Effects of high-intensity training on lipid metabolism in Thoroughbreds.

The research article investigates the effects of high-intensity training on the metabolism of carbohydrates and fats in Thoroughbred horses. The training led to increased oxidative capacity in the horses’ muscles, indicating a shift from carbohydrate use to fatty acid use during intensive exercise.

Research Methodology and Purpose

• The research aimed to study the impacts of high-intensity training (HIT) on the metabolism of fats and carbohydrates in Thoroughbred horses.
• The focus was on 12 Thoroughbreds aged 3-4 years old, including equal numbers of males and females.
• These horses underwent HIT for 18 weeks, exercising at 90% or 110% of their maximum oxygen consumption for 3 minutes, 5 days per week. Incremental exercise testing was conducted before and after the training.
• Researchers collected blood samples during the incremental exercise tests and obtained muscle samples from the gluteus medius muscle immediately after these tests.
• To measure glycolytic and oxidative capacities, the activities of phosphofructokinase, citrate synthase, and β-3-hydroxyacyl CoA dehydrogenase (β-HAD) were evaluated.

Measurements and Analysis

• The research team used western blotting to detect the protein contents of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and fatty acid translocase (FAT/CD36).
• A metabolome analysis using capillary electrophoresis-electrospray ionization mass spectrometry was carried out to measure concentrations of substrates related to carbohydrate metabolism.
• The increase in peak speed during the incremental exercise test and maximum oxygen consumption after the high-intensity training were noted.

Research Findings

• The research saw an increase in the activities of citrate synthase and β-HAD after the high-intensity training, but the activity of phosphofructokinase was unchanged.
• The protein contents of PGC-1α and FAT/CD36 increased after HIT, and there was a decrease in plasma lactate concentration and the respiratory exchange ratio.
• The plasma free fatty acid concentration increased after HIT, meanwhile, the glucose concentration remained the same.
• The concentrations of Fructose 1,6-diphosphate, phosphoenolpyruvate, and pyruvate reduced after HIT.
• Overall, the research concluded that high-intensity training led to an increase in oxidative capacity in equine muscle, which suggests a decrease in the dependency on carbohydrate utilization and a shift toward fatty acid utilization during intense exercise.