Dietary protein influences acid-base responses to repeated sprints.

The research article focuses on the influence of dietary protein on acid-base responses in Arabian horses during repeated sprints. The findings suggest that a low-protein diet can more effectively manage acidosis induced by intensive exercise than a high-protein one.

Study Design and Methodology

• The study used ten Arabian horses as subjects, randomly assigned to two groups – one group was fed a low-protein diet (7.5% crude protein and 12% fat), while the other was on a high-protein diet (14.5% crude protein and 12% fat).
• The low-protein diet was supplemented with lysine and threonine to match the amino acid levels found in the high-protein diet, aligning them on these metrics.
• The horses’ daily feed intake averaged to about 8.1 kg, and they were conditioned for 9 weeks before undergoing a specific exercise regime which included walks, trots, and sprints on a slope.
• Blood samples were taken from the horses at rest, during the last 15 seconds of each sprint, and several intervals during the recovery period.

Testing and Analysis

• Blood samples were analysed for various factors such as total protein, lactate, pH level, PCO2, PO2, HCO3-, Sodium, Potassium, and Chloride.
• The samples were also used to calculate the Strong Ion Difference (SID) and total weak acids (Atot).
• Analysis of variance (ANOVA) with repeated measures was used to evaluate the effects of diet, exercise, recovery time, and any possible interactions among these factors.

Results

• The study found that plasma pH level tended to be higher in the low-protein group after the first sprint and the HCO3- levels remained higher throughout the exercise and recovery phases.
• Both groups experienced a decline in pH during exercise, indicating an exercise-induced acidosis, but in the low-protein group, the pH level remained higher than in the high-protein group.
• The decline in pH was mainly attributable to an increase in PCO2 during recovery and a higher SID+ during most of the exercise and recovery period.
• The study also suggests that the low-protein diet enhanced the lactate-storage function of the horses’ red blood cells, as indicated by a lower lactate response and higher chloride level.

Conclusion

• The research concludes that dietary protein restriction for 9 weeks moderated sprint-induced acidosis in fat-adapted horses. This suggests that a low-protein diet is more beneficial in managing acid-base balance in horses during repeated sprints.