Effect of duodenal amino acid infusion on solid gastric emptying in pigs.

The emptying of a 400-g test meal of cubed liver was studied in eight pigs equipped with duodenal cannulas. Gastric effluent was diverted to measure both the rate of emptying and the distribution of particle sizes. The effect of emptying and particle size of infusing normal saline or an isosmolar amino acid solution into the small bowel was studied. Normal saline infusion did not alter the proportion of particles emptied, which were less than 1 mm in diameter. Infusion of the amino acid solution at the same rate significantly decreased the mass of liver emptied from 69.9 to 38.4 g compared with normal saline, and the percentage of particles less than 1 mm in diameter in the gastric effluent increased from 66 to 82%. We conclude that the amino acid solution produced both a reduction in the rate of gastric emptying and an increase in the proportion of small particles in the gastric effluent. We postulate that this may have been due to changes in gastric motility, together with alterations in gastric secretion and digestion, produced by the infusion of the amino acid solution into the small bowel.