Impacts of F18+Escherichia coli on Intestinal Health of Nursery Pigs and Dietary Interventions

Impacts of replacing soybean meal with processed soybean meal on intestinal health and growth of nursery pigs challenged with F18+ Escherichia coli

OBJECTIVE

This study aimed to investigate the impact of different level of soybean meal (SBM) replaced by soy protein concentrate on intestinal health and growth performance of nursery pigs under F18+ Escherichia coli (E. coli).

METHODS

Forty-eight newly weaned pigs (6.6±0.3 kg) were randomly allotted to 4 treatments arranged by 2×2 factors using randomized complete block design with initial body weight and sex as blocks. Two factors were F18+ E. coli challenge (0 or 2.1×1010 colony-forming units [CFU]) and the level of SBM (24% or 12% in phase 1 and 26% or 14% in phase 2). Pigs were fed for 25 d in 2 phases (phase 1 for 11 d and phase 2 for 14 d). At the end of study, all pigs were euthanized to collect jejunal mucosa and tissues.

RESULTS

The F18+ E. coli challenge decreased (p<0.05) overall average daily gain (ADG) and average daily feed intake (ADFI) and decreased (p<0.05) gain to feed ratio on d 7 to 11. The high SBM tended to have a greater overall ADG (p = 0.054) and ADFI (p = 0.078) compared with low SBM under F18+ E. coli challenge, but not in unchallenged conditions. The F18+ E. coli challenge increased (p<0.05) fecal score on d 7 to 18. The tumor necrosis factor-α and interleukin-1β in jejunal mucosa were decreased (p<0.05) in high SBM treatments. The high SBM tended to increase (p = 0.085) occludin expression in jejunum. high SBM increased crypt depth in jejunum under F18+ E. coli challenge, but not in unchallenged conditions (p<0.05).

CONCLUSION

High SBM in nursery diets could alleviate the detrimental effects of F18+ E. coli challenge on growth performance of pigs under compared to low SBM inclusion, which might be attributed to decreased intestinal inflammation and improved intestinal integrity.

Antibiotics and Opportunities of Their Alternatives in Pig Production: Mechanisms Through Modulating Intestinal Microbiota on Intestinal Health and Growth

Antibiotics at subtherapeutic levels have been used in pig diets as antimicrobial growth promoters. However, concerns about antibiotic resistance have increased the demand for alternatives to these antimicrobial growth promoters. This review paper explores the mechanisms through which antimicrobial growth promoters and their alternatives exert their antimicrobial effects. Additionally, this systemic review also covers how modulation of intestinal microbiota by antimicrobial growth promoters or their alternatives affects intestinal health and, subsequently, growth of pigs. The mechanisms and effects of antimicrobial growth promoters and their alternatives on intestinal microbiota, intestinal health, and growth are diverse and inconsistent. Therefore, pig producers should carefully assess which alternative is the most effective for optimizing both profitability and the health status of pigs in their production system.

Recombinant Saccharomyces cerevisiae EBY100/pYD1-FaeG: a candidate for an oral subunit vaccine against F4+ ETEC infection

Diarrheal diseases attributable to multidrug-resistant F4+ enterotoxigenic Escherichia coli (ETEC) are escalating in severity, posing significant risks to the health and safety of both humans and animals. This study used Saccharomyces cerevisiae EBY100 to display the FaeG subunit of F4 colonizing factor as an oral vaccine against F4+ ETEC infection. Mice were orally immunized twice with 108 CFU of EBY100/pYD1-FaeG, followed by a challenge with F4+ ETEC EC6 on day 7 post-immunization. The results showed that the recombinant strain EBY100/pYD1-FaeG orally enhanced the growth of the small intestine villi, significantly boosted the expression of tight junction proteins (ZO-1, Occludin, MUC2, and Claudin) (P < 0.05), and modulated the gut microbiota composition. Additionally, immunization with EBY100/pYD1-FaeG also upregulated the levels of IL-2, IL-4, and IFN-γ in the intestines of mice (P < 0.01), while serum IgG and fecal sIgA titer significantly increased (P < 0.05). These immune responses enhanced the capacity to fight against ETEC, leading to an increased survival rate of mice and relieved damage to tissues and organs of mice infection. In summary, the study suggested that the recombinant Saccharomyces cerevisiae EBY100/pYD1-FaeG could effectively stimulate the immune response and generate specific antibodies against F4+ ETEC, showing its potential to serve as a subunit oral vaccine candidate for preventing F4+ ETEC infection.IMPORTANCEThe multidrug-resistant F4+ enterotoxigenic Escherichia coli (ETEC) strains are the primary clinical pathogens responsible for post-weaning diarrhea in piglets, resulting in substantial economic losses in the pig farming industry. In the study, we developed an oral vaccine candidate, Saccharomyces cerevisiae EBY100/pYD1-FaeG, to prevent diarrhea caused by multidrug-resistant F4+ ETEC. Oral administration of EBY100/pYD1-FaeG significantly enhanced immune responses, improved intestinal health, and provided protection against F4+ ETEC infection in mice. This approach offers a potential application prospect for preventing F4+ ETEC infections that lead to post-weaning diarrhea in clinical settings and provides a promising solution for addressing the growing threat of antibiotic resistance in bacterial pathogens.

Dietary supplementation of blend of organic acids and monoglycerides alleviated diarrhea and systemic inflammation of weaned pigs experimentally infected with enterotoxigenic Escherichia coli F18

BACKGROUND

The emergence of antibiotic resistant microorganisms associated with conventional swine production practices has increased interest in acid-based compounds having antimicrobial properties and other biological functions as nutritional interventions. Despite the interest in organic acids and monoglycerides, few studies have examined the effects of the combination of these acid-based additives in weaned pigs under disease challenge conditions. Therefore, this study aimed to investigate the effects of dietary supplementation with blend of organic acids and/or medium-chain fatty acid monoglycerides on intestinal health and systemic immunity of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli (ETEC) F18 at 4-week of age.

RESULTS

Dietary supplementation of organic acids, monoglycerides, or both organic acids and monoglycerides (combination) reduced (P < 0.05) the diarrhea frequency of ETEC F18-infected pigs throughout the experimental period (d -7 to 21 post-inoculation). This is consistent with the reduced (P < 0.05) proportion of β-hemolytic coliforms in feces observed for the organic acid and combination treatments on d 10 post-inoculation. Supplementation of organic acids, monoglycerides, or combination also reduced (P < 0.05) bacterial translocation in mesenteric lymph nodes on d 21 post-inoculation. Pigs fed with monoglycerides or combination had lower (P < 0.05) white blood cells on d 5 post-inoculation, and pigs fed the combination also had lower (P < 0.05) lymphocytes than pigs in control group. Monoglyceride supplementation increased (P < 0.05) white blood cells and neutrophils compared with control group on d 14 post-inoculation. However, supplementation with organic acid blend, monoglyceride blend, or combination did not affect growth performance in this experiment.

CONCLUSIONS

Supplementation with monoglycerides or organic acids alone or in combination improves the detrimental effects of ETEC F18 infection in weaned pigs, as indicated by reduced diarrhea, fecal shedding of β-hemolytic coliforms, and bacterial translocation, and thus enhancing disease resistance. Monoglycerides reduced the inflammatory response during peak infection, but their immunomodulatory and possible synergistic effects with organic acids need to be further investigated.

Efficacy of ground herb-based and essential oil-based phytobiotics on the intestinal health and performance of nursery pigs challenged with F18+Escherichia coli

This study aimed to evaluate the efficacy of using ground herb-based phytobiotics and essential oil-based phytobiotics in pig diets on intestinal health and growth performance (GP) of nursery pigs challenged with F18+Escherichia coli. Forty nursery pigs (6.4 ± 0.1 kg) at 21 d of age were individually housed and assigned to 4 dietary treatments in a randomized complete block design, with body weight and sex as blocking factors. Basal diets were fed to pigs for 28 d in 3 phases. Treatments were negative control (NC): basal diet, non-challenged; positive control (PC): basal diet, challenged with F18+E. coli; HP: PC + 1% ground herb-based phytobiotics (Salcochek Pro, Ayurvet Limited, Kaushambi, India); EP: PC + 1% essential oil-based phytobiotics (Liq-biotic, Ayurvet Limited). The GP was recorded for each phase and fecal score (FS) was measured daily. On day 7 postweaning, the challenged groups were orally inoculated with F18+E. coli (2.0 × 1010 CFU), the NC treatment received a sterile saline solution. On day 28, pigs were euthanized to collect jejunal samples to evaluate intestinal health and relative abundance (RA) of jejunal mucosa-associated microbiota. Data were analyzed using the MIXED procedure on SAS 9.4. The PC increased (P < 0.05) the RA of Prevotellaceae, Lachnospiraceae, and Ruminococcaceae when compared to NC. The HP reduced (P < 0.05) the RA of Veillonellaceae, Prevotellaceae, and Lachnospiraceae when compared to PC. The EP tended to reduce the RA of Streptococcaceae (P = 0.073) and Corynebacteriaceae (P = 0.074) when compared to PC. The PC increased (P < 0.05) occludin and tended to increase (P = 0.096) toll-like receptor-4 (TLR4) when compared to NC. The PC decreased (P < 0.05) average daily gain and average daily feed intake when compared to NC in days 7 to 28. The PC increased FS (P < 0.05) compared to the HP and EP days 7 to 11. The HP and EP decreased (P < 0.05) FS when compared to PC during days 7 to 11 and days 7 to 18. In conclusion, F18+E. coli challenge disrupted the jejunal mucosa-associated microbiota, increased TLR4 expression and FS, and consequently reduced GP. Both HP and EP phytobiotics supported intestinal morphology during the challenge to F18+E. coli by supporting enterocyte maturation. The HP and EP treatments exhibited antimicrobial-like effects by altering the jejunal mucosa-associated microbiota and reduced FS during the first 2 weeks post-challenge. The HP treatment showed potential antioxidant effects.

Investigation of the nutritional and functional roles of a microencapsulated blend of botanicals on intestinal health and growth of nursery pigs challenged with F18+Escherichia coli

The study aimed to evaluate the effects of increasing levels of a microencapsulated blend of botanicals (MBB) on the intestinal health and growth performance of nursery pigs challenged with F18+E. coli. Sixty-four nursery pigs (6.8 ± 0.3 kg) were assigned to 4 dietary treatments in a randomized complete block design, with initial body weight and sex as blocks, and fed for 28 d in 3 phases. Treatments were a basal diet fed to pigs without F18+E. coli challenge (NC) and 3 levels of MBB (0.0%, 0.1%, and 0.2%) in pigs challenged with F18+E. coli. On day 7 of the study, pigs in the challenged group were orally inoculated with F18+E. coli (1.5 × 1010 CFU). On days 7 and 21 post-challenge, pigs were euthanized to collect jejunal tissues and mucosa. Compared to the NC, 0.0% MBB increased (P < 0.05) relative abundance (RA) of Staphylococcus saprophyticus and reduced (P < 0.05) Streptococcus parasuis at days 7 and 21 post-challenge, respectively. Increasing levels of MBB decreased (linear: P < 0.05) RA of S. saprophyticus on day 7 post-challenge. Compared to the NC, 0.0% MBB increased (P < 0.05) jejunal NOD2 and IL-6 expression and decreased (P < 0.05) ZO-1 on day 7 post-challenge. Compared to the NC, 0.0% MBB decreased (P < 0.05) jejunal IL-6, IL-8, and TNF-α and increased (P < 0.05) IgG on day 21 post-challenge. Increasing levels of MBB increased OCLN (linear: P < 0.05) and ZO-1 (linear and quadratic: P < 0.05) on day 7 post-challenge and decreased toll-like receptor 4 (TLR4; linear and quadratic: P < 0.05). Compared to the NC, 0.0% MBB decreased (P < 0.05) Ki-67+ on day 7 post-challenge. Increasing levels of MBB increased (linear: P < 0.05) Ki-67+ on day 7 post-challenge and villus height (VH):CD on d 21 post-challenge. In the overall period, compared to the NC, 0.0% MBB decreased (P < 0.05) average daily gain. Increasing daily MBB intake linearly increased OCLN on day 7 and VH:CD on day 21, and reduced TLR4 and IL-8 on day 21 post-challenge, but exhibiting quadratic effects (P < 0.05) on ZO-1 (optimal at 0.12% of MBB), IgG (optimal at 0.14% of MBB), and G:F during days 7 to 20 and days 7 to 28 (optimal at 0.22% and 0.10% of MBB, respectively). In conclusion, F18+E. coli challenge negatively modulated the jejunal mucosal microbiota and reduced intestinal morphology and growth of nursery pigs. Supplementation of MBB at 0.10% to 0.14% provided optimal mitigation of the impacts of F18+E. coli challenge on humoral immunity, intestinal integrity, jejunal morphology, and feed efficiency of pigs.

Saccharomyces yeast postbiotics mitigate mucosal damages from F18+ Escherichia coli challenges by positively balancing the mucosal microbiota in the jejunum of young pigs

BACKGROUND

Enterotoxigenic Escherichia coli (E. coli) is one of the most prevalent causes of diarrhea in young animals. Postbiotics derived from yeast have the potential to positively influence the mucosal microbiota in the jejunum, therefore it was hypothesized that Saccharomyces yeast postbiotics could enhance the microbiota and mucosal immune response in the jejunum, mitigating the effects of infection with enterotoxigenic E. coli. The purpose of this study was to investigate the effects of a Saccharomyces yeast postbiotic on the mucosal microbiota and mucosal immune response in the jejunum of newly weaned pigs challenged with F18+ E. coli.

RESULTS

Thirty-six individually housed nursery pigs were allotted into three treatments utilizing a randomized complete block design; negative control (NC: basal diet, no challenge), positive control (PC: basal diet, challenge), and SYP (basal diet + Saccharomyces yeast postbiotics at 175 g/ton, challenge). On d 7, PC and SYP were orally inoculated with F18+ E. coli, whereas NC received saline. On d 28, pigs were euthanized for sampling of the jejunum to analyze the mucosal microbiota, oxidative stress, immune status, and intestinal morphology. The PC reduced (P < 0.05) growth performance compared to NC. The SYP improved (P < 0.05) fecal score from d 7-18 when compared with PC. SYP reduced (P < 0.05) protein carbonyl, reduced (P < 0.05) gene expression of Toll-like receptor 4, and increased (P < 0.05) gene expression of mammalian target of rapamycin, compared with PC.

CONCLUSIONS

Challenge with F18+ E. coli negatively impacted jejunal mucosa-associated microbiota and jejunal morphology, affecting growth performance. Saccharomyces yeast postbiotics could reduce the negative effects associated with F18+ E. coli infection.

Effects of monoglyceride blend on systemic and intestinal immune responses, and gut health of weaned pigs experimentally infected with a pathogenic Escherichia coli

BACKGROUND

Monoglycerides have emerged as a promising alternative to conventional practices due to their biological activities, including antimicrobial properties. However, few studies have assessed the efficacy of monoglyceride blend on weaned pigs and their impacts on performance, immune response, and gut health using a disease challenge model. Therefore, this study aimed to investigate the effects of dietary monoglycerides of short- and medium-chain fatty acids on the immunity and gut health of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli F18.

RESULTS

Pigs supplemented with high-dose zinc oxide (ZNO) had greater (P < 0.05) growth performance than other treatments, but no difference was observed in average daily feed intake between ZNO and monoglycerides groups during the post-challenge period. Pigs in ZNO and antibiotic groups had lower (P < 0.05) severity of diarrhea than control, but the severity of diarrhea was not different between antibiotic and monoglycerides groups. Pigs fed with monoglycerides or ZNO had lower (P < 0.05) serum haptoglobin on d 2 or 5 post-inoculation than control. Pigs in ZNO had greater (P < 0.05) goblet cell numbers per villus, villus area and height, and villus height:crypt depth ratio (VH:CD) in duodenum on d 5 post-inoculation than pigs in other treatments. Pigs supplemented with monoglycerides, ZNO, or antibiotics had reduced (P < 0.05) ileal crypt depth compared with control on d 5 post-inoculation, contributing to the increase (P = 0.06) in VH:CD. Consistently, pigs in ZNO expressed the lowest (P < 0.05) TNFa, IL6, IL10, IL12, IL1A, IL1B, and PTGS2 in ileal mucosa on d 5 post-inoculation, and no difference was observed in the expression of those genes between ZNO and monoglycerides. Supplementation of ZNO and antibiotic had significant impacts on metabolic pathways in the serum compared with control, particularly on carbohydrate and amino acid metabolism, while limited impacts on serum metabolites were observed in monoglycerides group when compared with control.

CONCLUSIONS

The results suggest that supplementation of monoglyceride blend may enhance disease resistance of weaned pigs by alleviating the severity of diarrhea and mitigating intestinal and systemic inflammation, although the effectiveness may not be comparable to high-dose zinc oxide.

Effects of dietary Lactobacillus postbiotics and bacitracin on the modulation of mucosa-associated microbiota and pattern recognition receptors affecting immunocompetence of jejunal mucosa in pigs challenged with enterotoxigenic F18+ Escherichia coli

BACKGROUND

Enterotoxigenic Escherichia coli (E. coli) is a threat to humans and animals that causes intestinal disorders. Antimicrobial resistance has urged alternatives, including Lactobacillus postbiotics, to mitigate the effects of enterotoxigenic E. coli.

METHODS

Forty-eight newly weaned pigs were allotted to NC: no challenge/no supplement; PC: F18+ E. coli challenge/no supplement; ATB: F18+ E. coli challenge/bacitracin; and LPB: F18+ E. coli challenge/postbiotics and fed diets for 28 d. On d 7, pigs were orally inoculated with F18+ E. coli. At d 28, the mucosa-associated microbiota, immune and oxidative stress status, intestinal morphology, the gene expression of pattern recognition receptors (PRR), and intestinal barrier function were measured. Data were analyzed using the MIXED procedure in SAS 9.4.

RESULTS

PC increased (P < 0.05) Helicobacter mastomyrinus whereas reduced (P < 0.05) Prevotella copri and P. stercorea compared to NC. The LPB increased (P < 0.05) P. stercorea and Dialister succinatiphilus compared with PC. The ATB increased (P < 0.05) Propionibacterium acnes, Corynebacterium glutamicum, and Sphingomonas pseudosanguinis compared to PC. The PC tended to reduce (P = 0.054) PGLYRP4 and increased (P < 0.05) TLR4, CD14, MDA, and crypt cell proliferation compared with NC. The ATB reduced (P < 0.05) NOD1 compared with PC. The LPB increased (P < 0.05) PGLYRP4, and interferon-γ and reduced (P < 0.05) NOD1 compared with PC. The ATB and LPB reduced (P < 0.05) TNF-α and MDA compared with PC.

CONCLUSIONS

The F18+ E. coli challenge compromised intestinal health. Bacitracin increased beneficial bacteria showing a trend towards increasing the intestinal barrier function, possibly by reducing the expression of PRR genes. Lactobacillus postbiotics enhanced the immunocompetence of nursery pigs by increasing the expression of interferon-γ and PGLYRP4, and by reducing TLR4, NOD1, and CD14.

Dietary Intervention of Benzoic Acid for Intestinal Health and Growth of Nursery Pigs

The objectives of this review are to investigate how benzoic acid can mitigate the negative effects of weaning stress, improve the intestinal microbiota, intestinal health, and growth of nursery pigs, determine the optimal dose level of benzoic acid for the growth rate in nursery pigs, and compare the efficacy of benzoic acid and other acids in pig feeds. After weaning, pigs are exposed to less lactose and solid feed with high acid-binding capacity at infrequent intervals, causing an increase in digesta pH, reducing protein digestion, and increasing ammonia-producing bacteria in the stomach. Benzoic acid supplementation has improved the intestinal health and growth of nursery pigs through its antimicrobial properties and pH reduction in the digesta. The positive modulation of luminal microbiota in the small intestine of pigs by benzoic acid improves intestinal morphology and enhances nutrient utilization, especially nitrogen, of nursery pigs. Benzoic acid supplementation of up to 1% in feeds also increases hippuric acid contents in the urine of nursery pigs, decreasing urinary pH, which is related to ammonia emission and barn conditions in intensive pig production. Supported by the beneficial impacts of benzoic acid, the growth performance of nursery pigs was also improved. However, excessive benzoic acid (over 2.5% up to 5%) in feeds reduces the growth performance of nursery pigs. Thus, this review conducted a meta-analysis of the results from 16 papers to determine the optimal dose level of benzoic acid for body weight gain of nursery pigs, which was found to be 0.60%. The efficacy of benzoic acid was similar to that of other organic acids, including citric acid, fumaric acid, formic acid, and formate salts. Collectively, benzoic acid supplementation can positively modulate the luminal and mucosal microbiota in the small intestine, increase nutrient utilization and intestinal health, decrease urinary pH, and improve the growth performance of nursery pigs.

- Invited Review - Pig production in Latin America

Latin America is a culturally, geographically, politically, and economically diverse region. Agriculture in Latin America is marked by a remarkable diversity of production systems, reflecting various agroecological zones, farm sizes, and technological levels. In the last decade, the swine industry increased by 30.6%, emerging as a great contributor to food security and economic development in Latin America. Brazil and Mexico dominate the pig production landscape, together accounting for 70% of sow inventory in the region. The swine industry in Latin America is predominantly comprised of small and medium-sized farms, however, in the past 30 years, the number of pig producers in Brazil dropped by 78%, whereas pork production increased by 326%. Similar to the global pork industry, the growing demand for pork, driven by population growth and changing dietary habits, presents an opportunity for the industry with an expected growth of 16% over the next decade. The export prospects are promising, however subject to potential disruptions from global market conditions and shifts in trade policies. Among the challenges faced by the swine industry, disease outbreaks, particularly African Swine Fever (ASF), present significant threats, necessitating enhanced biosecurity and surveillance systems. In 2023, ASF was reported to the Dominican Republic and Haiti, Porcine Reproductive and Respiratory Syndrome (PRRS) in Mexico, Costa Rica, the Dominican Republic, Colombia, and Venezuela, and Porcine Epidemic Diarrhea (PED) in Mexico, Peru, the Dominican Republic, Colombia, and Ecuador. Additionally, feed costs, supply chain disruptions, and energy expenses have affected mainly the smaller and less efficient producers. The swine industry is also transitioning towards more sustainable and environmentally friendly practices, including efficient feed usage, and precision farming. Ensuring long-term success in the swine industry in Latin America requires a holistic approach that prioritizes sustainability, animal welfare, and consumer preferences, ultimately positioning the industry to thrive in the evolving global market.

- Invited Review - Current status of global pig production: an overview and research trends

Global pig production has increased by 140% since the 1960s. The increase in global population, coupled with improving socioeconomic conditions of many countries has led to an increased consumption of meat globally, including pork. To keep up with demand and capitalize on economic opportunities, the countries of China, the United States (US), and the European Union (EU) have become the top 3 pork producers globally. China is of particular interest, as it is the both the largest country in pork production and pig numbers, as well as being the largest importer of pork from other countries. Globally, the efficiency of pork production has improved, in relation to the integration of pig production and the dramatic increase in research efforts in pig nutrition and production. Through integration, large producers can consolidate resources and maximize profits and efficiency. The increased research interest and efforts in pig production have given scientists and producers the opportunity to collaborate to adapt to challenges and identify possible solutions to issues brought on by a volatile global market. Intestinal health (23%), general nutrition and growth (23%), and amino acid nutrition (15%) were the top 3 areas (61%) leading research trends in pig nutrition and production. Major dietary interventions with feed additives evaluated include functional amino acids, feed enzymes, pre-/pro-/post-biotics, and phytobiotics with a common goal to improve the growth efficiency by enhancing nutrient utilization and intestinal health. With increasing global issues with environment, pig producers and the supporting scientists should continue their efforts to improve the production efficiency and to reduce the environmental footprint from pig production.

Nutritional and functional roles of β-mannanase on intestinal health and growth of newly weaned pigs fed two different types of feeds

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.