Effects of orally administered Escherichia coli Nissle 1917 on growth performance and jejunal mucosal membrane integrity, morphology, immune parameters and antioxidant capacity in early weaned piglets

Biosynthesis of Melanin with Engineered Probiotics for Oral Treatment of Ulcerative Colitis

Ulcerative colitis (UC) is a chronic intestinal inflammation characterized by immune overactivity and gut microbiota imbalance, leading to oxidative stress and inflammation. New therapeutics are required because existing ones are frequently unsuccessful and have long-term adverse effects. The research aims to manage oxidative stress and restore gut microbiota balance. The benefits of probiotics for UC can be compromised by gastrointestinal conditions that interfere with their adhesion and activity. Coating methods enhance bacterial survival in the gastrointestinal environment but face challenges like instability at low pH, short-lived effects, complexity, layer interactions, and biosafety issues. Melanin-like nanozymes are stable in the gastrointestinal environment and effectively scavenge reactive oxygen species, specifically targeting colitis lesions. We developed biosynthetic melanin-producing engineered bacteria (EcN-Mel) derived from genetically modified Nissle 1917 Escherichia coli expressing tyrosinase genes. This study evaluated the feasibility and effectiveness of administering EcN-Mel orally in UC mouse models. Results showed that EcN-Mel produced and secreted melanin, exhibiting targeted intestinal adhesion, a free radical scavenging ability, and gastrointestinal stability. In vivo imaging revealed increased colonization efficiency and retention time of EcN-Mel in inflamed intestinal segments. EcN-Mel enhances beneficial bacteria of the Lactobacillus genus while decreasing harmful members of the Proteobacteria genus, promoting gut microbiota homeostasis, and alleviating colitis. EcN-Mel alleviated intestinal mucosal damage through combined actions, including gut microbiota modulation, oxidative stress reversal, cytokine regulation, and barrier restoration. Our findings confirm the safety, feasibility, and effectiveness of EcN-Mel for UC treatment.

Effects of Escherichia coli Nissle 1917 on immunity, blood constituents, antioxidant capacity, egg quality and performance in laying Japanese quail

This study was conducted to evaluate the effects of E.coli Nissle 1917 (EcN) on immune responses, blood parameters, oxidative stress, egg quality, and performance of laying Japanese quail. A total of one-hundred day-old quail chicks were assigned to 1 of 4 treatments based on probiotic concentration: 1 (0 CFU/mL; control), 2 (104 CFU/mL), 3 (106 CFU/mL), and 4 (108 CFU/mL). The average egg production throughout the 8 wks of the laying phase increased with the increase in EcN supplementation (R2= 0.96). The egg production was also significantly different in wk 4, 7, and 8 of the laying phase with the control group demonstrating the poorest performance. External egg quality parameters, including shell strength, Roche index, albumen height, yolk weight, shell weight, shell thickness, and Haugh unit, also showed higher values in groups receiving EcN. Likewise, these groups demonstrated heavier egg weight (EW) and lower MDA in the meat sample. The MDA concentration of fresh yolk samples in groups receiving EcN was higher but diminished after iron-inducing (P < 0.05). No differences were observed in ADFI, FCR, EM, yolk cholesterol and triglyceride, hematocrit, SRBC, NDV, CMI immune responses (DNCB and PHA), H:L ratio, and internal organ weights. Plasma cholesterol and uric acid were the only blood constituents showing higher values in male birds in groups of EcN (P < 0.05); no appreciable differences were observed in the rest of the blood parameters in male birds and none in females. Further, a substantially higher Avian Influenza Virus (AIV) titer resulted from treatments 3 and 4 in male birds among humoral immune responses. These results demonstrated that EcN in the birds' drinking water could profoundly influence laying performance, egg quality, immune function, and enhanced antioxidant capacity.

Dietary tryptophan improves growth and intestinal health by promoting the secretion of intestinal β-defensins against enterotoxigenic Escherichia coli F4 in weaned piglets

Adequate dietary L-tryptophan (Trp) governs intestinal homeostasis in piglets. However, the defensive role of Trp in the diet against enterotoxigenic Escherichia coli F4 (K88) in pigs is still poorly understood. Here, sixty (6.15 ± 1.52 kg, 24-day-old, Duroc × Landrace × Yorkshire) weaned piglets were used for an E. coli F4 attack test in a 2 × 2 factorial design. The growth (ADG, ADFI, GH), immune factors (IL-10, IgA, IgG, IgM), Trp metabolite 5-HT, intestinal morphology (jejunal and colonic VH), mRNA expression of β-defensins (jejunal BD-127, BD-119, ileal BD-1, BD-127), and abundance of beneficial microorganisms in the colon (Prevotella 9, Lactobacillus, Phascolarctobacterium, Faecalibacterium) were higher in the piglets in the HT (High Trp) and HTK (High Trp, K88) groups than in the LT (Low Trp) and LTK (Low Trp, K88) groups (P<.05), while FCR, diarrhea rate, diarrhea index, serum Trp, Kyn, IDO, D-LA, ET, and abundance of harmful microorganisms in the colon (Spirochaetes, Fusobacteria, Prevotella, Christensenellaceae R7) were lower in the HT and HTK groups than in the LT and LTK groups (P<.05). High Trp reduced the expression of virulence genes (K88 and LT) after E. coli F4 attack (P<.05). The IL-6, TNF-α was lower in the HTK group than in the LT, LTK group (P<.05). In short, a diet containing 0.35% Trp protected piglets from enterotoxigenic E. coli F4 (K88) via Trp metabolism promoting BD expression in the intestinal mucosa, which improved growth and intestinal health.

Protective effects of taurine on growth performance and intestinal epithelial barrier function in weaned piglets challenged without or with lipopolysaccharide

We evaluated whether weaned piglets were protected from bacterial endotoxins by placing the animals on a taurine-supplemented diet. A total of 40 weaned Landrace × Yorkshire piglets (5.75 ± 0.58 kg, weaned at 21 days) were allocated to four groups with 10 barrows per group, following a 2 × 2 factorial design with two inclusion levels of lipopolysaccharide (LPS) (no or one time peritoneal injection by the dose of 100 µg/kg bodyweight on Day 7 of the trial) and two inclusion levels of dietary taurine (no or 0.1% taurine in a basal diet in the whole trial). There was a significant interaction between LPS and taurine with regard to growth and small intestinal mucosal membrane integrity, morphology, immune parameters, and antioxidant capacity (P < 0.05). Feed conversion, daily weight gain, daily feed intake, villus height, and the villus to crypt ratio, vascular endothelial growth factor, regenerating islet-derived protein 3 gamma, trefoil factor-3, transforming growth factor β-1 expression, number of goblet cells and the least amount of claudin-1, occludin, zonula occludens-1, serum glutathione peroxidase, nitrogen oxide synthase, superoxide dismutase, peroxidase, and total antioxidant was lowest in LPS-challenged animals. Furthermore, animals in the LPS group had the highest serum diamine oxidase concentration, number of lymphocytes, concentrations of calprotectin, sIgA, toll-like receptor-4, mRNA levels of interleukin-1β, interleukin-8, toll-like receptor-4, and tumour necrosis factor-α (P < 0.05). These data suggested that the peritoneal injection administration of LPS decreased growth performance and disrupted small intestinal mucosal membrane integrity and triggered an inflammatory response in the small intestinal mucosal membrane. Dietary administration of taurine improved growth performance, increased small intestinal villus height, stimulated immune and antioxidant function and improved small intestinal mucosal membrane integrity in weaned piglets challenged without or with LPS (P < 0.05). The beneficial effects of taurine were likely due to decreased stimulation of the immune response to LPS and an improvement in intestinal epithelial barrier function. Dietary administration of taurine could prevent weaned piglets from intestinal damage by LPS of Gram-negative bacteria.