The research investigated the impact of stressors such as hospitalization and surgery on the concentration of immunoglobulin A (IgA) in the intestines of horses. The findings show that these stressors led to a significant drop in IgA concentrations, implying that they can weaken the local immune system in the intestines and potentially cause gastrointestinal diseases.

Study Design and Methods

• The study was designed as a prospective clinical trial involving 110 hospitalized horses, with 14 horses serving as a control group.
• The horses were categorized into different grades according to the level of pain they were experiencing upon arrival at the hospital.
• The nature of the surgery that the horses underwent was also taken into consideration, and was classified either as elective or strenuous. Strenuous surgeries lasted longer than two hours and were usually performed in emergency or traumatic situations.
• The researchers collected feces and blood samples from each horse on day 1, day 2, day 3, and day 7 of hospitalization. For those that underwent surgery, an additional blood sample was collected after general anaesthesia on day 2.
• The IgA concentration within these samples was then measured using an Enzyme-Linked Immunosorbent Assay (ELISA). The resulting optical density was measured at 450nm.

Key Findings

• The study found that the control group demonstrated constant IgA concentrations across all days, with a mean value of 0.30 OD (Optical Density).
• However, for the horses that underwent general anaesthesia, there was a significant decrease in fecal IgA concentration, regardless of the type or duration of surgery.
• This decline was observed to be similar in both elective surgeries (P < 0.001) and traumatic surgeries (P = 0.043).
• A weak correlation was found between high plasma cortisol concentrations and low fecal IgA on the day after surgery (P = 0.012, day 3, correlation coefficient r = 0.113).

Study Conclusion

• The research concluded that stressors like hospitalization and surgery cause a significant decrease in equine fecal IgA concentrations.
• This decrease indicates that such stressors can affect the local intestinal immune function, making horses more susceptible to developing gastrointestinal conditions such as enterocolitis.