Antibody titres to core lipopolysaccharides in horses with gastrointestinal disorders which cause colic

Abstract

Summary Serum immunoglobulin (Ig) titres to core lipopolysaccharide (LPS) were determined in 102 horses admitted to a university referral hospital during a 12‐month period for evaluation of colic. Serum samples were collected again 10–14 days later from 84 of the horses. Titres to core LPS were quantitated by an indirect enzyme‐linked immunosorbent assay (ELISA), utilising the J‐5 mutant of Escherichia coli 0111:B4 as the solid‐phase antigen. All horses had natural antibodies to core LPS at the time of admission and the titre was not affected significantly by age, sex or type of gastrointestinal disorder. The geometric mean titres to core LPS increased significantly within 14 days of admission in those horses with large colon displacement (25), ileal impaction (13), small intestinal strangulating obstruction (11) and small colon obstruction (4). Twenty four (28.6 per cent) of the horses had at least a 4‐fold rise in titre (seroconversion) to core LPS within 14 days of admission. The incidence of seroconversion to core LPS was significantly greater (P<0.05) in horses with disorders requiring surgical intervention (35.8 per cent) than in those with disorders (proximal enteritis, colitis, large colon impaction and unknown) which only required medical treatment (16.1 per cent). Seroconversion rate was not statistically different between groups of horses with diseases of the small intestine which required surgical or medical treatments. The results of this study indicate that gastrointestinal disorders that cause colic in horses result in IgG production to core LPS, and the latter is more prevalent in disorders requiring surgery.