A Resistant Protein, Sericin Improves Atropine-Induced Constipation in Rats

Abstract

In this study we found that dietary supplementation of 4% of a silk protein, sericin, to a 20% casein diet significantly reduced apparent protein digestibility in rats compared to a 24% casein diet, and that the pattern of amino acid composition of feces from the rats fed the sericin-supplemented diet was similar to that of the amino acid composition of sericin; the pattern of amino acid composition of feces from rats fed the control (casein) diet was different from that of the amino acid composition of casein. In vitro experiments with pepsin and pancreatin also showed that the digestibility of sericin was markedly lower than that of casein. We further examined the possibility that consumption of sericin suppresses constipation because of its low digestibility along with high water-holding capacity. The results indicated that consumption of the 4% sericin supplemented diet suppressed atropine-induced constipation in rats. These results suggest that a resistant protein, sericin could represent a useful agent for the treatment of constipation.