Response of broiler chicks to dietary full-fat soybeans extruded at different temperatures prior to or after grinding

Whole (WSB) or ground (GSB) full-fat soybeans were extruded at 80, 100, 120 or 140°C and incorporated into broiler diets at 30% inclusion level during a 3-week trial.Extrusion of soybeans at 140 °C improved feed intake compared to those extruded at lower temperatures (P < 0.05). However, there were no significant effects of the extrusion temperature on weight gain, feed:gain ratio or mortality rate (P > 0.05). Also, there were no significant effects of whether the extrusion was undertaken prior to or after grinding of the soybeans on feed intake, weight gain, feed:gain ratio, or mortality rate (P > 0.05). There was no significant interaction between the extrusion temperature and the form extruded on any of the performance parameters (P > 0.05).Although increase in extrusion temperature reduced the trypsin inhibitor activity (TIA) of the soybeans, there were no significant effects of the extrusion temperature or type of soybean extruded on nitrogen, fat, calcium or phosphorus retention or diet ME (P > 0.05).It is concluded that low temperature extrusion of full fat soybeans does not reduce TIA to a satisfactory level (< 10 mg g⁻¹ sample) that will enable high dietary inclusion of such extruded soybeans for broilers.