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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.
Effect of sodium bicarbonate on racing Standardbreds. Twenty-two Standardbred horses in race training were used in a crossover experiment to determine the effect of oral sodium bicarbonate (NaHCO3) administration on performance and metabolic responses to a 1.6-km (1-mile) race. Horses were paired and one horse in each pair was treated with either NaHCO3 (300 mg/kg BW) or a placebo, 2.5 h before they raced against each other. Each horse was scheduled to compete in two races, approximately 1 wk apart, one on each treatment. Horses always raced in the same pairs. Fourteen horses successfully completed both races. Jugular blood samples were obtained ...
Calcium-ionophore-induced formation of platelet-activating factor and leukotrienes by horse eosinophils: a comparative study. Horse eosinophils preincubated with 3H-labelled acetate and stimulated with the Ca2+ ionophores ionomycin or A23187 form a radioactive compound, which we have shown to be 1-O-alkyl-2-[3H]acetyl-sn-glycero-3-phosphocholine (platelet-activating factor). We could detect no 1-O-acyl-2-[3H]acetyl-glycero-3-phosphocholine in the radioactive fraction. The formation of platelet-activating factor was strongly correlated to the generation of leukotriene C4, the main arachidonate metabolite in horse eosinophils, suggesting that platelet-activating factor and leukotriene C4 have a common precursor pool (1...
Effects of transportation on early embryonic death in mares. Incidence of early embryonic death (EED) and associated changes in serum cortisol, progesterone and plasma ascorbic acid (AA) in transported mares were investigated. Mares were transported for 472 km (9 h) during either d 16 to 22 (T-3 wk, n = 15) or d 32 to 38 (T-5 wk, n = 15) of gestation. Blood samples were drawn from control, nontransported mares (NT-3 wk, NT-5 wk, n = 24) and transported mares pre-trip, midtrip, and at 0, 12, 24, 48 and 72 h post-transport and daily for the next 2 wk. Incidence of EED between transported and nontransported mares was not different (P greater than .05). Ser...
The characterisation of equine interleukin-1. Equine interleukin-1 has been produced from peripheral blood monocytes by stimulation with E. coli lipopolysaccharide. Sephacryl S200 gel filtration revealed a molecular weight of 17-18 kD. Chromatofocusing of the 17-18 kD peak identified four active fractions. Two major peaks were detected at pH 6.7 and pH 7, with smaller peaks at pH 6.3 and pH 5.9. The pI 7 molecule is probably the equine form of IL-1 beta.
Influence of variable content of dietary zinc on copper metabolism of weanling foals. The influence of variable zinc content (29.1, 250, 1,000 and 2,000 mg/kg of dry weight) in a basic diet containing 7.7 mg of copper/kg on the ability of weanling foals to maintain normal copper balance was investigated. Serum copper and zinc concentrations were monitored, and terminal hepatic copper and zinc contents were measured in 4 weanling foals fed the basic diet containing 29.1 mg of zinc/kg and in 2 foals each fed the higher-zinc diets. Foals fed the lower-zinc diets (29.1 and 250 mg/kg) maintained normal serum copper and zinc concentrations for 14 to 15 weeks, whereas those fed the 2 ...
Effect of transportation on the estrous cycle and concentrations of hormones in mares. Effect of transportation on estrous behavior, duration of the estrous cycle, ovulation, pregnancy rates and concentrations of serum cortisol, plasma ascorbic acid (AA), LH, estradiol and progesterone in mares was investigated. Fifteen mares were transported for 792 km (12 h) during the preovulatory stage of estrus. Transported mares were bled immediately before transport (baseline), at midtrip and 0, 12, 24, 48 and 72 h post-transport and twice daily from d 1 before transport to d 1 (estrogen) or 3 (LH) post-ovulation. Blood samples also were taken for progesterone on d 0, 2, 6, 10, 15, 16, 17...
Equine growth hormone. Detection of immunoreactive sequences using poly- and monoclonal antibodies. The immunochemical behavior of several fragments of equine growth hormone (eGH) was examined using competitive binding assays with antibodies (Abs) to eGH obtained from different sources. Antigenicity was detected within the sequences 5-72 and 73-123 by rabbit Abs to eGH and by three mouse monoclonal antibodies (MAbs) produced by using bovine growth hormone as immunogen, but showing heteroclitic properties towards eGH. The polyclonal Abs to eGH also recognized as immunoreactive two smaller peptides corresponding to the amino acid residues 52-72 and 110-123. By contrast, the heteroclitic Abs to...
Amino acids in different layers of the matrix of the normal equine hoof. Possible importance of the amino acid pattern for research on laminitis. A method was developed for separating different layers of the matrix of the equine hoof wall by dissection, and the layers were then analyzed with respect to their amino acid composition. The results were used to compare the biochemistry of hard keratinization (e.g., in the hoof wall matrix) and soft keratinization (e.g., in the epidermis of the skin). Hard keratinization differed from soft keratinization not only by its previously well known high incorporation of cystine, but also by considerable incorporation of tyrosine and threonine into the outer layers of the keratogenous zone and by the...
Biochemical changes in articular cartilage opposing full- and partial-thickness cartilage lesions in horses. Using arthroscopic technique, identical diameter defects were created in the proximal articular surface of both intermediate carpal bones of 6 horses. One of each pair of defects was deepened to penetrate the subchondral plate. Removed cartilage was assayed for [35S] sulfate incorporation, total hexosamine content, and DNA content. Six weeks later, cartilage was harvested and similarly analyzed from the distolateral portion of the radius directly opposite the created lesions and the distomedial portion of the radius distant from the lesion. The repair tissue filling the full-thickness defect a...
In vivo regulation of plasma [H+] in ponies during acute changes in PCO2. The major objective of this study was to test the hypothesis that in ponies the change in plasma [H+] resulting from a change in PCO2 (delta H+/delta PCO2) is less under acute in vivo conditions than under in vitro conditions. Elevation of inspired CO2 and lowering of inspired O2 (causing hyperventilation) were used to respectively increase and decrease arterial PCO2 (Paco2) by 5-8 Torr from normal. Arterial and mixed venous blood were simultaneously sampled in 12 ponies during eucapnia and 5-60 min after Paco2 had changed. In vitro data were obtained by equilibrating blood in a tonometer at f...
Mycoplasmas from donkeys and horses in the Sudan. Seventeen isolates (4.27%) were recovered from 398 samples. Twelve isolates (4%) were obtained from 300 donkey nasal swabs, three (4.3%) and two (6.89%) isolates were recovered from 69 horse nasal swabs and 29 mare uterine washings, respectively. Nine isolates were lost during storage at -20 degrees C and the remaining eight were identified as mycoplasmas and their biological, biochemical and serological reactions were investigated. The isolates could be divided into two groups on the basis of glucose fermentation and arginine hydrolysis. The first group neither fermented glucose nor hydrolyse...
Effect of palosein (superoxide dismutase) and catalase upon oxygen derived free radical induced degradation of equine synovial fluid. The effect of oxygen derived free radicals (ODFR) upon the specific viscosity of equine synovial fluid was studied. ODFR were generated either by a mixture of ferrous iron and EDTA (Fe/EDTA) or by a mixture of hypoxanthine and xanthine oxidase (HX/XO). Incubation of the synovial fluid with both free radical generating systems decreased its specific viscosity. When the synovial fluid was incubated with Fe/EDTA the specific viscosity of the synovial fluid was reduced rapidly. By 2 mins, it was 53 +/- 3 per cent of the original specific viscosity and by 30 mins it was reduced to 39 +/- 5 per cent...
Prolonged effect of a single injection of human chorionic gonadotrophin on plasma testosterone and oestrone sulphate concentrations in mature stallions. The long term effect of a single injection of 6,000 iu of human chorionic gonadotrophin (hCG) was studied in two pony stallions. Peripheral plasma samples were analysed for testosterone and oestrone sulphate. Testosterone concentrations were markedly elevated for five days after injection in both stallions. No adverse effects of these high concentrations were observed on concentrations later in the experiment. There was an initial increase in oestrone sulphate in one stallion, after which concentrations decreased to below pre-injection levels. The other stallion (whose initial oestrone sulphat...
Radioimmunoassay for albuterol using a monoclonal antibody: application for direct quantification in horse urine. A monoclonal antibody was synthesized in mouse against the O-(3-carboxypropionyl) derivative of albuterol linked to bovine serum albumin. Isotyping of this material revealed the IgG1 class characterized by an affinity constant of 1.03 nM-1 and a density of sites of 0.55 nM. This antibody was found specific as its cross-reactivity to structurally related molecules was less than 1% except for clenbuterol (75%). A radioimmunoassay was set up with culture supernatant (final dilution 1/1000) and [3H] albuterol. The calibration curve was characterized by a maximum binding of 28%, an ED50 of 1.15 pmo...
Muscle buffering capacity and dipeptide content in the thoroughbred horse, greyhound dog and man. 1. Muscle buffering capacity (beta m) and dipeptide content were measured in locomotory muscles of the Thoroughbred horse, Greyhound dog and Man. 2. Beta m and carnosine contents were highest in the horse. Anserine was only found in dog muscle. 3. The higher beta m in horse and dog muscle, compared with man, appears to be predominantly due to higher muscle contents of histidine containing dipeptides in these species.
Further evidence for a silent allele in the transferrin locus of the horse. A silent allele in the transferrin locus (Tf) was observed in a Thoroughbred mare and in five of her offspring from three different matings. Evidence for the silent allele was obtained by quantitative immunodiffusion studies.
Population data and a fourth allele for equine complement component 3 (C3). The C3 polymorphism of equine serum or plasma revealed by agarose gel electrophoresis can be diagnosed with protein stain following acid protein fixation. In addition to the three alleles previously described (C31, C32, C33), a fourth allele (C34) was found. Population data for 25 domestic breeds and Equus przewalskii are presented.
An improved method for the study of equine haptoglobin heterogeneity. Equine serum haptoglobin was separated by polyacrylamide gel isoelectric focusing and visualized by protein staining or Western blotting. Conventional protein staining revealed up to three bands in the pI range 4.17 to 4.44. The blotting technique, however, showed an anodal group of 8 to 10 bands with a pI range of 4.11 to 4.52 and a cathodal group of 4 to 6 bands with a range of 4.55 to 5.14. The blotting method revealed that equine haptoglobin migrates outside the prealbumin area, in contrast to previous reports.
Plasma [H+] regulation and whole blood [CO2] in exercising ponies. The major objective was to determine in ponies whether factors in addition to changes in blood PCO2 contribute to changes in plasma [H+] during submaximal exercise. Measurements were made to establish in vivo plasma [H+] at rest and during submaximal exercise, and CO2 titration of blood was completed for both in vitro and acute in vivo conditions. In 19 ponies arterial plasma [H+] was decreased from rest 4.5 neq/l (P less than 0.05) during the 7th min of treadmill running at 6 mph, 5% grade (P less than 0.5). A 5.6-Torr exercise hypocapnia accounted for approximately 2.9 neq/l of this reduced ...
Allergens of horse epithelium. I. Physicochemical and immunochemical characterization of five different horse epithelium raw materials used for allergen extract preparation. We investigated five horse epithelial allergen extracts prepared from different qualities of raw material by several biochemical and immunochemical methods. Horse serum albumin and horse serum were used to identify serum-related antigens. We found high similarities as well as marked differences between the extracts. There were strong differences in the protein contents, the protein patterns obtained by isoelectric focusing and sodium dodecyl sulfate polyacrylamide gel electrophoresis, the total allergenic activities obtained by radioallergosorbent test inhibition assays and the amounts and num...
Conformational comparison in the growth hormone family. 1. The method of Kubota et al. [Biochim. biophys. Acta 701, 242-252 (1982)] was applied to several members of the growth hormone family in order to examine their conformational homology. 2. The method neither detects differences between rat, cow, sheep, horse and alpaca hormones, nor between monkey and human hormones. 3. Lack of homology between primate and non-primate growth hormones was found in segments 42-49 and 184-191. The first fragment could be linked to species-specificity.
The toxic factor in white snakeroot: identity, analysis and prevention. White snakeroot (Eupatorium rugosum Houtt) has been known to cause trembles in animals and milk sickness in humans since the American Revolution. It still continues to poison animals. Horses and goats are particularly sensitive to white snakeroot poisoning. Resurgence of livestock production on small farm units, and utilization of fresh raw milk may result in milk sickness; if the animals have white snakeroot exposure. The goat is the only animal with good toxicity threshold data. In other animals and humans the toxicity thresholds of white snakeroot are not known, and that until responsible t...
Hypoxanthine phosphoribosyltransferase activity in tissues and hypoxanthine concentrations in plasma and CSF of the horse in comparison with other species. 1. Plasma hypoxanthine and xanthine concentrations are very low in the horse and low in rat, mouse and greyhound compared to concentrations in beagles, man, sheep and rabbit. 2. Activities in erythrocytes of the main enzyme metabolizing hypoxanthine, hypoxanthine phosphori-bosyltransferase, show a similar pattern (Tax et al., 1976, Comp. Biochem. Physiol. 54B, 209-212); thus low activities have been found where plasma concentrations were low. 3. Hypoxanthine phosphoribosyltransferase activities in horse tissue other than erythrocytes are similar to those in man and rabbit with high activities ...
Effect of maternal treatment with altrenogest on pituitary response to exogenous GnRH in pubertal stallions. The pituitary response to exogenous GnRH was studied in 8 colts of Quarter Horse phenotype from 32 to 96 weeks of age. Colts were from dams treated daily from Day 20 to 325 of gestation with (1) 2 ml neobee oil per 50 kg body weight (controls); or (2) 2 ml altrenogest per 50 kg body weight. GnRH challenges (5 micrograms/kg body weight) were administered every 8 weeks from 32 to 96 weeks of age to estimate pituitary content of LH. Blood samples were collected every 20 min for 4 h before GnRH and 15, 30, 45, 60, 90, 120, 180, 240 and 360 min after GnRH. Serum concentrations of LH and FSH were de...
An attempt to determine the tissue origin of equine serum alkaline phosphatase by isoelectric focusing. The main purpose of this study was to ascertain whether isoelectric point determination of alkaline phosphatase (AP) using an isoelectric focusing technique on agarose gels could define the isoenzymes present in healthy equine serum. The isoelectric points of AP extracted from nine tissues ranged from pH 3.5 to 7.5 with all tissues having multiple bands. There was considerable similarity in band pattern among tissues, with only pancreatic and colostral AP having substantially different isoelectric points from the others. Sera contained thirteen bands with isoelectric points ranging from pH 3.5...
Changes in muscle free carnitine and acetylcarnitine with increasing work intensity in the Thoroughbred horse. Treadmill exercise in Thoroughbred horses of 2 min duration and increasing intensity resulted in increased formation and accumulation of acetylcarnitine in the working middle gluteal muscle. At high work intensities a plateau in acetylcarnitine formation was reached corresponding to approximately 70% of the total carnitine pool (approx. 30 mmol.kg-1 dry muscle). Formation of acetylcarnitine was mirrored by an equal fall in the free carnitine content, which stabilised, at the highest work intensities, at around 8 mmol.kg-1 dry muscle. Acetylcarnitine and carnitine reached their point of maximum...
Molecular forms of gastrin in antral mucosa of the horse. The predominant form of gastrin in the antral mucosa of the stomach of virtually all species previously examined is the 17 amino acid peptide little gastrin (G17). This report describes the occurrence in equine antral mucosa of an immunoreactive form of gastrin with elution properties on Sephadex G-50 superfine similar to human unsulfated big gastrin (G34-I). This putative equine big gastrin was a major component of the gastrin immunoreactivity present. A second peak of activity in equine antral mucosa eluted in an identical manner to human little gastrin (hG17-I). Inhibition curves of equine ...
Equus przewalskii plasma protease inhibitor (Pi) system. A detailed biochemical characterization of four of the five previously described alleles of the plasma protease inhibitor (Pi) system of Equus przewalskii was performed using both one- and two-dimensional electrophoretic techniques. The proteins have been characterized in terms of isoelectric point, relative molecular mass, inhibitory activity to bovine trypsin and chymotrypsin, immunochemical cross-reactivity, terminal sialic acid content and enzyme:inhibitor complex formation and the oxidation sensitivity of this interaction. Using these functional criteria, only three loci (Spi 1, 2 and 3) ...
Comparison of heparan sulfate proteoglycans from equine and human glomerular basement membranes. 1. Proteoglycans extracted from human and equine glomerular basement membranes (GBM) were purified by ion-exchange chromatography and gel filtration. 2. The glycoconjugates had an apparent molecular mass of 200-400 kDa and consisted of 75% protein and 25% glycosaminoglycan. Glycosidase and HNO2 treatment and the amino sugar and sulfate composition of both proteoglycan preparations identified heparan sulfate (HS) as the predominant saccharide chain. 3. Hydrolysis with trifluoromethanesulfonic acid yielded comparable core proteins with molecular masses of ca 160 and 120 kDa. 4. The HS chains had...
