Plasma acylcarnitine and fatty acid profiles during exercise and training in Standardbreds

OBJECTIVE:

To evaluate alterations in skeletal muscle carnitine metabolism during exercise and training by measuring changes in plasma acylcarnitine concentrations in Standardbreds.

ANIMALS:

10 Standardbred geldings with a mean +/- SD age of 20 +/- 2 months and weight of 384 +/- 42 kg.

PROCEDURES:

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 AND CLINICAL RELEVANCE:

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: 
C.M. Westermann, B. Dorland, M.G. de Sain-van der Velden, I.D. Wijnberg, E. van Breda, E. de Graaf-Roelfsema, H.A. Keizer, J.H. van der Kolk
Authors from the NMC: 
DOI: 
10.2460/ajvr.69.11.1469
Pages: 
2008; 69 (11): 1469-1475
Published in: 
American Journal of Veterinary Research
Date of publication: 
November, 2008
Status of the publication: 
Published/accepted