Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Metabolism
Equine metabolism encompasses the biochemical processes that occur within horses to maintain life, including the conversion of food into energy, the synthesis of necessary compounds, and the elimination of waste products. These processes are essential for supporting various physiological functions such as growth, reproduction, and physical performance. Key components of equine metabolism include carbohydrate, fat, and protein metabolism, each of which contributes to the overall energy balance and health of the horse. Factors influencing metabolic rate and efficiency in horses include age, breed, diet, exercise, and health status. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, regulation, and implications of metabolic processes in equine physiology.
Changes in selected biochemical constituents of blood collected from horses participating in a 50-mile endurance ride. The effects of strenuous exercise on serum electrolytes, blood metabolites, and serum enzymes were studied in a group of 13 horses participating in a 50-mile endurance ride. Blood samples were collected before, during, and at the end of the ride, as well as 1 hour and 16 hours after the completion of the ride. There were significant changes in these values when preride values were compared with those of samples taken at different sample-collection periods. Significant (P less than 0.001) decreases were observed in serum concentrations of chloride, potassium, and calcium. A significant increase...
The use of capillary column gas chromatography and negative ion chemical ionization mass spectrometry to confirm the administration of synthetic corticosteroids to horses. The negative ion chemical ionization mass spectra of the MO-TMS derivatives of the corticosteroids prednisolone, betamethasone and dexamethasone have been obtained using capillary column gas chromatography mass spectrometry. The spectra showed abundant diagnostic ions at m/z greater than 300 allowing for clear discrimination between the three steroid derivatives. A capillary column gas chromatographic mass spectrometric method using negative ion chemical ionization mass spectrometry has been developed to confirm the presence of the parent steroids in horse urine following the administration of...
Vitamin K-dependent carboxylase in horse liver, spleen and kidney. The presence of vitamin K-dependent carboxylase is demonstrated in the microsomal fraction of horse liver, spleen and kidney. The carboxylating enzyme systems in the spleen and in the kidney are susceptible to warfarin in a similar way as is carboxylase from the liver. It is concluded, that during the administration of vitamin K-antagonists (anticoagulation therapy) carboxylase in all these tissues is inhibited. Since most probably the majority of the reaction products of spleen and kidney carboxylase are no clotting factors, the inhibition of their production is a side-effect of the anticoagu...
3-Hydroxy- and 3-keto-3-phenylpropionic acids: novel metabolites of benzoic acid in horse urine. The metabolism of benzoic acid has been examined in the horse, using 14C- and deuterium-labelled compounds. Chromatographic analysis of the urine showed the presence of hippuric acid, benzoyl glucuronide and benzoic acid and a discrete band which accounted for 2% of the dose administered. This material was isolated by solvent extraction and HPLC and, following treatment with diazomethane, examined by GC/MS. The major component of this fraction was 3-hydroxy-3-phenylpropionic acid methyl ester, which was accompanied by very much smaller amounts of cinnamic acid methyl ester and acetophenone. Th...
Changes in blood neutrophil/lymphocyte ratio related to adrenocortical function in the horse. Blood neutrophil/lymphocyte ratio and plasma cortisol levels were measured before and after (1) the injection of adrenocorticotrophic hormone (ACTH1-24) in 8 Thoroughbreds and (2) exercise in 5 Thoroughbreds in training. Plasma cortisol levels were significantly (P less than 0.01) increased within 60 mins of injection of ACTH1-24 and immediately after exercise. The mean neutrophil/lymphocyte ratio altered significantly (P less than 0.01) at 240 mins after ACTH1-24 administration and at 180 mins after a training gallop. A transient lymphocytosis occurred following exercise.
Mineral metabolism and immobilization osteopenia in ponies treated with 25-hydroxycholecalciferol. The left thoracic limb was immobilized in a plaster cast in 6 grade weanling ponies for 6 weeks. Two ponies were injected intramuscularly each day with 2.4 micrograms of 25-hydroxycholecalciferol [25(OH)D3] per kg bodyweight, two with 1.2 micrograms and two received no injections. Immobilization of 25(OH)D3 treatment had no significant effect on mineral metabolism. Immobilization resulted in significantly decreased weight and specific gravity of metacarpus III (MCIII). Histologic examination and triple fluorochrome incorporation showed that the osteopenia was caused by atrophy of osteoblasts w...
The effect of ethacrynic acid, bumetanide, frusemide, spironolactone and ADH on electrolyte excretion in ponies. The effect of ethacrynic acid, bumetanide, frusemide, spironolactone and anti-diuretic hormone (ADH) on the urinary and faecal excretion of water and electrolytes by ponies was studied. Ethacrynic acid, bumetanide, and frusemide given intravenously, increased urinary sodium excretion, and, excepting frusemide, decreased faecal sodium excretion. Given by stomach tube ethacrynic acid reduced urinary and faecal sodium. Bumetanide, given intravenously, spironolactone, frusemide and ADH increased urinary sodium and all except frusemide intravenously decreased faecal sodium regardless of route of ad...
The measurement of liquid and solid digesta retention in ruminants, equines and rabbits given timothy (Phleum pratense) hay. 1. Digesta passage and retention were measured in heifers, sheep, goats, equines and rabbits of varying body-weights when given timothy (Phleum pratense) hay. 2. Two passage markers were compared, cobalt (III) ethylene diamine tetraacetate (CoEDTA) and chromiummordanted timothy fibre for liquid and solid phase respectively. Both markers were injected into the rumen of the ruminants and into the caecum of the equines and rabbits. 3. In ruminants, two different sets of rate constants (k1 and k2) were derived from a two-pool model for marker passage, using a graphical approach and a computer-base...
Bioavailability of phenylbutazone preparations in the horse. Plasma phenylbutazone concentrations were determined for up to 12 h in 6 horses following intravenous and oral phenylbutazone administration. To evaluate the bioavailability of different oral preparations, phenylbutazone was administered in a paste as well as the traditional powder form. The effect of the state of stomach contents on the absorption of phenylbutazone was investigated by administering the paste before and after feeding; the powder was given in a small bran mash and a full feed of lucerne chaff, wheaten chaff and bran. Despite great variability among individual horses both the pa...
Changes in circulating gut hormones in the horse during long distance exercise. Venous blood samples were collected before and immediately after an 80 km ride and a 42 km race. They were analysed for blood glucose and lactate, and for plasma non-esterified fatty acids, insulin, pancreatic glucagon, pancreatic polypeptide, gastrin, gastric inhibitory peptide, somatostatin and vasoactive intestinal polypeptide concentrations. The 80 km ride was associated with marked hypoglycaemia and a slight lactic acidaemia together with an increase in plasma glucagon, somatostatin, pancreatic polypeptide and vasoactive intestinal polypeptide values. The 42 km race produced hyperglycaemi...
Glucose utilization in the horse. 1. Total entry, irreversible loss and recycling rates of glucose were measured in four non-pregnant female Shetland ponies before and after a 24 h fast by the continuous intravenous infusion of a mixture of [U-14C]glucose and [2-3H]glucose. 2. The post-fasting fall in the concentration of glucose and the rise in the concentration of ketones in plasma were not significant. 3. After fasting the total entry rate fell from 1.44 +/- 0.11 (n4) to 1.19 +/- 0.12 mg/min per kg body-weight (P less than 0.01) and irreversible loss fell from 1.36 +/- 0.10 (n4) to 1.05 +/- 0.10 mg/min per kg body-weight (P...
Effects of nandrolone phenylpropionate in the horse: (3) skeletal muscle composition in the exercising animal. The effect of 11 weekly injections of nandrolone phenylpropionate (400 mg) on some skeletal muscle parameters was investigated in 6 Thoroughbred geldings undergoing training. Three muscles were sampled, the middle gluteal, the biceps femoris and the semitendinosus. Training alone produced increases in the percentage of fast twitch high oxidative fibres (FTH), glycogen content and the activities of citrate synthase, 3-hydroxyacl CoA dehydrogenase and cytochrome oxidase. In contrast the training programme did not alter water content, total protein content, the activities of lactate dehydrogenase...
Plasma concentrations and urinary excretion of nandrolone and/or its metabolites after intramuscular injection of nandrolone phenylpropionate to horses. A radioimmunological method was used as a screening procedure to determine the period of detection or "clearance time", for the horse, of therapeutic doses of the synthetic anabolic steroid nandrolone phenylpropionate. Seven horses, either at rest or being exercised, were given a course of weekly intramuscular injections of the steroid. On the separate occasion, some of the horses were given a single intramuscular injection of the same compound. The weekly injections maintained a high plasma concentration of nandrolone and/or metabolites. The mean (+/- sd) period of detection in plasma of thes...
Factors affecting absorption of non-steroidal anti-inflammatory agents in the horse. The absorption of orally administered phenylbutazone (5 mg/kg) was studied in 10 thoroughbreds, eight ponies and four pony foals. Large variations in area under the curve (AUC) and peak plasma concentrations were found both within an animal and within groups of animals. Administration of phenylbutazone (5 mg/kg) following an overnight fast resulted in no difference among the three groups of animals with respect to AUC (0 to 24 hours), mean (+/- sd) values of which were 132 +/- 68, 107 +/- 48 and 98 +/- 6, respectively. Absorption characteristics of two oral phenylbutazone preparations (Equipal...
Fatty acid composition of equine erythrocytes. Fatty acid composition of erythrocytes of healthy horses was determined. Three fatty acids (C16:0, C18:0, and C18:1) were found in approximately equal quantities and comprised 72.17% of the total. Nine other fatty acids were found in small amounts. Saturated fatty acids constituted 67.2% of the total. Marked variation was demonstrated in the occurrence and distribution of fatty acids in the sterol ester, triglyceride, phospholipid, and free fatty acid fractions.
Gentamicin sulfate in the horse: serum, synovial, peritoneal, and urine concentrations after single dose intramuscular administration. Ten healthy adult mares were given a single intramuscular dose (2.2 mg/kg) of gentamicin sulfate. Over a 48-h period, gentamicin concentrations were measured serially in the serum of all ten mares and in synovial fluid, peritoneal fluid, and urine of six of the mares. The mean peak serum gentamicin concentration was 5.73 micrograms/ml at 1 h. Gentamicin was detected in synovial fluid and peritoneal fluid, with mean peak gentamicin concentrations of 2.41 micrograms/ml and 3.92 micrograms/ml, respectively, observed at 2 h. These concentrations declined in parallel with serum concentrations and w...
Plasma glucose and insulin concentrations and feeding behavior in ponies. The hypothesis that changes in blood glucose concentrations and(or) utilization rate affect feeding behavior in ponies was tested. Ponies (n = 4) were fasted for 4 h, then given iv injections of 50% glucose [.2 g glucose/BW.75 kg (low dose, LD) or 1.0 g glucose/BW.75 kg (high dose, HD)] or an equal volume of normal saline (HDS; LDS) 5 min before being allowed access to pelleted feed. Blood samples were drawn at regular intervals pre- and post-treatment and analyzed for plasma glucose (PG), immunoreactive insulin (IRI) and glucagon concentrations. All glucose-treated animals immediately ate mea...
The enzymic reduction and kinetics of oxidation of cytochrome b-245 of neutrophils. 1. The absorption coefficient of human neutrophil plasma-membrane reduced-minus-oxidized cytochrome b-245 was determined [delta epsilon (mM; 559-540 nm) = 21.6 cm-1]. 2. Neutrophil polymorphonuclear leucocytes (neutrophils) were prepared from human, ox, horse and pig blood. In each case plasma-membrane fractions were found to contain low-potential cytochrome b. When membranes from horse neutrophils were incubated anaerobically with either NADH or NADPH the cytochrome b became reduced. Prior stimulation of the cells with phorbol myristate acetate did not increase the rate or extent of cytochrom...
Effect of glucose administration on equine fasting hyperbilirubinemia. The effects of several treatments and their routes of administration on the reduction of hyperbilirubinemia in 9 pony mares after a 3-day fast were studied. Treatments were as follows: glucose given at doses of 1.2, 2.4, and 3.7 mg/min/kg of body weight; refeeding the base-line diet; feeding straw; and IV administration of taurocholic acid at a dosage of 0.07 mumol/min/kg. The 3 glucose dosages were each given by 3 different routes: IV, intraduodenal, and intragastric. The smallest dosage of glucose given by IV route reduced the plasma bilirubin concentration only 7%, even though other measure...
Energy metabolism of the contagious equine metritis bacterium. The energy metabolism of the English E-CMO strain of contagious equine metritis bacterium was studied in whole cells and cell extracts. This bacterium appears to have an active Krebs cycle and probably obtains energy by oxidative phosphorylation since glycolysis and the hexose monophosphate pathways appear to be absent. These conclusions are based on the findings that [U-14C]glucose incorporation by this bacterium is below the level of detection, and that respiration is stimulated by Krebs cycle intermediates (i.e., malate, citrate, and succinate), but not by glucose, fructose, maltose, or suc...
Resonance-enhanced Raman identification of a ternary chemical intermediate during the equine liver alcohol dehydrogenase reduction of p-(dimethylamino)benzaldehyde. The nature of the binding of aromatic aldehyde and aromatic alcohol substrates to the catalytic zinc of equine liver alcohol dehydrogenase has been studied by using resonance-enhanced Raman spectroscopy. When an excess of both enzyme and coenzyme to substrate is used, a stable ternary chemical intermediate is formed between liver alcohol dehydrogenase and the reduced coenzyme, nicotinamide adenine dinucleotide, and the aldehyde, p-(dimethylamino)benzaldehyde, in the pH range 8.5-0.6. Resonance-enhanced Raman spectra clearly show that this same intermediate is formed between the excess enzyme, ...
Effect of diet on the oral glucose tolerance test in the horse. The effect of altering the diet during the week preceding the administration of an oral glucose tolerance test was studied in 7 horses. The results indicated that substantially lower oral glucose tolerance test curves are observed in horses fed a stable diet comprised of oat hay, a commercially prepared complete feed, and oat and alfalfa chaff, when compared with the curves for horses grazing clover and kikuyu pasture. It was concluded that, in utilizing the oral glucose tolerance test to assess small intestinal function in the horse, it may be necessary to consider the dietary history.
