title: Plasma acylcarnitine and fatty acid profiles during exercise and training in Standardbreds.
abstract: OBJECTIVE
  To evaluate alterations in skeletal muscle carnitine metabolism during exercise and training by measuring changes in plasma acylcarnitine concentrations in Standardbreds.
  
  
  METHODS
  10 Standardbred geldings with a mean +/- SD age of 20 +/- 2 months and weight of 384 +/- 42 kg.
  
  
  METHODS
  In a 32-week longitudinal study, training on a treadmill was divided into 4 phases as follows: phase 1, acclimatization for 4 weeks; phase 2, 18 weeks with alternating endurance and high-intensity exercise training; phase 3, increased training volume and intensity for another 6 weeks; and phase 4, deconditioning for 4 weeks. In phase 3, horses were randomly assigned to 2 groups as follows: control horses (which continued training at the same level as in phase 2) and high-intensity exercise trained horses. At the end of each phase, a standardized exercise test (SET) was performed. Plasma acylcarnitine, fatty acids, and lactic acid and serum beta-hydroxybutyric acid (BHBA) concentrations were assessed before and at different time points after each SET.
  
  
  RESULTS
  Plasma lactic acid, total nonesterified fatty acids, 3-hydroxyisobutyric acid, and acetylcarnitine (C2-carnitine) concentrations significantly increased during SETs, whereas serum BHBA, plasma propionylcarnitine (C3-carnitine), and plasma butyryl- and isobutyrylcarnitine (C4-carnitine) concentrations decreased significantly, compared with those before SETs.
  
  
  CONCLUSIONS
  Our findings indicated that the plasma acylcarnitine profile in horses likely reflects skeletal muscle carnitine metabolism following exercise, thereby providing a possible practical method to investigate potential disorders in carnitine metabolism in horses with myopathy.
authors.affiliation: Department of Equine Sciences, Medicine Section, Faculty of Veterinary Medicine, Utrecht University, 3508 TD Utrecht, The Netherlands.
authors.forename: Cornélie M
authors.initials: CM
authors.lastname: Westermann
authors.forename: Bert
authors.initials: B
authors.lastname: Dorland
authors.forename: Monique G
authors.initials: MG
authors.lastname: de Sain-van der Velden
authors.forename: Inge D
authors.initials: ID
authors.lastname: Wijnberg
authors.forename: Eric
authors.initials: E
authors.lastname: Van Breda
authors.forename: Ellen
authors.initials: E
authors.lastname: De Graaf-Roelfsema
authors.forename: Hans A
authors.initials: HA
authors.lastname: Keizer
authors.forename: Johannes H
authors.initials: JH
authors.lastname: Van der Kolk
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000097:blood; D000704:Analysis of Variance; D000818:Animals; D002331:Carnitine / Q000031:analogs & derivatives* / Q000097:blood; D005227:Fatty Acids / Q000097:blood*; D008401:Gas Chromatography-Mass Spectrometry; D006736:Horses / Q000097:blood / Q000378:metabolism*; D019344:Lactic Acid / Q000097:blood; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010805:Physical Conditioning, Animal / Q000502:physiology*
chemical_list: D005227:Fatty Acids; C116917:acylcarnitine; D019344:Lactic Acid; D002331:Carnitine; D020155:3-Hydroxybutyric Acid