LAUSR

The apparent and standardized ileal digestibility (AID and SID) of AA and CP and the apparent total tract digestibility (ATTD) of DM, GE, CP, NDF, and ADF of deactivated soybean (DS) and raw soybean (RS) extruded at 82°C (RS82), 122°C (RS122) and 137°C (RS137) were evaluated. RS was extruded mixed with corn starch (396.5g/kg RS and 603.5g/kg corn starch) in a single-screw extruder (MEX 250, Manzoni, Campinas, Brazil). Thirty-six barrows (7.26±0.94 kg BW) were fed a nitrogen free (N-free) diet, or four diets composed of 30% of each ingredient, as the only source of N, substituting for starch in N-free diet. Pigs were fed at 2.8 x maintenance (2.8 x 106 kcal digestible energy/kg BW0.75) for 10 days (5 d adaptation and 5 d feces collection), and on day 11 piglets were euthanized for ileal digesta collection. A randomized block design was used, with 8 replicates, using the pig as the experimental unit. ANOVA was performed and means were separated using Tukey test (5%). Increasing extrusion temperatures reduced trypsin inhibitors concentrations, from 29.47 in RS to 4.92, 2.24, and 1.48 mg/g CP in RS82, RS122, and RS137, respectively, and 1.39 mg/g CP was verified in DS. The AID and SID of CP and AA, as the ATTD of CP of RS122, RS137 and DS were similar (P >0.05), but 10–62% greater (P< 0.05) than of RS82. The ATTD of GE in RS122 was 3–4% higher (P< 0.05) compared to DS and RS82. RS82 and RS122 showed ATTD of EE 12–16% higher (P< 0.05) than DS. The ATTD of GE and EE of RS137 were similar (P >0.05) to the others ingredients. No effects (P >0.05) on ATTD of NDF and ADF were observed. Extruding soybean at 122oC improved CP, AA, and GE digestibility in young pigs, whereas extrusion at 82oC did not inactivated soybean antinutritional factors.