foals' post-natal growth, metabolism and sexual maturation, however, has been given little consideration. The objectives of this work were to analyse placental biometry and structure at term, growth of foals and yearlings, their metabolism and testicular maturation at one year of age. Twenty multiparous mares (M), aged over 6 y...
Donabédian M, van Weeren PR, Perona G, Fleurance G, Robert C, Léger S, Bergero D, Lepage O, Martin-Rosset W.Diagnosis of osteochondrosis (OC) is based on clinical signs and radiography, but alternative methods for detection at an early stage would be useful. Objective: To determine in the juvenile horse the relationship between serum concentrations of a number of biomarkers that reflect changes in cartilage and bone turnover and age, feeding level, growth, and the occurrence of OC. Methods: Foals were assigned to a high (n = 20) or moderate (n = 19) feeding level group from birth to age 1 year. Bodyweight, withers height and cannon width were measured. Osteoarticular status was assessed radiographic...
Rose RJ, Arnold KS, Church S, Paris R.Blood samples were taken from 20 horses competing in a 100 km endurance ride and plasma concentrations of sodium, potassium, chloride, bicarbonate and protein measured. Measurements were performed on samples taken before the ride (pre-ride), at the mid point and end of the ride and after a 30 min recovery period (post-ride). Sweat samples were collected from 6 horses competing in the endurance ride and 14 horses competing in a 3-day event competition and sweat concentrations of sodium, potassium and chloride measured. There were substantial decreases in plasma electrolyte concentrations, which...
Fenton JI, Chlebek-Brown KA, Peters TL, Caron JP, Orth MW.To determine whether glucosamine-3-sulfate, glucose-3-sulfate (control) and N-acetyl glucosamine inhibit experimentally induced degradation of equine articular cartilage explants similar to glucosamine HCl. Methods: Articular cartilage was obtained from the antebrachio-carpal and middle joints of horses (2-8 years old) killed for reasons unrelated to lameness. Cartilage discs were harvested from the weight-bearing region of the articular surface and cultured. Media were exchanged daily and the recovered media stored at 4 degrees C. On days 1 and 2 lipopolysaccharide (LPS, 10 microg/ml) was add...
Hussein HS, Vogedes LA, Fernandez GC, Frankeny RL.Twenty geldings (five groups; similar age and BW) were used in a completely randomized design experiment to determine effects of grain supplementation of an alfalfa-cube diet on apparent nutrient digestibility and hindgut fermentation. The geldings were housed individually, fed their diets in two equal meals (0600 and 1800), and adapted to five dietary treatments over 6 wk. The treatments were alfalfa cubes (1% of BW; DM basis) without (control) or with one of four rolled cereal grains (i.e., barley, corn, naked oats, or oats) to provide a target level of 0.4% of BW as total nonstructural carb...
Pagan JD, Hintz HF.Energy expenditure was measured in four geldings (433 to 520 kg) during submaximal exercise on a racetrack using a mobile open-circuit indirect respiration calorimeter. A total of 304 5-min measurements of O2 consumed and CO2 produced were taken. Measurements were made with and without riders. The amount of energy expended by the horses was exponentially related to speed and was proportional to the body weight of the riderless horse or the combined weight of the horse plus rider and tack. Total energy expended by the four horses walking, trotting, cantering was best described by the equation: ...
Rings LM, Swink JM, Dunbar LK, Burns TA, Toribio RE.The enteroinsular axis (EIA) comprises intestinal factors (incretins) that stimulate insulin release after PO ingestion of nutrients. Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the main incretins. The EIA has not been investigated in healthy neonatal foals but should be important because energy demands are high in healthy foals and dysregulation is frequent in sick foals. Objective: To evaluate the EIA response to carbohydrates or fasting in newborn foals. We hypothesized that incretin secretion would be higher after PO versus IV carbohydrate adm...
Gottlieb M, Essén-Gustavsson B, Lindholm A, Persson SG.Five Standardbred trotters were trained on a treadmill 3 times/wk for 12 wk by intervals of draft-loaded exercise. The draft load was 34 kp and the velocity approximately 7 m/s. Muscle biopsies were taken from the gluteus medius and longissimus muscles before training and after 2, 4, 8, and 12 wk of training and from the brachiocephalicus muscle before and after training. Both the percentage and the area of type IIa fibers increased and the percentage of type IIb fibers decreased in the gluteus medius muscle during the first 2 wk of training, and then no further significant difference was note...
Palmer J.Despite advances in neonatal intensive care sepsis, severe sepsis and septic shock remain the biggest killers of neonatal foals. Management of this severe syndrome remains difficult, requiring intensive intervention. Key aspects of management include infection control, hemodynamic support, immunomodulatory interventions, and metabolic/endocrine support. Infection control largely consists of early antimicrobial therapy, plasma transfusions, and local therapy for the infected focus. In cases with severe sepsis or septic shock, hemodynamic support with fluids, vasoactive agents, and respiratory s...
Berg EL, McNamara DL, Keisler DH.The aim of this study was to characterize concentrations of leptin, IGF-I, and thyroid stimulating hormone (TSH) in the blood serum of mares pre-and postpartum, in the milk serum of mares postpartum, and in the blood serum of their foals. Nine pregnant Quarter Horse mares and their offspring were used in this study. Once weekly between 1000 and 1200 h for 2 wk before their predicted parturition date, mares were weighed, assigned a BCS, and blood was sampled via jugular venipuncture. Within 2 h of parturition and before the foals nursed (d 0), blood samples were obtained from the mares and foal...
Lindholm A, Saltin B.LINDHOLM, ARNE and BENGT SALTIN: The physiological and biochemical response of standardbred horses to exercise of varying speed and duration. Acta vet. scand. 1974, 15, 310–324. — Welltrained standardbred horses were studied to examine the metabolic response to excercise of various speeds and duration. Comparisons between interval (400, 700, 1,000 and 2,000 m) and continuous trotting (1 hr., 2 hrs.) and racing were made. Muscle and rectal temperatures were recorded before and immediately after each work bout. Heart rate was linearly related to trotting speed, and maximal heart rate (240 be...
Chang M, Zhang F, Shen L, Pauss N, Alam I, van Breemen RB, Blond SY, Bolton JL.The risk factors for women developing breast and endometrium cancers are all associated with a lifetime of estrogen exposure. Estrogen replacement therapy (ERT) in particular has been correlated with a slight increased cancer risk, although the numerous benefits of ERT may negate this harmful side effect. Equilenin and equilin are equine estrogens which make up between 30% and 45% of the most widely prescribed estrogen replacement formulation, Premarin (Wyeth-Ayerst). In this study we have synthesized the catechol metabolites of equilenin [4-hydroxyequilenin (4-OHEN)] and equilin [4-hydroxyequ...
Tang L, Yan L, Jia H, Xiong Y, Ma X, Chu H, Sun Z, Wang L, Shalitanati M, Li K, Hu D, Zhang D.Host-associated microbiota can significantly impact host fitness. Therefore, naturally occurring variations in microbiota may influence the health and persistence of their hosts. This finding is particularly important in reintroduced animals, as they typically experience habitat changes during translocations. However, little is known about how microbiomes are altered in response to conservation translocation. Here, we accessed the gut microbiome of Przewalski's horse (Equus przewalskii) populations in China from three nature reserves (i.e. Xinjiang Kalamaili Nature Reserve, KNR; Dunhuang Xihu ...
Reisinger N, Schaumberger S, Nagl V, Hessenberger S, Schatzmayr G.Laminitis is one of the most common diseases in horses. It is not only painful for the animal, but also has a significant financial impact on the equine industry. This multifactorial disease affects the connective tissue of the hoof. However, the pathogenesis of laminitis is still not fully understood. Endotoxins, also known as lipopolysaccharides (LPS), and bacterial exotoxins seem to play an important role during the development of laminitis. The aim of our study was to investigate the effect of increasing LPS concentrations (0, 2.5, 5, 10, and 100 μg/mL) on cell viability of isolated epide...
Pösö AR, Viljanen-Tarifa E, Soveri T, Oksanen HE.Effects of graded intensity exercise on plasma lipids was studied in Standardbred and Finnishbred Trotters. The rate of lipolysis indicated by the elevated plasma concentrations of glycerol increased parallel with the intensity of the trot in the Standardbreds, but not as clearly in the Finnishbred trotters. During the exercise plasma triglyceride concentration increased significantly and the increase correlated with the intensity of the exercise as well as the activity of lipolysis. Together with the increase in plasma triglycerides, there was a parallel increase in the pre-beta fraction of l...
Karlíková R, Široká J, Jahn P, Friedecký D, Gardlo A, Janečková H, Hrdinová F, Drábková Z, Adam T.Atypical myopathy (AM) is a potentially fatal disease of grazing horses. It is reportedly caused by the ingestion of sycamore seeds containing toxic hypoglycin A. In order to study metabolic changes, serum and urine samples from nine horses with atypical myopathy and 12 control samples from clinically healthy horses were collected and then analysed using a high-performance liquid chromatography coupled with tandem mass spectrometry; serum metabolic profiles as the disease progressed were also studied. Metabolic data were evaluated using unsupervised and supervised multivariate analyses. Signif...
González-Fernández L, Sánchez-Calabuig MJ, Alves MG, Oliveira PF, Macedo S, Gutiérrez-Adán A, Rocha A, Macías-García B.Equine cumulus-oocyte complexes (COCs) are classified as compact (cCOC) or expanded (eCOC) and vary in their meiotic competence. This difference could be related to divergent glucose metabolism. To test this hypothesis in the present study, eCOCs, cCOCs and expanded or compact mural granulosa cells (EC and CC respectively) were matured in vitro for 30h, at which time maturation rate, glucose metabolism and the expression of genes involved in glucose transport, glycolysis, apoptosis and meiotic competence were determined. There were significant differences between eCOCs and cCOCs in maturation ...
Rose RJ, Hendrickson DK, Knight PK.To evaluate normal cardiorespiratory and metabolic responses of Thoroughbred horses to a standardised treadmill exercise test, we examined 28 horses ranging in age from 1 to 4 years. The group consisted of eight yearlings, eight 2-year-olds and twelve 3 and 4-year-olds. All horses except the yearlings were in training, and either racing or ready to race, at the time of examination. None of the horses had histories of performance problems. On the first day the horses received a full physical examination, resting electrocardiogram, upper respiratory tract endoscopy and either one or two acclimat...
Moore JN, Hardee MM, Hardee GE.Two cyclooxygenase inhibitors (flunixin meglumine and phenylbutazone) and a selective thromboxane synthetase inhibitor were assessed in the management of experimental equine endotoxemia. Drugs or saline solution were administered to 16 horses 15 minutes before administration of a sublethal dose of endotoxin (Escherichia coli 055:B5). Plasma concentrations of thromboxane B2 (TxB2), prostacyclin (6-keto PGF1 alpha), plasma lactate, and hematologic values and clinical appearance were monitored for 3 hours after endotoxin administration. Pretreatment with flunixin meglumine (1 mg/kg of body weight...
Karlström K, Essén-Gustavsson B, Lindholm A.Samples were taken at slaughter from heart and both locomotor and nonlocomotor muscles from animals of similar body weight but adapted to different levels of activity: three horses and three steers. All samples were analyzed biochemically to measure the activity of key metabolic enzymes. The skeletal muscles were analyzed histochemically for fibre type composition, fibre area and capillary supply. The general pattern of differences in fibre type composition and metabolic profile between muscle groups was similar in both horses and steers. The hearts of both species had high citrate synthase (C...
Anderson MG.A group of clinically normal horses was subjected to controlled strenuous exercise. Elevated serum concentrations of lactic dehydrogenase, aldolase and creatine kinase were observed after exercise but no significant change in serum glutamic-oxalacetic transaminase was noted. These changes were reduced by repeated exposure to exercise suggesting that measurement of serum enzyme elevations, particularly creatine kinase, might be a useful index of fitness in the horse. Administration of prednisolone prior to exercise also reduced these changes. Since the serum enzyme concentrations had returned t...
Robie SM, Janson CH, Smith SC, O'Connor JT.Concentrations of serum phospholipids, triglycerides, total cholesterol, nonesterified fatty acids, and glucose were determined for 9 months (September, 1972, to May, 1973) in 19 fasting horses and ponies (8 Morgan horses, 7 Thoroughbred horses, and 4 Shetland Ponies). Morgan horses had higher concentrations of total lipid than did Thoroughbreds, although the relative proportions of each type of lipid were similar in the 2 breeds. Shetland Ponies had higher nonesterified fatty acid and lower glucose concentrations than did either breed of horse. In both breeds of horses, concentrations of seru...
Suagee JK, Corl BA, Hulver MW, McCutcheon LJ, Geor RJ.Plasma insulin concentrations are elevated (hyperinsulinemia) in horses with obesity-associated insulin resistance. In other species, insulin resistance is partly due to reduced levels of insulin receptor and the insulin-sensitive glucose transporter, and, in vitro, chronic hyperinsulinemic conditions reduce the expression of these proteins. Consumption of grain-based concentrate feeds results in postprandial hyperinsulinemia in horses, and adaptation to these diets is associated with insulin resistance. As such, it is possible that the repeated, chronic postprandial hyperinsulinemia associate...
Lakritz J, Winder BS, Noorouz-Zadeh J, Huang TL, Buckpitt AR, Hammock BD, Plopper CG.To determine hepatic and pulmonary phase-I and phase-II enzyme activities in horses. Methods: Pulmonary and hepatic tissues from 22 horses that were 4 months to 32 years old. Methods: Pulmonary and hepatic tissues from horses were used to prepare cytosolic (glutathione S-transferase and soluble epoxide hydrolase) and microsomal (cytochrome P450 monooxygenases) enzymes. Rates of microsomal metabolism of ethoxyresorufin, pentoxyresorufin, and naphthalene were determined by high-performance liquid chromatography. Activities of glutathione S-transferase and soluble epoxide hydrolase were determine...
Wilson G, Chester N, Eubank M, Crighton B, Drust B, Morton JP, Close GL.Professional jockeys are unique among weight-making athletes, as they are often required to make weight daily and, in many cases, all year-round. Common methods employed by jockeys include dehydration, severe calorie restriction, and sporadic eating, all of which have adverse health effects. In contrast, this article outlines a structured diet and exercise plan, employed by a 22-yr-old professional National Hunt jockey in an attempt to reduce weight from 70.3 to 62.6 kg, that does not rely on any of the aforementioned techniques. Before the intervention, the client's typical daily energy intak...
Dunnett M, Harris RC, Orme CE.A simple, robust and reproducible analytical method for the determination of phosphocreatine (PCr), creatine (Cr) and creatinine (Cn) in equine skeletal muscle is presented. The technique used isocratic reverse-phase ion-pairing high-performance liquid chromatography. Neutralized perchloric acid extracts of equine muscle biopsies were analysed and the values obtained were compared with determinations from an established enzymic procedure. Good resolution of all three metabolites was achieved within a retention time of less than 11 min. Linearity for each metabolite within the concentration ran...
Bramer SA, Macedo A, Klein C.Secretion of histotroph during the prolonged pre-implantation phase in mares is crucial to pregnancy maintenance, manifested as increased embryonic loss in mares with age-related endometrial degeneration. Glycogen content of uterine histotroph is higher during the progesterone-dominated phase of the estrous cycle in mares, but regulatory mechanisms are not well understood. Methods: mRNA expression of glycogen-metabolizing enzymes (HK1, HK2, GSK3B, GYS1, PEPCK, PKM, PYGM) in endometrial samples were compared among mares in anestrus, estrus, and at Day 12 of diestrus and pregnancy. In addition, ...
Gulmez C, Atakisi O.It was aimed to investigate the effects of kumiss a fermented mare horse beverage on the sirtuin deacetylases in the oxidative stress which had been induced by 1,2-dimethyl hydrazine (DMH). Forty BALB/C male mice were divided into four groups as control, kumiss (2 × 10 cfu/mL), DMH (20 mg/kg), and kumiss + DMH (2 × 10 cfu/mL + 20 mg/kg). At the end of 20-week regimen, SIRT2, SIRT3 protein expressions by western blotting, immunolocalizations, and inhibitory anti-oxidant activity analysis in liver, colon, and kidney tissues were performed. SIRT2 and SIRT3 expressions in DMH g...
Ohmura H, Mukai K, Takahashi Y, Takahashi T.Thoroughbreds have high maximal oxygen consumption and show hypoxemia and hypercapnia during intense exercise, suggesting that the peripheral environment in skeletal muscle may be severe. Changes in metabolites following extreme alterations in the muscle environment in horses after exercise may provide useful evidence. We compared the muscle metabolites before and after supramaximal exercise to fatigue in horses. Six well-trained horses ran until exhaustion in incremental exercise tests. Biopsy samples were obtained from the gluteus medius muscle before and immediately after exercise for capil...
Schryver HF, Parker MT, Daniluk PD, Pagan KI, Williams J, Soderholm LV, Hintz HF.The voluntary salt consumption of mature unexercised horses was measured weekly for up to 45 weeks. Voluntary intake among horses was quite variable ranging from 19 to 143 g of salt per day and was inversely related to total salt intake (salt in feeds plus voluntary intake). Mean daily voluntary salt consumption was 53 g. Season of the year did not influence voluntary intake. In preference tests which evaluated every two choice combination of 0.2% and 4% NaCl in test diets fed daily for four days, ponies generally preferred diets containing the lower amount of salt. In similar preference studi...
Brøkner C, Austbø D, Næsset JA, Blache D, Bach Knudsen KE, Tauson AH.The hypothesis for this study was that a higher dietary proportion of soluble fibre would result in stable and constant plasma metabolite and regulatory hormone concentrations. The study was a 4×4 Latin Square design with a sequence of 17 days adaptation to the ration followed by 8 sampling days. The feed rations consisted of only timothy hay (H), hay plus molassed sugar beet pulp combined with either whole oats (OB) or barley (BB) and hay plus a loose chaff-based concentrate (M). Four horses were fitted with permanent caecal cannulas and liquid caecal content was withdrawn manually and blood...
