An experiment was performed to evaluate the energy contents of extruded-expelled soybean meal (EESBM) and the effects of thermal treatment on energy utilization in growing pigs. Eighteen growing barrows (18.03 ± 0.61 kg initial body weight) were individually housed in metabolism crates and randomly allotted to one of three dietary treatments to give six replicates per treatment. The three experimental diets were: a corn-soybean meal-based basal diet and two test diets with simple substitution of a basal diet with intact EESBM or heat-treated EESBM in a 70:30 ratio. Intact EESBM was autoclaved at 120°C for 60 mins to make heat-treated EESBM (heat-EESBM). Pigs were fed the experimental diets for 16 d, including 10 d for adaptation and 6 d for total collection of feces and urine. Pigs were then moved into indirect calorimetry chambers to determine 24-h heat production and 12-h fasting heat production. The energy contents of the tested DESBM were calculated by using the difference method. All data were analyzed using the Mixed procedure of SAS with the individual pig as the experimental unit. Pigs fed heat-EESBM diets showed lower (P < 0.05) apparent total tract digestibility of dry matter (DM), gross energy, and nitrogen than those fed intact EESBM. A trend (P < 0.10) was observed for greater heat increments in pigs fed intact EESBM than those fed heat-EESBM. This resulted in intact EESBM having greater (P < 0.05) digestible energy (DE) and metabolizable energy (ME) contents than heat-EESBM but comparable net energy contents between intact and heat-EESBM.
In conclusion, respective values of DE, ME, and net energy are 4,591 kcal/kg, 4,099 kcal/kg, and 3,242 kcal/kg on a DM basis. However, thermal damage during EESBM production should be considered in terms of DE and ME content of EESBM fed to growing pigs.
