β‐glucanase and xylanase activities in stomach and ileum of growing pigs fed wheat bran based diets with and without enzyme treatment

Abstract

Pigs were fed diets containing 40% wheat bran incubated with a water: acetic acid mixture (control C) and a cellulase (Cel‐i) or xylanase (Xyl‐i) preparation or with addition of the cellulase (Cel‐a) or xylanase (Xyl‐a) preparation immediately before feeding. Stomach and ileal samples were analysed for xylanase and ß‐glucanase activities by a standard method based on release of reducing substances and a modified method in which the actual pH of the sample was used. After feeding Cel‐treated diets xylanase and ß‐glucanase activities were higher in the stomach up to 4 hours after feeding. In the stomach the modified method gave significantly lower xylanase activities than the standard method. Ileal xylanase activity was significantly higher 2–6 hours after feeding Xyl‐treated diets and ileal ß‐glucanase activity was higher 4–6 hours after feeding Cel‐treated diets. In ileal samples, the modified method gave significantly higher xylanase and lower ß‐glucanase activities than the standard method. It is concluded that xylanase and ß‐glucanase activities can be measured in digesta samples with the methods employed and that the added enzymes were largely inactivated between the feedings. Measuring digesta enzyme activities in conditions (pH) similar to the ones in the gastrointestinal tract may give a more reliable picture of the actual activity of added enzymes.