Omneity® Pellets
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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.
Concentrations of immunoreactive leukotriene B4 in uterine lavage fluid from mares with experimentally induced and naturally occurring endometritis. Acute endometritis was induced in ovariectomized pony mares by infusion of a 1% solution of oyster glycogen. Maximum concentrations of immunoreactive leukotriene B4 in uterine washings coincided with the greatest rate of infiltration of neutrophils into the uterine lumen. Concentrations of immunoreactive leukotriene B4 decreased to basal levels 6 h after infusion and were unaffected by administration of ovarian steroids to ovariectomized mares. Uterine washings from mares with persistent endometritis did not contain significantly different concentrations of leukotriene B4 from genitally normal...
Studies of stallion sperm survival: preservation of progressive motility of stallion spermatozoa by low ionic strength media. Preservation of stallion sperm forward motility was studied using a video recording system in semen diluted with media of different ionic strength and sodium content. After 8 hr of incubation at room temperature, semen diluted in a low ionic strength media containing sucrose displayed 65 +/- 9% motility with 68 +/- 3% of the motile sperm showing forward motility (diameter of head trajectory greater than or equal to 80 microns). In contrast, sperm populations diluted and incubated with a normal ionic strength media containing sodium had 56 +/- 7% motile sperm of which only 36 +/- 7% displayed f...
Determination of clenbuterol and mabuterol in equine plasma by ion-pair liquid chromatography with electrochemical detection. Chromatographic and electrochemical characteristics. A method for the routine determination of the beta-adrenergic drugs clenbuterol and mabuterol in equine plasma has been developed. The drugs were isolated from alkalinized plasma by liquid-liquid extraction. The organic phase was evaporated to dryness and the residue was dissolved in the mobile phase prior to injection. The recoveries were 98% and 95% for clenbuterol and mabuterol, respectively. The drugs were separated by reversed-phase high-performance liquid chromatography and quantitated by a use of a coulometric detector set at +0.75 V vs. the internal reference electrode. The influence o...
Lipoprotein (a) and plasminogen are immunochemically related. Earlier studies demonstrated that lipoprotein (a), a lipoprotein of high atherogenicity, possesses proteolytic activity. In this report, we provide evidence that the lipoprotein (a)-specific antigen, apoprotein (a) is immunochemically related to plasminogen. This was demonstrated by polyclonal antisera from rabbit, sheep and horse, and with three monoclonal antibodies from mouse. Using immunospecific adsorbers against lipoprotein (a), all plasminogen could be adsorbed from lipoprotein (a)-positive and apparently lipoprotein (a)-negative plasma. As an additional similarity to plasminogen, lipop...
Radioimmunoassay for etorphine in horses with a 125I analog of etorphine. To improve the sensitivity and specificity of screening for etorphine in horses, an 125I-labeled etorphine analog was synthesized and an antibody to etorphine was raised in rabbits. A radioimmunoassay (RIA) for etorphine was developed, using these reagents. Bound and free 125I-labeled etorphine was separated by a double-antibody method that reduced interference from materials associated with equine urine. The 125I-labeled etorphine binding was rarely greater than 250 pg of background etorphine equivalents/ml in raw urine and was 100 pg/ml in hydrolyzed urine. The 125I-RIA was capable of detect...
Horse urinary kallikrein, II. Effect of subsite interactions on its catalytic activity. The effect of secondary-subsite interactions on the catalytic efficiency of horse urinary kallikrein was studied using as substrates oligopeptides and peptidyl-4-nitroanilides with L-Arg at P1. The known secondary specificity of tissue kallikreins for hydrophobic residues at P2 was also demonstrated for horse urinary kallikrein and a higher preference of this enzyme for L-Phe over L-Leu at P2 was evident. Interaction of subsites S3 with D-Pro and D-Phe enhanced the catalytic efficiency but tripeptidyl-4-nitroanilides with acetyl-D-Pro, L-Pro and acetyl-L-Pro at P3 were no better substrates tha...
Further studies on the diagnostic value of gamma-glutamyl transpeptidase and 5′-nucleotidase in cattle, sheep and horses. The distribution of 5'-nucleotidase (5'-NT) and gamma-glutamyl transpeptidase (gamma-GT) is similar in the tissues of the sheep, calf and horse, except that there is relatively less gamma-GT in calf liver than in the liver of the other two species. The liver lesion produced by the oral administration of chloroform is similar in the three species and is accompanied by the release of 5'-NT into the plasma of the sheep and calf but not of the horse. Conversely, gamma-GT is released into plasma of the horse but not of the sheep or calf. This difference is not related to the tissue distribution of ...
Effect of an interfering substance on determination of potassium by ion-specific potentiometry in animal urine. Analytical characteristics of photometry and ion-specific potentiometry for urine from sheep, horses, cows, dogs, and cats were determined, using solutions of sodium and potassium chloride. The performance of both methods were acceptable, but the ion-specific potentiometer (in the mode for urine analysis) was superior in terms of linearity of response and correlation between actual vs measured concentrations. Coefficients of variation of either method for repeated analyses of various concentrations of sodium and potassium were always less than 2.5%. The measurement of sodium concentration in u...
Influence of the autonomic nervous system in the horse urinary bladder. alpha and beta-adrenergic receptors in detrusor muscle and bladder base of horses were investigated by in vitro responses of smooth muscle strips to exogenous agonist and antagonist drugs. Noradrenaline, isoprenaline and salbutamol induced relaxation of detrusor muscle strips which was significantly inhibited by propranolol and butoxamine suggesting that the response is mediated by beta-2 adrenergic receptors. In the urinary bladder base noradrenaline, phenylephrine and B-HT 920 induced strong contractile effects. These contractile responses were inhibited by the alpha antagonist phenoxybenzam...
Relationships between the erythrocyte sedimentation rate, plasma proteins and viscosity, and leucocyte counts in thoroughbred racehorses. The influence of plasma proteins on erythrocyte aggregation was studied in a population of young thoroughbred racehorses, using the 60 minute erythrocyte sedimentation rate (ESR) with and without haematocrit standardisation. The ESR was correlated inversely with the haematocrit, but directly with fibrinogen, plasma viscosity and serum total globulins. When ESR values were standardised to a common haematocrit the correlation coefficients for the same plasma protein factors were increased. Albumin levels showed a strong direct relationship with haematocrit which accounted for the inverse correla...
Establishment of equine T-lymphocyte cultures dependent on recombinant human interleukin-2. Long-term equine lymphocyte cultures were initiated and maintained in continuous culture with medium containing recombinant human interleukin-2. Cultures were successfully maintained with lectin activation signals and recombinant human interleukin-2 or with recombinant human interleukin-2 alone. All cell cultures that were characterized had a T-lymphocyte phenotype and had lectin-dependent or -independent cytotoxicity directed to various cell types. These findings demonstrate that long-term equine T-lymphocytes cultures can be initiated and maintained easily.
Conformational restrictions of the sheep testicular receptor discriminates pituitary lutropin and placental gonadotropins. A membrane preparation from the testis of maturing Dorset-Leicester-Suffolk sheep, capable of discriminating pituitary LH (lutropin) from placental gonadotropins human choriogonadotropin (hCG) and equine choriogonadotropin is described. Maximum binding of 125I-oLH (ovine lutropin) to the testicular receptors occurred at 4 degrees C in a rapid manner, attaining equilibrium in 12-16 h. Under such optimal conditions, only unlabeled ovine LH or the structurally identical bovine LH effectively competed for receptor occupation. Other highly purified pituitary LH preparations from rat and human pitui...
Mitochondrial aldehyde dehydrogenase from horse liver. Correlations of the same species variants for both the cytosolic and the mitochondrial forms of an enzyme. The primary structure of the mitochondrial form of horse liver aldehyde dehydrogenase has been determined, utilizing peptide analyses and homology with other enzyme forms. The subunit exhibits N-terminal heterogeneity in size similar to that for the corresponding human mitochondrial protein, the longest form having 500 residues. Catalase was identified as a contaminant of the preparations. All four pairs within a set of aldehyde dehydrogenases can now be compared, including the same two species variants (horse and human) for both the cytosolic and mitochondrial enzyme, revealing characteristic...
The effects of high intensity exercise on the plasma concentration of lactate, potassium and other electrolytes. To study the effect of short term high intensity exercise on plasma lactate, potassium, sodium and chloride concentrations, five Thoroughbred horses were galloped on a treadmill at a 5 degree incline. Following a standardised warm-up period, they were galloped at 8, 10, or 12 metres/sec for 2 mins. One horse also galloped at 14 metres/sec for 1.5 mins. Sequential arterial and/or venous blood samples were collected during exercise and recovery. At 12 metres/sec, the effect of different recovery modes, ie, standing, walking or trotting, on the electrolytes was also examined. There was a progress...
Microanalysis of the amino-acid sequence of monomeric beta-lactoglobulin I from donkey (Equus asinus) milk. The primary structure and its homology with a superfamily of hydrophobic molecule transporters. The complete primary structure of donkey beta-lactoglobulin I was determined by pulsed-liquid phase microsequencing of tryptic peptides. The protein has been isolated in monomeric form and it corresponds to monomeric beta-lactoglobulin of type I. With the inclusion of donkey beta-lactoglobulin I there are 13% common residues amongst the members of the beta-lactoglobulin family. Donkey beta-lactoglobulin I is homologous to the retinol-binding protein, bilin-binding protein and five other proteins belonging to the new superfamily of hydrophobic molecule transporters. A rapid method for peptide i...
Determination of boldenone sulfoconjugate and related steroid sulfates in equine urine by high-performance liquid chromatography/tandem mass spectrometry. Sulfoconjugated anabolic steroids were separated by micro-bore high-performance liquid chromatography. The eluent was introduced into the atmospheric pressure ion source of the triple-quadrupole mass spectrometer via an ion spray liquid chromatograph/mass spectrometer interface operated in the negative ion mode. The limit of detection was 10 pg on-column by selected ion monitoring of the molecular ion and the response increased linearly over a concentration range of 2.4 orders of magnitude. Following work-up by a liquid-solid extraction procedure of equine urine samples, full-scan daughter ion...
[Sublimation-dried mare’s milk and the possibility of its use in creating infant and dietary food products]. The main biological parameters were studied in sublimated mare's milk: protein fraction composition, amino-acid spectrum, fatty-acid composition of lipids and the content of vitamins and mineral substances. A high biological value of the sublimated mare's milk has been proved, as well as significant proximity of its composition to human milk. Preliminary data have evidenced expediency of mare's milk use for the development of adapted milk mixtures for baby foods. However, the fatty component of the mixtures needs certain correction by addition of vegetable oil. The sublimated mare's milk can b...
Effect of feeding on renin-angiotensin-aldosterone system of the horse. The effect of feeding frequency and associated meal size on the renin-angiotensin-aldosterone system (RAAS) in seven horses was examined. A daily maintenance ration of hay-grain pellets was provided either as a multiple feeding regimen (MF), in which the ration was divided into six equal portions fed at 4-h intervals, or as a single large feeding (SF) given from 9 A.M. until 11 A.M. Plasma renin activity (PRA), aldosterone (PAC), cortisol (PCC), protein concentration (TP), packed cell volume (PCV), and serum sodium and potassium were measured serially. To prevent significant RAAS stimulation d...
Reduction and release of ferritin iron by plant phenolics. The reductive release of ferritin iron by several naturally occurring o-diphenols was studied. The initial rate of iron release was quantified by spectrophotometric measurement of the Fe(ferrozine)3(2+) complex, which absorbs maximally at 562 nm. The initial rate of iron release was dependent upon o-diphenol concentration, but not on the concentration of the chromophoric chelating agent, ferrozine, Stoichiometric measurements resulted in a ratio of 2Fe(II) released per molecule of o-diphenol. The series of o-diphenols studied included, caffeic acid, chlorogenic acid, dihydrocaffeic acid, 3,4-d...
Regional distribution and species variation of prolactin binding sites in the brain. The binding of 125I-labeled ovine prolactin (125I-oPRL) to membranes from different brain regions of pigeon, rabbit, rat, pig, calf, horse, and ewe was studied. The hypothalamus from rabbit, pig, horse, and pigeon showed a low but specific binding for 125I-oPRL clearly different from the other brain regions examined (cortex and cerebellum), whereas in the brain from rat, calf, and ewe the binding was very small and quite uniform in the various regions. Also the membranes from choroid plexus of rabbit, pig, calf, and horse showed an evident specific binding for prolactin. The binding of 125I-oP...
Effects of active immunization against gonadotropin releasing hormone on gonadotropin secretion after ovariectomy and testosterone propionate administration to mares. Five lighthorse mares were actively immunized against gonadotropin releasing hormone (GnRH) conjugated to bovine serum albumin (BSA) to study the involvement of GnRH in luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion following ovariectomy (OVX) and after administration of testosterone propionate (TP). Five mares immunized against BSA served as controls. Immunizations were started on November 1, and OVX was performed in June (d 1). All mares were treated with TP from d 50 to 59 after OVX. On the day of OVX, concentrations of LH were lower (P less than .05) in GnRH-immu...
Biochemical and genetic characterization of Corynebacterium pseudotuberculosis. Isolates (n = 94) of Corynebacterium pseudotuberculosis were obtained from sheep, goats, horses, and cattle from various parts of the world. The isolates were characterized biochemically and by restriction endonuclease analysis of DNA. We found near homogeneity in the ability of isolates to ferment carbohydrates and to produce urease. All isolates produced phospholipase D and catalase. The ability of isolates from horses to reduce nitrate, the inability of isolates from sheep and goats to do so, and the correlation of this characteristic with results of restriction endonuclease analyses confir...
Hematologic and serum biochemical alterations associated with multiple halothane anesthesia exposures and minor surgical trauma in horses. Five horses were anesthetized similarly by use of xylazine, guaifenesin, thiamylal sodium, and halothane in oxygen on 3 consecutive days, and minor surgical procedures were performed. For 1 to 10 days after the last anesthetic exposure, clinical, hematologic, and serum biochemical features were monitored, and after necropsy, histologic examination of major organ tissues was performed. Predominant hematologic changes from base-line values included leukocytosis (maximal at 27 hours, 10,500 +/- 1,750 cells/microliter), neutrophilia (maximal at 51 hours, 7,485 +/- 1,719 cells/microliter), and lymp...
