An experiment was conducted to determine the optimum temperature for wet extrusion of full-fat soybeans needed to produce maximum broiler performance. Soybeans were either unprocessed or extruded at five different temperatures (118, 120, 122@ 126 or 140 degrees C) in a wet extruder. A soybean meal diet was included as a control. The diets were fed to individual groups of 40 chicks for 35 days. Diets prepared with unprocessed soybeans, and soybeans extruded at 188 and 120 degrees C resulted in significantly lower body weights and in pancreatic hypertrophy. Maximum growth rate was obtained at 122 and 126 degrees C, while minimum pancreas weight was seen in chickens fed full-fat soybeans extruded at 140 degrees C. Trypsin inhibitor activity, urease activity and protein solubility in potassium hydroxide increased with increasing extrusion temperatures. Trypsin inhibitor activity provided the best prediction of feeding value of soybeans for broilers.

Perilia, N.S. and co-workers. 1997 Effect of temperature of wet extrusion on the nutritional value of full-fat soyabeans for broiler chickens. British Poultry Sci. 38(4) 412-416