Impacts of non-starch polysaccharide sources with enzymes influencing intestinal mucosa-associated microbiota and mucosal immunity of nursery pigs on growth and carcass traits at market weight

This study investigated the effects of different non-starch polysaccharide (NSP) sources with NSP degrading enzymes (NSPases) and the influence on the mucosa-associated microbiota and intestinal immunity of nursery pigs, on growth performance and carcass traits at market weight. One hundred and sixty newly weaned pigs at 7.0 ± 0.3 kg body weight (BW) were allotted in a 2 × 2 factorial with NSP sources and NSPases serving as factors. The 4 dietary treatments were: DDGS, corn distillers’ dried grains with solubles as source of NSP; DDGS + NSPases (DDGS +), DDGS with xylanase at 0.01%, 3,000 U/kg of feed and β-mannanase at 0.05%, 400 U/kg of feed; SHWB, soybean hulls and wheat bran replacing corn DDGS as the source of NSP; SHWB with NSPases (SHWB +), SHWB with xylanase at 0.01%, 3,000 U/kg of feed and β-mannanase at 0.05%, 400 U/kg of feed. Pigs were fed for 37 d and housed in groups of 4 pigs per pen. At d 37, the median body weight pig in each pen was euthanized for sampling to analyze intestinal health parameters. Remaining pigs were fed a common diet for subsequent phases to evaluate the carryover effect on growth and carcass traits. The SHWB decreased (P < 0.05) the relative abundance of Helicobacter, tended to increase (P = 0.074) the relative abundance of Lactobacillus, increased (P < 0.05) immunoglobulin G (IgG) in the jejunal mucosa, tended to increase (P = 0.096) the villus height (VH) in the jejunum, and tended to improve ADG (P = 0.099) and feed efficiency (P = 0.068) during phase 1 compared to DDGS treatment. Supplementation of NSPases increased (P < 0.05) Shannon index of diversity, increased the relative abundance of Streptococcus and Acinetobacter, and tended to increase (P = 0.082) dry matter digestibility. The BW of pigs fed SHWB was more uniform (P < 0.05) at the end of the 120 d study. Additionally, hot carcass weight of pigs fed SHWB tended to be more uniform (P = 0.089) than DDGS treatment. Soybean hulls and wheat bran replacing DDGS in nursery diets improved uniformity of pigs at market weight, which might be attributed to beneficial modulation of the mucosa-associated microbiota and enhanced intestinal morphology during the nursery phase. Supplementation of NSPases had beneficial effects on the intestinal mucosa-associated microbiota, digestibility, and intestinal immunity in SHWB treatment, whereas no carryover effects were overserved at market weight.