An evaluation with piglets of bovine milk, hydrolyzed bovine milk, and isolated soybean proteins included in infant milk formulas. II. Stomach-emptying rate and the postprandial change in gastric pH and milk-clotting enzyme activity

J Pediatr Gastroenterol Nutr. 1991 Feb;12(2):253-9. doi: 10.1097/00005176-199102000-00019.


The piglet was used as a model for the human infant to determine the effect of the protein source of a milk formula on stomach-emptying rate and the postprandial changes in gastric pH and milk-clotting enzyme activity. Three liquid milk formulas containing either intact bovine milk protein, hydrolyzed bovine milk protein, or isolated soybean protein as the sole source of dietary protein were given to five 37-day-old piglets that had undergone surgery for the preparation of a simple gastric fistula. At set times after commencement of a meal, the stomach contents were removed via a gastric cannula and weighed; then pH and milk-clotting enzyme activity were determined. The isolated soybean protein-based formula tended to empty from the stomach more slowly than did the bovine milk-based formulas. Maximum difference (p less than 0.05) was found at 3 h postfeeding, where 30% of the ingested soybean formula dry matter remained in the stomach; comparable values for the intact bovine milk-based formula and hydrolysate were 22 and 12%, respectively. The type of protein did not significantly (p greater than 0.05) affect the postprandial change in gastric pH or gastric milk-clotting enzyme activity. Gastric pH increased sharply after feeding, from pH 1.5 at 0 h to pH 5.2 at 1 h, and then fell gradually over the following 4 h to pH 1.84.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Food, Formulated*
  • Gastric Acidity Determination
  • Gastric Emptying / drug effects
  • Hydrolysis
  • Male
  • Milk Proteins / metabolism*
  • Milk Proteins / pharmacology*
  • Plant Proteins, Dietary / metabolism*
  • Plant Proteins, Dietary / pharmacology*
  • Soybean Proteins
  • Soybeans*
  • Stomach / drug effects*
  • Stomach / enzymology
  • Swine


  • Milk Proteins
  • Plant Proteins, Dietary
  • Soybean Proteins