Topic:Cholesterol
Cholesterol in horses is a lipid molecule found in the blood that plays a role in various physiological processes, including cell membrane structure and hormone synthesis. It is obtained from dietary sources and synthesized in the liver. Cholesterol levels in horses can be indicative of metabolic health and are influenced by factors such as diet, age, and activity level. Measuring cholesterol concentrations can assist in assessing the nutritional status and detecting metabolic disorders in equines. This page aggregates peer-reviewed research studies and scholarly articles that explore the metabolism, regulation, and clinical implications of cholesterol in equine health.
Serum platelet-activating factor acetylhydrolase and paraoxonase-1 activity in horses infected with Leptospira spp. The aim of the study was to investigate the effect of infection with Leptospira spp. in horses on activities of platelet-activating factor acetylhydrolase (PAF-AH) and paraoxonase-1 (PON1) considering the anti-inflammatory/anti-oxidative properties of both enzymes. A total of 63 sport and leisure horses' sera were chosen among those routinely serologically examined on leptospirosis during the year 2009 in Croatia. Sera were divided into three groups according to the estimated level of antibody titre against Leptospira spp; group 1: sera serologically negative to leptospirosis (antibody titre<5...
Effect of β-carotene Supplementation on Italian Trotter Mare Peripartum. When the mare's estrous cycle resumes in winter, the β-carotene content of hay is depleted. Sixty Italian trotter mares were randomly assigned to a Control or a Treated Group. Treated Group received 1g/d synthetic β-carotene for 15 days from parturition. Blood samples collected at parturition and on days 5, 10 and 15 after partum were analysed for β-carotene, vitamins A, progesterone, 17 β-estradiol, the energy parameters (glucose, cholesterol, NEFA), the protein profile (total protein, albumin, urea) and LDH. Some changes in these measures were attributable to treatment, which significant...
Cholesterol addition protects membrane intactness during cryopreservation of stallion sperm. Addition of cholesterol to sperm membranes improved equine sperm stability during semen cryopreservation; however, it also reduced in vivo fertility. The objective of the present study was to determine the effects of adding cholesterol to stallion sperm prior to freezing, and subsequently removing it from frozen-thawed sperm. Semen from 12 stallions was subjected to four treatments: (T1) control, semen was diluted with Kenney extender, centrifuged, and resuspended to 100 x 10(6)spermatozoa/mL in INRA 82 freezing extender, packaged into 0.5-mL straws, cooled to 5 degrees C, and cryopreserved in...
Cholesterol-loaded-cyclodextrins and fertility potential of stallions spermatozoa. Irreversible damage occurs to spermatozoal membranes, during the phase transition, when spermatozoa are cooled from room temperature to 5 degrees C. Some of this damage can be ameliorated by adding cholesterol to the membrane, thereby altering membrane lipid composition. Adding cholesterol-loaded cyclodextrins (CLCs) to stallion spermatozoa prior to freezing, increases cell cryosurvival. However, the fertilizing potential of CLC-treated stallion spermatozoa is unknown. To address this, experiments were conducted which evaluated the ability of CLC-treated stallion spermatozoa to capacitate, acr...
Osmotic tolerance limits and membrane permeability characteristics of stallion spermatozoa treated with cholesterol. Stallion spermatozoa exhibit osmotic damage during the cryopreservation process. Recent studies have shown that the addition of cholesterol to spermatozoal membranes increases the cryosurvival of bull, ram and stallion spermatozoa, but the exact mechanism by which added cholesterol improves cryosurvival is not understood. The objectives of this study were to determine if adding cholesterol to stallion sperm membranes alters the osmotic tolerance limits and membrane permeability characteristics of the spermatozoa. In experiment one, stallion spermatozoa were treated with cholesterol-loaded cycl...
Effects of high and low inspired fractions of oxygen on horse erythrocyte membrane properties, blood viscosity and muscle oxygenation during anaesthesia. To evaluate whether a period of hyperoxia or after a period of hypoxia produced changes attributable to reactive oxygen species in anaesthetized horses. Methods: Prospective randomized experimental study. Methods: Six healthy (ASA I) geldings, aged 4.5-9.5 years and weighing 510-640 kg(-1). Methods: After 30 minutes breathing air as carrier gas for isoflurane, horses were assigned randomly to breathe air as carrier gas (CG0.21) or oxygen as carrier gas (CG1.00) for a further 90 minutes. After an interval of 1 month each horse was re-anaesthetized with the other carrier gas for the 90 minute te...
Rapid infusion of a phospholipid emulsion attenuates the effects of endotoxaemia in horses. Endotoxaemia currently is associated with a poor prognosis in horses. The results of recent trials in other species indicate that phospholipid emulsions reduce the deleterious effects of endotoxin (LPS). However, in a previous study in horses, a 2 h infusion of emulsion caused an unacceptable degree of haemolysis. Objective: Rapid administration of a lower total dose of emulsion would reduce the effects of LPS and induce less haemolysis; the emulsion would reduce inflammatory effects of LPS in vitro. Methods: Twelve healthy horses received an i.v. infusion either of saline or a phospholipid em...
Dietary fish oil supplementation affects serum fatty acid concentrations in horses. Thirteen horses of Thoroughbred or Standardbred breeding were used to study the effect of dietary fish oil supplementation on blood lipid characteristics. Horses were assigned to either fish oil (n = 7) or corn oil (n = 6) treatment groups for 63 d. The fish oil contained 10.8% eicosapentaenoic acid (EPA) and 8% docosahexaenoic acid (DHA). Each horse received timothy hay and a mixed-grain concentrate at rates necessary to maintain BW. Oil (corn or fish) was top-dressed on the concentrate daily at a rate of 324 mg/ kg of BW. The n-6:n-3 ratio was approximately 3.6:1 for horses receiving the cor...
Relationships between serum serotonin and serum lipid levels, and aggression in horses. Levels of serum serotonin and serum lipids--triglyceride, total cholesterol, low-density lipoprotein, high-density lipoprotein and very low-density lipoprotein, were determined in normal horses and horses diagnosed with aggression on the basis of a questionnaire survey. Blood serotonin levels in aggressive horses were found to be significantly lower than in non-aggressive horses (P < 0.01), but no association was found with respect to blood lipids.
Cholesterol oxidase (ChoE) is not important in the virulence of Rhodococcus equi. To analyze further the role in virulence of the prominent cholesterol oxidase (ChoE) of Rhodococcus equi, an allelic exchange choE mutant from strain 103+ was constructed and assessed for virulence in macrophages, in mice, and in foals. There was no difference between the mutant and parent strain in cytotoxic activity for macrophages or in intra-macrophage multiplication. No evidence of attenuation was obtained in macrophages and in mice, but there was slight attenuation apparent in four intra-bronchially infected foals compared to infection of four foals with the virulent parent strain, based...
Cholesterol-to-phospholipid ratio in whole sperm and seminal plasma from fertile stallions and stallions with unexplained subfertility. Semen samples were collected from six fertile stallions and seven stallions with unexplained infertility. Percentages of motile sperm (77.5 +/- 11.3 versus 67.5 +/- 12.2, P = 0.2), and progressively motile sperm (70.8 +/- 13.6 versus 60.7 +/- 14.0, P = 0.2) were similar between fertile and subfertile stallions, respectively. Morphologic characteristics in ejaculates of control and affected stallions (% normal: 60.2 +/- 18.2 versus 52.9 +/- 11.3, P = 0.4; % abnormal heads 7.3 +/- 4.8 versus 12.1 +/- 5.0, P = 0.11; and % abnormal acrosomes 1.6 +/- 2.1 versus 3.0 +/- 3.4, P = 0.4) did not differ....
[Fat and content of yakutan horse fat tissue]. The gas chromatography method the fat acid content of the young Yakut horse meat fat tissue lipids was studied in relation to the age group, various parts of the body and anatomic topographic location of the fat/It was determined that the of sixth-month young horse is the source of the PUFA omega-3 that allows to recommend horse meat as a dietary product for atherosclerosis prevention. By medial chain fat content the lipids of the 6 month young horses are close to the lipids of milk fat.
Adding cholesterol to the stallion sperm plasma membrane improves cryosurvival. Cryopreservation induces partially irreversible damage to equine sperm membranes. Part of this damage occurs due to membrane alterations induced by the membrane changing from the fluid to the gel-state as the temperature is reduced lower than the membrane transition temperature. One way to prevent this damage is to increase the membrane fluidity at low temperatures by adding cholesterol to the membrane. Different concentrations of cholesterol-loaded-cyclodextrins (CLC) were added to stallion sperm to determine the CLC concentration that optimizes cryosurvival. Higher percentages of motile sper...
The effect of dietary fish oil supplementation on exercising horses. Ten horses of Thoroughbred or Standardbred breeding were used to study the effects of dietary fish oil supplementation on the metabolic response to a high-intensity incremental exercise test. Horses were assigned to either a fish oil (n = 6) or corn oil (n = 4) treatment. The fish oil (Omega Protein, Hammond, LA) contained 10.6% eicosapentaenoic acid and 8% docosahexaenoic acid. Each horse received timothy hay and a textured concentrate at a rate necessary to meet its energy needs. The supplemental oil was top-dressed on the concentrate daily at a rate of 324 mg/kg BW. Horses received their as...
Serum beta-carotene and alpha-tocopherol in horses fed beta-carotene via grass-meal or a synthetic beadlet preparation with and without added dietary fat. The serum response of beta-carotene as an indicator of bioavailability was compared after feeding beta-carotene (0.8 mg/kg body weight) either from grass meal or a synthetic beadlet preparation (Lucarotin). Both were each given without or with added dietary vegetable fat (2-2.5% vs. 6.6% fat in dry matter) in a Latin square design with four horses. The nutritionally complete diet was supplemented with alpha-tocopherol (4 mg/kg body weight). Each treatment period (4 weeks, two serum samples) was followed by a washout period of 4 weeks with low intakes of beta-carotene (traces) and alpha-tocophe...
Blood/gas partition coefficients of halothane, isoflurane and sevoflurane in horse blood. Blood/gas partition coefficients (lambda(b/g)) for volatile agents in horse blood are reported for halothane but not for isoflurane and sevoflurane. We measured the lambda(b/g) of halothane, isoflurane and sevoflurane in the blood of fasted horses. The correlation with age, weight and some haematological and biochemical variables was studied. The temperature correction factor for isoflurane solubility was calculated. Methods: Twenty-four horses were randomly allocated to halothane (n=8), isoflurane (n=8) or sevoflurane (n=8). Blood samples were taken after 10 h' fasting. Calculation of lambda(...
Effects of hypothyroidism and withholding of feed on plasma lipid concentrations, concentration and composition of very-low-density lipoprotein, and plasma lipase activity in horses. To evaluate selected concentrations of blood lipids and lipase activities in euthyroid and hypothyroid horses deprived of feed for 96 hours. Methods: 4 healthy adult mares and 4 thyroidectomized adult mares. Methods: Horses were deprived of feed for 96 hours. Blood samples were collected at 24-hour intervals and analyzed to determine concentrations of non-esterified fatty acid (NEFA), triglyceride (TG), total cholesterol (TC), and very-low-density lipoprotein (VLDL) as well as composition of VLDL. Plasma lipase activities were measured after feed was withheld for 96 hours and 12 days after res...
Rapid identification of Rhodococcus equi by a PCR assay targeting the choE gene. The actinomycete Rhodococcus equi is an important pathogen of horses and an emerging opportunistic pathogen of humans. Identification of R. equi by classical bacteriological techniques is sometimes difficult, and misclassification of an isolate is not uncommon. We report here on a specific PCR assay for the rapid and reliable identification of R. equi. It is based on the amplification of a fragment of the choE gene encoding cholesterol oxidase. The choE-based PCR was assessed by using a panel of strains comprising 132 isolates from different sources and of different geographical origins, all i...
The effect of dietary energy source on serum concentration of insulin-like growth factor-I growth hormone, insulin, glucose, and fat metabolites in weanling horses. Feeding diets high in soluble carbohydrates to growing horses has been implicated in the development of orthopedic diseases; as a result, substitution of dietary fat for soluble carbohydrates has received attention. Because IGF-I is integral to growth and cartilage development and because it is influenced by nutrition, we evaluated the effect of dietary fat substitution on metabolic endpoints and circulating GH and IGF-I in growing horses. Twelve Quarter Horse weanlings, four female and eight male, 151 to 226 d old, were blocked by sex and age and assigned to two treatment groups. Group one (C...
Influence of dietary beetpulp on the plasma level of triacylglycerols in horses. In a cross-over study with six adult horses, the effect of isoenergetic replacement of dietary glucose by beetpulp on the concentration of plasma triacylglycerols was studied. The test ration contained 25% beetpulp in the dietary dry matter. The feeding of beet pulp lowered plasma triacylglycerol concentrations (p = 0.058) in the fasting state and raised the activity of heparin-released lipoprotein lipase (LPL) (p = 0.059) and the concentration of HDL2 cholesterol (p = 0.058). In the fasting state, the plasma concentrations of free fatty acids (p = 0.073) and those of beta-hydroxybutyrate (p =...
Equine pyoderma associated with malnutrition and unhygienic conditions due to neglect in a herd. Twelve horses kept at a riding club suffered from pyoderma. All the horses displayed crusting, scaling and alopecia. The lesions were distributed in the chest, back, rump and limbs. Some of the horse patients also showed epilation with an attached crust similar to a 'paintbrush lesion' of dermatophilosis, but normal skin flora or opportunistic pathogenic bacteria were only isolated from the lesions. Some patients clearly showed weight loss, anemia and low levels of serum protein and cholesterol. General condition and skin lesions of the patients were improved gradually with improvement of feed...
Exercise- and metabolism-associated blood variables in Standardbreds fed either a low- or a high-fat diet. Feeding a high-fat diet increases fat utilisation and may decrease glycogen utilisation resulting in a lower lactate production during moderate exercise. The effects of fat feeding on exercise- and lipid metabolism-associated blood variables were evaluated in 6 Standardbred horses during submaximal exercise. The horses were fed a high- (11.8% fat in total dietary dry matter) or a low-fat diet (1.5% fat) in a cross-over experiment with feeding periods of 4 weeks. At the end of each feeding period, the horses were subjected to a submaximal standardised stepwise exercise test on a treadmill. Bloo...
Phosphorylation of protein tyrosine residues in fresh and cryopreserved stallion spermatozoa under capacitating conditions. Phosphorylation of tyrosine residues on sperm proteins is one important intracellular mechanism regulating sperm function that may be a meaningful indicator of capacitation. There is substantial evidence that cryopreservation promotes the capacitation of sperm and this cryocapacitation is frequently cited as one factor associated with the reduced longevity of cryopreserved sperm in the female reproductive tract. This study was designed to determine whether stallion sperm express different levels of tyrosine phosphorylation after in vitro capacitation and whether thawed sperm display similar ph...
Effect of feeding exercised horses on high-starch or high-fat diets for 390 days. Our hypothesis was that, because horses have not evolved as fat eaters, there may be negative metabolic long-term effects of feeding a high fat diet. The objective of the present study was to identify these long-term effects and compare them with the effects of isoenergetic long-term high starch feeding. This randomised block study with 20 exercised horses looked at the effect of feeding either a high starch (HS) or a high fat (HF) diet type in 3 periods during stabling (Stable 1), pasture, and stabling (Stable 2) over 390 days. The horses received a HS or HF concentrate, straw, hay and 6 h pa...
Characterization of lipoproteins in cerebrospinal fluid of mares during pregnancy and lactation. To measure apolipoproteins in cerebrospinal fluid (CSF) from healthy mares and to determine whether CSF concentrations of apolipoproteins change during pregnancy and lactation. Methods: 5 healthy pregnant mares. Methods: 2 sets of CSF samples were obtained; initial samples were obtained 10 to 30 days before parturition (mean, 18 days; median, 17 days), and second samples were obtained 19 to 26 days after parturition (mean, 23 days; median, 23 days). Cerebrospinal fluid was collected from the lumbosacral subarachnoid space of standing horses by use of routine collection techniques. Cerebrospina...
Effect of dietary medium chain triacylglycerols on plasma triacylglycerol levels in horses. The hypothesis tested was that the feeding of medium chain triacylglycerols (MCT) to horses would raise the level of plasma triacylglycerols by increasing the availability of glucose as lipogenic substrate, implying that the MCT effect would be greater with glucose in the diet instead of cellulose. A Latin square experiment was carried out with 4 horses and 4 dietary treatments. The experimental periods lasted 21 d. Blood samples were taken 16 h after feeding. The diets consisted of hay and experimental concentrates, differing in fat source (MCT or soybean oil) and carbohydrate source (corn st...
Fat feeding increases equine heparin-released lipoprotein lipase activity. The aim of this study was to establish the dose-response relationship between fat intake and heparin-released plasma lipoprotein lipase (LPL) activity in horses. Eight mature trotters were fed 4 rations with different fat levels (3.0, 5.0, 7.7, or 10.8% fat in the dry matter) according to a 4 X 4 Latin square design. The experimental rations consisted of hay and different concentrates; the concentrates and hay were given in a 3:1 ratio on an energy basis. Soybean oil was added to the concentrates at the expense of isoenergetic amounts of glucose. Blood samples were taken at the end of each die...
High density lipoprotein cholesteryl ester metabolism in the pony, an animal species without plasma cholesteryl ester transfer protein activity: transfer of high density lipoprotein cholesteryl esters to lower density lipoproteins and the effect of the amount of fat in the diet. The metabolism of high density lipoprotein cholesteryl esters (HDL CE) was studied in the pony, an animal species without plasma cholesteryl ester transfer protein (CETP) activity. Studies were done in ponies fed a low- (1.5% fat, w/w) and a high-fat diet (11.5%, w/w fat). The ponies fed the high-fat diet had higher plasma HDL CE concentrations (1.08+/-0.15 vs. 0.84+/-0.11 mmol/l, mean+/-S.D., n=6, P<0.01) and plasma lipoprotein lipase (LPL) activities (14.3+/-4.0 vs. 5.7+/-3.4 micromol free fatty acids (FFA)/ml per h, P<0.05) than those on the low-fat diet. Plasma triacylglycerol (TAG) ...