Kinetic analysis of D-xylose distribution after intravenous administration to mares.

This research examines how the sugar compound D-xylose is distributed in a horse’s body after being administered intravenously, and how dietary factors may influence this distribution.

Research Methodology

• The researchers applied a technique known as multicompartmental analysis to study the distribution of D-xylose in horses that were either deprived of food for 12 hours or for 96 hours.
• To measure excretion, they collected and analyzed urine samples over a 15-hour period following the injection of D-xylose.
• The plasma concentrations of D-xylose observed were similar to those found after oral tolerance testing, providing a comparative reference point.
• For the purpose of the analysis, the body of the horse was represented as two compartments (central and peripheral), and the behavior of D-xylose was modeled with linear kinetics.

Results

• The total volume of D-xylose distribution significantly decreased from 0.270 L/kg of body weight after 12 hours of food deprivation to 0.235 L/kg after 96 hours.
• The rate of transfer between the central and peripheral compartments remained unchanged during the extended period without food.
• Approximately one-third of the injected D-xylose was detected in the urine, indicating renal excretion.
• No significant difference in urinary elimination was recorded between the 12- and 96-hour periods.
• The non-renal elimination rate (i.e., elimination through other physiological mechanisms) was twice the rate of renal elimination.

Conclusion

• The study reveals insights into D-xylose distribution in horses and showcases the usefulness of formal kinetic analysis.
• It suggests that if a horse is deprived of food for an extended period, it might show an increase in plasma D-xylose concentration due to a reduced total distribution volume.
• This finding can be important for veterinary clinicians while interpreting results from D-xylose absorption tests in anorectic horses, as the circulating D-xylose concentration could be influenced by the horse’s feeding schedule.