Blood lactate concentration during exercise in horses fed a high-fat diet and administered sodium bicarbonate.

The research article investigates how a high-fat diet and sodium bicarbonate supplementation in Arabian horses impact the concentration of lactate in the bloodstream during exercise.

Methods

• The study involved eight Arabian horses, randomly categorized into two groups based on their diets — control and high-fat diets
• Each horse was subjected to two repeated sprint exercise tests to measure and compare their blood lactate levels
• Two hours before the exercise, two horses from each diet group received sodium bicarbonate dissolved in water while the remaining ones got plain water. The purpose of sodium bicarbonate was to induce metabolic alkalosis, a condition where the blood pH is higher than normal.
• Blood samples collected at rest and 15 seconds before the exercise test ended were subjected to lactate analysis
• Data were analyzed using variance for repeated measures to assess effects of diet, treatment, and exercise.

Results and Discussion

• The concentration of lactate in blood increased during each sprint and remained elevated
• Blood lactate level was significantly higher during exercise in horses on high-fat diet compared to those on the control diet. This increase might be due to an inhibitory effect on the Pyruvate Dehydrogenase (PDH) complex due to higher fatty acid oxidation, as observed in previous studies.
• Horses administered with sodium bicarbonate showed higher blood lactate levels than those that just received water, regardless of their diet
• The highest concentration of lactate in blood during exercise was seen in high-fat diet-adapted horses that received sodium bicarbonate. The study suggests that a high-fat diet combined with induced metabolic alkalosis may have a synergistic effect on lactate accumulation
• The research also found no significant difference in plasma PCO2 (partial pressure of carbon dioxide) between the bicarbonate and water groups; however, the decrease rate of PCO2 was greater in horses on a high-fat diet compared to the control diet. The difference in plasma PCO2 implies an increased fatty acid oxidation compared to carbohydrate oxidation in horses on a high-fat diet
• The researchers believe that the higher blood lactate concentration seen in horses after administering sodium bicarbonate was likely due to an increased outflow of lactate from muscle cells.