Effects of β-mannanase on intestinal health and growth performance of nursery to growing pigs fed diets with DDGS

A total of 84 pigs (17.6 ± 2.8 kg initial BW at 6 week of age) were used in a 40-d trial to evaluate the effects of dietary supplemental β-mannanase (400 U/kg feed, CTCBIO Inc., Seoul, Korea) on growth performance, digesta viscosity, ileal nutrient digestibility and intestinal health of pigs during the nursery to grower phase. Pigs were allotted to 2 treatments (14 pens per treatment, 3 pigs per pen) based on a randomized complete block design with sex as a block. Experimental diets included corn (starter: 50%; grower: 57%), soybean meal (starter: 27%; grower: 20%), and 20% DDGS with or without 400 U β-mannanase/kg feed. Growth performance (ADG, ADFI, and G:F ratio) was recorded weekly. Plasma was collected on d 35 to quantify tumor necrosis factor-alpha (TNF-α) and malondialdehyde (MDA). On d 35, 0.3% titanium oxide was added as an indigestible marker to the diets for an additional 4 d feeding. On d 40, 16 pigs (1 pig per pen, 8 pens per treatment) were euthanized to collect digesta from jejunum, ileum, and colon (to measure viscosity and pH value) and to collect tissues from duodenum, jejunum and ileum (for histomorphology, TNF-α, and MDA evaluation). Supplementation of β-mannanase reduced (P < 0.05) viscosity of jejunal digesta (2.52 to 1.97 cP, respectively), increased pH of colon digesta (5.99 to 6.33), and tended to reduce (P = 0.078) TNF-α concentration (7.94 to 6.46 pg/mg) in jejunal mucosa. Supplementation of β-mannanase decreased (P < 0.05) jejunal crypt depth (249 to 212 µm) whereas increasing (P < 0.05) ileal villus height (377 to 432 µm) and villus height to crypt depth ratios in both the jejunum (1.58 to 2.10) and ileum (1.65 to 2.02). Supplementation of β-mannanase increased ileal digestibility of neutral detergent fiber (31.3 to 41.1%) and acid detergent fiber (26.8 to 38.7%) whereas improving (P < 0.05) G:F ratio during the starter (0.593 to 0.617) and the overall period (0.572 to 0.589). Collectively, dietary β-mannanase (400 U/kg) could improve feed efficiency by decreasing digesta viscosity and increasing nutrient digestibility and could also maintain intestinal health by improving intestinal morphology and reducing inflammatory response.