Comparison of the effects of intragastric infusions of equal volumes of water, dioctyl sodium sulfosuccinate, and magnesium sulfate on fecal composition and output in clinically normal horses.

The research article compares the effects of three substances (water, a laxative named dioctyl sodium sulfosuccinate (DSS) and a laxative/purgative named magnesium sulfate at two different doses) on the fecal output and composition in healthy horses. The overarching finding is that, compared to water, both magnesium sulfate (especially at the higher dose) and DSS affect fecal output and composition, although the physiological mechanisms enabling these effects are still unclear and might be connected to reflex processes in the digestive tract.

Study Design and Treatment

• The study was performed using a design known as a Latin square design – a model often used in experiments that compares the effects of different treatments.
• Four healthy horses were intragastrically infused – that is, the substances water, DSS and magnesium sulfate were administered directly into the stomach – with each of the treatment options: DSS, low dosage of magnesium sulfate, high dosage of magnesium sulfate and water as a control (no treatment) option.

Effects of Treatment on Fecal Output and Composition

• All horses showed slightly softer feces from 5 to 33 hours after receiving the high dose of magnesium sulfate.
• One horse demonstrated mild colic, more frequent and deeper breaths (hyperpnea) and diarrhea after administration of DSS.
• All treatments, including water, made fecal output, fecal water, number of defecations, and percentage of water in feces higher in the first 6 and 12 hours post treatment.
• The higher dosage of magnesium sulfate had a stronger effect on fecal output and the water content in the feces than the lower dose and control (water) infusion.

Physiological Mechanisms of Response

• The effects of the high magnesium sulfate dose on fecal output preceded the arrival of polyethylene glycol and magnesium in the feces, suggesting that the magnesium sulfate effects could be mediated through reflex mechanisms in the digestive tract.
• None of the treatments, when compared to the control (water) infusion, influenced the excretion of polyethylene glycol and plastic particulate markers, nor did they increase water consumption.

Study Conclusion

• Based on these experimental results, the researchers concluded that the responses to intragastric infusions might involve reflex mechanisms in the gastrointestinal tract.
• The reactions could be utilized for treating problems like colon impactions in horses, although further investigation is necessary to identify the precise mechanisms that are at work.