Abstract
The gastric transit times of force-fed proteins, peptides and amino acids were compared in rats. The nitrogen sources used were lactalbumin or casein (protein), enzymatic hydrolysate of soy protein (peptide) and an amino acid mixture simulating the composition of the soy peptide. The solutions, containing 25% or 10% of the nitrogen sources (N × 6.25), were prepared and 1 ml or 2.5 ml per 100 g body weight was force-fed. The gastric transit time of the peptide medium was the fastest. The amino acid medium increased the volume in the stomach above the initial volume within 2 h of force-feeding. The peptide solution, which contained more nitrogen and had a higher osmotic pressure than the amino acid solution, showed a gastric transit time similar to that of the amino acid solution. These results indicate that the gastric transit time of peptides is shorter than that of other nitrogen sources, which may be due not only to the influence of osmotic pressure and molecular size but also to other, unknown mechanisms.
