Dietary protein restriction and fat supplementation diminish the acidogenic effect of exercise during repeated sprints in horses.

The research paper investigates how a diet with restricted protein and supplemented with fats and amino acids can reduce acid generation due to exercise in horses. This study involved 12 Arabian horses subject to different diets and exercise regimes, with measurements of certain blood parameters made at rest and during exercise.

Methodology and Experimental Design

• Twelve Arabian horses participated in the study, with the dietary experiment having two variables – fat and crude protein levels. The horses were divided into groups with either 0 or 10 g/100 g added corn oil (to vary fat levels) and either 7.5 g/100 g or 14.5 g/100 g of crude protein in their diet.
• The lower protein group diet was supplemented with 0.5% L-lysine and 0.3% L-threonine.
• The experiment started with a 4-week dietary adjustment period. Each horse then participated in an exercise test which consisted of six 1-minute sprints at 7 m/s.
• Following the initial exercise test, the horses underwent interval training for 11 weeks, after which another exercise test was conducted. This second test involved sprints at a faster speed of 10 m/s.

Data Collection and Analysis

• Blood samples were collected from the horses at rest and during the exercise tests. These samples underwent plasma analysis for several parameters including PCO2, PO2, sodium, potassium, chloride, lactate, pH and total protein levels.
• Other measures, such as bicarbonate, strong ion difference and total weak acids, were also calculated.
• The data thus obtained was analyzsed using repeated-measures analysis of variance.

Findings of the Research

• During the first test, the venous pH in the low protein group was found to be higher (P = 0.0056), indicating reduced acidity. The strong ion difference, an indicator of metabolic acidosis, also increased (P = 0.022) during sprints in the low-protein group.
• During the second test, after interval training, both venous pH and bicarbonate levels were higher for the low protein, high fat group (P = 0.022 and P = 0.043, respectively), suggesting less acid generation during exercise.
• Again, the strong ion difference became higher (P = 0.038) at the end of exercise in the low protein groups, indicating decreased acidosis.
• In conclusion, restricting dietary protein, especially when combined with fat adaptation, appears to reduce the acidogenic effect of exercise in horses.