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 body weight at 6 wk 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 two 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% distillers dried grains with solubles with or without 400 U β-mannanase/kg feed. Growth performance (average daily gain, average daily feed intake, and gain-to-feed ratio) was recorded weekly. Plasma was collected on day 35 to quantify tumor necrosis factor-alpha (TNF-α) and malondialdehyde (MDA). On day 35, 0.3% titanium oxide was added as an indigestible marker to the diets for an additional 4-d feeding. On day 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.