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Topic:Biochemistry
The study of biochemistry in horses encompasses the chemical processes and substances that occur within equine organisms. This field investigates the molecular interactions and pathways that are fundamental to horse physiology, including metabolism, enzyme activity, and genetic expression. Key areas of interest include the examination of metabolic disorders, nutrient absorption, and the biochemical basis of muscle function and energy production. Researchers utilize biochemical analysis to understand health and disease mechanisms in horses, contributing to the development of diagnostic tools and therapeutic strategies. This page gathers peer-reviewed studies and scholarly articles that explore various biochemical processes and their implications for equine health and performance.
Submaximal exercise training, more than dietary selenium supplementation, improves antioxidant status and ameliorates exercise-induced oxidative damage to skeletal muscle in young equine athletes. 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...
Lactoferrin increases sperm membrane functionality of frozen equine semen. During cryopreservation, sperm was submitted to an increase in reactive oxygen species generation. This work aimed to improve the quality of frozen equine sperm after the addition of antioxidants lactoferrin (Lf) and catalase (Cat) to a freezing extender. Semen from six stallions was frozen with the extenders: F1) control, INRA 82 freezing extender, F2) F1 + 500 μg/ml Lf and F3) F1 + 200 IU/ml Cat. After thawing, sperm motility parameters, membrane functionality and integrity, and acrosome integrity and spontaneous acrosome-reacted sperm were evaluated with a computer-assisted sperm anal...
Chondrogenic Differentiation of Defined Equine Mesenchymal Stem Cells Derived from Umbilical Cord Blood for Use in Cartilage Repair Therapy. Cartilage engineering is a new strategy for the treatment of cartilage damage due to osteoarthritis or trauma in humans. Racehorses are exposed to the same type of cartilage damage and the anatomical, cellular, and biochemical properties of their cartilage are comparable to those of human cartilage, making the horse an excellent model for the development of cartilage engineering. Human mesenchymal stem cells (MSCs) differentiated into chondrocytes with chondrogenic factors in a biomaterial appears to be a promising therapeutic approach for direct implantation and cartilage repair. Here, we cha...
Enterocin M and its Beneficial Effects in Horses-a Pilot Experiment. 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...
Constituents of neutrophil extracellular traps induce in vitro collagen formation in mare endometrium. Neutrophil extracellular traps (NETs) are DNA complexes carrying nuclear and cytoplasmic proteins, such as elastase (ELA), cathepsin-G (CAT) and myeloperoxidase (MPO). Mare endometrosis is a chronic degenerative process characterized by excessive collagen in endometrium. While NETs fight bacteria that cause endometritis, they may trigger endometrial fibrogenesis. The aim was to evaluate the in vitro effect of some NETs components on mare endometrial fibrogenesis and determine its relationship with histopathology or estrous cycle. Endometrial explants were incubated with NETs components (ELA, ...
Plasma adrenocorticotropic hormone (ACTH) concentrations in ponies measured by two different assays suggests seasonal cross-reactivity or interference. Analysis of plasma adrenocorticotropic hormone concentration [ACTH] aids diagnosis of pituitary pars intermedia dysfunction (PPID). Comparisons of the validated chemiluminescent-immunoassay (CI) and immunofluorescent (IF) assays are limited. Objective: To compare the results of [ACTH] analysis by CI and IF methods of samples collected in autumn and spring and assess cross-reactivity. Methods: Method comparison. Methods: Plasma from nonlaminitic ponies was analysed concurrently using the IF and CI methods in autumn and the following spring. Diagnostic thresholds for the IF method were derived u...
Evaluation of conjugated linoleic acid supplementation on markers of joint inflammation and cartilage metabolism in young horses challenged with lipopolysaccharide. Seventeen yearling Quarter Horses were used in a randomized complete block design for a 56-d trial to determine ability of dietary CLA to mitigate joint inflammation and alter cartilage turnover following an inflammatory insult. Horses were blocked by age, sex, and BW, and randomly assigned to dietary treatments consisting of commercial concentrate offered at 1% BW (as-fed) supplemented with either 1% soybean oil (CON; n = 6), 0.5% soybean oil and 0.5% CLA (LOW; n = 5; 55% purity; Lutalin, BASF Corp., Florham Park, NJ), or 1% CLA (HIGH; n = 6) top-dressed daily. Horses were fed individually ev...
Enhancing the dissolution of phenylbutazone using Syloid® based mesoporous silicas for oral equine applications. Three mesoporous silica excipients (Syloid® silicas AL-1 FP, XDP 3050 and XDP 3150) were formulated with a model drug known for its poor aqueous solubility, namely phenylbutazone, in an attempt to enhance the extent and rate of drug dissolution. Although other forms of mesoporous silica have been investigated in previous studies, the effect of inclusion with these specific Syloid® silica based excipients and more interestingly, with phenylbutazone, is unknown. This work reports a significant enhancement for both the extent and rate of drug release for all three forms of Syloid® silica at a ...
Serum bone biomarkers osteocalcin and pyridinoline in mares during pregnancy and lactation, and in foals during early post-natal life. 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...
The Effect of Methyl-β-cyclodextrin on Apoptosis, Proliferative Activity, and Oxidative Stress in Adipose-Derived Mesenchymal Stromal Cells of Horses Suffering from Metabolic Syndrome (EMS). 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...
Use of split-free nano-liquid chromatography-mass spectrometry/high resolution mass spectrometry interface to improve the detection of α-cobratoxin in equine plasma for doping control. Cobra (Naja naja kaouthia) venom contains a toxin called α-cobratoxin (α-Cbtx) containing 71 amino acids (MW 7821 Da) with a reported analgesic power greater than morphine. In 2013, the first analytical method for the detection of α-Cbtx in equine plasma was developed by Bailly-Chouriberry et al, allowing the confirmation of the presence of α-Cbtx at low concentrations (1-5 ng/mL or 130-640 fmol/mL) in plasma samples. To increase the method sensitivity and therefore to improve the detection of α-Cbtx in post-administration plasma samples, a nano-liquid chromatography-mass spectrometry/hi...
Interaction between the sequence of feeding of hay and concentrate, and boiling of barley on feed intake, the activity of hydrolytic enzymes and fermentation in the hindgut of Arabian mares. The interaction between the sequence of feeding of hay and concentrate and the hydrothermal processing of barley in alleviating concentrate effects on intake, and hindgut fermentation in horses was tested. Six Arabian mares (4-10 years of age, 410 ± 35 kg body weight) were used to evaluate the effects of feeding sequence (FS) and type of barley (TB) on intake, and faecal volatile fatty acids (VFA), activities of α-amylase (AA: EC 3.2.1.1), carboxymethyl cellulase (CMCase: EC 3.2.1.4), microcrystalline cellulase (MCCase: EC 3.2.1.91) and general filter paper degrading activity (FPD). Mare...
Immunohistochemical expression of insulin, glucagon, and somatostatin in pancreatic islets of horses with and without insulin resistance. 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...
Modulation of chaperone-like and membranolytic activities of major horse seminal plasma protein HSP-1/2 by L-carnitine. The major protein of horse seminal plasma, HSP-1/2, exhibits membranolytic and chaperone-like activities and plays a crucial role in regulating sperm capacitation. L-Carnitine is a small polar molecule present in high concentrations in mammalian seminal plasma. The present results demonstrate that L-carnitine binds to HSP-1/2 and increases its thermal stability, enhances cooperativity of its chemical unfolding and decreases both chaperone-like and membranolytic activities of this protein. The HSP-1/2-L-carnitine complex exhibits anti-oxidative behaviour by inhibiting the production of hydroxyl...
Prospective pre- and post-race evaluation of biochemical, electrophysiologic, and echocardiographic indices in 30 racing thoroughbred horses that received furosemide. Exercise induced cardiac fatigue (EICF) and cardiac dysrhythmias are well described conditions identified in high-level human athletes that increase in frequency with intensity and duration of exercise. Identification of these conditions requires an understanding of normal pre- and post-race cardiac assessment values. The objectives of this study were to (1) characterize selected indices of cardiac function, electrophysiologic parameters, and biochemical markers of heart dysfunction prior to and immediately after high level racing in Thoroughbred horses receiving furosemide; and (2) create pre...
Inhibition of 5α-reductase alters pregnane metabolism in the late pregnant mare. 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...
Survey on basal blood plasma catecholamine concentrations in Martina Franca donkey (Equus asinus). Catecholamines are among the most frequently investigated parameters for studying sympathoadrenal activity in response to stress conditions. Objective: To evaluate basal plasma concentrations of catecholamines (adrenaline, noradrenaline and dopamine) in healthy donkeys. Methods: Cross-sectional study. Methods: Catecholamine concentrations from 440 Martina Franca donkeys were determined: 269 females and 171 entire males, aged from 4 months to 24 years. Animals were subdivided into four age categories: under 12 months old (64 males and 54 females), from 13 to 36 months (56 males and 75 females),...
Excessive Endoplasmic Reticulum Stress Correlates with Impaired Mitochondrial Dynamics, Mitophagy and Apoptosis, in Liver and Adipose Tissue, but Not in Muscles in EMS Horses. Nowadays, endocrine disorders have become more frequent in both human and veterinary medicine. In horses, reduced physical activity combined with carbohydrate and sugar overload may result in the development of the so-called equine metabolic syndrome (EMS). EMS is characterized by insulin resistance, hyperinsulinemia, elevated blood triglyceride concentrations and usually obesity. Although the phenotypic features of EMS individuals are well known, the molecular mechanism underlying disease development remains elusive. Therefore, in the present study, we analyzed insulin-sensitive tissues, i.e....
Truncation of the Murine Neonatal Fc Receptor Cytoplasmic Tail Does Not Alter IgG Metabolism or Transport In Vivo. 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...
Effects of stacked wedge pads and chains applied to the forefeet of Tennessee Walking Horses for a five-day period on behavioral and biochemical indicators of pain, stress, and inflammation. OBJECTIVE To determine the effects of stacked wedge pads and chains applied to the forefeet of Tennessee Walking Horses on behavioral and biochemical indicators of pain, stress, and inflamation. ANIMALS 20 Tennessee Walking Horses. PROCEDURES Horses were randomly assigned to 2 treatment groups: keg shoes (control; n = 10) or stacked wedge pads and exercise with chains (10). Ten days before treatment application, an accelerometer was attached at the left metatarsus of each horse to record daily activity. Horses were exercised for 20 minutes daily, beginning on day -7. On day 0, exercise ceased,...
Estimation of dietary threonine requirement using plasma amino acid concentrations in mature thoroughbreds. 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.
Comparison of two methods for measurement of equine adrenocorticotropin. Accurate measurement of equine adrenocorticotropin (ACTH) is important for the diagnosis of equine pituitary pars intermedia dysfunction (PPID). Several radioimmunoassays (RIAs) and chemiluminescent immunoassays (CIAs) are used for measurement of ACTH concentration in horses; whether these methods yield similar results across a range of concentrations is not determined. We evaluated agreement between a commercial RIA and CIA. Archived plasma samples ( n = 633) were measured with both assays. Correlation between the 2 methods was moderate ( r = 0.49, p < 0.001). Bland-Altman analysis reveale...
Effect of side of the corpus luteum and pregnancy on estrogen and progesterone receptor expression and localization in the endometrium of mares. The effect of side of corpus luteum on uterine gene expression and protein localization of estrogen receptor α (ERα) and progesterone receptor (PR) in healthy cyclic and pregnant mares 13 days after ovulation (day 0) was investigated. Transcervical biopsies were performed to collect endometrium ipsilateral and contralateral regarding the side of corpus luteum on day 13 post-ovulation in cyclic (n = 6) and pregnant (n = 6) mares. Blood samples were collected daily from day 0 until the day of biopsy for 17β-estradiol (E2) and progesterone (P4) determinations. Receptor expression was d...
The effects of aging on hepatic microsomal scaling factor and hepatocellularity number in the horse. 1. Scaling factor values for the in vitro-in vivo extrapolation of hepatic metabolic clearance for xenobiotics have not yet been determined in horses. Scaling factors were determined by comparing the total protein and or cytochrome (CYP) P450 content in microsomes and cryopreserved hepatocytes against the content in the liver. 2. Microsomal protein per gram of liver (MPPGL) and hepatocellularity number per gram of liver (HPGL) using CYP P450 content method ranged 41-73 mg/gram of liver (mean= 57 mg/gram of liver, n = 39) and 146-320 × 10 cells/g of liver (mean = 227× 10 c...
Development and validation of an ultrahigh performance liquid chromatography-high resolution tandem mass spectrometry quantification method for hypoglycin A and methylene cyclopropyl acetic acid carnitine in horse serum in cases of atypical myopathy. Atypical myopathy (AM) is a fatal disease in horses presumably caused by hypoglycine A (HGA) from ingested maple seeds and its active metabolite methylene cyclopropyl acetic acid (MCPA). The aim of this study was the development and validation of a rapid and simple assay for HGA and MCPA-carnitine in horse serum and its application to authentic samples. Identification and quantification were carried out by ultra high performance liquid chromatography-high resolution tandem mass spectrometry (UHPLC-HRMS/MS) with full-scan/data-dependent MS/MS. Chromatographic separation was performed by isocrat...
Equine in vivo-derived metabolites of the SARM LGD-4033 and comparison with human and fungal metabolites. LGD-4033 has been found in human doping control samples and has the potential for illicit use in racehorses as well. It belongs to the pharmacological class of selective androgen receptor modulators (SARMs) and can stimulate muscle growth, much like anabolic steroids. However, SARMs have shown superior side effect profiles compared to anabolic steroids, which arguably makes them attractive for use by individuals seeking an unfair advantage over their competitors. The purpose of this study was to investigate the metabolites formed from LGD-4033 in the horse in order to find suitable analytical ...
Use of Confocal Microscopy to Evaluate Equine Zygote Development After Sperm Injection of Oocytes Matured In Vivo or In Vitro. Confocal microscopy was used to image stages of equine zygote development, at timed intervals, after intracytoplasmic sperm injection (ICSI) of oocytes that were matured in vivo or in vitro. After fixation for 4, 6, 8, 12, or 16 h after ICSI, zygotes were incubated with α/β tubulin antibodies and human anticentromere antibody (CREST/ACA), washed, incubated in secondary antibodies, conjugated to either Alexa 488 or Alexa 647, and incubated with 561-Phalloidin and Hoechst 33258. An Olympus IX81 spinning disk confocal microscope was used for imaging. Data were analyzed using χ 2 and Fisher's e...
Skeletal muscle from aged American Quarter Horses shows impairments in mitochondrial biogenesis and expression of autophagy markers. Aging is associated with decreased mitochondrial content and function in skeletal muscle, possibly due to compromised biogenesis and autophagic removal of dysfunctional mitochondria. The aim of this study was to compare markers of mitochondrial content and biogenesis and of autophagy between skeletal muscle from young and aged American Quarter Horses. Citrate synthase protein and mtDNA copy number were decreased in triceps brachii (TB) muscle (P<0.05) from aged horses, suggesting an age-related decline in mitochondrial content. Concomitantly, mRNA expression of PGC-1α and TFAM, regulators ...
Endometrial expression of estrogen and progesterone receptors in non-cyclic mares treated only with long-acting progesterone. Administration of progesterone (P4) after estradiol is usually performed to prepare non-cyclic mares as embryo recipients. However, there are successful pregnancy reports after embryo transfer in non-cyclic mares treated only with progestins. The objective of this study was to evaluate endometrial gene expression and immunostaining for estrogen receptor alpha (ERα), beta (ERβ) and progesterone receptor (PR) in seasonal anestrous mares treated with long acting P4 (LA P4). Endometrial tissue from eight seasonal anestrous mares was collected immediately before administration of 1.5 g of LA P4 ...
Skeletal muscle mitochondrial bioenergetics and associations with myostatin genotypes in the Thoroughbred horse. Variation in the myostatin (MSTN) gene has been reported to be associated with race distance, body composition and skeletal muscle fibre composition in the horse. The aim of the present study was to test the hypothesis that MSTN variation influences mitochondrial phenotypes in equine skeletal muscle. Mitochondrial abundance and skeletal muscle fibre types were measured in whole muscle biopsies from the gluteus medius of n = 82 untrained (21 ± 3 months) Thoroughbred horses. Skeletal muscle fibre type proportions were significantly (p < 0.01) different among the three MSTN genotypes and mito...
