Breath hydrogen excretion after oral administration of xylose to cats

Maximum breath hydrogen excretion after the oral administration of xylose to 11 healthy cats ranged from 0.13 ml/hour to 0.47 ml/hour, with a mean of 0.18 ml/hour. After oral administration of xylose, breath hydrogen excretion in five cats with chronic diarrhoea and, or, vomiting was significantly different (P<0.001) compared with healthy cats. Increased breath hydrogen excretion occurred before xylose was given and at all measurement times after its administration to the sick cats (P<0.05), indicating carbohydrate malassimilation. In four sick cats, large increases in breath hydrogen excretion occurred, with maximum values ranging from 1.21 to 1.56 ml/hour, but in one cat the maximum value was only 0.28 ml/hour. Plasma xylose concentrations in cats with chronic diarrhoea and, or, vomiting were not significantly different from healthy cats (P>0.05) and thus did not demonstrate carbohydrate malassimilation. A hiatus hernia was seen on radiographic views of the thorax and abdomen of one cat with chronic vomiting. Inflammatory bowel disease was found in three of the five sick cats after upper gastrointestinal endoscopic examination and mucosal biopsy. Clostridium species were isolated in increased numbers from the cats with chronic diarrhoea and, or, vomiting (P<0.005), after quantitative bacterial culture of small intestinal fluid specimens obtained endoscopically. Clostridium species were isolated from all five cats with chronic diarrhoea and, or, vomiting but from only one of eight healthy cats. However, whether a specific bacterial pathogen caused the increased breath hydrogen excretion found in these cats could not be determined from this study.