Effect of guar gum, lignin and pectin on proteolytic enzyme levels in the gastrointestinal tract of the rat: a time-based study

The effects of dietary pectin (P), guar gum (G) and lignin (L) on stomach emptying and potential levels of pepsin, trypsin and chymotrypsin during a 2-h period after force-feeding were investigated in growing rats. All of the fibers delayed stomach emptying by 21-26 min. Total potential pepsin activity over 2 h decreased for P (57%), G (44%) and L (20%). In the intestine, total potential trypsin activity over 2 h increased for L (16%) but decreased for P (21%). Total potential chymotrypsin activity over 2 h increased for L (54%) and G (39%). Sixteen to 21% of the variability in intestinal activity over time was statistically attributable to variation in the weight of intestinal contents. The results indicate that fiber components altered proteolytic enzyme levels in the gastrointestinal tract, but the decreased protein utilization previously observed with these fibers is probably not due to reduced levels of intestinal proteases.