44 Investigation of the nutritional and functional roles of mannanase on intestinal health and growth of newly weaned pigs fed a low-cost formulated diet

Abstract

Abstract This study aimed to investigate the nutritional and functional roles of mannanase on the intestinal health and growth of newly weaned pigs fed a typical or low-cost formulated diet reducing the inclusion of highly digestible protein ingredients. Twenty-four newly weaned pigs at 6.2 ± 0.5 kg initial body weight (BW) were allotted to three dietary treatments based on a randomized complete block design with sex and BW as blocks. Pigs were fed for 37 d in three phases (P1, P2, and P3) and weighed at the end of each phase. Low-cost formulation was achieved by reducing the use of animal protein (fish meal, poultry meal, and blood plasma) and processed soybean meal whereas increasing the use of soybean meal from 13% in typical diets to 28% in P1, from 15% to 32% in P2, and 20.5% to 35% in P3. Treatments were 1) control diet (CON, typical nursery feed), 2) low-cost formulated diet (LCD), and 3) LCD + mannanase inclusion (0 vs. 100 g/t of Natupulse, BASF, providing 800 Thermostable Mannanase Unit, TMU, per ton of feed). On d 37 of feeding, all pigs were euthanized and jejunal mucosal tissues were taken to analyze intestinal health parameters, and gene expression of tight junction proteins and mucins. Pigs fed LCD had reduced (P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI) during the overall period and increased (P < 0.05) fecal score during P3. The LCD decreased (P < 0.05) malondialdehyde and the gene expression of Zona occludens-1 (ZO-) in the jejunum and increased (P < 0.05) serum insulin. The inclusion of mannanase in LCD tended to increase (P = 0.059) BW at d 37, increased (P < 0.05) ADFI during P1, increased (P < 0.05) ADG and gain to feed ratio (G:F) during the overall period, reduced (P < 0.05) fecal score during the overall period, and decreased (P < 0.05) the viscosity of jejunal digesta. However, no effects were observed on intestinal immune response at d 37. In conclusion, feeding LCD negatively affected growth performance and intestinal health of nursery pigs. The inclusion of mannanase to the LCD (800 TMU/t feed) mitigated the negative effects of lowering feed quality observed in growth performance by reducing digesta viscosity and fecal score.