Bacillus amyloliquefaciens attenuates the intestinal permeability, oxidative stress and endoplasmic reticulum stress: transcriptome and microbiome analyses in weaned piglets.

Endoplasmic reticulum (ER) stress is related to oxidative stress (OS) and leads to intestinal injury. Bacillus amyloliquefaciens SC06 (SC06) can regulate OS, but its roles in intestinal ER stress remains unclear. Using a 2 × 2 factorial design, 32 weaned piglets were treated by two SC06 levels (0 or 1 × 108 CFU/g), either with or without diquat (DQ) injection. We found that SC06 increased growth performance, decreased ileal permeability, OS and ER stress in DQ-treated piglets. Transcriptome showed that differentially expressed genes (DEGs) induced by DQ were enriched in NF-κB signaling pathway. DEGs between DQ- and SC06 + DQ-treated piglets were enriched in glutathione metabolism pathway. Ileal microbiome revealed that the SC06 + DQ treatment decreased Clostridium and increased Actinobacillus. Correlations were found between microbiota and ER stress genes. In conclusion, dietary SC06 supplementation increased the performance, decreased the permeability, OS and ER stress in weaned piglets by regulating ileal genes and microbiota.

Gut microbiota metabolites, redox status, and the related regulatory effects of probiotics.

Oxidative stress is a state of imbalance between oxidation and antioxidation. It is caused by excess levels of free radicals and leads to the damage of DNA, proteins, and lipids. The crucial role of gut microbiota in regulating oxidative stress has been widely demonstrated. Studies have suggested that the redox regulatory effects of gut microbiota are related to gut microbiota metabolites, including fatty acids, lipopolysaccharides, tryptophan metabolites, trimethylamine-N-oxide and polyphenolic metabolites. In recent years, the potential benefits of probiotics have been gaining increasing scientific interest owing to their ability to modulate gut microbiota and oxidative stress. In this review, we summarise the adverse health effects of oxidative stress and discuss the role of the gut microbiota and its metabolites in redox regulation. Based on the influence of gut microbiota metabolites, the roles of probiotics in preventing oxidative stress are highlighted.

Effects of Lactiplantibacillus plantarum on oxidative stress, mitophagy, and NLRP3 inflammasome activation in broiler breast meat.

Poultry meat has a high polyunsaturated fatty acids content, making it vulnerable to oxidative stress. Mitophagy participates in the regulation of oxidative stress and the nucleotide-binding and oligomerization domain (NOD)-like receptor family as well as pyrin domain-containing protein 3 (NLRP3) inflammasome activation. Lactiplantibacillus plantarum P8 (P8) is a probiotic strain with an antioxidant capacity. In the present study, we investigated the effects of P8 on oxidative stress, mitochondrial function, mitophagy, and NLRP3 inflammasome in the breast meat of oxidatively stressed broilers. Four hundred 1-day-old male broilers were assigned to a 2 × 2 factorial design with 2 P8 levels (0 or 1 × 108 cfu/g), either with or without dexamethasone (DEX) injection, for a 21-day experimental period. DEX was injected intraperitoneally once daily from d 16 to 21. The breast meat was collected on d 21. The results showed that P8 supplementation decreased malondialdehyde (MDA) levels, increased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and activated the Keap1-Nrf2 pathway in DEX-injected broilers. Moreover, P8 supplementation downregulated mitochondrial DNA (mtDNA) copy number and increased the expressions of peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α), silent information regulator 1 (SIRT1), mitochondrial fusion protein 1 (Mfn1), and optic atrophy protein 1 (OPA1) in DEX-treated broilers. In addition, the decreased mitophagy level in DEX-treated broilers was elevated with P8 supplementation, as reflected by the increased gene expression of autophagy-related gene 5 (ATG5), Bcl-2-interacting protein (Becline-1), Parkin, PTEN-induced kinase 1 (PINK1), light chain 3 II (LC3II)/LC31, and the protein expression of Parkin as well as decreased p62 expression. In addition, P8 supplementation inhibited NLRP3 inflammasome activation by decreasing the transcription of NLRP3, IL-18, cysteinyl aspartate-specific proteinase-1 (Caspase-1), and the expression of NLRP3 and IL-18 in DEX-treated broilers. In conclusion, dietary P8 supplementation alleviates oxidative stress, improves mitophagy, and inhibits NLRP3 inflammasome activation in the breast meat of oxidatively stressed broilers.

Multi-omics reveals the mechanisms underlying Lactiplantibacillus plantarum P8-mediated attenuation of oxidative stress in broilers challenged with dexamethasone.

Oxidative stress is a common phenomenon in poultry production. Several molecules, including antioxidant genes, miRNAs, and gut microbiota metabolites, have been reported to participate in redox regulation. Lactiplantibacillus plantarum P8 (P8) was shown to improve the antioxidant capacity of chickens, but the specific molecular mechanisms remain unclear. In this study, 400 broilers were allocated to 4 treatment groups: control diet (Con group), control diet + dexamethasone injection (DEX group), control diet containing 1 × 108 CFU/g P8 (P8 group), and control diet containing 1 × 108 CFU/g P8 + DEX injection (DEX_P8 group). Integrated analysis of the microbiome, metabolomics, and miRNAomics was conducted to investigate the roles of P8 in oxidative stress in broilers. Results demonstrated that P8 supplementation significantly improved growth performance, jejunal morphology, and antioxidant function in DEX-treated broilers. Analysis of the gut microbiota revealed a higher abundance of Barnesiella (P = 0.01) and Erysipelatoclostridium (P = 0.05) in the DEX_P8 group than in the DEX group. Functional prediction indicated that certain pathways, including the phenylacetate degradation pathway, were enriched in the DEX_P8 group compared to the DEX group. Metabolites in the cecal contents were distinct between the groups. P8 supplementation increased the content of metabolites with antioxidant capacity, e.g., urobilinogen (P < 0.01), and decreased that of metabolites related to oxidative stress, e.g., genistein (P < 0.01). Functional prediction indicated that metabolites that differed between the DEX_P8 and DEX groups were enriched in pathways including "tryptophan metabolism" and "primary bile acid biosynthesis". The miRNAomics analysis further showed that, compared to the DEX group, several miRNAs in the jejunum, such as gga-miR-21-3p (P = 0.03), were increased, whereas gga-miR-455-3p (P = 0.02) was decreased in the DEX_P8 group. The PI3K-Akt, Ras, and Rap1 signaling pathways were enriched in the DEX_P8 group compared to the DEX group through KEGG analysis. Correlation analysis revealed potential interactions between growth performance, oxidation/antioxidation, jejunal morphology, gut microbiota, cecal content metabolites, and jejunal miRNAs. Overall, our results indicate that P8 supplementation may improve the growth performance, jejunal morphology and antioxidant capacity of DEX-treated broilers by regulating gut microbiota, its metabolites, and intestinal miRNAs.

Hepatic Proteomics Analysis Reveals Attenuated Endoplasmic Reticulum Stress in Lactiplantibacillus plantarum-Treated Oxidatively Stressed Broilers.

Endoplasmic reticulum (ER) stress plays important roles in oxidative stress (OS), contributing to liver injury. Lactiplantibacillus plantarum P8 (P8) was reported to regulate broiler OS and the gut microbiota in broilers, but its roles in hepatic ER stress remain unclear. In the present study, the role of P8 in liver OS and ER stress was evaluated, and proteomics was performed to determine the mechanism. Results revealed that P8 treatment decreased liver OS and ER stress in dexamethasone (DEX)-induced oxidatively stressed broilers. Proteomics showed that differentially expressed proteins (DEPs) induced by DEX cover the "cellular response to unfold protein" term. Moreover, the DEPs (GGT5, TXNDC12, and SRM) between DEX- and DEX + P8-treated broilers were related to OS and ER stress and enriched in the glutathione metabolism pathway. RT-qPCR further confirmed the results of proteomics. In conclusion, P8 attenuates hepatic OS and ER stress by regulating GGT5, TXNDC12, SRM, and glutathione metabolism in broilers.