The objective of the current study was to evaluate the effect of a subtilisin protease, without or with inclusion of carbohydrases, on digestibility and retention of energy and protein, as well as the solu-bilization and disappearance of non-starch polysaccha-rides (NSP) from corn-soybean meal based diets fed to broiler chickens. Two hundred eighty-eight Ross 308 male broiler chickens were used for the experiment. On d 14, the birds were weighed and allocated to 6 treatments and 8 replicates per treatment with 6 birds per replicate. Treatments were: 1) corn-soybean meal based control diet; 2) control diet plus supplemental protease at 5,000 (P5000) protease units (PU)/kg); 3) control plus 10,000 PU/kg protease (P10000); or con-trol plus an enzyme combination containing xylanase, amylase, and protease (XAP) added to achieve pro-tease activity of: 4) 2,500 PU/kg (XAP2500); 5) 5,000 PU/kg (XAP5000); or 6) 10,000 PU/kg (XAP10000). The enzymes in XAP were combined at fixed ra-tios of 10:1:25 of xylanase:amylase:protease. Data were analyzed by ANOVA and specific orthogonal contrasts between treatments were performed. Addition of xy-lanase and amylase increased (P < 0.05) the ileal di-gestibility of protein by 4.2% and 2.1% at XAP5000 and XAP10000, respectively (relative to P5000 and P10000, respectively), exhibiting a plateau after the XAP5000 dose. Increment (P < 0.05) in AME due to protease was evident, particularly in P10000. At the ileal level, XAP reduced (P < 0.05) the flow of insoluble xylose and arabinose, which indicates an increase in the solu-bilization of arabinoxylan polymers in the small intes-tine. Protease on its own reduced (P < 0.05) the flow of insoluble arabinose but did not affect the flow of in-soluble xylose. XAP reduced (P < 0.05) the pre-cecal flow of insoluble and total glucose and galactose. It was concluded that whereas protease by itself improved nu-trient utilization and increased solubilization of NSP components, at the lower dose, a combination of xy-lanase, amylase, and protease produced effects greater than those of protease alone.
Olukosi, O. A., Beeson, L. A., Englyst, K., & Romero, L. F. (2015). Effects of exogenous proteases without or with carbohydrases on nutrient digestibility and disappearance of non-starch polysaccharides in broiler chickens. Poultry Science, 94(11), 2662–2669. https://doi.org/10.3382/ps/pev260