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.
Exploring Potential Bioactive Peptides in Fermented Bactrian Camel’s Milk and Mare’s Milk Made by Mongolian Nomads. To date, bioactive proteins and peptides from minor livestock milks and their fermented products have been scarcely reported. In Mongolia, nomads are commonly rearing five livestock animal species (i.e., cow, camel, goat, horse, and sheep) for milking and other purposes. In this study, we analyzed the peptide composition in fermented milks of Bactrian camels () and horses, produced by Mongolian nomads for self-consumption. Peptides from skimmed fermented milks were separated by ultrafiltration and reverse-phase high-performance liquid chromatography. Then, their amino acid sequences were deter...
Metabolic changes induced by oral glucose tests in horses and their diagnostic use. 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 ...
Clinical and biochemical factors associated with survival in equids attacked by dogs: 28 cases (2008-2016). Trauma from dog attacks has been associated with mortality rates as high as 23% in some species. However, the prognosis and clinical features of this type of injury have not been described in equids. Objective: To describe survival rate, signalment, clinical features, and biochemical results in equids presented for emergency care after presumed dog attacks. We hypothesized there would be differences between survivors and nonsurvivors. Methods: A total of 28 equids presented for presumed dog attacks from 3 referral centers. Methods: A retrospective study was performed using data from 3 hospital...
Derivation of Intermediate Pluripotent Stem Cells Amenable to Primordial Germ Cell Specification. Dynamic pluripotent stem cell (PSC) states are in vitro adaptations of pluripotency continuum in vivo. Previous studies have generated a number of PSCs with distinct properties. To date, however, no known PSCs have demonstrated dual competency for chimera formation and direct responsiveness to primordial germ cell (PGC) specification, a unique functional feature of formative pluripotency. Here, by modulating fibroblast growth factor (FGF), transforming growth factor β (TGF-β), and WNT pathways, we derived PSCs from mice, horses, and humans (designated as XPSCs) that are permissive for dire...
Concentrations of Circulating Irisin and Myostatin in Race and Endurace Purebred Arabian Horses-Preliminary Study. Skeletal muscle is considered to be the largest endocrine organ determining the maintenance of energy homeostasis. Adaptive changes in skeletal muscles in response to physical exercise influence the production as well as secretion of myokines, which are bioactive factors that play a crucial role in energy expenditure processes. The aim of the study was to investigate the impact of two different types of exercise on the circulating level of two of these, myostatin and irisin, in trained horses. Twenty purebred Arabian horses were involved in the study: 10 three-year-old horses trained on the ra...
Effect of Dietary Flaxseed Oil Supplementation on the Redox Status, Haematological and Biochemical Parameters of Horses’ Blood. This study compared the effect of two dietary vegetable oils on plasma biochemical indices, haematological parameters, and redox status of horses. Forty riding horses (20 mares and 20 stallions) of the Malopolski breed were divided equally into two groups that were similar in terms of age, sex, and body weight (on average 530 ± 30 kg). The horses received soybean oil (SO) or flaxseed oil (FO) in the amount of 25 mL per 100 kg BW/day. After 60 days, blood was collected for biochemical and haematological analyses. The results show that horses receiving FO as compared to the SO group had signifi...
The effects of metabolic substrates glucose, pyruvate, and lactate added to a skim milk-based semen extender for cooled storage of stallion sperm. Under in vitro conditions, stallion sperm might preferentially use energy substrates that primarily undergo mitochondrial metabolism. The present study sought to determine the effects of glucose, pyruvate, lactate, or their combinations on the quality of stallion sperm subjected to cooled storage at different temperatures, when using a skim milk-based semen extender. In Experiment 1, no substrate (Control), glucose (40 mM; Glu-40), pyruvate (2 mM, 19.8 mM; Pyr-2, Pyr-19), lactate (2 mM, 19.8 mM; Lac-2, Lac-19, respectively), or their combinations (G/P/L-2 or G/P/L-19, respectively) were ...
In Vitro Induction of Pluripotency from Equine Fibroblasts in 20% or 5% Oxygen. The cellular reprogramming into pluripotency is influenced by external and internal cellular factors, such as culture conditions (e.g., environmental oxygen concentration), and the aging process. Herein, we aimed to generate and maintain equine iPSCs (eiPSCs) derived from fibroblasts of a horse older than 20 years and to evaluate the effect of different levels of oxygen tension (atmospheric 20% O, 5% O, or 20% to 5% O) on these cells. Fibroblasts were reprogrammed, and putative eiPSCs were positive for positive alkaline phosphatase detection; they were positive for pluripotency-related genes ...
Seminal plasma components from fertile stallions involved in the epididymal sperm freezability. Seminal plasma (SP) plays a crucial role in sperm protection and functionality. However, the effect of SP on the sperm cryopreservation is dependent on the stallion and SP composition. The use of epididymal spermatozoa incubated in the presence of SP could help the identification of the components of SP that are able to confer protection upon the spermatozoa during freezing. The aims of this study were (i) to identify SP components involved in the potential protection of epididymal spermatozoa during the freeze-thawing process and (ii) to identify and evaluate the proteins likely related to sp...
Preanalytical variables affecting the measurement of serum paraoxonase-1 activity in horses. Paraoxonase-1 (PON-1) activity is a new inflammatory and oxidative marker. Technical effects and biological factors could affect the accuracy of PON-1 activity measurement. We investigated the effects of storage at different temperatures, repeated freeze-thaw cycles, interferences from hemolytic, lipemic, and icteric samples, and seasonal effects on PON-1 activity in horses. We evaluated 2 substrates with an automated spectrophotometer. Ten equine serum samples were stored under different conditions. Although storage at room (21°C) or refrigeration (4°C) temperature induced a statistically s...
Effects of dietary fish oil and alpha-tocopherol supplementation on selected blood parameters and fatty acid profiles in mares and their foals. The effects of fish oil (40 ml/day) supplementation, with or without synthetic all-rac-alpha-tocopherol-acetate (2,500 IU/day), during the last 65 days before expected parturition were investigated in 15 adult mares (553 ± 24 kg BW) and their foals. Mares were assigned to one of three diets: control (n = 5), control plus fish oil and alpha-tocopherol (n = 4; FO + AT) or control with just fish oil (n = 6; FO). Blood samples were obtained from the mares before a 15-day dietary adaptation period (T1) and from mares and foals the first (T2) and fifth (T3) days post-partum. Colostrum...
Transport processes in equine oocytes and ovarian tissue during loading with cryoprotective solutions. Rational design of cryopreservation strategies for oocytes and ovarian cortex tissue requires insights in the rate at which cryoprotective agents (CPA) permeate and concomitant water transport takes place. The aim of the current study was to investigate possible differences in permeation kinetics of different CPAs (i.e., glycerol/GLY, ethylene glycol/EG, dimethyl sulfoxide/DMSO, and propylene glycol/PG), in equine oocytes as well as ovarian tissue. Membrane permeability of oocytes to water (Lp) and to CPAs (Ps) was inferred from video microscopic imaging of oocyte volume responses during perfu...
Selected hematological, biochemical, and acid-base variables of Paso Fino horses living at different altitudes. This study aimed at describing selected hematological, biochemical, and acid-base variables of adult horses living at sea level and comparing them to those living at 5 different altitudes. One hundred and thirty-eight healthy Paso Fino horses > 2 years old were enrolled. Altitudes included the following: altitude A (0 to 50 m above sea level, masl; n = 23), B (1000 to 1050 masl; n = 25), C (1450 masl; n = 30), D (1950 to 2050 masl; n = 30), and E (2950 to 3100 masl; n = 30). A portable blood gas analyzer was used to determine selected biochemical and acid-base variab...
Gene Expression Profile in Similar Tissues Using Transcriptome Sequencing Data of Whole-Body Horse Skeletal Muscle. Horses have been studied for exercise function rather than food production, unlike most livestock. Therefore, the role and characteristics of tissue landscapes are critically understudied, except for certain muscles used in exercise-related studies. In the present study, we compared RNA-Seq data from 18 Jeju horse skeletal muscles to identify differentially expressed genes (DEGs) between tissues that have similar functions and to characterize these differences. We identified DEGs between different muscles using pairwise differential expression (DE) analyses of tissue transcriptome expression d...
Sarcolipin Exhibits Abundant RNA Transcription and Minimal Protein Expression in Horse Gluteal Muscle. Ca regulation in equine muscle is important for horse performance, yet little is known about this species-specific regulation. We reported recently that horse encode unique gene and protein sequences for the sarcoplasmic reticulum (SR) Ca-transporting ATPase (SERCA) and the regulatory subunit sarcolipin (SLN). Here we quantified gene transcription and protein expression of SERCA and its inhibitory peptides in horse gluteus, as compared to commonly-studied rabbit skeletal muscle. RNA sequencing and protein immunoblotting determined that horse gluteus expresses the gene (SERCA1) as the predomin...
A novel DDB2 mutation causes defective recognition of UV-induced DNA damages and prevalent equine squamous cell carcinoma. Squamous cell carcinoma (SCC) occurs frequently in the human Xeroderma Pigmentosum (XP) syndrome and is characterized by deficient UV-damage repair. SCC is the most common equine ocular cancer and the only associated genetic risk factor is a UV-damage repair protein. Specifically, a missense mutation in horse DDB2 (T338M) was strongly associated with both limbal SCC and third eyelid SCC in three breeds of horses (Halflinger, Belgian, and Rocky Mountain Horses) and was hypothesized to impair binding to UV-damaged DNA. Here, we investigate DDB2-T338M mutant's capacity to recognize UV lesions in ...
Application of Raman Spectroscopy for the Evaluation of Metabolomic Dynamic Analysis in Athletic Horses. Raman spectroscopy is a rapid qualitative and quantitative technique that allows the simultaneous determination of several components, both biomolecules both chemical compounds, in the biological fluids to assess the metabolic status. In this study, the serum composition was evaluated in regularly trained athletic horses using Raman spectroscopy to identify biomarkers of sports performance. Five clinically healthy and regularly trained Italian Saddle horses were subjected to a standardized obstacle course (350 m/minute; eleven 1.25 high jumps) preceded by a warm-up. On the collected sera, at ...
Equine Drug Transporters: A Mini-Review and Veterinary Perspective. Xenobiotic transport proteins play an important role in determining drug disposition and pharmacokinetics. Our understanding of the role of these important proteins in humans and pre-clinical animal species has increased substantially over the past few decades, and has had an important impact on human medicine; however, veterinary medicine has not benefitted from the same quantity of research into drug transporters in species of veterinary interest. Differences in transporter expression cause difficulties in extrapolation of drug pharmacokinetic parameters between species, and lack of knowledg...
The effect of serial administration of bicarbonate on plasma total CO2 concentrations in horses. The administration of alkalinising agents including bicarbonate is of concern to racing authorities because resultant alkalosis may enhance performance and interfere with the detection of drugs in post-race urine. A threshold for total carbon dioxide (TCO ) of 36.0 mmol/L in plasma (with action limit of 37.0 mmol/L) has been set. Serial dosing of sodium bicarbonate has gained popularity in human athletes but has not been studied in horses previously. Sodium bicarbonate (200 g per horse) and 60 g of an electrolyte-vitamin complex was administered in 2-L water via nasogastric intubation to five ...
Effects of exercise, furosemide, blood depletion, and reinfusion on body fluid compartment volumes in horses. High pulmonary blood pressure contributes to exercise-induced pulmonary hemorrhage. The objective of this study was to use bioimpedance spectroscopy to assess body fluid compartment volumes under 3 conditions in 6 racehorses: i) Pre- and post-supramaximal treadmill exercise (control); ii) Exercise 4 hours after furosemide (0.5 mg/kg body weight, IV); iii) Exercise, removal of ~14 L of blood and subsequent reinfusion of the blood. Statistical analysis used linear mixed effects models. Body compartment volumes did not change during the control runs. Total body water (TBW) ( = 0.007, = 0.007), e...
Serial measurements of Paraoxonase-1 (PON-1) activity in horses with experimentally induced endotoxemia. Paraoxonase-1 (PON-1) is an antioxidant enzyme, whose activity decreases during the acute phase response in many species. Little is known about PON-1 and its role as a negative acute phase protein during septic inflammation in horses, but promising findings about its utility in diagnosing SIRS and predicting the outcome in diseased horses, were recently highlighted. The objective of the study was to investigate the behaviour of PON-1 in horses after experimentally induced endotoxemia. To this aim, PON-1 activity was measured on 66 plasma samples collected from six clinically healthy mares, pre...
Cationic contrast-enhanced computed tomography distinguishes between reparative, degenerative, and healthy equine articular cartilage. Cationic contrast-enhanced computed tomography (CECT) is a quantitative imaging technique that characterizes articular cartilage, though its efficacy in differentiating repair tissue from other disease states is undetermined. We hypothesized that cationic CECT attenuation will distinguish between reparative, degenerative, and healthy equine articular cartilage and will reflect biochemical, mechanical, and histologic properties. Chondral defects were created in vivo on equine femoropatellar joint surfaces. Within defects, calcified cartilage was retained (Repair 1) or removed (Repair 2). At sac...
The SLC7A11: sperm mitochondrial function and non-canonical glutamate metabolism. Spermatozoa are redox-regulated cells, and stallion spermatozoa, in particular, present an intense mitochondrial activity in which large amounts of reactive oxygen species (ROS) are produced. To maintain the redox potential under physiological conditions, sophisticated mechanisms ought to be present, particularly in the mitochondria. In the present study, we investigated the role of the SLC7A11 antiporter. This antiporter exchanges intracellular glutamate for extracellular cystine. In the spermatozoa, cystine is reduced to cysteine and used for GSH synthesis. The importance of the antiporter f...
Structural and functional analysis of the inhibition of equine glutathione transferase A3-3 by organotin endocrine disrupting pollutants. Organotin compounds are highly toxic environmental pollutants with neurotoxic and endocrine-disrupting effects. They are potent inhibitors of glutathione transferases (GSTs), thus impeding their detoxication and antioxidant functions. Several GSTs, including equine GST A3-3 (EcaGST A3-3), exhibit steroid double-bond isomerase activity and are involved in the biosynthesis of testosterone and progesterone. We have performed enzyme kinetics analyses of the inhibition of EcaGST A3-3 by organotin compounds. We have also solved crystal structures of EcaGST A3-3 in complexes with glutathione, and wit...
Equine pregnancy-specific glycoprotein CEACAM49 secreted by endometrial cup cells activates TGFB. In early equine pregnancy, a highly invasive trophoblast cell subpopulation, the chorionic girdle cells, invade the endometrium and form endometrial cups (EC). These cells express classical MHC molecules, thereby stimulating a humoral and cellular immune response, resulting in a massive accumulation of maternal CD4+ and CD8+ T cells around the EC. Nevertheless, no immediate destruction of endometrial cups by maternal lymphoid cells occurs, presumably due to immune tolerance. Although the environment of EC is rich in TGFB and in FOXP3+, CD4+ T cells, the mechanisms leading to tolerance have not...
Relative Deficiency in Albumin Methionine Content is Associated With Decreased Antioxidant Capacity of Equine Plasma. Relative to other species, horses seem particularly susceptible to oxidative stress. Plasma albumin plays an important role in preventing oxidative damage, in part due to its methionine (MET) content. Equine albumin is highly unusual in that it contains no MET residues. Whether or not this causes deficient antioxidant capacity in equine plasma relative to that of other species has not yet been explored. The objective of this study was to compare the redox status of equine (no MET) to that of bovine (moderate amount of MET) plasma. Plasma was collected from healthy, nonpregnant Quarter Horse ma...
Effects of Feeding Coenzyme Q10-Ubiquinol on Plasma Coenzyme Q10 Concentrations and Semen Quality in Stallions. Although coenzyme Q10 (CoQ10) serves as an antioxidant and energy source for spermatozoa when added to stallion semen before cooling or freezing, the effects of feeding CoQ10 on semen quality have not been studied. We assessed the effects of daily oral ingestion of CoQ10-ubiquinol by stallions on their plasma CoQ10 concentrations and semen quality. Seven mature Andalusian stallions ate 1g ubiquinol/day for 4 weeks followed by a 4-week washout period. Four horses initially completed an additional 4-week control period without ubiquinol. Blood was sampled weekly for determination of plasma CoQ1...
Characterization of Adult and Neonatal Articular Cartilage From the Equine Stifle. A significant portion of equine lameness is localized to the stifle joint. Effective cartilage repair strategies are largely lacking, however, recent advances in surgical techniques, biomaterials, and cellular therapeutics have broadened the clinical strategies of cartilage repair. To date, no studies have been performed directly comparing neonatal and adult articular cartilage from the stifle across multiple sites. An understanding of the differences in properties between the therapeutic target cartilage (i.e., adult cartilage) as well as potential donor cartilage (i.e., neonatal cartilage) c...
Evaluation of podocin in urine in horses using qualitative and quantitative methods. No sensitive method for diagnosing early kidney dysfunction in horses has been identified so far. Many studies carried out in humans and small animals show that podocin can be useful to diagnose various kidney diseases, mainly affecting the glomeruli. The aim of this study was to perform a qualitative and quantitative analysis of podocin in urine samples obtained from healthy horses, horses with clinical kidney dysfunction and horses at risk of acute kidney injury. The study objectives aimed to assess: (1) whether the selected podocin tryptic peptide for LC-MS-MRM allows for podocin detection ...
A high glucose concentration during early stages of in vitro equine embryo development alters expression of genes involved in glucose metabolism. Equine embryos exhibit an unusual pattern of glucose tolerance in vitro and are currently cultured in hyperglycaemic conditions. Objective: Our main objective was to analyse the effect of different glucose concentrations on in vitro-produced equine embryo development and quality. Methods: Experiments comparing in vitro and in vivo produced embryos. Methods: Oocytes (n = 641) were collected from post-mortem ovaries, matured in vitro and fertilised by intracytoplasmic sperm injection (ICSI). Embryo culture was divided from Day 0 to Day 4 and from Day 4 to Day 9 in three groups: 5-10 (5 and 10...