Effect of Different Thermal and Non-Thermal Processing Methods on Chemical Composition, Quality Indicators and Apparent Nutrient Digestibility of Full-Fat Soybean

Amino acids and energy digestibility in extruded or roasted full fat soybean fed to broiler chickens without or with multienzyme supplement containing protease, phytase, and fiber degrading enzymes

Effects of processing and multienzyme supplement (MES) on standardized ileal digestibility (SID) of amino acids, apparent retention (AR) of components and metabolizable energy (AME) content in full fat soybean seeds (FFSB) were investigated in broiler chickens. The FFSB were either extruded (EFFSB) or roasted (RFFSB). A nitrogen free diet (NFD) was formulated for SID of AA calculation. The FFSB diets contained 20% crude protein with the ratio of corn starch: sucrose: soy oil (sole sources of energy in NFD) kept constant for calculation of AME. The FFSB diets were fed without or with MES containing phytase, protease, and fiber degrading enzymes. All diets had TiO2 indigestible marker. A total of 400-dayu-old Ross 708 male chicks were fed a commercial diet to d 13. On d 14, birds were weighed individually and allocated to cages (10 birds/cage, n = 8). Birds had free access to feed and water. Excreta samples were collected on d 18 to 20, and all birds were necropsied on d 21 for terminal ileal digesta samples. There was no (P > 0.05) interaction between processing and MES on SID of AA. Birds fed EFFSB had higher (P ≤ 0.048) SID of Arg, Ile, Lys, and Met than birds fed RFFSB. Birds fed MES had higher (85.5 vs. 80.8%; P = 0.050) SID of Lys than birds fed non-MES diet. There was interaction (P ≤ 0.036) between processing and MES on AR of Ca and P; MES improved retention but largely in EFFSB. There was an interaction (P = 0.016) between processing and MES on energy utilization such that MES improved AR of GE, AME, and AMEn in RFFSB only. In general, birds fed EFFSB exhibited higher (P < 0.01) energy utilization than birds fed RFFSB. In conclusion, lower Lys and energy utilization in RFFSB relative to EFFSB reflected the impact of the processing regimen. Supplemental enzyme improvement on Lys and minerals digestibility in FFSB and energy utilization in RFFSB suggested value in heat processed feedstuffs.