Feasibility of Serum and Faecal Interleukin Assessment in Equine Surgical Colic: A Pilot Study

Cytokines may provide information about inflammation in equine colic, but their clinical relevance remains uncertain. This pilot study assessed short-term changes in serum and faecal interleukin (IL)-1β, IL-6 and IL-8 in eight horses undergoing colic surgery and compared measurements with six healthy controls. Colic horses were sampled at admission (D0), 24 h (D1) and day 7 (D7); controls provided serum at D0 and faeces at all three time points. Cytokines were assayed using MILLIPLEX and MAGPIX. Admission faeces were unavailable from 3/8 colic horses (37.5%). Serum IL-1β and IL-6 were below detection limits in 29/29 analysed samples (100%) for each cytokine. Serum IL-8 varied markedly without significant temporal change. Thirty-nine faecal extracts were analysed without faecal assay validation. Faecal estimates were generally lower in colic horses, with nominal between-group differences for IL-6 at D1 (p = 0.045), IL-1β at D7 (p = 0.033) and IL-8 at D7 (p = 0.004). No consistent temporal pattern in faecal estimates or significant association between serum and faecal IL-8 was detected. These findings do not establish the usefulness of these cytokines for clinical monitoring and highlight sampling and analytical limitations that should be addressed in larger, clinically diverse cohorts.