Abstract
This study evaluated the effects of two protease products added to feeds having two soybean meal (SBM) sources (South and North of Brazil). A total of five hundred and sixty, 21 d male broiler chickens were allocated into 7 dietary treatments: a nitrogen-free diet (NFD) and other six diets prepared with a 40% replacement of the NFD with each SBM source. Two commercial protease products (RONOZYME® ProAct and ProAct 360(TM)) were added at 15,000 PROT and 30,000 NFP per kg feed, respectively. After 5-day diet adaptation, all birds were euthanized for ileal digesta collection. Results show that the North SBM sample was inherently higher (P < 0.05) in apparent ileal digestibility (AID) of dry matter (DM), nitrogen (N), and the standardized ileal amino acid digestibility (SIAAD) compared to South SBM sample. The DM digestibility and SIAAD of North SBM sample were not different from the un-treated control and protease treatments (P > 0.05, except Val and Ile, which had higher digestibility with ProAct 360). The DM digestibility and SIAAD from South SBM sample were increased (P < 0.05, except Met, Asp and Cys) with both supplemental proteases. Correlation analysis showed that AA digestibility of the two SBM samples were negatively associated with the effect of protease products. These data demonstrated that the SIAAD of SBM was influenced by SBM source with the South SBM sample being lower than that from the North while the protease effects were more evident in the SBM sample from South; responses of ProAct 360 were superior to ProAct. Exogenous proteases can enhance nutritional value of SBM, particularly for those with inherently low amino acid digestibility.