Zutao Zhou

Weaning impairs intestinal function and growth performance in piglets. This study evaluated a fermented herbal formulation (FHF) composed of five bioactive herbal ingredients—Radix isatidis, Folium isatidis, Radix scutellariae, Fructus forsythiae, and Radix glycyrrhizae—fermented with Enterococcus faecium and Saccharomyces cerevisiae and characterized by flavonoids, phenolic acids, and hydroxylated fatty acids, using the porcine intestinal epithelial cell line (IPEC-J2) and weaned piglets. In vitro, IPEC-J2 cells were pretreated with FHF extract (100–1000 μg/mL) for 3 h prior to lipopolysaccharide (LPS) challenge. In vivo, 72 piglets were weaned at 32 days of age and, after a 3-day post-weaning adaptation period, entered a 35-day feeding trial. The piglets were then randomly assigned to three treatment groups: control (basal diet), A1 (basal diet + 0.4% FHF), and A2 (basal diet + 0.6% FHF during days 1–18, followed by 0.3% FHF during days 19–35). FHF dose-dependently alleviated the LPS-induced decrease in cell viability and suppressed IL-6, IL-8, IL-1β, and TNF-α expression. In piglets, the A2 group showed higher final body weight, average daily gain (ADG), and average daily feed intake (ADFI), lower feed conversion ratio (FCR), and a lower diarrhea rate than the control group. FHF also improved intestinal morphology, reduced serum TNF-α and diamine oxidase (DAO) levels, increased jejunal tight junction protein expression, enriched Limosilactobacillus and Lactobacillus, and elevated acetic and butyric acids. FHF improved intestinal health and growth performance in weaned piglets, with the A2 group showing the best overall efficacy.

Background: Enteropathogenic Escherichia coli (EPEC) disrupts intestinal barrier integrity by adhering to epithelial cells, leading to diarrhea, impaired nutrient absorption, oxidative stress, and intestinal inflammation in young animals. This study aimed to isolate and characterize a neutral exopolysaccharide (EPS-T1) from Enterococcus faecium HDRsEf1, evaluate its functional activities in vitro, and assess its protective effects against EPEC-induced enteritis in vivo. Results: EPS-T1, with a molecular weight of 81.21 ± 1.28 kDa, was mainly composed of glucose, galactose, rhamnose, and mannose, and exhibited a porous, sheet structure with relatively high thermal stability. In vitro, EPS-T1 (200 μg/mL) significantly inhibited EPEC growth and biofilm formation, reduced bacterial adhesion to intestinal epithelial cells, and exhibited broad-spectrum free radical scavenging activity. In vivo, EPS-T1 treatment alleviated EPEC-induced weight loss and intestinal tissue damage, reduced the intestinal EPEC load, downregulated pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6), upregulated the anti-inflammatory cytokine IL-10, and improved serum antioxidant indices (T-AOC, SOD, and GSH-PX) while decreasing MDA levels. Conclusions: These results demonstrate that EPS-T1 derived from Enterococcus effectively mitigates EPEC-induced intestinal inflammation and oxidative stress, highlighting its potential as an immunobiotic functional candidate.

Riemerella anatipestifer infection is a critical disease that is a major threat to the poultry industry worldwide. The adhesion and invasion of host cells are key steps in the primary stages of bacterial infection. However, the outer membrane proteins that mediate these events in R. anatipestifer are poorly characterized. In this study, the PorV and PosF proteins, as well as the previously described OMP71 protein, were identified as important mediators of the adhesion and invasion of duck embryo fibroblast (DEF) cells by R. anatipestifer. Affinity chromatography-based surface proteomics was used to screen for adhesion proteins. The surface proteins on DEF cells were labelled with biotin-avidin to enrich for outer membrane proteins of R. anatipestifer, which generated 11 candidate proteins that were tested further. Protein adhesion and blocking assays and polyclonal antiserum inhibition analysis revealed that the PorV, PosF, and OMP71 proteins are adhesion factors. Knockout of porV or posF reduced the adhesion and invasion of R. anatipestifer in DEF cells. Moreover, the pathogenicity of the mutant strains was significantly attenuated, which supports the hypothesis that PorV and PosF are important virulence factors required for the pathogenicity of R. anatipestifer. The PorV protein is a key component of the type IX secretory system and is responsible for transporting effector substrates to the extracellular environment, whereas PosF belongs to the porin superfamily of barrel-shaped transmembrane proteins. This is the first description that PorV is an adhesin involved in host‒microbial interactions, which represents a breakthrough in pathogenicity studies of R. anatipestifer and other members of Flavobacteriaceae.

Mycoplasma synoviae (M. synoviae) is a major bacterial pathogen that causes serious economic losses in the global poultry industry. Systemic changes in specific pathogen free White Leghorn egg-laying hens after M. synoviae infection were investigated using intra-tracheally inoculated animals. Samples were collected 10 days post-infection (dpi) (204-day-old) and 52 dpi (246-day-old). Infection caused air sac lesion, footpad swelling and oviduct atrophy. The qPCR and in situ hybridization showed that bacteria colonized the trachea and oviduct, and that bacterial loads in the magnum and uterus were significantly higher than in the infundibulum and isthmus. Histopathological examination revealed increased tracheal mucosal thickening accompanied by inflammatory cell infiltration, and that tubular glands of the uterus were edematous or dissolved. Infection also induced decreased egg production and eggshell strength, and eggshell apex abnormalities appeared at 14 dpi. Plasma metabolomics of hens analyzed by liquid chromatography-tandem mass spectrometry showed 168 and 128 differentially-expressed metabolites (DEM) at 10 and 52 dpi, respectively. Pathway analysis revealed that DEM at 10 dpi were enriched in five distinctive pathways: regulation of the actin cytoskeleton, neuroactive ligand-receptor interaction, sphingolipid metabolism, gap junctions, and necroptosis. In contrast, DEM at 52 dpi were enriched in fifteen pathways involved in steroid hormone biosynthesis, ferroptosis, the calcium signaling pathway, apelin signaling pathway, progesterone-mediated oocyte maturation, and oocyte meiosis. Combined metabolic analysis demonstrated that changes in ethylsalicylate, nicotinamide, (3-Methoxy-4-hydroxyphenyl) ethylene glycol sulfate, sphingosine-1-phosphate (d18:1), carnitine C24:6, and 15(R)-prostaglandin E1 correlated the best with M. synoviae infection. This study provides new insights into understanding pathogen mechanisms and signposts novel treatments for M. synoviae infection in poultry.

The impact of nutritional enrichment with bio-fermented distillers grain (FDG) on broiler growth, intestines, and cecal microbial community were evaluated. A total of 240 five-day-old male chicks were randomly and evenly distributed into three treatment groups (each with eight biological replicates of 10 chicks): 0% FDG (group A), 2.5% FDG (group B), and 5% FDG (group C). In this study, we observed that FDG caused no significant variations in the body weight and feed intake of broilers (p > 0.05). The FDG significantly enhanced villus height and the villus height/crypt depth ratio (VCR) of the small intestine compared with the control group (p < 0.05). Taxonomic composition of the gut microbiota revealed a higher relative abundance of Bacteroidetes in the cecal samples of broilers from groups B and C compared to the control group (p < 0.05). At the genus level, the relative abundances of Bacteroides and Phascolarctobacterium were increased with the addition of FDG to broiler diets, whereas the relative abundance of the Christensenellaceae_R-7_group was decreased. These results suggest that fermented feeds significantly influence the composition of cecal microbiome in broilers, potentially affecting growth performance, nutritional status, and intestinal health.