Two Net Energy Values of Extruded Soybean Meal for Pigs experiments were conducted to determine the net energy (NE) content of dry extruded-expelled soybean (DESBM) and the effect of a multi-enzyme carbohydrase (MC) mixture on the net energy (NE) content of DESBM and to determine the effect of diet design on NE values in growing pigs using indirect calorimetry (IC).

In the first experiment, 24 barrows weighing about 19.6 kg were randomly allotted to four dietary treatments: 1) a corn–soybean meal basal diet, 2) a diet containing the basal diet and DESBM in an 80:20 ratio with a constant crude protein, 3) a diet with an 80:20 ratio of basal diet and DESBM with a constant corn: soybean meal ratio, and 4) a diet with simple substitution of basal diet with DESBM in an 80:20 ratio. Pigs were fed in metabolism crates for a period of 16 d to determine the digestible energy (DE) and metabolic energy (ME) and then were moved into an indirect calorimeter where O2 consumption and CO2 production were measured to determine heat production and fasting heat production. The NE content of DESBM was calculated (difference method) to be 2,632, 2,548 and 2,540 kcal/kg dry matter for dietary treatments 2, 3 and 4, respectively. Respective values obtained with published prediction equations were 2,624, 2,530 and 2,436 kcal/kg.

In the second experiment 24 barrows weighing about 16.9 kg were randomly allotted to one of four treatments. The diets were a corn–soybean meal basal diet and a diet containing the basal diet and DESBM in an 80:20 ratio with a constant corn: soybean meal ratio with or without two levels (0.05% and 0.1%) of MC. The experimental procedures were similar to those described in the first experiment. Enzyme supplementation improved (P < 0.0001) the DE, ME, and NE content of the DESBM. The multi-enzyme carbohydrase included in the diet at 0.05% and 0.1% improved NE values of DESBM by 4.9% and 3.7%, respectively. The researchers concluded that the NE values of DESBM obtained with the IC method were slightly higher than the values obtained with prediction equations; the average NE value of DESBM evaluated was 2,544 kcal/kg dry matter; and a multi-enzyme carbohydrase enzyme supplementation improved the NE content of DESBM fed to growing pigs.