Site of exoenzyme action in gastrointestinal tract of broiler chicks

Abstract

The site of exoenzyme action was estimated on the basis of the changes in digesta viscosity, total reducing sugar content and pH in the four sections of digestive tract: crop, gizzard, duodenum and jejunum (anterior small intestine) and ileum from Meckel's diverticulum to colo-cecal junction (posterior small intestine) in broiler chicks fed rye-based diets without and with supplementation of two enzymes and a control wheat-based diet. There was a significant reduction (P < 0.05) in extract viscosity of the digesta taken from the foregut and especially in the posterior small intestine but not from the crop and gizzard of chickens fed the rye-based diet containing added enzyme compared to chicks fed the same diet without enzyme. Also, the higher concentration of readily fermentable reducing sugars (P < 0.05) and the lower pH (P < 0.05) in the digesta of rye-fed compared to wheat-fed chicks was attributable to the higher viscosity of extracts prepared from rye digesta. These results are consistent with the viscosity changes as influenced by enzyme and suggest that the posterior small intestine and to a lesser degree the anterior small intestine are the main sites of action of the exogenous enzymes. Key words: Viscosity, reducing sugar, digesta, enzymes, broilers