Twin-Screw Extruder Increased Metabolizable Energy of Soybean Meal and Improved Growth Performance in Weaned Piglets by Increasing Nutrient Digestibility

Experiments were conducted to explore effects of extrusion on available energy and nutrient digestibility in soybean meal (SBM) fed to growing pigs and effects of different levels of extruded SBM on growth performance, nutrient digestibility, and intestinal microbial composition of weaned piglets. In Exp. 1, crossbreed growing pigs (initial BW, 32.6 ± 2.7 kg; n=24) were randomly assigned to four treatments including a corn basal diet, SBM, single-screw extruded soybean meal (SSBM) and twin-screw extruded soybean meal (TSBM) diets. Simultaneously, cannulated pigs (initial BW, 22.3 ± 1.8 kg; n=8) were allocated with an 8 × 3 Youden square design. The experimental diets include a N-free diet and three diets containing 40% different sources of SBM. The results showed that metabolizable energy (ME) and digestible energy (DE) of twin-screw extruded SBM had an increasing tendency (P < 0.10). In Exp.2, pigs (initial BW,6.60 ± 0.54 kg; n=192) were fed with diets supplemented with 0%, 3%, 6%, and 9% extruded SBM and dispersed into 4 treatment groups with an randomized design. Each treatment has 6 replicates (4 boars and 4 gilts). The results showed that average daily feed intake (ADFI) reduced linearly with the increase of extruded SBM levels at d0-14 (P < 0.05). At the d15-28, average daily gain (ADG) of weaning piglets in a 9% extruded SBM group increased appreciably compared with the 0% extruded SBM group (P < 0.05), furthermore, the ATTD was noticeably higher in GE, DM, OM and CP as opposed to the other groups. (P < 0.05). A diet containing 3% extruded SBM increased the population of Bifidobacteria in the weaning piglets' feces (P < 0.05). In conclusion, adding an inclusion level of 9% extruded SBM into the diet can improve weaning piglets' nutrient digestibility and growth performance.