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.
Expression and regulation of regulator of G-protein signaling protein-2 (RGS2) in equine and bovine follicles prior to ovulation: molecular characterization of RGS2 transactivation in bovine granulosa cells. The luteinizing hormone preovulatory surge stimulates several signal pathways essential for ovulation, and the regulator of G-protein signaling protein-2 (RGS2) is thought to be involved in this process. The objectives of this study were to characterize the regulation of RGS2 transcripts in equine and bovine follicles prior to ovulation and to determine its transcriptional control in bovine granulosa cells. To assess the regulation of equine RGS2 prior to ovulation, RT-PCR was performed using total RNA extracted from equine follicles collected at various times after human chorionic gonadotropi...
Upflow anaerobic solid-state (UASS) digestion of horse manure: Thermophilic vs. mesophilic performance. Energetic use of complex lignocellulosic wastes has gained global interest. Thermophilic digestion of horse manure based on straw was investigated using the upflow anaerobic solid-state (UASS) process. Increasing the organic loading rate from 2.5 to 5.5gvsL(-)(1)d(-)(1) enhanced the average methane production rate from 0.387 to 0.687LCH4L(-)(1)d(-)(1), whereas the yield decreased from 154.8 to 124.8LCH4kgvs(-)(1). A single-stage and two-stage process design showed almost the same performance. Compared to prior experiments at mesophilic conditions, thermophilic conditions showed a significantly...
Hormonal composition of follicular fluid from abnormal follicular structures in mares. The objective was to characterise the hormonal composition of follicular fluid from mares with distinct anovulatory-cystic follicles. Follicular fluid was aspirated from six mares that presented with cystic follicles and from pre-ovulatory follicles of five normal mares (controls). Differences in progesterone, oestradiol, testosterone, IGF-I and IGF binding were analysed using Fisher's exact test. There were greater (P < 0.03) follicular fluid oestradiol concentrations in normal follicles and the testosterone concentration of the cystic fluid was greater (P < 0.05) than that of t...
Leptin and leptin receptor are detectable in equine spermatozoa but are not involved in in vitro fertilisation. In human and swine, leptin (OB) has been identified in seminal plasma and leptin receptors (OB-R) on the cell surface of spermatozoa, indicating that spermatozoa are a target for OB. This hormone has also been detected in follicular fluid (FF) in women and mares, although its role requires further study. The aims of this study were to investigate the immunolocalisation and the expression of OB and OB-R in equine spermatozoa and to evaluate the involvement of OB in equine in vitro fertilisation (IVF). Since progesterone (P) and OB are both found in FF, the individual and combined effects of the...
Peripheral Blood-Derived Mesenchymal Stromal Cells Promote Angiogenesis via Paracrine Stimulation of Vascular Endothelial Growth Factor Secretion in the Equine Model. Mesenchymal stromal cells (MSCs) have received much attention as a potential treatment of ischemic diseases, including ischemic tissue injury and cardiac failure. The beneficial effects of MSCs are thought to be mediated by their ability to provide proangiogenic factors, creating a favorable microenvironment that results in neovascularization and tissue regeneration. To study this in more detail and to explore the potential of the horse as a valuable translational model, the objectives of the present study were to examine the presence of angiogenic stimulating factors in the conditioned medium...
Progress on low susceptibility mechanisms of transmissible spongiform encephalopathies. Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of fatal neurodegenerative diseases detected in a wide range of mammalian species. The "protein-only" hypothesis of TSE suggests that prions are transmissible particles devoid of nucleic acid and the primary pathogenic event is thought to be the conversion of cellular prion protein (PrP(C)) into the disease-associated isoform (PrP(Sc)). According to susceptibility to TSEs, animals can be classified into susceptible species and low susceptibility species. In this review we focus on several species with l...
Gene and protein expression and cellular localisation of cytochrome P450 enzymes of the 1A, 2A, 2C, 2D and 2E subfamilies in equine intestine and liver. Among the cytochrome P450 enzymes (CYP), families 1-3 constitute almost half of total CYPs in mammals and play a central role in metabolism of a wide range of pharmaceuticals. This study investigated gene and protein expression and cellular localisation of CYP1A, CYP2A, CYP2C, CYP2D and CYP2E in equine intestine and liver. Real-time polymerase chain reaction (RT-PCR) was used to analyse gene expression, western blot to examine protein expression and immunohistochemical analyses to investigate cellular localisation. Results: CYP1A and CYP2C were the CYPs with the highest gene expression in the ...
Cryotolerance of stallion spermatozoa is related to ROS production and mitochondrial membrane potential rather than to the integrity of sperm nucleus. Although cryopreservation of stallion spermatozoa allows long-term preservation of spermatozoa from particular stallions and facilitates international trade, it is understood to inflict damages on sperm cells that may finally reduce their fertilizing ability. In addition, individual differences are known to exist in the sperm ability to withstand freeze-thawing protocols. To date, these differences have mainly been reported on the basis of sperm motility and membrane integrity. For this reason, the present work sought to determine differences between good (good freezability ejaculates: GFE) an...
Development of a method for absolute quantification of equine acute phase proteins using concatenated peptide standards and selected reaction monitoring. The aim of this study was the development of a quantitative assay that could support future studies of a panel of acute phase proteins (APPs) in the horse. The assay was based on a quantification concatamer (QconCAT) coupled to selected reaction monitoring methodology. Thirty-two peptides, corresponding to 13 putative or confirmed APPs for the Equus caballus (equine) species were selected for the design of a QconCAT construct. The gene encoding the QconCAT was synthesized and expressed as an isotope-labeled chimaeric protein in Escherichia coli. The QconCAT tryptic peptides were analyzed on a ...
The effects of sample handling and N-phenylmaleimide on concentration of adrenocorticotrophic hormone in equine plasma. Previous reports suggest that adrenocorticotrophic hormone (ACTH) degrades rapidly, limiting its use as a diagnostic test. Objective: This study quantified effects of processing delays on ACTH concentrations and investigated the addition of N-phenylmaleimide (maleimide), a protease inhibitor, as a means of reducing ACTH degradation. Methods: Experimental study. Methods: Venous blood was collected from 8 healthy horses and 8 horses with pituitary pars intermedia dysfunction (PPID) with a range of ACTH concentrations. Baseline ACTH concentrations were established immediately using a chemilumines...
Effects of the combination of microfracture and self-assembling Peptide filling on the repair of a clinically relevant trochlear defect in an equine model. The goal of this study was to test the ability of an injectable self-assembling peptide (KLD) hydrogel, with or without microfracture, to augment articular cartilage defect repair in an equine cartilage defect model involving strenuous exercise. Methods: Defects 15 mm in diameter were created on the medial trochlear ridge and debrided down to the subchondral bone. Four treatment groups (n = 8 each) were tested: no treatment (empty defect), only defect filling with KLD, only microfracture, and microfracture followed by filling with KLD. Horses were given strenuous exercise throughout the one-ye...
Pharmacokinetics of intravenous, plain oral and enteric-coated oral omeprazole in the horse. The objectives were to document the pharmacokinetics of intravenous, enteric-coated oral and plain oral omeprazole in fasted horses and to investigate the impact of feeding on the bioavailability of an enteric-coated omeprazole. Twelve horses received four treatments: intravenous omeprazole (0.5 mg/kg) in the fasted state (IV-Fasted), enteric-coated omeprazole (4 mg/kg) orally in the fasted state (ECO-Fasted), enteric-coated omeprazole (4 mg/kg) orally in the fed state (ECO-Fed) and plain omeprazole (4 mg/kg) orally in the fasted state (PL-Fasted). Plasma omeprazole concentrations were det...
Development and validation of a hydrophilic interaction liquid chromatography with tandem mass spectrometry method for the simultaneous detection and quantification of etilefrine and oxilofrine in equine blood plasma and urine. A sensitive hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry method was developed and validated for the simultaneous detection and quantification of etilefrine and oxilofrine in equine blood plasma and urine. The method is highly sensitive and specific with good precision and accuracy. In plasma the limit of detection and limit of quantification are 0.03 and 0.1 ng/mL, respectively, for both analytes. In urine the limit of detection and limit of quantification are 0.3 and 1 ng/mL, respectively, for both analytes. The suitability of the method for doping con...
A specific adenylyl cyclase inhibitor (DDA) and a cyclic AMP-dependent protein kinase inhibitor (H-89) block the action of equine growth hormone on in vitro maturation of equine oocytes. The objectives of this study were firstly to determine whether the stimulatory function of equine growth hormone (eGH) on equine oocyte maturation in vitro is mediated via cyclic adenosine monophosphate (cAMP); and secondly if the addition of eGH in vitro influences oocyte nuclear maturation and if this effect is removed when GH inhibitors are added to the culture. Cumulus-oocyte complexes (COCs) were recovered from follicles <25 mm in diameter and randomly allocated as follows: (i) control (no additives); and (ii) 400 ng/ml of eGH. A specific inhibitor against cyclic AMP-dependent protein ...
Flow cytometric detection of circulating platelet-derived microparticles in healthy adult horses. To develop a flow cytometric assay to quantify platelet-derived microparticles (PMPs) in equine whole blood and plasma. Methods: Citrate-anticoagulated whole blood from 30 healthy adult horses. Methods: Platelet-poor plasma (PPP) was prepared from fresh whole blood by sequential low-speed centrifugation (twice at 2,500 × g). Samples of fresh whole blood and PPP were removed and stored at 4° and 24°C for 24 hours. Platelet-derived microparticles were characterized in fresh and stored samples on the basis of the forward scatter threshold (log forward scatter < 10(1)) and labeling with anne...
Serum insulin-like growth factor 1 in the aging horse. Insulin-like growth factor 1 (IGF-1) has important roles in anabolic processes in the musculoskeletal system and has been reported to decrease with age in both people and horses. Objective: The objective of this study was to determine serum IGF-1 levels in the aging horse from early to late adulthood (age range 5-27 years). Methods: Healthy horses (n = 72) were used in a cross-sectional study, while 37 paired serum samples were available for a longitudinal study. Serum IGF-1 protein was determined using an ELISA kit validated for use in equine samples. Results: No association was found betw...
Disposition and metabolic profile of the weak androgen Dehydroepiandrosterone (DHEA) following administration as part of a nutritional supplement to exercised horses. In order to ensure the welfare of performance horses and riders as well as the integrity of the sport, the use of both therapeutic and illegal agents in horse racing is tightly regulated. While Dehydroepiandrosterone (DHEA) is not specifically banned from administration to racehorses in the United States and no screening limit or threshold concentration exists, the metabolic conversion of DHEA to testosterone make its presence in nutritional supplements a regulatory concern. The recommended regulatory threshold for total testosterone in urine is 55 and 20 ng/mL for mares and geldings, respec...
Oxidant-antioxidant status in the blood of horses with symptomatic recurrent airway obstruction (RAO). Systemic oxidative stress in horses with recurrent airway obstruction (RAO) is poorly characterized. Objective: The goal of this study was to investigate whether equine RAO is associated with systemic disturbances in the oxidant-antioxidant equilibrium. Methods: Seven healthy horses and 7 horses with symptomatic RAO. Methods: A prospective study. Healthy and RAO-affected horses were exposed to a 48-hour challenge with moldy hay and straw to induce clinical exacerbation of RAO. Venous blood was collected and the activities of the superoxide dismutase (SOD), catalase (CAT), glutathione peroxidas...
The use of liquid chromatography tandem mass spectrometry to detect proteins in saliva from horses with and without systemic inflammation. The objective of the study was to assess global expression of proteins in equine saliva using liquid chromatography tandem mass spectrometry (LC-MS/MS). Saliva was obtained from seven horses with and six horses without evidence of systemic inflammatory disease. Tryptic peptides from saliva were analysed by LC-MS/MS. Of 195 unique proteins identified, 57 were detected only in saliva samples from horses with systemic inflammation (in two to six of the seven horses). Among the differentially expressed proteins were several acute phase proteins (APPs) such as serum amyloid A, fibrinogen, haptoglob...
Clinical utility of serum biochemical variables for predicting acid-base balance in critically ill horses. Profiles from serum biochemical analyzers include the concentration of strong electrolytes (including l-lactate), total carbon dioxide (tCO2 ), and total protein. These variables are associated with changes in acid-base balance. Application of physicochemical principles may allow predicting acid-base balance from serum biochemistry without measuring whole blood pH and pCO2 . Objective: The purpose of the study was to determine if the acid-base status of critically ill horses could be accurately predicted using variables included in standard serum biochemical profiles. Methods: Two jugular veno...
Effects of milk proteins on sperm binding to the zona pellucida and intracellular Ca(2+) concentration in stallion sperm. Objectives were to determine the effects of extracellular Ca(2+) and milk proteins on intracellular Ca(2+) concentrations in stallion sperm; and to determine the effects of single caseins on sperm binding to the zona pellucida (ZP). In Experiment I, sperm were incubated in media containing 2 or 4mM Ca(2+) and intracellular Ca(2+) concentration was determined after ionomycin treatment and long-term incubation (3h). Extracellular Ca(2+) concentrations (2 compared with 4mM) did not affect baseline intracellular Ca(2+) concentration of sperm. However, incubating sperm in a medium containing 4 comp...
Determining ACTB, ATP5B and RPL32 as optimal reference genes for quantitative RT-PCR studies of cryopreserved stallion semen. Equine germplasm bank management involves not only the conservation and use of semen doses, in addition it can also be a resource to study stallion semen quality and after thawing semen properties for reproductive purposes. A possible criterion to measure quality may be based on differential gene expression of loci involved during spermatogenesis and sperm quality maturation. The rapid degradation of sperm after thawing affects the integrity and availability of RNA. In this study we have analyzed genes expressed in equine cryopreserved sperm, which provided an adequate amplification, specifici...
Characterization of butyrate transport across the luminal membranes of equine large intestine. The diet of the horse, pasture forage (grass), is fermented by the equine colonic microbiota to short-chain fatty acids, notably acetate, propionate and butyrate. Short-chain fatty acids provide a major source of energy for the horse and contribute to many vital physiological processes. We aimed to determine both the mechanism of butyrate uptake across the luminal membrane of equine colon and the nature of the protein involved. To this end, we isolated equine colonic luminal membrane vesicles. The abundance and activity of cysteine-sensitive alkaline phosphatase and villin, intestinal luminal ...
Suberoylanilide hydroxamic acid (vorinostat): its role on equine corneal fibrosis and matrix metalloproteinase activity. To explore the effect of suberoylanilide hydroxamic acid (SAHA) (i) on corneal fibroblast differentiation, morphology, and viability; and (ii) on the expression levels of matrix metalloproteinases (MMPs) 2 and 9 using an in vitro model of equine corneal fibrosis. Methods: Healthy donor corneas were used to generate primary cultures of equine corneal fibroblasts. The fibroblasts were exposed to 5 ng/mL TGFβ1 to induce myofibroblast formation. The cultures were treated with either 5 μm or 10 μm SAHA for 72 h in the presence of TGFβ1. Real-time PCR and immunocytochemistry were used to determi...
Ultrashort cationic naphthalene-derived self-assembled peptides as antimicrobial nanomaterials. Self-assembling dipeptides conjugated to naphthalene show considerable promise as nanomaterial structures, biomaterials, and drug delivery devices. Biomaterial infections are responsible for high rates of patient mortality and morbidity. The presence of biofilm bacteria, which thrive on implant surfaces, are a huge burden on healthcare budgets, as they are highly resistant to current therapeutic strategies. Ultrashort cationic self-assembled peptides represent a highly innovative and cost-effective strategy to form antibacterial nanomaterials. Lysine conjugated variants display the greatest po...
Nestin expression in mesenchymal stromal cells: regulation by hypoxia and osteogenesis. The intermediate filament protein nestin is used as a marker for neural stem cells, and its expression is inversely correlated with cellular differentiation. More recently, nestin expression has also been described in other cell types including multipotential mesenchymal stromal cells (MSCs). In this study, we examined the expression of nestin in equine, canine and human bone marrow-derived MSCs undergoing osteogenic differentiation, to determine whether nestin levels were attenuated as the cells acquired a more mature phenotype. In addition, the expression of nestin may be under the influence...
Pituitary pars intermedia dysfunction does not necessarily impair insulin sensitivity in old horses. Equine pituitary pars intermedia dysfunction (PPID) has been associated with reduced insulin sensitivity in comparison with younger adult horses; however, the difference in insulin sensitivity between horses with PPID and aged-matched controls has not been well characterized. The objective of the study was to determine if aged horses with PPID had reduced insulin sensitivity and alterations in the insulin-mediated signaling pathways in the skeletal muscle when compared with healthy aged horses. Isoglycemic hyperinsulinemic clamp procedures were conducted in 12 horses that were classified as ei...
Gene expression of matrix metalloproteinases and LH receptors in mare follicular development. The period from the emergence of a dominant follicle until its formation requires tissue remodeling. Enzymes promoting collagen lysis, such as matrix metalloproteinases (MMPs), are fundamental for the process of extracellular matrix remodeling, which allows changes in ovarian tissue architecture during follicular growth. It has been suggested that the production of these enzymes may be affected by the rise in circulating concentrations of LH, which acts on the ovarian surface epithelium (OSE). The aim of this study was to determine the expression of MMP-1, MMP-2, and LH receptor (LHR) in the o...
Comparison of healing in forelimb and hindlimb surgically induced core lesions of the equine superficial digital flexor tendon. Even though equine multi-limb tendinopathy models have been reported, it is unknown if fore- and hindlimb tendon healing behave similarly. The aim of this study was to compare the healing process of surgically induced superficial digital flexor tendon (SDFT) core lesions of fore- and hindlimbs in horses. Methods: Tendon core lesions were surgically induced in the SDFT of both fore- and hindlimbs in eight horses. One randomly assigned forelimb and one randomly assigned hindlimb were injected with saline one and two weeks post-surgery. The healing process was monitored clinically and ultrasonogr...
Proteomic analysis reveals age-related changes in tendon matrix composition, with age- and injury-specific matrix fragmentation. Energy storing tendons, such as the human Achilles and equine superficial digital flexor tendon (SDFT), are highly prone to injury, the incidence of which increases with aging. The cellular and molecular mechanisms that result in increased injury in aged tendons are not well established but are thought to result in altered matrix turnover. However, little attempt has been made to fully characterize the tendon proteome nor determine how the abundance of specific tendon proteins changes with aging and/or injury. The aim of this study was, therefore, to assess the protein profile of normal SDFTs ...
