title: Exercise- and metabolism-associated blood variables in Standardbreds fed either a low- or a high-fat diet.
abstract: 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. Blood samples were obtained prior to the start, during the last 10 s of each exercise step, and after recovery (40 min walking in hand). Pre-exercise test values for plasma lactate, pH, pCO2, ionised sodium, ionised potassium, ionised calcium, ionised chloride, glucose, nonesterified fatty acids and glycerol did not differ for the 2 diets. The pre-exercise concentration of triacylglycerols was significantly lower on the high- compared to the low-fat diet (mean +/- s.d. 0.17 +/- 0.06 and 0.23 +/- 0.08 mmol/l, respectively), whereas the concentrations of cholesterol (3.00 +/- 0.47 and 2.11 +/- 0.49 mmol/l, respectively), HDL cholesterol (1.80 +/- 0.18 and 1.35 +/- 0.27 mmol/l, respectively) and phospholipids (2.30 +/- 0.11 and 1.72 +/- 0.20 mmol/l, respectively) were significantly higher. There was significantly less plasma lactate accumulation during exercise when the horses were given the high-fat diet (P = 0.011). Horses on a low-fat diet had significantly different plasma lipid values when compared to being on a high-fat diet. The alterations in these values during and after moderate exercise were comparable for both diets. These results indicate that fat metabolism is significantly adapted on a high-fat diet; feeding such a diet may enhance potential performance by delaying lactate accumulation and thereby delaying the onset of fatigue.
authors.affiliation: Department of Equine Sciences, Internal Medicine, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
authors.forename: M M
authors.initials: MM
authors.lastname: Sloet van Oldruitenborgh-Oosterbaan
authors.forename: M P
authors.initials: MP
authors.lastname: Annee
authors.forename: E J M M
authors.initials: EJ
authors.lastname: Verdegaal
authors.forename: A G
authors.initials: AG
authors.lastname: Lemmens
authors.forename: A C
authors.initials: AC
authors.lastname: Beynen
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D019540:Area Under Curve; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D018592:Cross-Over Studies; D018752:Diet, Fat-Restricted / Q000662:veterinary; D004041:Dietary Fats / Q000008:administration & dosage* / Q000378:metabolism; D004573:Electrolytes / Q000097:blood; D004734:Energy Metabolism / Q000502:physiology*; D005080:Exercise Test / Q000662:veterinary; D005260:Female; D006736:Horses / Q000097:blood / Q000378:metabolism* / Q000502:physiology; D007700:Kinetics; D007773:Lactates / Q000097:blood*; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology; D010743:Phospholipids / Q000097:blood; D010805:Physical Conditioning, Animal / Q000502:physiology*; D014280:Triglycerides / Q000097:blood
chemical_list: D008076:Cholesterol, HDL; D004041:Dietary Fats; D004573:Electrolytes; D007773:Lactates; D010743:Phospholipids; D014280:Triglycerides; D002784:Cholesterol