Lithocholic Acid Alleviates Deoxynivalenol-Induced Inflammation and Oxidative Stress via PPARγ-Mediated Epigenetically Transcriptional Reprogramming in Porcine Intestinal Epithelial Cells.

Deoxynivalenol (DON) is a common mycotoxin that induces intestinal inflammation and oxidative damage in humans and animals. Given that lithocholic acid (LCA) has been suggested to inhibit intestinal inflammation, we aimed to investigate the protective effects of LCA on DON-exposed porcine intestinal epithelial IPI-2I cells and the underlying mechanisms. Indeed, LCA rescued DON-induced cell death in IPI-2I cells and reduced DON-stimulated inflammatory cytokine levels and oxidative stress. Importantly, the nuclear receptor PPARγ was identified as a key transcriptional factor involved in the DON-induced inflammation and oxidative stress processes in IPI-2I cells. The PPARγ function was found compromised, likely due to the hyperphosphorylation of the p38 and ERK signaling pathways. In contrast, the DON-induced inflammatory responses and oxidative stress were restrained by LCA via PPARγ-mediated reprogramming of the core inflammatory and antioxidant genes. Notably, the PPARγ-modulated transcriptional regulations could be attributed to the altered recruitments of coactivator SRC-1/3 and corepressor NCOR1/2, along with the modified histone marks H3K27ac and H3K18la. This study emphasizes the protective actions of LCA on DON-induced inflammatory damage and oxidative stress in intestinal epithelial cells via PPARγ-mediated epigenetically transcriptional reprogramming, including histone acetylation and lactylation.

Alternatives to antibiotics in pig production: looking through the lens of immunophysiology.

In the livestock production system, the evolution of porcine gut microecology is consistent with the idea of "The Hygiene Hypothesis" in humans. I.e., improved hygiene conditions, reduced exposure to environmental microorganisms in early life, and frequent use of antimicrobial drugs drive immune dysregulation. Meanwhile, the overuse of antibiotics as feed additives for infectious disease prevention and animal growth induces antimicrobial resistance genes in pathogens and spreads related environmental pollutants. It justifies our attempt to review alternatives to antibiotics that can support optimal growth and improve the immunophysiological state of pigs. In the current review, we first described porcine mucosal immunity, followed by discussions of gut microbiota dynamics during the critical weaning period and the impacts brought by antibiotics usage. Evidence of in-feed additives with immuno-modulatory properties highlighting probiotics, prebiotics, and phytobiotics and their cellular and molecular networking are summarized and reviewed. It may provide insights into the immune regulatory mechanisms of antibiotic alternatives and open new avenues for health management in pig production.

Lactobacillus johnsonii N5 from heat stress-resistant pigs improves gut mucosal immunity and barrier in dextran sodium sulfate-induced colitis.

Developing effective strategies to prevent diarrhea and associated-gut disorders in mammals has gained great significance. Owing to the many health benefits provided by the commensal microbiota of the intestinal tract, such as against environmental perturbation, we explored the host phenotype-associated microbes and their probiotic potential. Based on the observations that the chronic heat stress-exposed weaned piglets present as heat stress-susceptible (HS-SUS) or heat stress-resistant (HS-RES) individuals, we confirmed the phenotypic difference between the two on growth performance (P < 0.05), diarrhea index (P < 0.001), intestinal heat shock protein 70 (HSP70) regulation (P < 0.01), and inflammatory responses (P < 0.01). By comparing the gut microbiome using 16S rRNA gene sequencing and KEGG functional analysis, we found that Lactobacillus johnsonii exhibited significantly higher relative abundance in the HS-RES piglets than in the HS-SUS ones (P < 0.05). Further experiments using a mouse model for chemical-induced inflammation and intestinal injury demonstrated that oral administration of a representative L. johnsonii N5 (isolated from the HS-RES piglets) ameliorated the clinical and histological signs of colitis while suppressing intestinal pro-inflammatory cytokines TNF-α and IL-6 production (P < 0.05). We found that N5 treatment enhanced tight junction proteins ZO-1 and occludin and cytoprotective HSP70 levels under physiological condition and restored their mucosal expressions in colitis (P < 0.05). In support of the high production of the anti-inflammatory cytokine IL-10, N5 promoted the intestinal Peyer's patches MHCII+ and CD103+ dendritic cell populations (P < 0.05), increased the regulatory T (Treg) cell numbers (P < 0.05), and decreased the Th17 population and its IL-17a production under physiological condition and during colitis (P < 0.01). Our results shed light on understanding the interaction between commensal Lactobacillus and the host health, and provide L. johnsonii N5 as an alternative to antibiotics for preventing diarrhea and intestinal diseases.

A meta-analysis of Lactobacillus-based probiotics for growth performance and intestinal morphology in piglets.

Antibiotics are widely used as growth promoters (AGPs) in livestock production to improve animal performance and health. However, pig producers today face the prohibition of in-feed antimicrobials and have to find safe and effective alternatives. Lactobacillus species are active microorganisms that convey multiple beneficial effects to the host and are one of the most promising AGPs replacements. Here, we aim to comprehensively assess the effects of Lactobacillus spp. supplementation on growth performance and intestinal morphology (villus height [VH], crypt depth [CD], and the V/C ratio) of piglets. Among the 196 identified studies, 20 met the criteria and were included in the meta-analysis. The effects of Lactobacillus-based probiotics supplementation on growth performance and intestinal morphology were analyzed using a random-effects model. And the publication bias was evaluated by funnel plots. Our results revealed that Lactobacillus spp. supplementation significantly improved the growth performance, including average daily feed intake (ADFI), average daily gain (ADG), and the gain-to-feed ratio (G/F) in piglets (P < 0.05). Meanwhile, Lactobacillus spp. remarkably increased VH and the V/C ratio (P < 0.05) in the small intestine, including the duodenum, jejunum, and ileum, which might contribute to an improved digestive capacity of these animals. In conclusion, our findings provide concrete evidence of the growth-promoting effects of Lactobacillus spp. supplementation in piglets and a better understanding of the potential of Lactobacillus-based probiotics as AGPs alternatives in pig production.

Epithelial Heat Shock Proteins Mediate the Protective Effects of Limosilactobacillus reuteri in Dextran Sulfate Sodium-Induced Colitis.

Defects in gut barrier function are implicated in gastrointestinal (GI) disorders like inflammatory bowel disease (IBD), as well as in systemic inflammation. With the increasing incidence of IBD worldwide, more attention should be paid to dietary interventions and therapeutics with the potential to boost the natural defense mechanisms of gut epithelial cells. The current study aimed to investigate the protective effects of Limosilactobacillus reuteri ATCC PTA 4659 in a colitis mouse model and delineate the mechanisms behind it. Wild-type mice were allocated to the control group; or given 3% dextran sulfate sodium (DSS) in drinking water for 7 days to induce colitis; or administered L. reuteri for 7 days as pretreatment; or for 14 days starting 7 days before subjecting to the DSS. Peroral treatment with L. reuteri improved colitis severity clinically and morphologically and reduced the colonic levels of Tumor necrosis factor-α (TNF-α) (Tnf), Interleukin 1-ß (Il1ß), and nterferon-γ (Ifng), the crucial pro-inflammatory cytokines in colitis onset. It also prevented the CD11b+Ly6G+ neutrophil recruitment and the skewed immune responses in mesenteric lymph nodes (MLNs) of CD11b+CD11c+ dendritic cell (DC) expansion and Foxp3+CD4+ T-cell reduction. Using 16S rRNA gene amplicon sequencing and RT-qPCR, we demonstrated a colitis-driven bacterial translocation to MLNs and gut microbiota dysbiosis that were in part counterbalanced by L. reuteri treatment. Moreover, the expression of barrier-preserving tight junction (TJ) proteins and cytoprotective heat shock protein (HSP) 70 and HSP25 was reduced by colitis but boosted by L. reuteri treatment. A shift in expression pattern was also observed with HSP70 in response to the pretreatment and with HSP25 in response to L. reuteri-DSS. In addition, the changes of HSPs were found to be correlated to bacterial load and epithelial cell proliferation. In conclusion, our results demonstrate that the human-derived L. reuteri strain 4659 confers protection in experimental colitis in young mice, while intestinal HSPs may mediate the probiotic effects by providing a supportive protein-protein network for the epithelium in health and colitis.