Intestinal Damages by F18+Escherichia coli and Its Amelioration with an Antibacterial Bacitracin Fed to Nursery Pigs

Multi-omics profiling of dairy cattle oxidative stress identifies hindgut-derived Phascolarctobacterium succinatutens exhibiting antioxidant activity

An imbalance between oxidative and antioxidant processes in the host can lead to excessive oxidation, a condition known as oxidative stress (OS). Although changes in the hindgut microbiota have been frequently linked to OS, the specific microbial and metabolic underpinnings of this association remain unclear. In this study, we enrolled 81 postpartum Holstein cows and stratified them into high oxidative stress (HOS, n = 9) and low oxidative stress (LOS, n = 9) groups based on the oxidative stress index (OSi). Using a multi-omics approach, we performed 16S rRNA gene sequencing to evaluate microbial diversity, conducted metagenomic analysis to identify functional bacteria, and utilized untargeted metabolomics to profile serum metabolites. Our analyses revealed elevated levels of kynurenine, formyl-5-hydroxykynurenamine, and 5-hydroxyindole-3-acetic acid in LOS dairy cows. Additionally, the LOS cows had a higher abundance of short-chain fatty acids (SCFAs)-producing bacteria, including Bacteroidetes bacterium, Paludibacter propionicigenes, and Phascolarctobacterium succinatutens (P. succinatutens), which were negatively correlated with OSi. To explore the potential role of these bacteria in mitigating OS, we administered P. succinatutens (108 cfu/day for 14 days) to C57BL/6 J mice (n = 10). Oral administration of P. succinatutens significantly increased serum total antioxidant capacity, decreased total oxidants, and reduced OSi in mice. Moreover, this treatment promoted activation of the Nrf2-Keap1 antioxidant pathway, significantly enhancing the enzymatic activities of GSH-Px and SOD, as well as the concentrations of acetate and propionate in the colon. In conclusion, our findings suggest that systemic tryptophan metabolism and disordered SCFAs production are concurrent factors influenced by hindgut microbiota and associated with OS development. Modulating the hindgut microbiota, particularly by introducing specific SCFAs-producing bacteria, could be a promising strategy for combating OS.

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.

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.

Effects of dietary supplementation of myristic acid on jejunal mucosa-associated microbiota, mucosal immunity, and growth performance of nursery pigs

The objective of this study was to investigate the effects of myristic acid on jejunal mucosal microbiota, mucosal immunity, and growth performance of nursery pigs. Thirty-six pigs (6.6 ± 0.4 kg of body weight) were assigned to three treatments (n = 12) for 35 d in three phases: (NC) basal diet; (PC) NC + bacitracin; and (MA) NC + myristic acid compound. Pigs were euthanized to collect jejunal mucosa, jejunal tissues, and ileal digesta. The PC increased (p < 0.05) the relative abundance (RA) of Lactobacillus spp., and Bifidobacterium boum than the NC group. The MA increased (p < 0.05) RA of Bifidobacterium dentium and Megasphaera spp. than the NC group. The PC tended to decrease IL-8 (p = 0.053) and protein carbonyl (p = 0.075) whereas IgG (p = 0.051) and IL-8 (p = 0.090) in jejunal mucosa were decreased by the MA. The PC increased (p < 0.05) the villus height to crypt depth ratio than the NC group. Both bacitracin and myristic acid improved the intestinal health and growth performance of nursery pigs. Effects of bacitracin were rather immediate whereas the effects of myristic acid were obtained after a 3-week feeding.

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.

Investigation of the nutritional and functional roles of a combinational use of xylanase and β-glucanase on intestinal health and growth of nursery pigs

BACKGROUND

Xylanase and β-glucanase combination (XG) hydrolyzes soluble non-starch polysaccharides that are anti-nutritional compounds. This study aimed to evaluate the effects of increasing levels of XG on intestinal health and growth performance of nursery pigs.

METHODS

Forty pigs (6.5 ± 0.4 kg) were assigned to 5 dietary treatments and fed for 35 d in 3 phases (11, 9, and 15 d, respectively). Basal diets mainly included corn, soybean meal, and corn distiller's dried grains with solubles, contained phytase (750 FTU/kg), and were supplemented with 5 levels of XG at (1) 0, (2) 280 TXU/kg xylanase and 125 TGU/kg β-glucanase, (3) 560 and 250, (4) 840 and 375, or (5) 1,120 and 500, respectively. Growth performance was measured. On d 35, all pigs were euthanized and jejunal mucosa, jejunal digesta, jejunal tissues, and ileal digesta were collected to determine the effects of increasing XG levels and XG intake on intestinal health.

RESULTS

Increasing XG intake tended to quadratically decrease (P = 0.059) viscosity of jejunal digesta (min: 1.74 mPa·s at 751/335 (TXU/TGU)/kg). Increasing levels of XG quadratically decreased (P < 0.05) Prevotellaceae (min: 0.6% at 630/281 (TXU/TGU)/kg) in the jejunal mucosa. Increasing XG intake quadratically increased (P < 0.05) Lactobacillaceae (max: 40.3% at 608/271 (TXU/TGU)/kg) in the jejunal mucosa. Increasing XG intake quadratically decreased (P < 0.05) Helicobacteraceae (min: 1.6% at 560/250 (TXU/TGU)/kg) in the jejunal mucosa. Increasing levels of XG tended to linearly decrease (P = 0.073) jejunal IgG and tended to quadratically increase (P = 0.085) jejunal villus height to crypt depth ratio (max: 2.62 at 560/250 (TXU/TGU)/kg). Increasing XG intake tended to linearly increase the apparent ileal digestibility of dry matter (P = 0.087) and ether extract (P = 0.065). Increasing XG intake linearly increased (P < 0.05) average daily gain.

CONCLUSIONS

A combinational use of xylanase and β-glucanase would hydrolyze the non-starch polysaccharides fractions, positively modulating the jejunal mucosa-associated microbiota. Increased intake of these enzyme combination possibly reduced digesta viscosity and humoral immune response in the jejunum resulting in improved intestinal structure, and ileal digestibility of nutrients, and finally improving growth of nursery pigs. The beneficial effects were maximized at a combination of 550 to 800 TXU/kg xylanase and 250 to 360 TGU/kg β-glucanase.

Effects of β-mannanase supplementation on intestinal health and growth of nursery pigs

Two experiments were conducted using 120 pigs to test the hypothesis that supplementation of β-mannanase could reduce digesta viscosity, enhance nutrient digestion, and improve intestinal health and growth of nursery pigs. In experiment 1, 48 crossbred barrows were randomly allotted to four treatments with increasing levels of β-mannanase at 0, 200, 400, and 600 U/kg in feeds. All pigs were euthanized on day 12 to collect jejunal digesta to measure digesta viscosity and ileal digesta to measure apparent ileal digestibility (AID) of dry matter (DM), gross energy (GE), neutral detergent fiber (NDF), and acid detergent fiber (ADF). In experiment 2, 72 nursery pigs were randomly allotted to three treatments with increasing levels of β-mannanase at 0, 400, and 600 U/kg in feeds. Plasma collected on day 9 was used to measure tumor necrosis factor-α (TNF-α), immunoglobulin G (IgG), malondialdehyde (MDA), and protein carbonyl (PC). All pigs were euthanized on day 10 to collect duodenal and jejunal tissues to evaluate the production of TNF-α, IL-6, and MDA, morphology, crypt cell proliferation, and expression of tight junction proteins in the jejunum. Data were analyzed using the MIXED procedure for polynomial contrasts and the NLMIXED procedure for broken-line analysis of SAS. In experiment 1, β-mannanase supplementation tended to have quadratic effects on digesta viscosity (P = 0.085) and AID of GE (P = 0.093) in the pigs. In experiment 2, jejunal digesta viscosity of the pigs was reduced (P < 0.05) when β-mannanase was supplemented at 360 U/kg of feed. β-Mannanase supplementation linearly reduced (P < 0.05) TNF-α, IgG, MDA, and PC in the duodenum, and TNF-α, IgG, and MDA in the jejunum of the pigs. β-Mannanase supplementation linearly increased (P < 0.05) villus height to crypt depth ratio and crypt cell proliferation in the jejunum. β-Mannanase supplementation tended to linearly improve (P = 0.083) expression of zonula occludens-1 in the jejunum. In conclusion, supplementation of β-mannanase at 360 U/kg reduced the digesta viscosity and up to 600 U/kg positively affected intestinal health and growth of pigs by reducing inflammation and oxidative stress whilst enhancing structure and barrier function in the jejunum.

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

This review focused on the impact of F18+E. coli on pig production and explored nutritional interventions to mitigate its deleterious effects. F18+E. coli is a primary cause of PWD in nursery pigs, resulting in substantial economic losses through diminished feed efficiency, morbidity, and mortality. In summary, the F18+E. coli induces intestinal inflammation with elevated IL6 (60%), IL8 (43%), and TNF-α (28%), disrupting the microbiota and resulting in 14% villus height reduction. Besides the mortality, the compromised intestinal health results in a 20% G:F decrease and a 10% ADFI reduction, ultimately culminating in a 28% ADG decrease. Among nutritional interventions to counter F18+E. coli impacts, zinc glycinate lowered TNF-α (26%) and protein carbonyl (45%) in jejunal mucosa, resulting in a 39% ADG increase. Lactic acid bacteria reduced TNF-α (36%), increasing 51% ADG, whereas Bacillus spp. reduced IL6 (27%), increasing BW (12%). Lactobacillus postbiotic increased BW (14%) and the diversity of beneficial bacteria. Phytobiotics reduced TNF-α (23%) and IL6 (21%), enhancing feed efficiency (37%). Additional interventions, including low crude protein formulation, antibacterial minerals, prebiotics, and organic acids, can be effectively used to combat F18+E. coli infection. These findings collectively underscore a range of effective strategies for managing the challenges posed by F18+E. coli in pig production.

Characterization of β-Glucans from Cereal and Microbial Sources and Their Roles in Feeds for Intestinal Health and Growth of Nursery Pigs

The objectives of this review are to investigate the quantitative, compositional, and structural differences of β-glucans and the functional effects of β-glucans on the intestinal health and growth of nursery pigs. Banning antibiotic feed supplementation increased the research demand for antibiotic alternatives to maintain the intestinal health and growth of nursery pigs. It has been proposed that β-glucans improve the growth efficiency of nursery pigs through positive impacts on their intestinal health. However, based on their structure and source, their impacts can be extensively different. β-glucans are non-starch polysaccharides found in the cell walls of yeast (Saccharomyces cerevisiae), bacteria, fungi (Basidiomycota), and cereal grains (mainly barley and oats). The total β-glucan content from cereal grains is much greater than that of microbial β-glucans. Cereal β-glucans may interfere with the positive effects of microbial β-glucans on the intestinal health of nursery pigs. Due to their structural differences, cereal β-glucans also cause digesta viscosity, decreasing feed digestion, and decreasing nutrient absorption in the GIT of nursery pigs. Specifically, cereal β-glucans are based on linear glucose molecules linked by β-(1,3)- and β-(1,4)-glycosidic bonds with relatively high water-soluble properties, whereas microbial β-glucans are largely linked with β-(1,3)- and β-(1,6)-glycosidic bonds possessing insoluble properties. From the meta-analysis, the weight gain and feed intake of nursery pigs increased by 7.6% and 5.3%, respectively, through the use of yeast β-glucans (from Saccharomyces cerevisiae), and increased by 11.6% and 6.9%, respectively, through the use of bacterial β-glucans (from Agrobacterium sp.), whereas the use of cereal β-glucans did not show consistent responses. The optimal use of yeast β-glucans (Saccharomyces cerevisiae) was 50 mg/kg in nursery pig diets based on a meta-analysis. Collectively, use of microbial β-glucans can improve the intestinal health of nursery pigs, enhancing immune conditions, whereas the benefits of cereal β-glucans on intestinal health were not consistent.

Effect of antibiotics and low-crude protein diets on growth performance, health, immune response, and fecal microbiota of growing pigs

This study aimed to investigate the effects of diets with and without antibiotics supplementation and diets with 18.5% and 13.0% crude protein (CP) on growth performance, carcass characteristics, disease incidence, fecal microbiota, immune response, and antioxidant capacity of growing pigs. One hundred and eighty pigs (59-day-old; 18.5 ± 2.5 kg) were distributed in a randomized complete block design in a 2 × 2 factorial arrangement, nine replicates, and five pigs per pen. The factors were CP (18.5% or 13.0%) and antibiotics (none or 100 mg/kg tiamulin + 506 mg/kg oxytetracycline). Medicated diets were fed from days 59 to 73. After that, all pigs were fed their respective CP diets from 73 to 87 days. Data were analyzed using the Mixed procedure in SAS version 9.4. From days 59 to 73, pigs fed antibiotics diets had higher (P < 0.05) average daily feed intake (ADFI), average daily weight gain (ADG), gain to feed ratio (G:F), compared to the diets without antibiotics. From days 73 to 87 (postmedicated period), any previous supplementation of antibiotics did not affect pig growth performance. Overall (days 59 to 87), pigs-fed antibiotics diets had higher (P < 0.05) G:F compared to pigs-fed diets without antibiotics. In all periods evaluated, pigs fed 18.5% CP diets had higher (P < 0.05) ADG and G:F compared to pigs fed 13.0% CP. Pigs fed the 13.0% CP diets had lower (P < 0.05) fecal score and diarrhea incidence than those fed 18.5% CP. Pigs fed 18.5% CP diets had improved (P < 0.05) loin area compared to pigs-fed diets with 13.0% CP. At 66 days of age, pigs-fed antibiotics diets had lower (P < 0.05) alpha diversity estimated with Shannon and Simpson compared to the pig-fed diets without antibiotics. At family level, pigs fed 18.5% CP diets had higher (P < 0.05) relative abundance of Streptococcaceae, and lower (P < 0.05) relative abundance of Clostridiaceae at days 66 and 87 compared with pigs fed 13.0% CP. Pigs-fed antibiotics diets had lower (P < 0.05) immunoglobulin G and protein carbonyl concentrations at day 66 compared to the pigs-fed diets without antibiotics. The reduction of dietary CP from 18.5% to 13.0% reduced the growth performance and loin muscle area of growing pigs, although it was effective to reduce diarrhea incidence. Antibiotics improved growth performance, lowered diarrhea incidence, improved components of the humoral immune response, and reduced microbiota diversity. However, in the postmedicated period, we found no residual effect on the general health of the animals, and considering the overall period, only G:F was improved by the use of antibiotics.