Effect of a commercial anionic dietary supplement on urinary pH and concentrations of electrolytes and pH in blood of horses.

This research study investigates how a commercial anionic dietary supplement affects the pH levels and electrolyte concentrations in the urine and blood of healthy horses. The study’s findings reveal that while the supplement did lower urine pH in horses consuming specific diets, it had no significant clinical impact as the pH did not fall below a critical threshold for the formation of calcium carbonate uroliths.

Study Design and Execution

• The research involved eight healthy horses consuming three different diets in a randomly assigned crossover design pattern. An anionic supplement was added to the feeds to achieve a Dietary Cation-Anion Difference (DCAD) of 85, 0, or -40 mEq/kg DM.
• Each diet was fed for a span of 14 days with an intervening washout period of 7 days to exclude any residual effects of the previous diet.
• Daily urine pH measurements were recorded and blood samples were collected on the initiation day, Day 7, and Day 14 for each diet period to monitor pH and electrolyte concentration developments.

Research Findings

• The anionic supplement lowered the average urine pH in horses on the diets with a DCAD of 0 or -40 mEq/kg DM as compared to the control diet (DCAD of 85 mEq/kg DM), specifically from Days 1-12 and 14.
• No change was detected in the blood pH, ionised calcium, or anion gap in the horses regardless of their specific diet. However, horses fed the 0 mEq/kg diet showed lower concentrations of bicarbonate in their blood compared to the control diet (85 mEq/kg DM) on Day 14.
• Despite the lowering of urine pH through anionic supplementation, this reduction was not large enough to reach a pH below 6.5, the critical threshold for preventing the formation of calcium carbonate uroliths. As such, the actual clinical impact of the anionic supplement was limited.

Palatability and Effectiveness of the Supplement

• The acceptance of the anionic supplement was variable among the sample horses. While four out of the eight horses willingly consumed the supplement with their feed, the other four required oral administration of the supplement via a dose syringe.
• Overall, the supplement showcased minimal potential as an effective urinary acidifier at the administered doses, due to its limited impact on lowering urine pH below the critical threshold, and its inconsistent palatability.