Metabolic response of horses to a high soluble carbohydrate diet: Effects of low-intensity submaximal exercise and sodium bicarbonate supplementation

Abstract

Summary Four mares fed a low fiber, high soluble carbohydrate diet were used in a crossover design to evaluate the effects of dietary sodium bicarbonate (NaHCO3) supplementation during daily low-intensity submaximal working conditions. Mares were fed the diet at 1.7 times the maintenance energy requirement for mature horses at work. The horses tolerated the diet well and had no clinical abnormalities. Resting venous blood bicarbonate (HCO3), standard HCO3, and base excess (be) concentrations significantly (P < 0.05) increased with NaHCO3 supplementation, but no significant changes in resting venous blood pH or carbon dioxide tension (Pco2) were recorded. Venous blood HCO3, standard HCO3, be, hemoglobin, and heart rate were significantly (P < 0.05) increased and plasma lactate concentration was significantly (P < 0.05) decreased in the control horses and in the horses given the NaHCO3 supplement during low-intensity submaximal exercise. There were no significant changes in venous blood pH, Pco2, or plasma protein concentration with exercise. Venous blood HCO3, standard HCO3, and be concentrations were significantly (P < 0 05) greater during submaximal exercise in horses given the NaHCO3 supplement. There were no significant differences in plasma lactate or total protein concentrations, blood pH, Pco2, or hemoglobin concentration between the 2 groups during exercise.