Proteins are essential macromolecules that play diverse roles in the physiology and health of horses. They are composed of amino acids and are involved in various biological processes, including tissue growth, repair, and the synthesis of enzymes and hormones. Dietary proteins are a key component of equine nutrition, influencing muscle development, immune function, and overall performance. Horses require a balanced intake of essential amino acids, which must be obtained through their diet, as they cannot be synthesized endogenously. This page compiles peer-reviewed research studies and scholarly articles that explore the types, functions, and dietary requirements of proteins in horses, as well as their impact on equine health and performance.
Miquelis R, Simon C.1. The subcellular particles of horse and rat thyroids were fractionated in a B XIV zonal rotor on a non-linear gradient of Ficoll after labelling with radioactive iodine in vitro (horse) or in vivo (rat). In the horse, the resulting fractions were analysed for radioactive iodine, protein and enzymes representative of certain subcellular particles. In the rat, iodine turnover and thyrotrophin stimulation were studied. 2. The population of iodinated particles could be subdivided into three main classes, characterized by differences in beta-galactosidase and acid phosphatase content and position...
Hoy TG, Harrison PM, Shabbir M, Macara IG.The rate of release of iron to 1,10-phenanthroline from ferritin fractions of different iron contents has been studied. The experimental results could be interpreted by a simple hypothetical model of the shape of the hydrous ferric oxide micelle at different iron contents, and reasonable correlation obtained between the rate of release and the calculated micelle surface areas. Initial rates of release did not correlate significantly with protein concentration.
Wilson S, Laurie G, Logan L.Multiple injections of horses with the membrane-microsome fraction from human thymocytes plus Freund's adjuvant gave rise to antithymocyte membrane serum with the immunosuppressive activity located in the γ2 region. Use of lymphoblast membrane-microsome fraction as antigen did not reduce the level of absorption required. Batch purification with QAE-Sephadex combined with ammonium sulfate fractionation gave 100% pure γG-globulins in good yield with reduced γ1-globulin content. The antithymocyte membrane globulin prolonged skin allografts in the cynomolgus monkey, chimpanzee, and man, showed ...
Crichton RR.The researchers investigated the biochemical properties of ferritin, a protein responsible for iron storage in the body. They identified its distribution and structure, noting variations in different species and tissues. […]
Creutz C, Sutin N.The kinetics of the reduction of horseheart ferricytochrome c by sodium dithionite (phosphate buffer-sodium chloride; pH 6.5, mu = 1.0, 25 degrees ) features two reaction pathways; one with the rate constant k(3) = 1.17 x 10(4) M(-1) sec(-1), the other with the rate constant k(1)k(2)/k(-1) = 6.0 x 10(4) M(-1) sec(-1). These pathways are interpreted in terms of remote attack (possibly by way of the exposed edge of the porphyrin system) and adjacent attack (requiring the opening of the heme crevice). The limiting rate for the adjacent pathway (k(1) = 30 sec(-1)) is in good agreement with the rat...
Crichton RR, Millar JA, Cumming RL, Bryce CF.1. Ferritin was isolated from human and horse spleen and liver, and apoferritin prepared therefrom. 2. The electrophoretic mobilities of the four apoferritins were determined on polyacrylamide gels and on cellulose acetate strips, and all found to be equal. 3. Homologous ferritins share reactions of identity in immunodiffusion experiments, whereas heterologous ferritins show only partial identity. 4. The subunit molecular weight of each of the apoferritins was determined by polyacrylamide-gel electrophoresis in sodium dodecyl sulphate and by chromatography on agarose columns in 6m-guanidine-HC...
Hedlund B, Danielson C, Lovrien R.Organic phosphates, ATP, AMP, and 2,3-di-phosphoglycerate (DPG) were interacted with horse oxyhemo-globin. Binding parameters were obtained by means of dialysis equilibrium in buffers at 5°, and from calorimetry at 5 and 25°, all in the pH mom 6.5-7.3. The calorimetric results were evaluated assuming a single strong site, and assuming that the pH shifts which occur in the absence of added salt are due to electrostatic effects and not to changes in side-chain titration, upon mixing samples previously ad-justed to the same pH. There was obtained for ATP and 2,3- diphosphoglycerate. respectivel...
Reitnour CM, Salsbury RL.Protein digestion, nitrogen retention, plasma protein, plasma urea, and plasma-free amino acids were determined for ponies fed 3 different protein supplements. Substitution of casein, corn gluten meal, or corn gluten meal plus lysine for a portion of the cornstarch in a low-protein basal ration increased apparent digestion of protein. Substitution with either casein or corn gluten meal plus lysine produced a significant increase (P less than 0.05) in nitrogen retention, whereas the corn gluten meal substitution did not. Nitrogen retention, expressed as percentage of nitrogen absorbed, was incr...
Dai CB, Xiao Y, Lu H, Shen RX, Shao YM.Membrane protein GP90 of China equine infectious anemia virus (EIAV) vaccine strain (DLV) and its parental wild type LN strain were expressed with Bac-to-Bac baculovirus expression system and BALB/c mice were inoculated with purified protein, thereby to explore the availability of protein for differential diagnosis and potential for preparing genetically engineered vaccine. Methods: The authors infected donkey PBMC culture with China EIAV vaccine strain (DLV) and its parental wild type LN strain, extracted its proviral DNA as template, amplified the GP90 of DLV and LN, respectively, and expres...
Miller PA, Lawrence LM.Six mature Quarter Horse mares were used in a crossover design to assess the effect of dietary protein level on metabolic response to exercise. After a 2-wk adaptation period to either a 12.9% (control) or an 18.5% CP (high-protein) diet, each mare performed a standard exercise test. The test consisted of a 15-min exercise period at 4.5 m/sec on a 9% grade motorized treadmill. Exercise resulted in an increase in heart rate (P less than .001), but there was no difference (P less than .05) between dietary treatments. In the jugular vein, lactate increased (P less than .01) from 6.3 to 52.0 mg/10...
Wieringa R, de Vries AA, Rottier PJ.Equine arteritis virus (EAV) is an enveloped, positive-stranded RNA virus belonging to the family Arteriviridae of the order NIDOVIRALES: Six transmembrane proteins have been identified in EAV particles: the nonglycosylated membrane protein M and the glycoprotein GP(5) (previously named G(L)), which occur as disulfide-bonded heterodimers and are the major viral envelope proteins; the unglycosylated small envelope protein E; and the minor glycoproteins GP(2b) (formerly designated G(S)), GP(3), and GP(4). Analysis of the appearance of the GP(2b), GP(3), and GP(4) proteins in viral particles by g...
Sticht H, Willbold D, Rösch P.Two molecular dynamics (MD) simulations were performed in order to increase the understanding of the dependence of protein conformation on solvent environment. The protein used for these simulations is the transcriptional activator of the equine infectious anemia virus (EIAV-Tat). The structure of this protein has been determined by nuclear magnetic resonance (NMR) in aqueous solution (Willbold et al., Science 264, 1584 (1994)) and in 40% (v/v) trifluoroethanol (TFE) (Sticht et al., Eur. J. Biochem., submitted) showing considerable differences in the stability of the secondary structure elemen...
Rey F, Hallebeek JM, Beynen AC.The question addressed was whether apparent crude fibre digestibility in ponies would change after lowering protein intake from adequate to borderline deficient. Four adult ponies were fed a low- and high-protein diet according to a cross-over design. The diets consisted of grass hay and concentrates and provided either 1.5 or 3.6 g digestible crude protein/kg(0.75) per day. The two whole rations provided 2.4 g crude fibre/kg body weight per day. Apparent crude fibre digestibility was not affected by protein intake (low-protein diet: 42.9 +/- 4.03%; high-protein diet: 38.1 +/- 1.14%, means +/-...
Hilbert BJ, Rowley G, Antonas KN, McGill CA, Reynoldson JA, Hawkins CD.Sodium hyaluronate was injected into normal horse joints and joints that had undergone an arthrotomy and experimental cartilage damage. The elimination half-life for hyaluronic acid in normal joints was found to be approximately 96 h. The injection caused a non-significant increase (42%) in synovial fluid protein concentration and a fall in the intrinsic viscosity of the fluid. In the arthrotomy group the synovial fluid hyaluronic acid concentration fell after surgery but it was unaffected by the injection of sodium hyaluronate. An initial rise in the intrinsic viscosity of the synovial fluid ...
Lees P, Higgins AJ.A model of acute inflammation was used in a cross-over study in Welsh mountain ponies to assess the actions of flunixin meglumine on selected components of a localised inflammatory reaction induced by injecting 0.5 ml of a 2 per cent carrageenin solution into subcutaneously implanted tissue cages. Samples of exudate were harvested at predetermined times between three and 48 hours. Increases in leucocyte numbers and protein concentration were not prevented by flunixin treatment. Prostaglandin E2-like activity was present in exudates from untreated ponies with the highest mean concentration occu...
Peters GJ, Oosterhof A, Veerkamp JH.1. Activities of ADA, PNP and AK were measured in splenocytes and thymocytes of newborn children, young horses, pigs, sheep, rats and mice and compared with the activities previously found in peripheral lymphocytes. 2. With all species, except horse, the activity of ADA (per 10(6) cells) was higher in thymocytes than in lymphocytes. Activity of ADA was highest in splenocytes of pig and sheep. Activity of ADA was lowest in all lymphoid cells of the horse and only about 10% of the activity in human splenocytes and lymphocytes. 3. With all species, except horse, the activity of PNP was lower in t...
Parma AE, Cerone SI, Sansinanea SA.The antigenic relationship between Leptospira interrogans, equine cornea and lens was previously noted in our studies. Serum antibodies from horses inoculated with serovars wolffi, pomona, icterohaemorrhagiae, and tarassovi, were able to bind to five antigenic fractions from both cornea and lens, as demonstrated by immunoblotting. These antigens seem to be made up of protein and carbohydrates. After treatment with periodate for cleavage of glycoside ring structures, those fractions kept their condition of target for anti-Leptospira antibodies. Nevertheless, all fractions lost that condition af...
Wyler M, Sage SE, Marti E, White S, Gerber V.The diagnostic value of allergen-specific immunoglobulin E (IgE) in horses with asthma is uncertain. A recently developed protein microarray detected abnormally high latex-specific IgE concentrations in the serum of horses with severe asthma. Objective: The main objective was to characterize the IgE profiles of asthmatic horses in Switzerland using a protein microarray platform in serum and bronchoalveolar lavage fluid (BALF). The secondary objective was to determine whether serological and BALF allergen-specific IgE concentrations correlated. Methods: Forty-four asthmatic and 39 control horse...
Poyet JL, Srinivasula SM, Alnemri ES.vCLAP, the E10 gene product of equine herpesvirus-2, is a caspase-recruitment domain (CARD)-containing protein that has been shown to induce both apoptosis and NF-kappaB activation in mammalian cells. vCLAP has a cellular counterpart, Bcl10/cCLAP, which is also an activator of apoptosis and NF-kappaB. Recent studies demonstrated that vCLAP activates NF-kappaB through an IkappaB kinase (IKK)-dependent pathway, but the underlying mechanism remains unknown. In this report, we demonstrate that vCLAP associates stably with the IKK complex through direct binding to the C-terminal region of IKKgamma....
Kizaki T, Mizuno Y, Takasawa T, Shiokawa H.Analysis of the quantitative precipitin reaction of acylphosphatase from porcine skeletal muscle with rabbit antiserum indicated the presence of at least two antigenic determinants on the porcine enzyme molecule. Immunological cross-reactivities of acylphosphatases from equine and rabbit skeletal muscles were examined. In double immunodiffusion with the antiserum, the precipitin lines of the porcine and equine enzymes completely fused, while the rabbit enzyme gave no precipitin line. The reaction between the 125I-labeled porcine enzyme and its antibody was inhibited to the same extent by the p...
Jensen-Jarolim E, Pacios LF, Bianchini R, Hofstetter G, Roth-Walter F.Owners and their domestic animals via skin shedding and secretions, mutually exchange microbiomes, potential pathogens and innate immune molecules. Among the latter especially lipocalins are multifaceted: they may have an immunomodulatory function and, furthermore, they represent one of the most important animal allergen families. The amino acid identities, as well as their structures by superposition modeling were compared among human lipocalins, hLCN1 and hLCN2, and most important animal lipocalin allergens, such as Can f 1, Can f 2 and Can f 4 from dog, Fel d 4 from cats, Bos d 5 from cow's...
van Berlo MF, Rottier PJ, Spaan WJ, Horzinek MC.Intracellular virus-specific proteins induced by equine arteritis virus (EAV) have been compared with in vitro translation products of virion and intracellular EAV RNAs. In infected BHK-21 cells, the two major virion proteins (C and E1) and polypeptides with mol. wt. of 60,000 (p60), 42,000 (p42) and 30,000 (p30) were found. There were no indications that the viral proteins were processed from a larger precursor as shown by pulse-chase, amino acid analogue and protease inhibitor experiments. The six polyadenylated RNAs that occur in EAV-infected cells were isolated and translated in an mRNA-de...
Deregt D, de Vries AA, Raamsman MJ, Elmgren LD, Rottier PJ.Monoclonal antibodies (MAbs) to equine arteritis virus (EAV) proteins were produced and characterized. The protein specificities of eight MAbs were determined definitively by immunoprecipitation of EAV proteins expressed from vaccinia virus recombinants (VVRs). Included were two new VVRs produced for this study, expressing the M and the GL proteins, respectively. Three MAbs were determined to be N-specific and five MAbs recognized the GL protein. One GL-specific MAb, 17F5, of the IgA class, efficiently neutralized EAV infectivity. In competitive binding assays (CBAs), the N-specific MAbs defin...
Kolmakova MV, Kuskova ZR, Ratner GM, Laptakova LM.Horse serum albumin has been shown to meet the requirements to protein preparations for microanalysis and thus to be suitable for use in kits of reagents for the radioimmunological determination of insulin and myoglobin, for the determination of tick-borne encephalitis virus antigen by the method of the enzyme immunoassay and for the stabilization of proteins in the hemagglutination test and the hemagglutination inhibition test.
Word TA, Larsen RW.Here the molar volume and enthalpy changes associated with the early events in the folding of ferrocytochrome c (Cc) at high pH have been examined using time resolved photoacoustic calorimetry (PAC). The data reveal an overall volume change of 1.3 ± 0.3 mL mol and an enthalpy change of 13 ± 7 kcal mol occurring subsequent to photodissociation of the unfolded CO bound Cc species in <∼20 ns. Two additional kinetic phases are observed that are associated with non-native His binding (ΔH and ΔV of 2 ± 4 kcal mol and -0.5 mL mol, τ ∼ 2.5 μs ) and Met binding (ΔH an...
Milne EM, Doxey DL, Gilmour JS.The analysis of peritoneal fluid is of value in the differential diagnosis of equine colic but its characteristics have not been evaluated in grass sickness. Peritoneal fluid was collected from 15 normal horses and from 11 cases of medical colic, 11 cases of surgical colic, 20 cases of acute grass sickness and 13 cases of subacute grass sickness. The fluid was analysed for its appearance, total and differential white cell count, specific gravity, total protein concentration and total and intestinal alkaline phosphatase activity. Fluid from cases of medical colic was normal in these respects. S...
Evenberg A, Meyer H, Gaastra W, Verheij HM, De Haas GH.The complete amino acid sequence of phosphlipase A2 (EC 3.1.1.4) from horse pancreas was determined. The protein controls of a single polypeptide chain of 125 amino acids and has a molecular weight of 13,927. The chain is crosslinked by seven disulfide bridges. The sequence was determined by automated Edman degradation of the intact protein and several of the large peptide fragments. Smaller peptides were analyzed by manual Edman degradation. Fragmentation of the peptide chain was accomplished by enzymatic digestion with trypsin, chymotrypsin, and thermolysin. The final overlap was found by di...
Deschene K, Céleste C, Boerboom D, Theoret CL.As a transient hypoxic state exists within skin wounds in horses and may be important for the healing process, this study sought to identify a molecular hypoxia response occurring in horse limb and body wounds healing by second intention. Hypoxia-inducible factor 1α (HIF1α) protein expression was studied throughout repair by Western blotting and immunofluorescence. Paradoxically, HIF1α was strongly expressed in intact skin and its expression decreased dramatically following wounding (p<0.01), despite the expected hypoxic state within the wounded tissue. HIF1α levels reincreased in parallel...
Brinkmann J, Koudelka T, Keppler JK, Tholey A, Schwarz K, Thaller G, Tetens J.The production and consumption of mare's milk in Europe has gained importance, mainly based on positive health effects and a lower allergenic potential as compared to cows' milk. The allergenicity of milk is to a certain extent affected by different genetic variants. In classical dairy species, much research has been conducted into the genetic variability of milk proteins, but the knowledge in horses is scarce. Here, we characterize two major forms of equine αS2-casein arising from genomic 1.3 kb in-frame deletion involving two coding exons, one of which represents an equid specific duplicati...
van Niekerk FE, van Niekerk CH.In the main experiment the total daily protein intake and quality (essential amino-acids) was varied in 4 groups of mares. The incidence of oestrus in mares during the transitional period was unaffected by protein nutrition. Ovarian activity, as evaluated by follicular development and size of the ovaries, was affected. Mares that received low-quality protein (Groups 1 and 2) had a higher number of smaller follicles (< 10 mm) that developed during the transitional period compared to mares on a high-quality protein intake (Groups 3 and 4). The mares that received the high quality protein ovulate...
Barbey C, Cauchard S, Cauchard J, Laugier C, Hartke A, Petry S.Rhodococcus equi remains a significant pathogen, causing severe pneumonia in foals. The development of vaccines and serologic diagnosis could be greatly facilitated by studying the humoral immune response to this equine pathogen. In this study, a crude extract of R. equi ATCC 33701-secreted proteins combined with the Montanide® ISA70 adjuvant was found to be highly immunogenic in mice with the highest titer of 99,000 on day 42 after the first subcutaneous immunization. This immune response was dependent on the quantity of proteins injected and the presence of adjuvant. By dot-blotting, eight ...
Koch DW, Berglund AK, Messenger KM, Gilbertie JM, Ellis IM, Schnabel LV.Tendon injury in the horse carries a high morbidity and monetary burden. Despite appropriate therapy, reinjury is estimated to occur in 50-65% of cases. Although intralesional mesenchymal stem cell (MSC) therapy has improved tissue architecture and reinjury rates, the mechanisms by which they promote repair are still being investigated. Additionally, reevaluating our application of MSCs in tendon injury is necessary given recent evidence that suggests MSCs exposed to inflammation (deemed MSC licensing) have an enhanced reparative effect. However, applying MSC therapy in this context is limited...
Ueno Y, Uemura R, Niwa H, Higuchi T, Sekiguchi S, Sasaki Y, Sueyoshi M.Equine proliferative enteropathy (EPE) caused by Lawsonia intracellularis is characterized by hypoproteinemia. There are currently no reliable reports that provide a reference value for the total serum protein (TP) concentration to clinically diagnose EPE. The objective of this study was to statistically determine the reference value. Feces and sera of 99 foals with EPE-like clinical signs and of 35 healthy foals were obtained. The samples were used for specific-gene detection of L. intracellularis, TP measurement, and specific-antibody detection against L. intracellularis. Based on these resu...
Loos CMM, McLeod KR, Vanzant ES, Stratton SA, Bohannan AD, Coleman RJ, van Doorn DA, Urschel KL.The objective of the study was to characterize the temporal changes of phosphorylation patterns of mTOR signaling proteins in response to two dietary protein sources in insulin dysregulated (ID, n = 8) and non-ID (n = 8) horses. Horses were individually housed and fed timothy grass hay and 2 daily concentrate meals so that protein was the first limiting nutrient and the total diet provided 120% of daily DE requirements for maintenance. On sample days, horses randomly received 0.25 g CP/kg BW of a pelleted alfalfa (AP) or commercial protein supplement (PS). Blood samples were collected before a...
Yu NH, Ho EN, Wan TS, Wong AS.Recombinant human erythropoietin (rhEPO), darbepoetin alfa (DPO) and methoxy polyethylene glycol-epoetin beta (PEG-EPO) are synthetic analogues of the endogenous hormone erythropoietin (EPO). These erythropoiesis-stimulating agents have the ability to stimulate the production of red blood cells and are commercially available for the treatment of anaemia in humans. These drugs are understood to have performance-enhancing effects on human athletes due to their stimulation of red blood cell production, thereby improving delivery of oxygen to the muscle tissues. Although their effect on horses has...
Dubin A, Potempa J, Turyna B.Horse blood leucocyte cytosol exhibits a broad inhibitory activity against serine proteinases. The purified inhibitor was exposed to investigated enzymes (trypsin, chymotrypsin, elastases and serine proteinase from S. aureus) for variable time and the products were analyzed by gradient polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. The molar ratio I:E, association rate constants k on and inhibition constants Ki for the enzymes and inhibitor were determined. The examined elastases form stable, stoichiometric complexes with the inhibitor (Ki less than 10(-10) M), ...
Thway TM, Wolfe MW.Equids and primates are the only species known to express the placental hormone chorionic gonadotropin (CG). CG is a member of the heterodimeric glycoprotein family and is composed of an alpha subunit linked to a hormone-specific beta subunit. Previously, we have reported that epidermal growth factor (EGF) regulates the equine glycoprotein hormone alpha subunit promoter through a protein kinase C (PKC)/mitogen-activated protein kinase (MAPK) signal transduction pathway in trophoblasts. The current study investigates the regulatory element/factors involved in the induction of equine glycoprotei...
