This study aimed to investigate the nutritional and functional roles of β-mannanase on the intestinal health and growth of newly weaned pigs fed a typical or low-cost formulated feeds (LCF). Twenty-four newly weaned pigs at 6.2 kg ± 0.4 body weight (BW) were allotted to three dietary treatments based on a randomized complete block design with sex and initial BW as blocks. Three dietary treatments are as follows: Control, typical nursery feeds including animal protein supplements and enzyme-treated soybean meal; LCF with increased amounts of soybean meal, decreased amounts of animal protein supplements, and no enzyme-treated soybean meal; LCF+, low-cost formulated feed with β-mannanase at 100 g/t, providing 800 thermostable β-mannanase unit (TMU) per kg of feed. Pigs were fed based on a three-phase feeding program for a total of 37 d. On day 37 of feeding, all pigs were euthanized and the gastrointestinal tract was removed for sample collection to analyze intestinal health parameters, mucosa-associated microbiota, and gene expression of tight junction proteins. Pigs fed LCF increased (P < 0.05) the relative abundance of Proteobacteria and Helicobacter in the jejunal mucosa, tended to decrease (P = 0.097; P = 0.098) the concentration of malondialdehyde (MDA) and the expression of zona occluden 1 (ZO-1) gene in the jejunum, tended to decrease average daily gain (ADG; P = 0.084) and final BW (P = 0.090), and decreased (P < 0.05) average daily feed intake. Pigs fed LCF + tended to decrease (P = 0.088) digesta viscosity, decreased (P < 0.05) the relative abundance of Helicobacter, and increased (P < 0.05) Lactobacillus in the jejunal mucosa compared to LCF. Additionally, LCF + tended to increase final BW (P = 0.059) and ADG (P = 0.054), increased (P < 0.05) gain to feed ratio (G:F), and reduced (P < 0.05) fecal score compared to LCF. LCF with decreased amounts of animal protein supplements and increased amounts of soybean meal had negative effects on the composition of the mucosa-associated microbiota, intestinal integrity, and growth performance of nursery pigs. Beta-mannanase supplementation to LCF decreased digesta viscosity, increased the relative abundance of potentially health-benefitting microbiota such as Lactobacillus, and improved growth and fecal score, thus reflecting its efficacy in low-cost formulated feeds with increased amounts of soybean meal.
Keywords: growth performance; intestinal health; nursery pigs; β-mannanase.
Immediately following weaning, pigs are exposed to various stressors associated with environmental, social, and dietary shifts that can result in depressed growth, high incidence of diarrhea, and increases in mortality. Major plant-based feedstuffs such as soybean meal contain anti-nutritional compounds including nonstarch polysaccharides causing negative impacts on the intestinal health and growth of nursery pigs due to the immaturity of the intestine and intestinal immune system. β-mannanase hydrolyzes β-mannans, nonstarch polysaccharides, resulting in elimination of anti-nutritional properties and the release of mannooligosaccharides. The aim of this study was to investigate the nutritional and functional roles of β-mannanase on intestinal health and growth of newly weaned pigs fed a low-cost formulated feed (LCF). This study showed that increased amounts of soybean meal in LCF increased pathogenic bacteria associated to the jejunal mucosa of nursery pigs, impaired intestinal integrity, and decreased growth. Supplementation of β-mannanase to LCF decreased digesta viscosity, increased Lactobacillus in the jejunal mucosa, reduced diarrhea, and improved growth performance of nursery pigs.
© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.