Omneity® Pellets
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Topic:Metabolism
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.
Structural elucidation of phase I and II metabolites of bupivacaine in horse urine and fungi of the Cunninghamella species using liquid chromatography/multi-stage mass spectrometry. Bupivacaine is a local anaesthetic prohibited in equine sports. It is highly metabolized in the horse but a thorough description of its metabolite profile is lacking. An administration study should find appropriate analytical targets for doping control. Furthermore, knowledge of an in vitro system for production of metabolites would be beneficial. Methods: Marcain® (bupivacaine hydrochloride) was administered subcutaneously to a horse and urine samples were collected. In vitro metabolic systems consisting of the fungi Cunninghamella elegans and Cunninghamella blakesleeana were incubated with ...
A forage-only diet alters the metabolic response of horses in training. Most athletic horses are fed a high-starch diet despite the risk of health problems. Replacing starch concentrate with high-energy forage would alleviate these health problems, but could result in a shift in major substrates for muscle energy supply from glucose to short-chain fatty acids (SCFA) due to more hindgut fermentation of fibre. Dietary fat inclusion has previously been shown to promote aerobic energy supply during exercise, but the contribution of SCFA to exercise metabolism has received little attention. This study compared metabolic response with exercise and lactate threshold (VLa...
Expression of sweet receptor components in equine small intestine: relevance to intestinal glucose transport. The heteromeric sweet taste receptor T1R2-T1R3 is expressed on the luminal membrane of certain populations of enteroendocrine cells. Sensing of sugars and other sweet compounds by this receptor activates a pathway in enteroendocrine cells, resulting in secretion of a number of gut hormones, including glucagon-like peptide 2 (GLP-2). This subsequently leads to upregulation in the expression of intestinal Na(+)/glucose cotransporter, SGLT1, and increased intestinal glucose absorption. On the basis of the current information available on the horse genome sequence, it has been proposed that the ge...
Evaluation of coronary band temperatures in healthy horses. To measure coronary band temperature (CBT) in healthy horses fed high-fructan or low-carbohydrate diets and to analyze the association of CBT with diet, time of day, and ambient temperature. Methods: 6 healthy horses. Methods: Horses were fed 3 diets (treatment 1, 1 g of fructan/kg fed daily in the morning; treatment 2, 1 g of fructan/kg fed daily in the afternoon; and treatment 3, a low-carbohydrate [7.2%] diet) in a 3 × 3 Latin square study design. For each horse, the CBT of all 4 limbs as well as rectal and ambient temperatures were recorded by use of infrared thermometry and standard ther...
Plasma protein changes in horse after prolonged physical exercise: a proteomic study. Physical exercise induces various stress responses and metabolic adaptations that have not yet been completely elucidated. Novel biomarkers are needed in sport veterinary medicine to monitor training levels and to detect subclinical conditions that can develop into exercise-related diseases. In this study, protein modifications in horse plasma induced by prolonged, aerobic physical exercise were investigated by using a proteomic approach based on 2-DE and combined mass spectrometry procedures. Thirty-eight protein spots, associated with expression products of 13 genes, showed significant quant...
Acepromazine pharmacokinetics: a forensic perspective. Acepromazine (ACP) is a useful therapeutic drug, but is a prohibited substance in competition horses. The illicit use of ACP is difficult to detect due to its rapid metabolism, so this study investigated the ACP metabolite 2-(1-hydroxyethyl)promazine sulphoxide (HEPS) as a potential forensic marker. Acepromazine maleate, equivalent to 30mg of ACP, was given IV to 12 racing-bred geldings. Blood and urine were collected for 7days post-administration and analysed for ACP and HEPS by liquid chromatography-mass spectrometry (LC-MS). Acepromazine was quantifiable in plasma for up to 3h with little r...
Physical fitness and mitochondrial respiratory capacity in horse skeletal muscle. Within the animal kingdom, horses are among the most powerful aerobic athletic mammals. Determination of muscle respiratory capacity and control improves our knowledge of mitochondrial physiology in horses and high aerobic performance in general. Results: We applied high-resolution respirometry and multiple substrate-uncoupler-inhibitor titration protocols to study mitochondrial physiology in small (1.0-2.5 mg) permeabilized muscle fibres sampled from triceps brachii of healthy horses. Oxidative phosphorylation (OXPHOS) capacity (pmol O(2) • s(-1) • mg(-1) wet weight) with combined Complex...
Supplementation of Ascorbic Acid in Weanling Horses Following Prolonged Transportation. Though horses synthesize ascorbic acid in their liver in amounts that meet their needs under normal circumstances, prolonged stress results in low plasma concentrations due to enhanced utilization and renal excretion and can reduce immune function. It was hypothesized that plasma ascorbic acid could be maintained in weanling horses by oral supplementation following prolonged transportation. Weanlings were supplemented with no ascorbic acid (Tx 0: n = 4), 5 grams ascorbic acid twice daily for 5 days (Tx 1: n = 4) or for 10 days (Tx 2: n = 4) following >50 hours of transportation. Supplementa...
Plasma leptin concentration in donkeys. Donkeys appear to be more predisposed than large breed horses to suffer from hyperlipemia. The reason for that predisposition is unknown but anorexia is a consistent feature of the disease. Leptin, a protein synthesized in fat tissue, is one of the major inhibitors of appetite in mammals. Objective: We hypothesized that donkeys could have elevated plasma leptin concentrations compared to horses. Methods: Blood samples were obtained from 50 donkeys for measurement of leptin, triglycerides (TGs), glucose, and insulin. Glucose/insulin ratio, modified insulin to glucose ratio, and reciprocal of th...
An altered hormonal profile and elevated rate of bone loss are associated with low bone mass in professional horse-racing jockeys. Horse-racing jockeys are a group of weight-restricted athletes, who have been suggested as undertaking rapid and extreme weight cycling practices in order to comply with stipulated body-mass standards. The aim of this study was to examine bone mass, turnover and endocrine function in jockeys and to compare this group with age, gender and body mass index matched controls. Twenty male professional jockeys and 20 healthy male controls participated. Dual energy X-ray absorptiometry scans and early morning fasting blood and urine samples were used to measure bone mass, turnover and a hormonal profi...
Voluntary feed intake and leptin sensitivity in ad libitum fed obese ponies following a period of restricted feeding: a pilot study. The relation between plasma leptin and daily ad libitum roughage intake was evaluated during a 14-day period in eight obese Shetland ponies. When the feeding strategy was changed from maintenance feeding to ad libitum feeding, feed intake increased the first day, decreased the second day and increased again during the following days to reach a constant level after 8 days. Plasma leptin concentration increased during the first 2 days, but remained constant afterwards. Although the same pattern was found in all ponies, the magnitude of the increase in leptin on day 1 and the resulting decrease i...
Changes in heart rate, heart rate variability, and atrioventricular block during withholding of food in Thoroughbreds. To determine whether withholding of food affects autonomic nervous system balance by analysis of heart rate (HR), HR variability (HRV), and frequency of second-degree atrioventricular block in horses. Methods: 5 healthy Thoroughbreds. Methods: For two 24-hour periods in a crossover study, food was withheld from horses or horses were maintained on their regular feeding schedule (control conditions) in their stalls and Holter monitor ECG recordings were obtained. The ECGs were analyzed by use of fast-Fourier transformation, and power spectrum densities were calculated for low-frequency (0.01 to ...
Myosin heavy chain pattern in the Akhal-Teke horses. This study investigates the myosin heavy chain (MyHC) isoform composition in the gluteus medius muscle of the Akhal-Teke horses using SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis). Fifteen horses aged between 1.5 and 23.5 years were used in this study and divided into three age groups: 1.5 to 4 (n = 6), 9 to 13 (n = 5) and 18.5 to 23.5 years (n = 4). The average content of the MyHC I isoform was 11.72 ± 1.07% (variation between individuals: 7.09% to 20.14%). The relative content of the MyHC IIa and IIx isoforms was subsequently 38.20 ± 1.46% (30.73% to 48.78%) and 50.0...
Serum lipid and lipoprotein patterns of Iranian horses. Patterns of serum biochemical parameters vary among horse breeds. The objective of the present study was to compare serum lipoproteins of Iranian Caspian ponies with those of other horses (Arabs and Thoroughbreds) in the Iranian region. Serum lipoprotein values were determined by agar-agarose gel electrophoresis and measured by scan densitometry. Moreover, serum triglyceride and cholesterol concentrations were determined and the results were analysed by one-way analysis of variance. Serum triglyceride and cholesterol values were 1.13 +/- 0.23 and 2.38 +/- 0.18 mmol/l in Caspian ponies, 1.96 +/...
The hour of transition into luteolysis in horses and cattle: a species comparison. Hourly blood sampling in both horses and cattle indicate that the transition between the end of preluteolysis and the beginning of luteolysis occurs within 1 h, as manifested by a change in progesterone concentrations. Each species presents a separate temporality enigma on the relationship between pulses of a prostaglandin (PG) F2α metabolite (PGFM) and the hour of the progesterone transition. In horses, relatively small pulses of PGFM occur during preluteolysis (before transition) and at transition. Oxytocin, but not estradiol, increases and decreases concomitantly with the small PGFM pulse ...
Adaptation strategies to seasonal changes in environmental conditions of a domesticated horse breed, the Shetland pony (Equus ferus caballus). Recent results suggest that the wild ancestor of the horse, the Przewalski horse, exhibits signs of a hypometabolism. However, there are speculations that domestic animals lost the ability to reduce energy expenditure during food shortage and adverse environmental conditions. Therefore, we investigated physiological and behavioural strategies employed by a robust domesticated horse breed, the Shetland pony, over the course of a year under temperate conditions by measuring ambient temperature (T(a)), subcutaneous temperature (T(s)), locomotor activity (LA), lying time, resting heart rate, body ...
Effect of different blood-guided conditioning programmes on skeletal muscle ultrastructure and histochemistry of sport horses. The effects of three different blood-guided conditioning programmes on ultrastructural and histochemical features of the gluteus medius muscle of 2-year-old sport horses were examined. Six non-trained Haflinger horses performed three consecutive conditioning programmes of varying lactate-guided intensities [velocities eliciting blood lactate concentrations of 1.5 (v1.5 ), 2.5 (v2.5 ) and 4 (v4 ) mm respectively] and durations (25 and 45 min). Each conditioning programme lasted 6 weeks and was followed by a 5-week resting period. Pre-, post- and deconditioning muscle biopsies were analyse...
Change of Ferritin-binding Activity in the Serum of Foal after Birth. In mammal circulation, various ferritin-binding proteins (FBPs) are thought to be involved in the clearance of circulating ferritin after complex formation with it. However, horse FBPs are known to cause inhibitory effects on ferritin immunoassay due to the concealment of the ferritin molecule to anti-ferritin antibodies used in the ferritin immunoassay. These inhibitory effects are eliminated by heat treatment of horse serum at 75°C for 15 min. The inhibitory effects on ferritin immunoassay in the sera of ten foal sera (5 females and 5 males) from 1 to 18 months were detected during all peri...
Optimizing human in vivo dosing and delivery of β-alanine supplements for muscle carnosine synthesis. Interest into the effects of carnosine on cellular metabolism is rapidly expanding. The first study to demonstrate in humans that chronic β-alanine (BA) supplementation (~3-6 g BA/day for ~4 weeks) can result in significantly augmented muscle carnosine concentrations (>50%) was only recently published. BA supplementation is potentially poised for application beyond the niche exercise and performance-enhancement field and into other more clinical populations. When examining all BA supplementation studies that directly measure muscle carnosine (n=8), there is a significant linear correlation...
Long term intensive exercise training leads to a higher plasma malate/lactate dehydrogenase (M/L) ratio and increased level of lipid mobilization in horses. Continuous high intensity training may induce alterations to enzyme activities related to glucose and lipid metabolism in horses. In our study, five Thoroughbred race horses (3 male and 2 female, avg age=5 yrs old) were compared against five riding horses (1 male, 1 female, 3 gelding, avg age=13 yrs old) in terms of energy metabolism, by examining plasma malate (MDH) and lactate (LDH) dehydrogenase activities and M/L ratio. MDH is involved in NADH and ATP generation, whereas LDH can convert NADH back into NAD(+) for ATP generation. An increase in plasma M/L ratio can reflect heightened energy ...
Repeated post-exercise administration with a mixture of leucine and glucose alters the plasma amino acid profile in Standardbred trotters. The branched chain amino acid leucine is a potent stimulator of insulin secretion. Used in combination with glucose it can increase the insulin response and the post exercise re-synthesis of glycogen in man. Decreased plasma amino acid concentrations have been reported after intravenous or per oral administration of leucine in man as well as after a single per oral dose in horses. In man, a negative correlation between the insulin response and the concentrations of isoleucine, valine and methionine have been shown but results from horses are lacking. This study aims to determine the effect of ...
Physiological changes in jeju crossbred riding horses by swim training. The changes in physiologic parameters by swim exercise duration were examined in five female well-trained Jeju crossbred riding horses that had riding experience of more than three years without swim training experience. The horses were performed with swim exercise for 10 min (60.0 m/min) once a day for 14 days. Physiologic characteristics and haematic parameters were measured before swimming, immediately after swimming, and after a 10 min rest at first day (D0), 7 days (D7), and 14 days (D14) of training. After 14 days of swim training, heart rate (p<0.05), blood glucose (p<0.05), lacta...
Differential gene expression of CYP3A isoforms in equine liver and intestines. Recently, seven CYP3A isoforms - CYP3A89, CYP3A93, CYP3A94, CYP3A95, CYP3A96, CYP3A97 and CYP129 - have been isolated from the horse genome. In this study, we have examined the hepatic and intestinal gene expression of these CYP3A isoforms using TaqMan probes. We have also studied the enzyme activity using luciferin-isopropyl acetal (LIPA) as a substrate. The results show a differential gene expression of the CYP3A isoforms in the liver and intestines in horses. In the liver, CYP3A89, CYP3A94, CYP3A96 and CYP3A97 were highly expressed, while in the intestine there were only two dominating isof...
Fermentation of six different forages in the semi-continuous fermentation technique Caesitec. The aim of the present study was to compare carbohydrate degradation of forages which store carbohydrates either predominantly as fructan or starch, in horses' hindgut. The effects of an abrupt change from hay-based feeding to green fodder-based feeding on the caecal flora were tested with the in vitro hindgut simulation technique 'Caesitec'. Six trials with different forages (English ryegrass, tall fescue, grass mixture-horses, grass mixture-cows, lucerne, white clover) were conducted. During a 4-day stabilisation period, samples were taken once a day before loading the fermenters with hay. A...
Synovial fluid chondroitin sulphate indicates abnormal joint metabolism in asymptomatic osteochondritic horses. Alternative methods to evaluate the joint condition in asymptomatic osteochondrosis dissecans (OCD) and other joint diseases may be useful. Objective: To investigate possible changes in synovial fluid composition that may lead to joint conditions in asymptomatic OCD, in mature horses. Methods: Animals aged >2 years, of different breeds, with OCD in the intermediate ridge of distal tibia, symptomatic or not, were studied. Synovial fluid samples (10 healthy; 11 asymptomatic OCD; 25 symptomatic OCD) were collected by arthroscopy from 29 horses. Glycosaminoglycans (GAGs) were analysed by a comb...
The influence of road transport on the activities of glutathione reductase, glutathione peroxidase, and glutathione-S-transferase in equine erythrocytes. Transport of horses may have significant impact on serum biochemical and hematologic analytes and resistance to infection. Objective: The aim of our study was to assess the influence of transport stress on selected enzymatic antioxidants in equine blood. Methods: The study was conducted on a group of 60 horses of different breeds and ranging in age from 4 to 10 years. Venous blood was collected immediately before loading horses onto trailers for 8 hours of transport (I), immediately after unloading them from the trailer (II), and after subsequent stall rest for 24 hours (III). Hemolysates of b...
Amino acid supplementation does not alter whole-body phenylalanine kinetics in Arabian geldings. Stable isotope infusion methods have not been extensively used in horses to study protein metabolism. The objectives were to develop infusion and sampling methodologies for [1-(13)C] phenylalanine and apply these methods to determine whether the addition of supplemental amino acids to a control diet affected whole-body phenylalanine kinetics in mature horses. Arabian geldings were studied using a 6-h primed (9 μmol/kg), constant (6 μmol · kg(-1) · h(-1)) i.v. infusion of L-[1-(13)C] phenylalanine, with blood and breath sampled every 30 min, to measure whole-body phenylalanine kinet...
