Short Administration of Combined Prebiotics Improved Microbial Colonization, Gut Barrier, and Growth Performance of Neonatal Piglets

Different Physiochemical Properties of Novel Fibre Sources in the Diet of Weaned Pigs Influence Animal Performance, Nutrient Digestibility, and Caecal Fermentation

The effect of including micronised fibre sources (FS) differing in fermentability and hydration capacity (HC) on growth performance, faecal digestibility, and caecal fermentation was investigated in piglets. There were four dietary treatments: a control diet (CON) and three treatments differing in the HC and fermentability of FS added at 1.5% to prestarter (28-42 d) and starter (42-61 d) diets. These were: LHC (low-HC by-product-based insoluble fibre (IF) with a prebiotic fraction (PF) from chicory root); MHC (medium-HC by-product-based IF with a PF); and HHC (high-HC non-fermentable wood-based IF with no PF). There were eight replicates per treatment. Over the entire period, LHC and MHC piglets showed a 10% increase in daily growth and feed intake (p ≤ 0.019) and tended to have a reduced feed conversion ratio (p = 0.087) compared to HHC piglets. At 42 d, faecal protein digestibility increased by 5% in the LHC and MHC groups compared with the HHC group (p = 0.035) and did not differ from the CON group. Both LHC and MHC fibres were more fermented in vitro with caecal inocula from 61 d old piglets than HHC fibre (p ≤ 0.003). These results suggest that balanced soluble and insoluble fibre concentrates can improve piglet performance.

Bacillus coagulans restores pathogen-induced intestinal dysfunction via acetate-FFAR2-NF-κB-MLCK-MLC axis in Apostichopus japonicus

Skin ulceration syndrome (SUS) is currently the main disease threatening Apostichopus japonicus aquaculture due to its higher mortality rate and infectivity, which is caused by Vibrio splendidus. Our previous studies have demonstrated that SUS is accompanied by intestinal microbiota (IM) dysbiosis, alteration of short-chain fatty acids (SCFAs) content and the damage to the intestinal barrier. However, the mediating effect of IM on intestine dysfunction is largely unknown. Herein, we conducted comprehensive intestinal microbiota transplantation (IMT) to explore the link between IM and SUS development. Furthermore, we isolated and identified a Bacillus coagulans strain with an ability to produce acetic acid from both healthy individual and SUS individual with IM from healthy donors. We found that dysbiotic IM and intestinal barrier function in SUS recipients A. japonicus could be restored by IM from healthy donors. The B. coagulans strain could restore IM community and intestinal barrier function. Consistently, acetate supply also restores intestinal homeostasis of SUS-diseased and V. splendidus-infected A. japonicus. Mechanically, acetate was found to specifically bind to its receptor-free fatty acid receptor 2 (FFAR2) to mediate IM structure community and intestinal barrier function. Knockdown of FFAR2 by transfection of specific FFAR2 siRNA could hamper acetate-mediated intestinal homeostasis in vivo. Furthermore, we confirmed that acetate/FFAR2 could inhibit V. splendidus-activated NF-κB-MLCK-MLC signaling pathway to restore intestinal epithelium integrity and upregulated the expression of ZO-1 and Occludin. Our findings provide the first evidence that B. coagulans restores pathogen-induced intestinal barrier dysfunction via acetate/FFAR2-NF-κB-MLCK-MLC axis, which provides new insights into the control and prevention of SUS outbreak from an ecological perspective.IMPORTANCESkin ulceration syndrome (SUS) as a main disease in Apostichopus japonicus aquaculture has severely restricted the developmental A. japonicus aquaculture industry. Intestinal microbiota (IM) has been studied extensively due to its immunomodulatory properties. Short-chain fatty acids (SCFAs) as an essential signal molecule for microbial regulation of host health also have attracted wide attention. Therefore, it is beneficial to explore the link between IM and SUS for prevention and control of SUS. In the study, the contribution of IM to SUS development has been examined. Additionally, our research further validated the restoration of SCFAs on intestinal barrier dysfunction caused by SUS via isolating SCFAs-producing bacteria. Notably, this restoration might be achieved by inhibition of NF-κB-MLCK-MLC signal pathway, which could be activated by V. splendidus. These findings may have important implications for exploration of the role of IM in SUS occurrence and provide insight into the SUS treatment.

Bamboo fiber improves piglet growth performance by regulating the microbial composition of lactating sows and their offspring piglets

Introduction

Feeding bamboo powder is a kind of fiber raw material mainly composed of insoluble dietary fiber (IDF). In this study, IDF-based rice husk meal and feeding bamboo powder were used to compare the effects of bamboo fiber on fecal microflora and the performance of lactating sows and their offspring piglets.

Methods

Thirty healthy crossbred gilts (Yorkshire × Landrace) at day 105 of gestation were randomly allocated into three groups: CON, TRE1 supplemented with 2% BBF1 (feeding bamboo powder), and TRE2 supplemented with 2% BBF2 (99% feeding bamboo powder +1% bamboo fiber polymer material). The reproductive performance, serum indexes, and fecal microbiota of sows and piglets were analyzed. The results showed that, compared with CON, the average feed intake of sows in TRE1 during the second week of lactation was significantly increased by 21.96% (p < 0.05), the average daily gain (ADG) per litter in TRE1 on 11-21 days and 3-21 days of lactation was significantly increased by 50.68 and 31.61%, respectively (p < 0.05), and the serum triglyceride content of sows in TRE1 on the 21st day of lactation was significantly increased (p < 0.05). The 16S rRNA analysis showed that dietary bamboo fiber significantly increased the fecal microbial richness index Ace, Chao, and Sobs of sows (p < 0.05) and tended to increase the Sobs index of suckling piglets on day 21 (p < 0.10). Compared with CON, BBF1 supplementation significantly decreased the abundance of Christensenellaceae_R-7_group in feces of sows on days 7 and 21 after delivery (p < 0.05), while BBF2 decreased the genera Christensenellaceae_R-7_group on days 7 (p < 0.10) and 21 (p < 0.05) after delivery. Spearman correlation analysis showed that the abundance of Phascolarctobacterium in the feces of piglets on the 21st day after delivery was significantly positively correlated with diarrhea rate and significantly negatively correlated with ADG per litter, day 21 litter weight, and 3- to 21-day survival rate. In contrast, Christensenellaceae_R-7_group was significantly negatively correlated with diarrhea rate and positively correlated with ADG per litter.

Discussion

These results indicated that maternal BBF1 supplementation improved the litter weight gain of suckling piglets, which was associated with the improvement of diversity and structure of the fecal microbiota in the piglets.

Strain specificity of lactobacilli with promoted colonization by galactooligosaccharides administration in protecting intestinal barriers during Salmonella infection

INTRODUCTION

Galactooligosaccharides (GOS) are lactogenic prebiotics that exert health benefits by stimulating the growth of different Lactobacillus strains in the gastrointestinal (GI) tract.

OBJECTIVES

This study aimed to investigate the mechanism of action of different GOS-enriched lactobacilli in intestinal health.

METHODS

Piglets and mice were supplemented with GOS to identify specific enrichment of Lactobacillus. The protective effects of individual GOS-enriched lactobacilli were investigated in Salmonella-infected mice. Macrophage depletion and transcriptome analysis were further performed to assess the involvement of macrophages and the underlying mechanisms of individual lactobacilli. An in vitro cell co-culture system was also used to evaluate the anti-adhesive and anti-invasive activities of lactobacilli against Salmonella in epithelial cells.

RESULTS

GOS markedly increased the relative abundance of three lactobacilli including L. delbrueckii, L. johnsonii, and L. reuteri in both piglets and mice. Supplementation with GOS further alleviated Salmonella infection in mice. L. delbrueckii (ATCC®BAA 365™), but not L. johnsonii or L. reuteri, enhanced propionate production in the intestinal tract and ameliorated Salmonella-induced intestinal inflammation and barrier dysfunction by suppressing the JAK2-STAT3 signaling and M1 macrophage polarization. L. johnsonii (BNCC 186110), on the other hand, inhibited Salmonella adhesion and invasion of epithelial cells through competitive exclusion. However, L. reuteri (BNCC 186135) failed to protect mice against Salmonella infection.

CONCLUSION

GOS-enriched lactobacilli show a differential role in protecting against Salmonella-induced intestinal barrier dysfunction and inflammation. Our results provide novel insights into the mechanism of action of GOS and individual Lactobacillus strains in the control and prevention of intestinal inflammatory disorders.

Lactobacillus amylovorus Promotes Lactose Utilization in Small Intestine and Enhances Intestinal Barrier Function in Intrauterine Growth Restricted Piglets

BACKGROUND

Intrauterine growth restriction (IUGR) resulted in high mortality and many physiological defects of piglets, causing huge economic loss in the swine industry. Lactobacillus amylovorus (L. amylovorus) was identified as one of the main differential bacteria between IUGR and normal piglets. However, the effects of L. amylovorus on the growth performance and intestinal health in IUGR piglets remained unclear.

OBJECTIVES

This study aimed to investigate the promoting effects of L. amylovorus Mafic1501, a new strain isolated from normal piglets, on the growth performance and intestinal barrier functions in IUGR piglets.

METHODS

Newborn mice or piglets were assigned into 3 groups: CON (normal birth weight, control), IUGR (low birth weight), and IUGR+L. amy (low birth weight), administered with sterile saline or L. amylovorus Mafic1501, respectively. Growth performance, lactose content in the digesta, intestinal lactose transporter, and barrier function parameters were profiled. IPEC-J2 cells were cultured to verify the effects of L. amylovorus Mafic1501 on lactose utilization and intestinal barrier functions.

RESULTS

L. amylovorus Mafic1501 elevated body weight and average daily gain of IUGR mice and piglets (P < 0.05). The lactose content in the ileum was decreased, whereas gene expression of glucose transporter 2 (GLUT2) was increased by L. amylovorus Mafic1501 in IUGR piglets during suckling period (P < 0.05). Besides, L. amylovorus Mafic1501 promoted intestinal barrier functions by increasing the villus height and relative gene expressions of tight junctions (P < 0.05). L. amylovorus Mafic1501 and its culture supernatant decreased the lactose level in the medium and upregulated gene expressions of transporter GLUT2 and tight junction protein Claudin-1 of IPEC-J2 cells (P < 0.05).

CONCLUSION

L. amylovorus Mafic1501 improved the growth performance of IUGR piglets by promoting the lactose utilization in small intestine and enhancing intestinal barrier functions. Our results provided the new evidence of L. amylovorus Mafic1501 for its application in the swine industry.

Investigation of gut microbiota changes and allergic inflammation of mice with milk protein-induced allergic enteritis

This study aimed to investigate the changes of gut microbiota and allergic inflammation in mice with allergic enteritis caused by milk protein. In this study, female BALB\C mice in the whey protein (WP-sensitized) group were gavaged with WP and normal saline, the sham-sensitized group was given normal saline once a week for 5 weeks. One week later, the WP-sensitized mice were administered 60 mg β-lactoglobulin (BLG). The results showed that mice's body weight decreased, feces with loose and bloody, and systemic allergic reactions and ear swelling increased in the WP-sensitized group. The levels of WP-specific Ig, mMCP-1, calprotectin of feces, and inflammation-related factors in the WP-sensitized group were increased. WP-sensitized group intestine tissues were damaged severely and the expressions of ZO-1, Claudin-1, and Occludin reduced. The results of 16S rRNA sequencing showed that there were differences in operational taxonomic units (OUT) levels of gut microbes between the two groups, o_Clostridiales, c_Clostridia, and f_Lachnospiraceae were more abundant in the WP-sensitized group. In conclusion, the WP sensitization can induce the allergic inflammation, intestinal injury and intestinal barrier dysfunction in mice, and the gut microbes were also changed, which provided a reference for the treatment of WP-sensitized mice.

Fructo-oligosaccharide-mediated alteration in claudin expression in small intestinal absorptive Caco-2 cells is positively associated with the induction of inflammatory genes and the glucan receptor gene CLEC7A

OBJECTIVES

Indigestible carbohydrates may strengthen tight junctions (TJs) independently of intestinal bacteria. This study investigated whether indigestible carbohydrates (i.e., fructo-oligosaccharides [FOS]) promote TJs directly to intestinal absorptive Caco-2 cells and examined the association between the expression of genes constructing TJs and other genes using mRNA microarray analysis.

METHODS

Caco-2 cells at 1.0 × 105/mL were seeded in a type I collagen plate and cultured in high-glucose Dulbecco's modified Eagle medium (DMEM) supplemented with 10% fetal calf serum (FCS); the cells reached confluence at 7 d after seeding. Ten days after the cells reached confluency, they were cultured for 24 h in 10% FCS-containing DMEM medium supplemented with 0%, 5%, or 10% FOS. We performed mRNA microarray to identify the genes whose expression was altered by FOS. Subsequently, quantitative reverse transcription polymerase chain reaction was performed for these altered genes, including CLEC7A encoding the glucan receptor, and for the claudin (CLDN) family genes. The expression of CLDN2, CLDN4, and CLEC7A proteins was assessed using western blot analysis.

RESULTS

FOS decreased the mRNA and protein expression of CLDN2, which weakens TJs, and increased those of CLDN4, which strengthens TJs, in Caco-2 cells. FOS treatment (10%) reduced the mRNA expression of antioxidative genes and induced the expression of immune response-related genes, including CLEC7A, CCL2, and ITGA2. Furthermore, the expression of CLEC7A protein was enhanced by FOS.

CONCLUSIONS

Induction of TJ-strengthening CLDN4 and reduction of TJ-weakening CLDN2 by FOS treatment in small intestinal absorptive Caco-2 cells is positively associated with the induction of inflammatory genes, including CLEC7A.

Dietary Prebiotic Oligosaccharides and Arachidonate Alter the Fecal Microbiota and Mucosal Lipid Composition of Suckling Pigs

BACKGROUND

Early intestinal development is important to infant vitality, and optimal formula composition can promote gut health.

OBJECTIVES

The objectives were to evaluate the effects of arachidonate (ARA) and/or prebiotic oligosaccharide (PRE) supplementation in formula on the development of the microbial ecosystem and colonic health parameters.

METHODS

Newborn piglets were fed 4 formulas containing ARA [0.5 compared with 2.5% of dietary fatty acids (FAs)] and PRE (0 compared with 8 g/L, containing a 1:1 mixture of galactooligosaccharides and polydextrose) in a 2 x 2 factorial design for 22 d. Fecal samples were collected weekly and analyzed for relative microbial abundance. Intestinal samples were collected on day 22 and analyzed for mucosal FAs, pH, and short-chain FAs (SCFAs).

RESULTS

PRE supplementation significantly increased genera within Bacteroidetes and Firmicutes, including Anaerostipes, Mitsuokella, Prevotella, Clostridium IV, and Bulleidia, and resulted in progressive separation from controls as determined by Principal Coordinates Analysis. Concentrations of SCFA increased from 70.98 to 87.37 mM, with an accompanying reduction in colonic pH. ARA supplementation increased the ARA content of the colonic mucosa from 2.35-5.34% of total FAs. PRE supplementation also altered mucosal FA composition, resulting in increased linoleic acid (11.52-16.33% of total FAs) and ARA (2.35-5.16% of total FAs).

CONCLUSIONS

Prebiotic supplementation during the first 22 d of life altered the gut microbiota of piglets and increased the abundance of specific bacterial genera. These changes correlated with increased SCFA, which may benefit intestinal development. Although dietary ARA did not alter the microbiota, it increased the ARA content of the colonic mucosa, which may support intestinal development and epithelial repair. Prebiotic supplementation also increased unsaturation of FAs in the colonic mucosa. Although the mechanism requires further investigation, it may be related to altered microbial ecology or biohydrogenation of FA.

Amylopectin Partially Substituted by Cellulose in the Hindgut Was Beneficial to Short-Chain Fatty Acid Production and Probiotic Colonization

Undigested amylopectin fermentation in the hindguts of humans and pigs with low digestive capacity has been proven to be a low-efficiency method of energy supply. In this study, we researched the effects and mechanisms of amylopectin fermentation on hindgut microbiota and metabolite production using an in vitro fermentation trial and ileal infusion pigs model. In addition, we also researched the effects of interaction between amylopectin and cellulose during hindgut fermentation in this study. Our results showed that amylopectin had higher short-chain fatty acid (SCFA) production and dry matter digestibility (DMD) than cellulose but was not significantly different from a mixture of amylopectin and cellulose (Amycel vitro) during in vitro fermentation. The Amycel vitro group even had the highest reducing sugar content and amylase activity among all groups. The ileal infusion trial produced similar results to vitro fermentation trial: the mixture of amylopectin and cellulose infusion (Amycel vivo) significantly increased the levels of reducing sugar, acetate, and butyrate in the hindgut compared with the amylopectin infusion (Amy vivo). The mixture of amylopectin and cellulose infusion also resulted in increased Shannon index and probiotic colonization in the hindgut. The relative abundance of Romboutsia in the Amycel vivo group, which was considered a noxious bacteria in the Amycel vivo group, was also significantly lower than that in the Amy vivo group. In summary, the high level of amylopectin fermentation in the hindgut was harmful to intestinal microbiota, but amylopectin partially substituted with cellulose was beneficial to SCFA production and probiotic colonization. IMPORTANCE A high-starch (mainly amylopectin) diet is usually accompanied by the fermentation of undigested amylopectin in the hindgut of humans and pigs with low digestive capacity and might be detrimental to the intestinal microbiota. In this research, we investigated the fermentation characteristics of amylopectin through an in vitro fermentation method and used an ileal infusion pig model to verify the fermentation trial results and explore the microbiota regulatory effect. The interaction effects between amylopectin and cellulose during hindgut fermentation were also researched in this study. Our research revealed that the large amount of amylopectin fermentation in the hindgut was detrimental to the intestinal microbiota. Amylopectin partially substituted by cellulose was not only beneficial to antioxidant ability and fermentation efficiency, but also promoted SCFA production and probiotic colonization in the hindgut. These findings provide new strategies to prevent intestinal microbiota dysbiosis caused by amylopectin fermentation.

Sciadonic acid attenuates high-fat diet-induced obesity in mice with alterations in the gut microbiota

Obesity has been reported to be associated with dysbiosis of gut microbiota. Sciadonic acid (SC) is one of the main functional components of Torreya grandis "Merrillii" seed oil. However, the effect of SC on high-fat diet (HFD)-induced obesity has not been elucidated. In this study, we evaluated the effects of SC on lipid metabolism and the gut flora in mice fed with a high-fat diet. The results revealed that SC activates the PPARα/SREBP-1C/FAS signaling pathway and reduces the levels of total cholesterol (TC), triacylglycerols (TG), and low-density lipoprotein cholesterol (LDL-C), but increases the level of high-density lipoprotein cholesterol (HDL-C) and inhibits weight gain. Among them, high-dose SC was the most effective; the TC, TG and LDL-C levels were reduced by 20.03%, 28.40% and 22.07%, respectively; the HDL-C level was increased by 8.55%. In addition, SC significantly increased glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels by 98.21% and 35.17%, respectively, decreased oxidative stress, and ameliorated the pathological damage to the liver caused by a high-fat diet. Furthermore, SC treatment altered the composition of the intestinal flora, promoting the relative abundance of beneficial bacteria such as Lactobacillus and Bifidobacterium, while simultaneously decreasing the relative abundance of potentially harmful bacteria such as Faecalibaculum, norank_f_Desulfovibrionaceae, and Romboutsia. Spearman's correlation analysis indicated that the gut microbiota was associated with SCFAs and biochemical indicators. In summary, our results suggested that SC can improve lipid metabolism disorders and regulate the gut microbial structure.

Obeticholic acid protects against methamphetamine-induced anxiety-like behavior by ameliorating microbiota-mediated intestinal barrier impairment

Methamphetamine (Meth) abuse can cause severe anxiety disorder and interfere with gut homeostasis. Obeticholic acid (OCA) has emerged as a protective agent against diet-related anxiety that improves gut homeostasis. The potential for OCA to ameliorate Meth-induced anxiety, and the microbial mechanisms involved, remain obscure. Here, C57/BL6 mice were intraperitoneally injected with Meth (15 mg/kg) to induce anxiety-like behavior. 16 S rRNA sequence analysis and fecal microbiome transplantation (FMT) were used to profile the gut microbiome and evaluate its effects, respectively. Orally administered OCA was investigated for protection against Meth-induced anxiety. Results indicated that Meth mediated anxiety-like behavior, aroused hippocampal neuroinflammation through activation of the TLR4/MyD88/NF-κB pathway, weakened intestinal barrier and disturbed the gut microbiome. Specifically, abundance of anxiety-related Rikenella was increased. FMT from Meth-administrated mice also weakened intestinal barrier and elevated serum LPS, inducing hippocampal neuroinflammation and anxiety-like behavior in recipient mice. Finally, OCA pretreatment ameliorated Meth-induced impairment of gut homeostasis by reshaping the microbial composition and improving the intestinal barrier. Meth-induced anxiety-like behavior and hippocampal neuroinflammation were also ameliorated by OCA pretreatment. These preliminary findings reveal the crucial role of gut microbiota in Meth-induced anxiety-like behavior and neuroinflammation, highlighting OCA as a potential candidate for the prevention of Meth-induced anxiety.

Combination Therapy with Indigo and Indirubin for Ulcerative Colitis via Reinforcing Intestinal Barrier Function

Indigo and indirubin, the active molecules of traditional Chinese medicine indigo naturalis, exert therapeutic activity for ulcerative colitis (UC). Indigo and indirubin are isomers and have distinctive profiles in anti-inflammation, immune regulation, intestinal microbiota regulation, oxidative stress regulation, and intestinal mucosal repair for UC treatment. Thus, exploring its combined administration's integrated advantages for UC is critical. This study is aimed at clarifying the effect and mechanisms of the combined administration of indigo and indirubin on colitis mouse models. The results showed that all the treatment groups could improve the disease symptoms, and the combined administration showed the best effect. Additionally, compared with indigo and indirubin alone, the combination group could significantly reinforce intestinal barrier function by increasing the expression of E-cadherin, occludin, ZO-1, and MUC2 and improving intestinal permeability. The treatment groups significantly improved the expression of cytokines, including TNF-α, IFN-γ, IL-12, IL-23, and IL-17A, and indirubin presented the most potent anti-inflammatory effect. Furthermore, all the treatment groups reduced the infiltration of the immune cells in intestinal lamina propria and the production of ROS/RNS. Notably, indigo exhibited a more substantial capacity to regulate natural killer (NK) cells, ILC3, neutrophils, and dendritic cells, followed by the combination group and indirubin alone. Finally, all the treatment groups modulated intestinal microbiota composition, increased the proportion of beneficial microbiota, and decreased the proportion of microbiota. Our results indicated that indigo and indirubin synergistically reinforced the intestinal barrier function, which may be associated with integrating the indirubin anti-inflammatory and intestinal microbiota regulating strength and indigo immune and ROS/RNS regulation advantage.

Integrated Network Pharmacology and Gut Microbiota Analysis to Explore the Mechanism of Sijunzi Decoction Involved in Alleviating Airway Inflammation in a Mouse Model of Asthma

Background

Asthma is a chronic inflammatory disease of the airways with recurrent attacks, which seriously affects the patients' quality of life and even threatens their lives. The disease can even threaten the lives of patients. Sijunzi decoction (SJZD), a classical Chinese medicine formula with a long history of administration, is a basic formula used for the treatment of asthma and demonstrates remarkable efficacy. However, the underlying mechanism has not been elucidated.

Materials and Methods

We aimed to integrate network pharmacology and intestinal flora sequencing analysis to study the mechanism of SJZD in the treatment of allergic asthmatic mice. The active compounds of SJZD and their asthma-related targets were predicted by various databases. We performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses to identify potentially relevant pathways for target genes. Furthermore, the active compound-target and target-signaling pathway network maps were constructed by using Cytoscape 3.8.2. These results were combined with those of the intestinal flora sequencing analysis to study the influence of SJZD on airway inflammation in allergic asthmatic mice.

Result

We obtained 137 active compounds from SJZD and associated them with 1445 asthma-related targets acquired from the databases. A total of 109 common targets were identified. We visualized active compound-target and target-signaling pathway network maps. The pathological analysis and inflammation score results suggested that SJZD could alleviate airway inflammation in asthmatic mice. Sequencing analysis of intestinal flora showed that SJZD could increase the relevant abundance of beneficial bacterial genus and maintain the balance of the intestinal flora. The core toll-like receptor (TLR) signaling pathway was identified based on network pharmacology analysis, and the important role TLRs play in intestinal flora and organismal immunity was also recognized. The analysis of the correlation between environmental factors and intestinal flora revealed that beneficial bacterial genera were negatively correlated with TLR2 and positively correlated with the TLR7 expression. Furthermore, they were positively correlated with IFN-γ and IL-10 levels and negatively correlated with IL-4 and IL-17 levels.

Conclusion

SJZD alleviated the airway inflammation state in asthmatic mice. The findings suggest that increasing the relevant abundance of beneficial intestinal bacteria in mice with asthma, regulating intestinal flora, interfering with the level of TLR2 and TLR7 expression to adjust the secretion of inflammatory factors, and alleviating asthmatic airway inflammation may be the possible mechanism involved in the treatment of asthma by SJZD, providing a basis for further studies on SJZD.

Assessment of the role and mechanism of Bifidobacterium animalis subsp. lactis isolated from neonates' feces in protecting neonatal rats from Salmonella infection

OBJECTIVES

It is now well known that Bifidobacterium animalis subsp. lactis (B. lactis), an important early-life colonizer of the gut, provides immune-related benefits to infants. The aim of the work is to explore the intraspecific resistance to Salmonella infection of B. lactis isolated from neonatal feces, and to learn more insights into how B. lactis mediates beneficial roles in early-life infection resistance.

METHODS

Five strains of B. lactis (NFBAL11/NFBAL23/NFBAL44/NFBAL63/NFBAL92) were screened from fecal samples of neonates born within fifteen days and pretreated neonatal rats prior to infection with Salmonella typhimurium (S. typhimurium) SL1344. The survival rate, fecal occult blood, diarrhea and hepatosplenomegaly were detected to assess the ability of B. lactis to prevent S. typhimurium infection. Furthermore, the structure of mucus layer, gene expression, cytokine levels, antioxidant levels and intestinal microflora composition were detected to explore the mechanism.

RESULTS

All strains showed activity against S. typhimurium, with B. lactis NFBAL23 being the most active, followed by NFBAL63 and NFBAL92. And these advantages weren't attained by enhancing physical growth and development. Mechanistically, the neonatal rats treated with B. lactis (NFBAL23/NFBAL63/NFBAL92) had improved intestinal barrier function involving physical, chemical, immune and biological barriers in the face of challenges posed by S. typhimurium.

CONCLUSIONS

These findings revealed the intraspecific difference, beneficial roles and mechanisms of action of B. lactis against Salmonella infection early in life, which highlighted the necessity of supplementing appropriate B. lactis, and provided several potential B. lactis candidates for Salmonella infection treatment.

Enteroendocrine peptides, growth, and the microbiome during the porcine weaning transition

Background

Growth rate in pigs can be affected by numerous factors that also affect feeding behavior and the microbiome. Recent studies report some communication between the microbiome and the enteroendocrine system. The present study examined if changes in the piglet microbiome between birth and during the weaning transition can be correlated either positively or negatively with growth rate and plasma concentrations of enteroendocrine peptides.

Results

During the post-weaning transition, a 49% reduction in average daily gain was observed at day 24 (P < 0.05) relative to day 21. Pigs recovered by day 28 with body weight and average daily gain increases of 17% and 175%, respectively relative to day 24 and the highest rate of gain was measured at day 35 (462 g/day). The time interval between day 21–24 had the highest number of correlations (n = 25) between the relative abundance differences in taxa over time and corresponding percent weight gain. Amplicon sequence variants with the greatest correlation with percent weight gain between day 21–24 belonged to families Prevotellaceae NK3B31 (ρ = 0.65, P < 0.001), Veillonellaceae (ρ = 0.63, P < 0.001) and Rikenellaceae RC9 (ρ = 0.62, P < 0.001). Seven taxa were positively correlated with percent weight gain between day 24–28. Eight taxa were positively correlated with percent weight gain between day 28–35, of which four were Clostridia. Only Lactobacillus reuteri was positively correlated across both day 24–28 and day 28–35 analyses. Insulin-like growth factor 1 (IGF-1; R2 = 0.61, P < 0.001), glucose-dependent insulinotropic polypeptide (GIP; R2 = 0.20, P < 0.001), glucagon-like peptide 1 (GLP-1; R2 = 0.51, P < 0.001), and glucagon-like peptide 2 (GLP-2; R2 = 0.21, P < 0.001) were significantly associated with the piglet fecal community NMDS, while serotonin showed no significant association (R2 = 0.03, P = 0.15). Higher concentrations of GLP-1 and GLP-2 characterized day 1 fecal communities, while GIP levels had the strongest relationship primarily with samples ordinated with the day 21 cluster.

Conclusions

Demonstration of an association of certain taxa with individual gut peptides at specific ages suggests the potential for the microbiome to elicit changes in the gut enteroendocrine system during early postnatal development in the pig.

Direct Action of Non-Digestible Oligosaccharides against a Leaky Gut

The epithelial monolayer is the primary determinant of mucosal barrier function, and tight junction (TJ) complexes seal the paracellular space between the adjacent epithelial cells and represent the main "gate-keepers" of the paracellular route. Impaired TJ functionality results in increased permeation of the "pro-inflammatory" luminal contents to the circulation that induces local and systemic inflammatory and immune responses, ultimately triggering and/or perpetuating (chronic) systemic inflammatory disorders. Increased gut leakiness is associated with intestinal and systemic disease states such as inflammatory bowel disease and neurodegenerative diseases such as Parkinson's disease. Modulation of TJ dynamics is an appealing strategy aiming at inflammatory conditions associated with compromised intestinal epithelial function. Recently there has been a growing interest in nutraceuticals, particularly in non-digestible oligosaccharides (NDOs). NDOs confer innumerable health benefits via microbiome-shaping and gut microbiota-related immune responses, including enhancement of epithelial barrier integrity. Emerging evidence supports that NDOs also exert health-beneficial effects on microbiota independently via direct interactions with intestinal epithelial and immune cells. Among these valuable features, NDOs promote barrier function by directly regulating TJs via AMPK-, PKC-, MAPK-, and TLR-associated pathways. This review provides a comprehensive overview of the epithelial barrier-protective effects of different NDOs with a special focus on their microbiota-independent modulation of TJs.

Dietary Supplementation of 25-Hydroxyvitamin D3 Improves Growth Performance, Antioxidant Capacity and Immune Function in Weaned Piglets

This study was conducted to evaluate the effects of 25-hydroxyvitamin D3 (25(OH)VD3) and Vitamin D3 (VD3) supplemented in the diet of weaned piglets on their growth performance, bone quality, intestinal integrity, immune function and antioxidant capacity. A total of 192 weaned piglets were allocated into four groups and they were fed a control diet containing 2000 IU VD3 (negative control, NC), NC + 100 ppm colistin sulfate (positive control, PC), NC + 2000 IU VD3 (VD3) and NC + 2000 IU 25(OH)VD3 (25(OH)VD3). The results showed that 25(OH)VD3 improved the growth performance, bone quality and antioxidase activity of piglets compared with the other groups. Meanwhile, 25(OH)VD3 up-regulated ileal mRNA expressions of tight junction proteins and host defense peptides. The VD3 group had an increased intestinal sIgA content and mRNA expression of pBD-1 compared with the NC group. Both groups of VD3 and 25(OH)VD3 altered the microbial β-diversity compared with the NC group, and 25(OH)VD3 increased ileal concentrations of acetate and butyrate. In conclusion, our findings indicated that a regular dosage of 2000 IU VD3 in the weaned piglets' diet did not achieve optimal antioxidant capacity and immune function. 25(OH)VD3 had better growth performance than VD3 at the same inclusion level, which is associated with the improved intestinal integrity and antioxidant capacity.

Consumption of Dietary Fiber with Different Physicochemical Properties during Late Pregnancy Alters the Gut Microbiota and Relieves Constipation in Sow Model

Constipation is a common problem in sows and women during late pregnancy. Dietary fiber has potential in the regulation of intestinal microbiota, thereby promoting intestinal motility and reducing constipation. However, the effects of fibers with different physicochemical properties on intestinal microbe and constipation during late pregnancy have not been fully explored. In this study, a total of 80 sows were randomly allocated to control and one of three dietary fiber treatments from day 85 of gestation to delivery: LIG (lignocellulose), PRS (resistant starch), and KON (konjaku flour). Results showed that the defecation frequency and fecal consistency scores were highest in PRS. PRS and KON significantly increased the level of gut motility regulatory factors, 5-hydroxytryptamine (5-HT), motilin (MTL), and acetylcholinesterase (AChE) in serum. Moreover, PRS and KON promoted the IL-10 level and reduced the TNF-α level in serum. Furthermore, maternal PRS and KON supplementation significantly reduced the number of stillborn piglets. Microbial sequencing analysis showed that PRS and KON increased short-chain fatty acids (SCFAs)-producing genera Bacteroides and Parabacteroides and decreased the abundance of endotoxin-producing bacteria Desulfovibrio and Oscillibacter in feces. Moreover, the relative abundance of Turicibacter and the fecal butyrate concentration in PRS were the highest. Correlation analysis further revealed that the defecation frequency and serum 5-HT were positively correlated with Turicibacter and butyrate. In conclusion, PRS is the best fiber source for promoting gut motility, which was associated with increased levels of 5-HT under specific bacteria Turicibacter and butyrate stimulation, thereby relieving constipation. Our findings provide a reference for dietary fiber selection to improve intestinal motility in late pregnant mothers.

Early-life galacto-oligosaccharides supplementation alleviates the small intestinal oxidative stress and dysfunction of lipopolysaccharide-challenged suckling piglets

BACKGROUND

Galacto-oligosaccharides (GOS) are non-digestible food ingredients that promote the growth of beneficial bacteria in the gut. This study investigated the protective effect of the early-life GOS supplement on the piglets' gut function against the oxidative stress induced by lipopolysaccharide (LPS)-challenge.

METHODS

Eighteen neonatal piglets were assigned to three groups including CON, LPS and LPS + GOS groups. The piglets in CON group and LPS group received physiological saline, while those in LPS + GOS group received GOS solution for 13 d after birth. On d 14, the piglets in LPS group and LPS + GOS group were injected with LPS solutions, while the piglets in CON group were injected with the same volume of physiological saline.

RESULTS

The results showed that the early-life GOS supplement blocked the LPS-induced reactive oxygen species (ROS) secretion, malondialdehyde (MDA) production and the increase of pro-apoptotic factor expression. Meanwhile, the early-life GOS supplement improved the activities of antioxidant enzymes, disaccharidase enzymes activities, and digestive enzymes activities, and increased the mRNA abundance of the gene related to nutrient digestion and absorption and the relative protein expression of tight junction. The study also showed that the early-life GOS supplement improved the expression of Hemeoxygenase-1 (HO-1) and NAD(P)H/quinone acceptor oxidoreductase-1 (NQO-1), and activated the AMP-activated protein kinase (AMPK).

CONCLUSIONS

These results suggested that GOS enhanced the gut function, reduced the ROS production and pro-apoptotic factors gene expression, and activated the AMPK signaling pathway in LPS-challenged piglets.

Effects of Maternal Factors and Postpartum Environment on Early Colonization of Intestinal Microbiota in Piglets

Intestinal microbiota significantly influences the intake, storage, and utilization of body nutrients, as well as animal growth and development. The establishment of microbiota is affected by many factors, such as delivery and feeding modes, antibiotics, disease, and the surrounding environment. In this study, we selected Chinese indigenous Mashen and Jinfen White pigs as the study subjects. To explore the source and factors affecting the piglet intestinal microbiota, 16S rRNA gene sequencing was performed to analyze the microbial composition of the feces, saliva, vaginal secretions, and colostrum of parturient sows, feces and saliva of newborn piglets, and surrounding environment samples. The results showed that the microbiota of the saliva of sows and piglets is structurally similar to that of the environment and is dominated by the phylum Proteobacteria, including Acinetobacter, Actinomyces, and Pseudomonas. The core genus in the vaginal secretions and colostrum of sows was Pseudomonas. Among the fecal samples, the core bacterial genera in sows before and after delivery were Clostridium sensu_stricto_1 and Christensenellaceae_R-7_group, while in piglets at 1 d of age, Pseudomonas and Escherichia-Shigella were most abundant. These results indicate that microbiota in feces, colostrum, and vaginal secretions of sows more easily colonized piglet intestines through a symbiotic effect. The environmental and salivary microbiota could also affect the early colonization and succession of the intestinal microbiota of piglets to some extent. This study provides a theoretical basis for sow delivery protection and early nursing of piglets and background for the research and development of microbial agents to improve piglet intestinal health.

Fructooligosaccharide Reduces Weanling Pig Diarrhea in Conjunction with Improving Intestinal Antioxidase Activity and Tight Junction Protein Expression

This study was to illustrate the effects of fructooligosaccharide (FOS) on the antioxidant capacity, intestinal barrier function, and microbial community of weanling pigs. Results showed that FOS reduced the incidence of diarrhea (6.5 vs. 10.8%) of pigs (p < 0.05) but did not affect growth performance when compared with the control group. A diet supplemented with FOS increased ileal mRNA expression of occludin (1.7 vs. 1.0), claudin-1 (1.9 vs. 1.0), claudin-2 (1.8 vs. 1.0), and claudin-4 (1.7 vs. 1.0), as well as colonic mRNA expression of ZO-1 (1.6 vs. 1.0), claudin-1 (1.7 vs. 1.0), occludin (1.9 vs. 1.0), and pBD-1 (1.5 vs. 1.0) when compared with the control group (p < 0.05). FOS supplementation improved the anti-oxidase activity and expression of nuclear factor erythroid-2 related factor 2 (Nrf2), and decreased concentrations of D-lactate (3.05 U/L vs. 2.83 U/L) and TNF-α (59.1 pg/mL vs. 48.0 pg/mL) in the serum when compared with the control group (p < 0.05). In addition, FOS increased Sharpea, Megasphaera, and Bacillus populations in the gut when compared with the control group (p < 0.05). Association analysis indicated that mRNA expression of occludin and claudin-1 in the ileal mucosa were correlated positively with populations of Sharpea and Bacillus (p < 0.05). Furthermore, mRNA expression of occludin and claudin-1 in the colonic mucosa were correlated positively with abundances of Sharpea, Lactobocillus, and Bifidobacterium (p < 0.05). In conclusion, FOS activated Nrf2 signaling and increased the expression of specific tight junction proteins, which were associated with reduced diarrhea incidence.

Chitosan Oligosaccharides Alleviate Colitis by Regulating Intestinal Microbiota and PPARγ/SIRT1-Mediated NF-κB Pathway

Chitosan oligosaccharides (COS) have been shown to have potential protective effects against colitis, but the mechanism underlying this effect has not been fully elucidated. In this study, COS were found to significantly attenuate dextran sodium sulfate-induced colitis in mice by decreasing disease activity index scores, downregulating pro-inflammatory cytokines, and upregulating Mucin-2 levels. COS also significantly inhibited the levels of nitric oxide (NO) and IL-6 in lipopolysaccharide-stimulated RAW 264.7 cells. Importantly, COS inhibited the activation of the NF-κB signaling pathway via activating PPARγ and SIRT1, thus reducing the production of NO and IL-6. The antagonist of PPARγ could abolish the anti-inflammatory effects of COS in LPS-treated cells. COS also activated SIRT1 to reduce the acetylation of p65 protein at lysine 310, which was reversed by silencing SIRT1 by siRNA. Moreover, COS treatment increased the diversity of intestinal microbiota and partly restored the Firmicutes/Bacteroidetes ratio. COS administration could optimize intestinal microbiota composition by increasing the abundance of norank_f_Muribaculaceae, Lactobacillus and Alistipes, while decreasing the abundance of Turicibacte. Furthermore, COS could also increase the levels of propionate and butyrate. Overall, COS can improve colitis by regulating intestinal microbiota and the PPARγ/SIRT1-mediated NF-κB pathway.

The probiotic effects of AB23A on high-fat-diet-induced non-alcoholic fatty liver disease in mice may be associated with suppressing the serum levels of lipopolysaccharides and branched-chain amino acids

Alisol B 23-acetate (AB23A) is a natural triterpenoid isolated from Rhizoma alisamatis that has been widely used as a traditional Chinese medicine (TCM). Previous studies have documented the beneficial effect of AB23A on non-alcoholic fatty liver disease (NAFLD), but the functional interactions between gut microbiota and the anti-NAFLD effect of AB23A remain unclear. In this study, we investigated the benefits of experimental treatment with AB23A on gut microbiota dysbiosis in NAFLD with an obesity model. C57BL/6J mice were administrated a high-fat diet (HFD) with or without AB23A for 12 weeks. AB23A significantly improved metabolic phenotype in the HFD-fed mice. Moreover, results of 16S rRNA gene-based amplicon sequencing in each group reveled that AB23A not only reduced the abundance of the Firmicutes/Bacteroidaeota ratio and Actinobacteriota/Bacteroidaeota ratio, but regulated the abundance of the top 10 genera, including norank_f__Muribaculaceae, Lactobacillus, Ileibacterium, Turicibacter, Faecalibaculum, the Lachnospiraceae_NK4A136_group, unclassified_f__Lachnospiraceae, and norank_f__Lachnospiraceae. AB23A significantly reduced the serum levels of lipopolysaccharide and branched-chain amino acids, which are positively correlated with the abundances of Ileibacterium and Turicibacter. Moreover, AB23A led to remarkable reductions in the activation of TLR4, NF-κB, and mTOR, and upregulated the expression of tight junction proteins, including ZO-1 and occludin. These results revealed that AB23A displayed a prebiotic capacity in HFD-fed NAFLD mice.

Fermentation Supernatants of Pleurotus eryngii Mushroom Ameliorate Intestinal Epithelial Barrier Dysfunction in Lipopolysaccharide-Induced Caco-2 Cells via Upregulation of Tight Junctions

In recent years, modulation of gut microbiota through prebiotics has garnered interest as a potential to ameliorate intestinal barrier dysfunction. The aim of the study was to examine the in vitro effect of fermentation supernatants (FSs) from rich in β-glucan Pleurotus eryngii mushrooms on the expression levels of tight junctions (TJs) genes in Caco-2 cells stimulated by bacterial lipopolysaccharides (LPS). Mushrooms were fermented using fecal inocula in an in vitro batch culture model. Caco-2 cells were subjected to LPS and FS treatment under three different conditions: pre-incubation with FS, co- and post-incubation. Reverse transcription PCR was applied to measure the expression levels of zonulin-1, occludin and claudin-1 genes. FSs from P. eryngii mushrooms led to a significant upregulation of the TJs gene expression in pre-incubation state, indicating potential preventive action. Down-regulation of all TJs gene expression levels was observed when the cells were challenged with LPS. The FS negative control (gut microbiota of each donor with no carbohydrate source) exhibited a significant upregulation of TJs expression levels compared to the cells that were challenged with LPS, for all three conditions. Overall, our data highlighted the positive and potential protective effects of P. eryngii mushrooms in upregulation of TJs’ genes.

Preventive Effects of Bacillus licheniformis on Heat Stroke in Rats by Sustaining Intestinal Barrier Function and Modulating Gut Microbiota

Heat stroke (HS) models in rats are associated with severe intestinal injury, which is often considered as the key event at the onset of HS. Probiotics can regulate the gut microbiota by inhibiting the colonization of harmful bacteria and promoting the proliferation of beneficial bacteria. Here, we investigated the preventive effects of a probiotic Bacillus licheniformis strain (BL, CMCC 63516) on HS rats as well as its effects on intestinal barrier function and gut microbiota. All rats were randomly divided into four groups: control (Con) + PBS (pre-administration with 1 ml PBS twice a day for 7 days, without HS induction), Con + BL group (pre-administration with 1 ml 1 × 10⁸ CFU/ml BL twice a day for 7 days, without HS induction), HS + PBS (PBS, with HS induction), and HS + BL (BL, with HS induction). Before the study, the BL strain was identified by genomic DNA analysis. Experimental HS was induced by placing rats in a hot and humid chamber for 60 min until meeting the diagnostic criterion of HS onset. Body weight, core body temperature, survival rate, biochemical markers, inflammatory cytokines, and histopathology were investigated to evaluate the preventive effects of BL on HS. D-Lactate, I-FABP, endotoxin, and tight-junction proteins were investigated, and the fluorescein isothiocyanate-dextran (FD-4) test administered, to assess the degree of intestinal injury and integrity. Gut microbiota of rats in each group were analyzed by 16S rRNA sequencing. The results showed that pre-administration with BL significantly attenuated hyperthermia, reduced HS-induced death, alleviated multiple-organ injury, and decreased the levels of serum inflammatory cytokines. Furthermore, BL sustained the intestinal barrier integrity of HS rats by alleviating intestinal injury and improving tight junctions. We also found that BL significantly increased the ratios of two probiotic bacteria, Lactobacillus and Lactococcus. In addition, Romboutsia, a candidate biomarker for HS diagnosis, was unexpectedly detected. In summary, BL pre-administration for 7 days has preventative effects on HS that may be mediated by sustaining intestinal barrier function and modulating gut microbiota.

Using Nutritional Strategies to Shape the Gastro-Intestinal Tracts of Suckling and Weaned Piglets

This is a comprehensive review on the use of nutritional strategies to shape the functioning of the gastro-intestinal tract in suckling and weaned piglets. The progressive development of a piglet's gut and the associated microbiota and immune system offers a unique window of opportunity for supporting gut health through dietary modulation. This is particularly relevant for large litters, for which sow colostrum and milk are insufficient. The authors have therefore proposed the use of supplemental milk and creep feed with a dual purpose. In addition to providing nutrients to piglets, supplemental milk can also serve as a gut modulator in early life by incorporating functional ingredients with potential long-term benefits. To prepare piglets for weaning, it is important to stimulate the intake of solid feed before weaning, in addition to stimulating the number of piglets eating. The use of functional ingredients in creep feed and a transition diet around the time of weaning helps to habituate piglets to solid feed in general, while also preparing the gut for the digestion and fermentation of specific ingredients. In the first days after weaning (i.e., the acute phase), it is important to maintain high levels of feed intake and focus on nutritional strategies that support good gastric (barrier) function and that avoid overloading the impaired digestion and fermentation capacity of the piglets. In the subsequent maturation phase, the ratio of lysine to energy can be increased gradually in order to stimulate piglet growth. This is because the digestive and fermentation capacity of the piglets is more mature at this stage, thus allowing the inclusion of more fermentable fibres. Taken together, the nutritional strategies addressed in this review provide a structured approach to preparing piglets for success during weaning and the period that follows. The implementation of this approach and the insights to be developed through future research can help to achieve some of the most important goals in pig production: reducing piglet mortality, morbidity and antimicrobial use.