Effect of novel soya bean meal processing technologies on broiler performance and digestibility

Locally produced soybean meal (SBM) may be an important constituent of European broiler diets in the future. In the present trial, extrusion or cooking processes in combination with dehulling and pressing were used to produced 4 partly defatted SBMs from European soybeans (var. Ecudor) harvested in 2015 in the South of France (30 T/ha; 44 CP % DM, 25 Trypsin Inhibitor (TI) units/mg). Broiler starter (d0-14) and grower (d15-28) diets were offered to 288 Ross 308 male broilers as coarse mash in a 2x2 design: 2 processing methods ((Extrusion-pressing (E) vs Flaking-pressing-cooking (F)) x 2 hulling methods ((de-hulling (D) vs no dehulling (ND)). TI values were 2.6, 3.5, 3.6 and 7.6 TIU/mg for E/ND, E/D, F/ND and FD meals, respectively. The KOH protein solubility was increased by dehulling for E (70 vs. 76%) and F processes (82 vs. 89%, for non- and dehulled- meals, respectively). Variables measured on broilers consisted of ADG, ADFI, FCR, DM and CP digestibility and jejunal histomorphometry at d14 and d28 of age. In addition, carcass yield and carcass part yield, organ weight, and empty gastrointestinal tract (GIT) weight and length per small intestinal GIT segment were assessed at d28. Processing method did not affect any of the variables tested. On the other hand, hull presence increased (P < 0.05) ADFI over the starter period, but not over the grower period. In addition, hulled treatments increased proventriculus, gizzard and jejunum weight, and reduced carcass yield at d28 of age likely due to their higher fibre content. Method of processing and hulling significantly interacted (P < 0.05) for ADFI and ADG at the end of the starter period being the highest for the E/ND treatment, but overall broiler performance was similar between dietary treatments. Similarly, small intestinal architecture and DM and CP digestibility were not affected by dietary treatments at either d14 or d28 post hatch. In conclusion, all 4 methods of production resulted in comparable results in relation to performance variables. Hull removal did not confer a significant advantage, possibly due to the adaptive growth of the gizzard and proventriculus, aside from increased carcass yield.