EFFECTS OF EXTRUSION COOKING OF BARLEY ON ILEAL AND FECAL DIGESTIBILITIES OF DIETARY COMPONENTS IN PIGS

Abstract

The effect of extrusion cooking on ileal and fecal digestibilities of dietary components in the pig was studied. Five crossbred ileal-cannulated pigs were fed a raw barley-based diet or an extruded barley-based diet in a crossover design. Klason lignin increased and starch decreased with extrusion cooking. Extrusion cooking also caused a shift of insoluble nonstarch polysaccharides (NSP) to soluble NSP. Ileal dry matter was lower and fecal dry matter higher from pigs fed the extruded diet compared to pigs fed the raw diet. Pigs fed the extruded diet had higher ileal digestibilities for dry matter, energy, starch and Klason lignin. No significant differences in fecal digestibilities were found, except for Klason lignin, when comparing pigs fed raw and extruded diets. Fecal digestibilities tended to be higher than ileal digestibilities for all dietary components for both diets except for crude fat, where there was no difference. Pigs fed the extruded diet had higher soluble NSP and lower insoluble NSP ileal digestibilities. Extrusion altered the chemical composition and dietary component digestibilities at the ileum but not at the feces. Increased energy utilization of the extruded diet in the upper tract occurred primarily because of an increased digestion of starch. Key words: Extrusion cooking, barley, digestibility, pigs