PRELIMINARY-RESULTS OF A COMBINED XYLOSE ABSORPTION HYDROGEN EXCRETION TEST IN HORSES WITH CHRONIC INTESTINAL DISEASE

In the present study the breath hydrogen (H-2) excretion test was comb ined with the xylose absorption rest in 4 normal horses and 9 clinical . patients with chronic diarrhoe (n = 3) or chronic weight loss withou t diarrhoe (n = 6). All horses underwent a thorough clinical examinati on. Laboratory evaluations consisted of haematalogy and serum biochemi stry as well as bacteriological and parasitological examination of fec es, In addition, serum electrophoresis and abdominocentesis was perfor med in all the clinical patients. Gastroscopy was carried out in 6 pat ients and rectal biopsies were obtained from 4 animals. Two animals we re euthanased within 4 weeks after the evaluation. The diagnosis of ch ronic granulomatous enteritis was confirmed in one of them at necropsy , the cause of weight loss in the other remained unexplained. In the r emaining animals, specific causes such as management, parasites, chron ic infections and diseases of liver, kidneys and heart were excluded, but no specific diagnosis could be obtained. For the combined xylose a bsorption/H-2 excretion test, the animals were starved overnight and g iven 0.5 g/kg/bwt xylose as a 10% solution by stomach tube the next mo rning. Blood samples were collected for plasma xylose analysis at 30 m in intervals for 4 brs, and breath samples were also collected:at 30 m in: intervals for 8 hrs. With the exception of the animal with granulo matous enteritis, the diseased horses showed only slight alterations i n either peak concentrations dr times to reach peak levels of plasma x ylose. None of the healthy animals showed an increase in breath H-2 pr oduction after xylose administration, whereas five of the diseased ani mals showed distinct increases of variable heights. In addition, the d iseased horses showed higher fasting breath H-2 levels (range 7.5-61.5 ppm) than normal horses (range 0-5 ppm). It is concluded that gastroi ntestinal disorders might be influenced or even induced by a change in intestinal microbial composition, as evidenced by an increased hydren ogenic metabolism.