Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
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.
Lactate-driven equine conditioning programmes. Equine conditioning programmes are rarely driven by science. Indeed, the scientific literature on conditioning responses often refers to conventional technique rather than physiological driving parameters. This, alongside poor classification of conditioning protocols, has reduced the possibility of comparative data analysis. Recent interest into lactate-driven conditioning programmes has driven this review which provides a summary of equine protocols used to date and their responses. Key areas identified for further standardisation and/or investigation include (1) the treadmill acclimation pro...
Effects of aerobic and anaerobic fluid collection on biochemical analysis of peritoneal fluid in healthy horses and horses with colic. To determine whether in healthy horses and those with colic, exposure of peritoneal fluid to room air affects values obtained on biochemical analysis. Methods: Prospective study. Methods: Adult horses with a primary complaint of acute abdominal pain (n=29) and 12 healthy horses. Methods: Peritoneal fluid was aseptically collected under aerobic and anaerobic conditions. After collection, pH, PCO(2) , PO(2) , HCO(3) (-) , Na(+) , ionized Ca(2+) , K(+) , lactate, and glucose were immediately measured using a commercial blood gas analyzer. Biochemical variables were compared between aerobically an...
Influence of seminal plasma on fresh and post-thaw parameters of stallion epididymal spermatozoa. Fresh and post-thaw parameters (motility, morphology and viability) of stallion epididymal spermatozoa that have been and have not been exposed to seminal plasma were evaluated, and directly compared to fresh and post-thaw parameters of ejaculated spermatozoa. Six sperm categories of each stallion (n=4) were evaluated for motility, morphology and viability. These categories were fresh ejaculated spermatozoa (Fr-E), fresh epididymal spermatozoa that had been exposed to seminal plasma (Fr-SP+), fresh epididymal spermatozoa that had never been exposed to seminal plasma (Fr-SP-), frozen-thawed eja...
Plasma vitamin K concentration in horses supplemented with several vitamin K homologs. The effect of several vitamin K homologs on plasma vitamin K concentration was determined to assess their potential as a vitamin K supplement for adult horses. Sixteen Thoroughbred horses consisting of 8 mares and 8 geldings, aged 8.4 ± 3.6 yr and weighing 520.8 ± 36.1 kg, were allocated to 4 groups (n = 4). Each group was given phylloquinone, menaquinone-4, or menadione at 58 µmol/d, or no vitamin K supplement for 7 d. Plasma samples were collected before feeding, and 2, 4, and 8 h after feeding on d 7, and plasma concentrations of phylloquinone and menaquinone-4 were determined. Plasma ph...
Morphometric and ultrastructural features of the mare oviduct epithelium during oestrus. Morphometric, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations have displayed regional differences in the mare oviductal epithelium. The entire mucosa of the oviduct was lined with a pseudostratified epithelium, which consisted of two distinct cell types, ciliated and non-ciliated. Ciliated cells were predominant in the three different segments of the oviduct and their percentage increased from fimbriae to ampulla and significantly decreased in the isthmus. SEM revealed in the infundibulum finger-like mucosal folds, some of them interconnected, in th...
Effect of training and detraining on monocarboxylate transporter (MCT) 1 and MCT4 in Thoroughbred horses. The aim of this study was to investigate the effects of training and detraining on the monocarboxylate transporter (MCT) 1 and MCT4 levels in the gluteus medius muscle of Thoroughbred horses. Twelve Thoroughbred horses were used for the analysis. For 18 weeks, all the horses underwent high-intensity training (HIT), with running at 90-110% maximal oxygen consumption (VO2 max ) for 3 min, 5 days week(-1). Thereafter, the horses either underwent detraining for 6 weeks by either 3 min of moderate-intensity training (MIT) at 70% VO2 max, 5 days week(-1) (HIT-MIT group) or stall rest (HIT-SR group)....
Fatty acids and plasmalogens of the phospholipids of the sperm membranes and their relation with the post-thaw quality of stallion spermatozoa. Fatty acids and plasmalogens were extracted from the phospholipids of the plasma membrane of stallion spermatozoa, to determine their relation with sperm quality after freezing and thawing. Sperm quality was rated using a quality index that combined the results of the analysis of sperm motility and velocity (CASA analysis), membrane status and mitochondrial membrane potential (flow cytometry) post thaw. Receiving operating system (ROC) curves were used to evaluate the value of specific lipid components of the sperm membrane herein studied as forecast of potential freezeability. From all parame...
Use of a defined diluent increases the sex-sorting efficiency of stallion sperm. The low efficiency of flow cytometric sex-sorting of stallion sperm has been attributed to the use of an opaque skim milk-based diluent during Hoechst 33342 (H33342) staining. Three experiments were conducted to formulate an optically clear stallion semen diluent for use during H33342 staining, and to determine whether a clear diluent improved resolution during sorting. For Experiment 1, sperm were incubated at 34 °C in each of five diluents containing either no protein, skim milk, 0.25% Cohn's Fraction V BSA, 0.5% BSA, or 1% BSA, following an 18 h storage (15 °C) period, or shortly after co...
Production of calcium maintenance factor Stanniocalcin-1 (STC1) by the equine endometrium during the early pregnant period. A factor responsible for progression to pregnancy establishment in the mare has not been definitively characterized. To identify factors possibly involved in the establishment of equine pregnancy, the endometrium was collected from day 13 (day 0=day of ovulation) cyclic and day 13, 19 and 25 pregnant animals. From initial subtractive hybridization studies, a calcium regulating factor, Stanniocalcin-1 (STC1) mRNA, was found as a candidate molecule expressed uniquely in the pregnant endometrium. Endometrial expression of STC1 mRNA was noted on day 19 and was markedly increased in the day 25 grav...
A preliminary study on the changes in some potential markers of muscle-cell degradation in sub-maximally exercised horses supplemented with a protein and amino acid mixture. In this preliminary study, time-dependent changes in plasma CK and AST activity, tyrosine (Tyr), 3-methyl-histidine (3mHis), glucose and lactate concentrations were analysed in nine horses under two different conditions. Furthermore, intramuscular concentrations of Tyr, 3mHis and activities of cathepsin B, acid phosphatase (ACP), glucose-6-phosphate dehydrogenase (G6PDH) and mRNA expression of ubiquitin were determined at the same time. After studying the effects of exercise alone, the effects of exercise and feeding of an experimental protein/amino acid (AA) supplement were analysed. Horses w...
Use of in vitro technologies to study phase II conjugation in equine sports drug surveillance. Within equine drug surveillance, there is significant interest in analyzing intact phase II conjugates of drugs in urine, but progress has been limited by a lack of reference material. Methods: In this study, in vitro techniques using equine liver fractions were employed to produce glucuronide and sulfate conjugates of stanozolol, 16β-hydroxystanozolol and nandrolone, the glucuronide conjugate of morphine and the glutathione metabolite of chlordinitrobenzene for the first time in equine sports drug surveillance. Results: The glucuronide conjugate of the synthetic progestagen altrenogest was a...
Peripheral serotoninergic response to physical exercise in athletic horses. The purpose of this study was to evaluate the influence of exercise on plasma tryptophan (TRP) and free serotonin (f5-HT), whole blood-5-HT (WB-5-HT) and f5-HT/WB-5-HT ratio in Italian Saddle horses. Six clinically healthy Italian Saddle horses were subjected to a 450 meters obstacles course. Blood samples were collected from each horse by jugular venipuncture using vacutainer tubes with K(3)-EDTA at rest, immediately after exercise, and after 30 min. TRP, f5-HT and WB-5-HT were analyzed by HPLC. Immediately after exercise, statistically significant increases of f5-HT (p <0.001) and WB-5-HT (p...
Comparative human-horse sequence analysis of the CYP3A subfamily gene cluster. Cytochrome P450 enzymes (CYP450s) represent a superfamily of haem-thiolate proteins. CYP450s are most abundant in the liver, a major site of drug metabolism, and play key roles in the metabolism of a variety of substrates, including drugs and environmental contaminants. Interaction of two or more different drugs with the same enzyme can account for adverse effects and failure of therapy. Human CYP3A4 metabolizes about 50% of all known drugs, but little is known about the orthologous CYP450s in horses. We report here the genomic organization of the equine CYP3A gene cluster as well as a compara...
Structural annotation of equine protein-coding genes determined by mRNA sequencing. The horse, like the majority of animal species, has a limited amount of species-specific expressed sequence data available in public databases. As a result, structural models for the majority of genes defined in the equine genome are predictions based on ab initio sequence analysis or the projection of gene structures from other mammalian species. The current study used Illumina-based sequencing of messenger RNA (RNA-seq) to help refine structural annotation of equine protein-coding genes and for a preliminary assessment of gene expression patterns. Sequencing of mRNA from eight equine tissues...
Genomic structure, polymorphism and expression of ACCN1 and ACCN3 genes in the horse. A category of cation gate proteins was shown to be present in sensory neurons and act as receptors of protons present in tissues such as muscles. The Amiloride-sensitive Cation Channel, Neuronal (ACCN) gene family is known to play a role in the transmission of pain through specialized pH sensitive neurons. Muscles from horses submitted to strenuous exercises produce lactic acid, which may induce variable pain through ACCN differential properties. The sequences of the equine cDNAs were determined to be 2.6 kb in length with an open reading frame of 1539 bp for ACCN1 and 2.1 kb in length with an...
Cardiolipin modulates allosterically peroxynitrite detoxification by horse heart cytochrome c. Upon interaction with bovine heart cardiolipin (CL), horse heart cytochrome c (cytc) changes its tertiary structure disrupting the heme-Fe-Met80 distal bond, reduces drastically the midpoint potential out of the range required for its physiological role, binds CO and NO with high affinity, and displays peroxidase activity. Here, the effect of CL on peroxynitrite isomerization by ferric cytc (cytc-Fe(III)) is reported. In the absence of CL, hexa-coordinated cytc does not catalyze peroxynitrite isomerization. In contrast, CL facilitates cytc-Fe(III)-mediated isomerization of peroxynitrite in a d...
Developmental validation of feline, bovine, equine, and cervid quantitative PCR assays. Accurate DNA quantification is essential for optimizing DNA testing and minimizing sample consumption. Real-time quantitative polymerase chain reaction (qPCR) assays have been published for human and canine nuclear DNA, and the need for quantifying other forensically important species was evident. Following the strategy employed for the canine qPCR assay, we developed individual assays to accurately quantify feline, bovine, equine, and cervid nuclear DNA. Each TaqMan-based assay incorporates a genus-specific probe targeting the Melanocortin-1 Receptor gene and includes a piece of synthetic DNA...
Cyclooxygenase-2 mRNA expression in equine nonglandular and glandular gastric mucosal biopsy specimens obtained before and after induction of gastric ulceration via intermittent feed deprivation. To measure the expression of cyclooxygenase-2 (COX-2) mRNA in gastric biopsy specimens serially obtained from horses before, during, and after an 8-day intermittent feed-deprivation trial and to investigate the mucosal location of COX-2. Methods: 9 mixed-breed horses for retrieval of gastric biopsy specimens and 16 additional horses for immunohistochemical analysis. Methods: Gastric biopsy specimens were obtained from 6 horses; 3 of these horses and 3 more participated in an intermittent feed-deprivation trial 9 weeks later. A quantitative PCR assay was used to determine the amount of COX-2 mR...
Oral administration of tepoxalin in the horse: a PK/PD study. Tepoxalin is a non-steroidal anti-inflammatory drug with analgesic, anti-inflammatory, and antipyretic properties and has been recently introduced into veterinary medicine. The aim of this study was to evaluate the pharmacokinetic/pharmacodynamic (PK/PD) profile of tepoxalin to assess whether it would be suitable for clinical use in horses. Six female fasting/fed horses were given 10mg/kg tepoxalin orally in a cross-over study. After administration, tepoxalin underwent rapid and extensive hydrolytic conversion to its carboxylic acid metabolite RWJ-20142. In animals that had been fed, the plasm...
Immunotherapy for pythiosis: Effect on NTPDase activity in lymphocytes of an experimental model. NTPDase (EC 3.6.1.5) occurs in lymphocytes and plays an important role in immune function, in that hydrolyzes extracellular nucleoside tri- and/or diphosphates to form AMP. Pythium insidiosum causes the disease pythiosis, a pyogranulomatous disease of horses, dogs, cattle, cats and humans. Most antifungal drugs are ineffective against this pathogen, and immunotherapy, a treatment approach that relies on the injection of P. insidiosum antigen, has been successfully used in humans and horses to manage this disease. In this study, we investigated NTPDase activity in lymphocytes from rabbits inocu...
The secretory mechanisms in equine platelets are independent of cytoskeletal polymerization and occur through membrane fusion. Studies in animal models are useful to understand the basic mechanisms involved in hemostasis and the functional differences among species. Ultrastructural observations led us to predict differences in the activation and secretion mechanisms between equine and human platelets. The potential mechanisms involved have been comparatively explored in the present study. Equine and human platelets were activated with thrombin (0.5 U/ml) and collagen (20 µg/ml), for 90 seconds, and samples processed to evaluate: i) ultrastructural changes, by electron microscopy, ii) actin polymerization and cy...
The effects of deferoxamine mesylate on iron elimination after blood transfusion in neonatal foals. Hepatic failure is one of the more common complications in foals requiring blood transfusion to treat neonatal isoerythrolysis. Iron intoxication is likely the cause of hepatic injury. Objective: To determine the effects of deferoxamine on iron elimination in normal foals. Methods: Thirteen neonatal foals. Methods: Randomized-controlled trial. At 1-3 days of age, foals received either 3 L of washed packed dam's red blood cells (RBC) or 3 L of saline IV once. Foals were treated with deferoxamine (1 g) or saline (5 mL) SC twice daily for 14 days. Foals were randomly assigned to 1 of 3 gr...
Cytochromes: Reactivity of the “dark side” of the heme. Ligand binding to the heme distal side is a paradigm of heme-protein biochemistry, the proximal axial ligand being in most cases a His residue. NO binds to the ferrous heme-Fe-atom giving rise to hexa-coordinated adducts (as in myoglobin and hemoglobin) with His and NO as proximal and distal axial ligands, respectively, or to penta-coordinated adducts (as in soluble guanylate cyclase) with NO as the axial distal ligand. Recently, the ferrous derivative of Alcaligenes xylosoxidans cytochrome c' (Axcyt c') and of cardiolipin-bound horse heart cytochrome c (CL-hhcyt c) have been reported to bind ...
Confirmatory analysis of continuous erythropoietin receptor activator and erythropoietin analogues in equine plasma by LC-MS for doping control. Continuous erythropoietin receptor activator (CERA) is the third generation of recombinant human erythropoietin (rhEPO) medication that retains the effect of promoting red blood cell production but has longer duration of action in the body. CERA, rhEPO, and darbepoetin alpha (DPO) can be misused to enhance performance in both human and equine athletes. To deter such misuse, a very selective and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method has now been developed for identification of CERA, rhEPO, and DPO in equine plasma. The method employs a new signature tryptic...
Enantiomeric composition analysis of pranoprofen in equine plasma and urine by chiral liquid chromatography-tandem mass spectrometry in selected reaction monitoring mode. The enantioseparation of pranoprofen after its addition in racemic form into equine plasma and urine was conducted by chiral liquid chromatography-tandem mass spectrometry in selected reaction monitoring mode. The methods for the assay of both enantiomers were linear (r≥0.9943) in the low range from 0.001 to 0.1μg/mL and high range from 0.01 to 1.0μg/mL with good precision (% RSD≤5.6) and accuracy (% RE=-5.3 to 1.9). When racemic pranoprofen was orally administered to four horses at a single dose of 3.1mg/kg, the median plasma concentrations of (R)-pranoprofen were lower than the levels ...
Modulation of circulating purines and pyrimidines by physical exercise in the horse. This study was designed to examine the influence of sub-maximal exercise on purine and pyrimidine catabolism in horses. Ten horses were initially trained for 12 weeks at the end of which they underwent a standardized exercise test (SET); venous blood samples were taken at rest, 5 and 30 min after the SET. Six untrained healthy horses, from which a blood withdrawal was taken at rest, were used as the control group. Samples were analyzed by HPLC for the simultaneous determination of uric acid, uridine, β-pseudouridine and creatinine in plasma. Glucose and lactate were measured in blood. Trained...
Immunolocalization of the hyaluronan receptor CD44 in the reproductive tract of the mare. Hyaluronan (HA), a glycosaminoglycan, is a major component of the pericellular matrix which envelopes mammalian cells. Binding of hyaluronan to one of its specific receptors, CD44, modulates transduction of intracellular signals which direct a variety of processes, including embryogenesis, wound healing, inflammation, and neoplasia. Since regulation of these processes is critical to equine reproductive success, localization of constitutive CD44 expression was evaluated by immunohistochemical methods in ovarian, oviductal, and uterine tissues from healthy mares. Ovarian stroma contained thecal ...
Cyclooxygenase-2 expression in animal cancers. Cyclooxygenase (COX; also known as prostaglandin endoperoxide synthase) is a key enzyme in the biochemical pathway leading to the synthesis of prostaglandins. A large amount of epidemiological and experimental evidence supports a role for COX-2, the inducible form of the enzyme, in human tumorigenesis, notably in colorectal cancer. COX-2 mediates this role through the production of PGE(2) that acts to inhibit apoptosis, promote cell proliferation, stimulate angiogenesis, and decrease immunity. Similarly, COX-2 is believed to be involved in the oncogenesis of some cancers in domestic animals. H...
High-throughput UHPLC-MS/MS method for the detection, quantification and identification of fifty-five anabolic and androgenic steroids in equine plasma. Anabolic and androgenic steroids (AASs) are synthetic substances related to the primary male sex hormone, testosterone. AASs can be abused in both human and equine sports and, thus, are banned by the International Olympic Committee and the Association of Racing Commissioners International (ARCI). Enforcement of the ban on the use of AASs in racehorses during competition requires a defensible and robust method of analysis. To address this requirement, a high-throughput ultra high-performance liquid chromatography-mass spectrometric (UHPLC-MS) method was developed for the detection, quantificati...
Amino acid profile during exercise and training in Standardbreds. The objective of this study is to assess the influence of acute exercise, training and intensified training on the plasma amino acid profile. In a 32-week longitudinal study using 10 Standardbred horses, training was divided into four phases, including a phase of intensified training for five horses. At the end of each phase, a standardized exercise test, SET, was performed. Plasma amino acid concentrations before and after each SET were measured. Training significantly reduced mean plasma aspartic acid concentration, whereas exercise significantly increased the plasma concentrations of alanin...
