Radiologic observations of gastric mixing and emptying of food in growing pigs.

The stomachs of 10 Large White x Landrace pigs were examined radiographically from weaning (at 26 to 28 days of age) until 6 or 16 weeks of age. Conventional radiographs were taken and observations were made with a television chain and 35-mm cinecamera linked to an image intensifier. Before radiography, each animal was fed its normal diet that contained a barium sulfate suspension and/or radio-opaque pellets. The basic pattern of motility in the major chamber of the pig's stomach was similar to that described in animals with a simple stomach. Type II peristaltic waves were clearly identified as indentations of the body of the stomach that moved towards the pyloric antrum, which became circular as it filled with digesta. A terminal antral contraction then occurred, the antrum decreased in diameter, and the ingesta and barium sulfate either entered the duodenum or were returned to the body of the stomach. Liquids and finely ground food left the stomach more rapidly than did the radio-opaque pellets that were retained for up to 44 hours. The radio-opaque pellets demonstrated the movement of ingesta within the gastric lumen and showed that ingesta was retropulsed into the body of the stomach by the terminal antral contraction. In 4 pigs, barium and ingesta were present in the 2nd chamber of the stomach, the gastric diverticulum. In 1 pig, a movement of the diverticulum was observed on a single occasion.