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Efficacy of protease on growth, gut health, and nutrient digestibility in nursery pigs fed diets with different levels of soybean meal
This study was to determine the effect of supplemental protease (Versazyme, BRI, Durham, NC) on the growth performance, gut health, and digestibility of newly weaned pigs fed diets with different levels of soybean meal (SBM). One-hundred twenty pigs (60 barrows and 60 gilts) were weaned at 21 d of age and fed a common early wean feed for 4 d. On 25 d of age (7.77 ± 0.63 kg BW), pigs were randomly allotted to 4 treatments (2 × 2 factorial arrangement) with 10 pens (3 pigs per pen, 5 barrow and 5 gilt pens) per treatment, and fed experimental diets for 3 wk. Factors were SBM levels (22 and 29%) and protease (0 and 0.05%). All diets were calculated to meet or exceed the NRC nutrient requirements. Body weight and feed intake were measured weekly. Titanium dioxide (0.3%) was added to experimental diets from d 18 to 21 as an indigestible marker. Blood samples were taken on d 20 to measure tumor necrosis factor alpha (TNF-α) and malonedialdehyde (MDA). On d 21, 24 pigs (1 from each pen and 6 pens per treatment) were euthanized to obtain the duodenal and jejunal mucosa to measure TNF-α, MDA, and morphology. The jejunal and ileal digesta were obtained to measure viscosity and nutrient digestibility, respectively. Data were analyzed using PROC MIXED procedure in SAS with pen as the experimental unit. Overall, G:F was increased (P < 0.05) as SBM levels increased from 22 to 29% (0.742 vs. 0.770, respectively) or protease was supplemented (0.744 vs. 0.768, respectively). There was no difference in ADG and ADFI among treatments. Viscosity and nutrient digestibility were not affected by SBM and protease. Supplemental protease decreased (P < 0.05) concentration of TNF-α in the duodenal (2.49 vs. 3.06 pg/mg) and jejunal (2.11 vs. 2.99 pg/mg) mucosa. Increased use of SBM decreased (P < 0.05) villus height (627 to 564 μm) whereas the use of protease increased (P < 0.05) villus height (573 to 617 μm) without interaction between 2 factors. Collectively, dietary supplementation of protease enhanced feed efficiency and gut health as measured by deceased TNF-α and increased villus height.
Keywords: growth performance, gut health, nursery pigs, protease, soybean meal