Rate of movement of marker particles in the digestive tract of the rabbit.

Using small (50-100 micrometer) and large (800-1000 micrometer) polystyrene particles as a marker substance, transit through the gastrointestinal tract of the rabbit was studied during the formation of hard and soft faeces (caecotrophe). Both fractions of the marker were transported at an equal rate during soft faeces formation. During the formation of hard faeces a significantly higher amount of small particles was present in the caecum, whereas in the distal colon and rectum the number of large particles was elevated significantly.