[Characteristics of milk protein digestion in the early postnatal period of development]

It is found that in the period of the 1st to the 20th day of life there takes place shifting of the cavitary digestion of milk proteins toward the distal part of the small intestine. The change-over from the milk to the definite alimentation is accompanied by a shift of the process of the milk proteins digestion to the proximal part of the small intestine. The jejunum chyme of the 3, 12 and 20-day old rats contains roughly equal amounts of free amino acids, whereas in the jejunum chyme of the 30-day old animals their concentration is twice as high. The results of determining the speed of the amino acids release in tests with incubation in vitro of the jejunum chyme in 3, 12 and 20-day old rats bear proof to the existence at the young age of two types of digestion, viz. of the cavitary and intracellular (and/or membranous).