Energetics of endurance exercise in young horses determined by nuclear magnetic resonance metabolomics

Abstract

Long-term endurance exercise severely affects metabolism in both human and animal athletes resulting in serious risk of metabolic disorders during or after competition. Young horses (up to 6 years old) can compete in races up to 90 km despite limited scientific knowledge of energetic metabolism responses to long distance exercise in these animals. The hypothesis of this study was that there would be a strong effect of endurance exercise on the metabolomic profiles of young horses and that the energetic metabolism response in young horses would be different from that of more experienced horses. Metabolomic profiling is a powerful method that combines Nuclear Magnetic Resonance (NMR) spectrometry with supervised Orthogonal Projection on Latent Structure (OPLS) statistical analysis. 1H-NMR spectra were obtained from plasma samples drawn from young horses (before and after competition). The spectra obtained before and after the race from the same horse (92 samples) were compared using OPLS. The statistical parameters showed the robustness of the model (R2Y = 0.947, Q2Y = 0.856 and cros-validated ANOVA p < 0.001). For confirmation of the predictive value of the model, a test set of 104 sample spectra were projected by the model, which provided perfect predictions as the area under the receiving-operator curve was 1. The metabolomic profile determined with the OPLS model showed that glycemia after the race was lower than glycemia before the race, despite the involvement of lipid and protein catabolism. An OPLS model was calculated to compare spectra obtained on plasma taken after the race from 6-year-old horses and from experienced horses (cross-validated ANOVA p < 0.001). The comparison of metabolomic profiles in young horses to those from experienced horses showed that experienced horses maintained their glycemia with higher levels of lactate and a decrease of plasma lipids after the race.

Global Metabolic Stress of Isoeffort Continuous and High Intensity Interval Aerobic Exercise: A Comparative 1H NMR Metabonomic Study

“…In support, we found a significant rise in plasma glycerol in all three protocols suggesting increase in lipolysis 37,47 . We also observed a significant rise in circulating span 1 and 2 TCA 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 15 the differences in circulating citrate in LI vs. the other two protocols should be examined experimentally.…”

The lipidome of Thoroughbred racehorses before and after supramaximal exercise

“…In horses, along with carbohydrates, plasma NEFA serve as substantial energy substrates for skeletal muscle in all types of exercise [1]. Both breed and type of exercise (duration and intensity) may affect the relative contribution of lipids and carbohydrates to muscle contraction [8]. A greater use of fat for energy in Arabian vs. Thoroughbred horses has been suggested when performing endurance-like exercise due to a lower proportion of type I and IIa muscle fibres in the latter [26].…”

“…Also, a positive correlation between plasma lipid content and speed during endurance races was reported [8]. These studies provided valuable information regarding the effect of training and age on the metabolic energy pathways of endurance horses and indicated that lipidomics might be a useful tool for future assessment of fitness in endurance horses [8]. A recent study reported the metabolome of Thoroughbreds in training [10].…”

“…Recent studies using "omics" methodologies showed that endurance exercise modifies the lipid of Arabian horses, mainly affecting the plasma levels of NEFA, triacylglycerols and phospholipids [7]. Also, a positive correlation between plasma lipid content and speed during endurance races was reported [8]. These studies provided valuable information regarding the effect of training and age on the metabolic energy pathways of endurance horses and indicated that lipidomics might be a useful tool for future assessment of fitness in endurance horses [8].…”

“…Thus, its use enables global screening of the effect of a particular stimulus, such as exercise, conditioning or added dietary fat, on lipid metabolism. The use of lipidomics in endurance horses led to a global understanding of the metabolic stresses undergone by these horses and its influence on performance [7][8][9]. Recent studies using "omics" methodologies showed that endurance exercise modifies the lipid of Arabian horses, mainly affecting the plasma levels of NEFA, triacylglycerols and phospholipids [7].…”