CASEINPHOSPHOPEPTIDES (CPP) IN FECES AND CONTENTS IN DIGESTIVE-TRACT OF RATS FED CASEIN AND CPP PREPARATIONS

A part of caseinphosphopeptides (CPP) formed during the digestion of c asein in the small intestine of rats fed casein was not hydrolyzed in the digestive tract, but was excreted into the feces, Amino acid compo sitions of CPP fraction of feces for wk 1 and 2 were almost identical. The residual CPP in the feces expressed by the rate of bound phosphos erine in the CPP fraction of feces to bound phosphoserine ingested (ph osphoserine-CPP/phosphoserine-ingested rate) in the ileum was the high est 4 h after the start of feeding of casein but decreased significant ly after 10 h. No significant difference was observed in the rats of c ontents in jejunum, cecum, and colon between 4 h and 10 h after the st art of feeding. No significant difference was observed in the phosphos erine-CPP/phosphoserine-ingested rate in contents of any part of the d igestive tract between 50% casein and 50% CPP I (a commercial CPP prod uct with nearly the same amino acid composition as that of casein) 4 h and 10 h after the start of feeding, except for the cecum 411 after t he start of feeding. No significant difference in phosphoserine-CPP/ph osphoserine-ingested rate was observed in the contents of any part of digestive tract between the groups fed 50% casein and 5% CPP III + 45% soybean protein isolate (SPI) 4 h or 10 h after the start of feeding (CPP III is a commercial CPP product containing nearly 8 times the con centration of phosphoserine as CPP I). The phosphoserine-CPP/phosphose rine-ingested rate of the 5% CPP I +45% SPI group was significantly hi gher in any part of digestive tract than those of 50% casein and 5% CP P III + 45% SPI groups 4 h after the start of feeding.