Pilot Study to Assess Meal Progression Through the Gastrointestinal Tract of Habituated Dogs Determined by Fluoroscopic Imaging Without Sedation or Physical Restraint

Abstract

A limiting factor of radiographic contrast studies is the requirement for restraint of the animal in order to reduce movement artifacts. To demonstrate that gastrointestinal transit can be analyzed by a barium meal in nonsedated and unrestrained dogs, a pilot study of six adult Labrador retriever dogs was undertaken. Study subjects were selected by convenience sampling from an available population of Labrador dogs and were trained to stand motionless during radiographic fluoroscopy. Following a meal containing 7% w/w powdered barium sulfate, radiographic images were generated using a digital fluoroscope C-arm, at intervals of 5, 15, and 30 min, and at 1, 2, 3, 4, 5, 6, 7, and 8 h. A qualitative assessment of fill density using a 5-point scale was made for the stomach, small intestine, and ascending, transverse, and descending regions of the colon at each timepoint. Gastric emptying half-time occurred between 1 and 2 h postmeal. Mean fill density of the small intestine increased from 15 min postmeal and reached a peak at 3 h postmeal. Mean fill density of the proximal large intestine mirrored that of the small intestine. The distal large intestine remained empty for the first 2 h postmeal, then increased between hours 2 and 5 postmeal, and was subsequently at maximum fill density from hour 6 postmeal onwards. Fluoroscopic observation of a barium contrast meal provided an effective indication of the amount and progression of ingested food through the various regions of the gastrointestinal tract in habituated, fully conscious dogs.

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“…This can be mitigated by training animals to willingly undergo non-invasive procedures whilst conscious. Wrigglesworth et al (30) used positive reinforcement training (PRT) techniques to assess meal progression through the gastrointestinal tract by fluoroscopic imaging without sedation or physical restraint of the trained dogs. Similarly, training dogs to be completely still during measurement of transepidermal water loss can give very accurate data without the need for sedation (31) .…”