Lactiplantibacillus plantarum L47 and inulin alleviate enterotoxigenic Escherichia coli induced ileal inflammation in piglets by upregulating the levels of α-linolenic acid and 12,13-epoxyoctadecenoic acid

Porcine β-Defensin 2 Expressed in Pichia pastoris Alleviates Enterotoxigenic Escherichia coli-Induced Intestinal Injury and Inflammatory Response in Mice

Enterotoxigenic Escherichia coli (ETEC), a common intestinal pathogen, can colonize the intestines and induce diarrhea in piglets, which brings great economic losses to the swine industry. Antibiotics are recommended to the treatment for diarrhea caused by ETEC in weaned piglets. However, with the emergence and spread of multidrug-resistant ETEC, there is an urgent need to develop alternatives to antibiotics. Due to the unique antibacterial mechanism of targeting bacterial membranes, antimicrobial peptides (AMPs) are promising candidates. In this study, the activity of crude recombinant porcine β-defensin 2 (rPBD2) expressed in Pichia pastoris (P. pastoris) was measured in vitro. Mice infected with ETEC were orally administered 16, 8, and 4 AU crude rPBD2 for 7 consecutive days to evaluate its anti-infective activity in vivo. The results showed that in addition to broad antibacterial activity against Gram-positive and -negative bacteria, crude rPBD2 displayed high tolerance to temperatures ranging from 20 to 60 °C, a broad range of pH, trypsin, pepsin, and physiological concentrations of salts. In an ETEC-induced mouse model, the oral administration of crude rPBD2 decreased diarrhea scores and the intestinal/carcass ratio and alleviated body weight loss. Additionally, crude rPBD2 decreased bacterial loads in stools and the colon (HP group), and the levels of serum pro-inflammatory cytokines IL-6 (HP group) and TNF-α (HP and MP groups), and increased the villus height and the ratio of villus height to crypt depth (VH/CD) in the ileum (HP and MP groups). Our study provides a cost-effective way for PBD2 production and identifies it as a promising candidate to combat ETEC-induced infection.

Lactiplantibacillus plantarum L47 and inulin affect colon and liver inflammation in piglets challenged by enterotoxigenic Escherichia coli through regulating gut microbiota

Introduction

Infection by pathogenic bacteria during weaning is a common cause of diarrhea and intestinal inflammation in piglets. Supplementing the diet with synbiotics is beneficial for animal health. The strain of Lactiplantibacillus plantarum L47 (L47) isolated in our lab exhibited good probiotic properties when combined with inulin. Here, the effectiveness of combining L47 and inulin (CLN) in protecting against enterotoxigenic Escherichia coli (ETEC) induced colon and liver inflammation in weaned piglets was evaluated.

Methods

Twenty-eight piglets aged 21 days were randomly assigned into 4 groups: CON (control), LI47 (oral CLN culture fluid, 1010 CFU/d of L47 and 1 g/d of inulin), ECON (oral ETEC culture fluid, 1010 CFU/d), and ELI47 (oral CLN and ETEC culture fluid). After 24 days, the colon and liver samples were collected for further analysis.

Results and discussion

CLN alleviated colon damage caused by ETEC challenge, as evidenced by an increase of colonic crypt depth, mRNA expression of tight junction Claudin-1 and Occludin, GPX activity, the concentration of IL-10 and sIgA (p < 0.05). Moreover, there was a decrease in MDA activity, the load of E. coli, the concentration of LPS, gene expression of TLR4, and the concentration of TNF-α and IL-6 (p < 0.05) in colonic mucosa. Additionally, CLN counteracted liver damage caused by ETEC challenge by modulating pathways associated with immunity and disease occurrence (p < 0.05).

Conclusion

Supplementing with CLN alleviated colon inflammation induced by ETEC challenge by decreasing the E. coli/LPS/TLR4 pathway and regulating hepatic immune response and disease-related pathways, suggesting that CLN could protect intestinal and liver health in animals.

Berberine alleviates ETEC-induced intestinal inflammation and oxidative stress damage by optimizing intestinal microbial composition in a weaned piglet model

Introduction

Enterotoxigenic Escherichia coli (ETEC) is the main diarrhea-causing pathogen in children and young animals and has become a global health concern. Berberine is a type of "medicine and food homology" and has a long history of use in China, particularly in treating gastrointestinal disorders and bacterial diarrhea.

Methods

In this study, we explored the effects of berberine on growth performance, intestinal inflammation, oxidative damage, and intestinal microbiota in a weaned piglet model of ETEC infection. Twenty-four piglets were randomly divided into four groups-a control group (fed a basal diet [BD] and infused with saline), a BD+ETEC group (fed a basal diet and infused with ETEC), a LB+ETEC group (fed a basal diet with 0.05% berberine and infused with ETEC infection), and a HB+ETEC group (fed a basal diet with 0.1% berberine and infused with ETEC).

Results

Berberine significantly improved the final body weight (BW), average daily gain (ADG), and average daily feed intake (ADFI) (P<0.05) of piglets, and effectively decreased the incidence of diarrhea among the animals (P<0.05). Additionally, berberine significantly downregulated the expression levels of the genes encoding TNF-α, IL-1β, IL-6, IL-8, TLR4, MyD88, NF-κB, IKKα, and IKKβ in the small intestine of piglets (P<0.05). ETEC infection significantly upregulated the expression of genes coding for Nrf2, CAT, SOD1, GPX1, GST, NQO1, HO-1, GCLC, and GCLM in the small intestine of the animals (P<0.05). Berberine significantly upregulated 12 functional COG categories and 7 KEGG signaling pathways. A correlation analysis showed that berberine significantly increased the relative abundance of beneficial bacteria (Gemmiger, Pediococcus, Levilactobacillus, Clostridium, Lactiplantibacillus, Weissella, Enterococcus, Blautia, and Butyricicoccus) and decreased that of pathogenic bacteria (Prevotella, Streptococcus, Parabacteroides, Flavonifractor, Alloprevotella) known to be closely related to intestinal inflammation and oxidative stress in piglets. In conclusion, ETEC infection disrupted the intestinal microbiota in weaned piglets, upregulating the TLR4/MyD88/NF-κB and Nrf2 signaling pathways, and consequently leading to intestinal inflammation and oxidative stress-induced damage.

Discussion

Our data indicated that berberine can optimize intestinal microbiota balance and modulate the TLR4/MyD88/NF-κB and Nrf2 signaling pathways, thus helping to alleviate intestinal inflammation and oxidative damage caused by ETEC infection in weaned piglets.

Palm Kernel Cake Extracts Obtained from the Combination of Bacterial Fermentation and Enzymic Hydrolysis Promote Swine Small Intestine IPEC-J2 Cell Proliferation and Alleviate LPS-Induced Inflammation In Vitro

Co-fermentation with bacteria and enzymes can reduce sugar content in palm kernel cake (PKC); however, the chemical changes and their effects on cell functionality are unclear. This study investigated the active components in pre-treated PKC extracts and their effects on pig small intestine IPEC-J2 cell proliferation and LPS-induced inflammation. The extracts contained 60.75% sugar, 36.80% mannose, 1.75% polyphenols and 0.59% flavone, as determined by chemical analyses, suggesting that the extracts were palm kernel cake oligosaccharides (PKCOS). Then, we found that 1000 µg/mL PKCOS counteracted the decrease in cell viability (CCK8 kit) caused by LPS induction by 5 µg/mL LPS (p < 0.05). Mechanistic studies conducted by RNA-seq and qPCR analyses suggested PKCOS promoted cell proliferation through the upregulation of TNF-α, PI3KAP1, MAP3K5 and Fos in the PI3K/MAPK signalling pathway; alleviated inflammation caused by LPS via the downregulation of the target genes Casp3 and TNF-α in association with apoptosis; and regulated the expression of the antioxidant genes SOD1, SOD2 and GPX4 to exert positive antioxidant effects (p < 0.05). Furthermore, PKCOS upregulated SLC5A1 (encoding SLGT1), HK and MPI in the glycolytic pathway (p < 0.05), suggesting cell survival. In summary, PKCOS has positive effects on promoting swine intestine cell proliferation against inflammation.