Effects of Combinational Use of Xylanase and Protease on Growth Performance and Gut Health of Newly Weaned Pigs

This study was to investigate the effect of supplemental xylanase (Xylamax, BRI, Durham, NC) and protease (Versazyme, BRI) on growth performance, digesta viscosity, apparent ileal digestibility of nutrients, and gut health in nursery pigs. Forty-eight pigs (24 barrows and 24 gilts at 21 d of age with 7.2 ± 0.4 kg BW) were randomly allotted to 4 treatments (2 × 2 factorial arrangement). Factors were xylanase (0 or 45,000 XU/kg) and protease (0 or 300,000 U/kg). Experimental diets formulated to meet nutrient requirements suggested by NRC (2012) in 2 phases (phase 1 for 10 d and phase 2 for 24 d). Feed intake and BW gain were measured d 10 and 24. Titanium oxide (0.25%) was added to all diets as an indigestible external marker from d 20 to 24. On d 24, all pigs were euthanized to obtain jejunal and ileal digesta to measure viscosity and apparent ileal digestibility, respectively. Jejunal mucosa was collected to measure immune and oxidative stress status. Jejunal tissues were used to measure morphology, proliferation of crypt cells by immunohistochemistry of Ki-67, and tight junction proteins by Western blot. Data were analyzed using the MIXED procedure in SAS with 2 factors and sex as fixed effects and initial BW block as a random effect. In phase 2, xylanase increased (P < 0.05) ADG (0.518 to 0.560 kg/d) which was further increased (P < 0.05, interaction) with protease. Overall, combinational use of xylanase and protease increased (P < 0.05) ADG (0.503 vs. 0.442 and 0.437 kg/d) compared with the use of xylanase or protease alone, wheras protease improved (P < 0.05) feed efficiency (0.765 to 0.793). In jejunum, xylanase reduced (P < 0.05) viscosity of digesta (2.69 to 2.36 mPa.s), mucosal MDA (1.14 to 0.95 μM), crypt depth (220 to 198 μm) and crypt cell proliferation (20.3 to 17.6%), and protease increased (P < 0.05) villus height (439 to 493 μm), crypt depth (229 to 189 μm) and crypt cell proliferation (21.5 to 15.9%). Combinational use of xylanase and protease increased (P < 0.05) claudin (0.047 to 0.076 band intensity) and occludin (0.126 to 0.161 band intensity) in jejunum. Apparent ileal digestibility of nutrients was not different among treatments. Collectively, xylanase could improve growth, digesta viscosity, and oxidative stress, and protease could improve feed efficiency and gut integrity. Combinational use of xylanase and protease enhanced growth performance and tight junction proteins in newly weaned pigs.