Evaluation of gastrointestinal transit times and pH in healthy cats using a continuous pH monitoring system.

ABSTRACT

OBJECTIVES: The aim of this study was to characterize gastrointestinal (GI) transit times and pH in healthy cats. METHODS: GI transit times and pH were measured in six healthy, colony-housed, purpose-bred spayed female cats using a continuous, non-invasive pH monitoring system in a sequential order design. For the first period ('pre-feeding'), food was withheld for 20 h, followed by oral administration of a pH capsule. Five hours post-capsule administration, cats were meal-fed by offering them their daily allowance of food for 1 h. For the second period ('post-feeding'), food was withheld for 24 h and cats were fed for 1 h, after which a pH capsule was orally administered. Studies in both periods were repeated three times. GI transit times and pH were compared between the two periods. RESULTS: The median transit times for the pre- and post-feeding periods, respectively, were gastric - 94 mins (range 1-4101) and 1068 mins (range 484-5521); intestinal - 1350 mins (range 929-2961) and 1534 mins (range 442-2538); and GI - 1732 mins (range 1105-5451) and 2795 mins (range 926-6563). The median GI pH values for the first and second periods, respectively, were esophageal - 7.0 (range 3.5-7.8) and 4.5 (range 2.9-6.4); gastric - 2.7 (range 1.7-6.2) and 2.0 (range 1.1-3.3); intestinal - 8.2 (range 7.6-8.7) and 7.8 (range 6.7-8.5); first-hour small intestinal - 8.2 (range 7.4-8.7) and 8.3 (range 7.9-8.6); and last-hour large intestinal - 8.5 (range 7.0-8.9) and 7.8 (range 6.3-8.7). Gastric (P <0.0020) and intestinal pH (P <0.0059) were significantly increased in the pre-feeding period compared with the post-feeding period. CONCLUSIONS AND RELEVANCE Gastric and intestinal pH differed significantly when the capsule was administered 5 h prior to feeding compared with 1 h after feeding. Transit times for both periods showed high degrees of intra- and inter-individual variability.