Mastitis, one of the most prevalent inflammatory diseases in female mammals, causes significant economic losses in livestock farming. Notably, the natural flavonoid compound baicalin exhibits potent anti-inflammatory activity. However, its efficacy in alleviating mastitis severity and the underlying molecular mechanisms remain unexplored. Therefore, this study aims to investigate the protective effects of baicalin in alleviating mastitis and its key molecular mechanisms.

This study demonstrated in vivo that baicalin effectively alleviates mastitis symptoms in dairy cows and mice, primarily manifested by reduced tissue pathological damage, decreased levels of pro-inflammatory cytokines, and maintain the integrity of the blood-milk barrier (BMB). Multi-omics sequencing analysis indicated that IL-17 and TNF signaling pathways play crucial roles in this process. Further studies demonstrated that IL-17RA^-/- mice exhibited a phenotype similar to that observed with baicalin treatment, confirming the importance of this pathway. Notably, network pharmacology screening combined with molecular dynamics simulations revealed stable binding of baicalin to IL-17RA, suggesting that baicalin exerts its protective effect to alleviate mastitis by targeting IL-17RA. Mechanistically, both baicalin treatment and IL-17RA deletion block activation of key downstream pathways of the IL-17 signaling pathway, including MAPK, ERK and NF-κB, thereby suppressing excessive activation of the TNF signaling pathway, preventing exacerbation of the inflammatory response and barrier damage.

In conclusion, this study demonstrates that baicalin inhibits excessive activation of the IL-17/TNF signaling pathway by targeting IL-17RA, thereby reducing inflammatory responses and BMB damage within the mammary gland and alleviating mastitis severity.

Baicalin is a bioactive flavonoid from Scutellaria baicalensis Georgi with antioxidant, anti-inflammatory and antibacterial properties. However, its bitter taste and susceptibility to ruminal degradation limit its practical use in mammals. Enteric coating technology might overcome these limitations by enabling targeted intestinal release. This study investigated effects of dietary supplementation with baicalin and coated baicalin on rumen fermentation, gastrointestinal microbiota, immune function and growth performance in Hu sheep.

Thirty-six lambs with similar body weight (33.01 ± 2.68 kg) were randomly assigned to three groups (4 replicates per group, 3 sheep per replicate). The control group was fed basal diet (CON) while treatment I (BAI) and treatment II (C-BAI) groups were fed a basal diet supplemented with 0.1% baicalin and coated baicalin, respectively. After a 60-d feeding trial, baicalin and coated baicalin supplementation improved total weight gain and average daily gain compared with CON group (P < 0.05). In addition, BAI and C-BAI groups exhibited higher total antioxidant capacity (P < 0.05) and catalase activity (P < 0.05) with associated lower malondialdehyde levels (P < 0.05). Immunoglobulin G and anti-inflammatory cytokines interleukin-4 (IL-4) were also increased (P < 0.001). Notably, IgM, IL-10 and IL-4 in the C-BAI group exceeded those of the BAI group (P < 0.001). Microbiome analysis revealed that baicalin supplementation enriched abundance of beneficial bacterial taxa including Firmicutes and Lachnoclostridium (P < 0.05) and reduced potential pathogen abundance, e.g., Treponema and Ralstonia (P < 0.05). The C-BAI group also showed increased abundance of the beneficial Bradyrhizobium compared with CON (P < 0.05). Metabolomic analysis revealed that baicalin altered propionate and tyrosine metabolic pathways (P < 0.05), while coated baicalin modulated penicillin metabolism and glyceride metabolism in jejunum (P < 0.05) increasing ATP production. Overall, these results indicated enhanced nutrient metabolism and gut health in the presence of dietary baicalin.

Dietary supplementation with baicalin and coated baicalin improved growth performance, antioxidant status, immunity and beneficially modulated the microbiome-metabolome crosstalk in Hu sheep. Notably, uncoated baicalin exerted more pronounced effects on growth performance and supported a role for baicalin as a potential and functional feed additive.

Amuc_1100, the most abundant outer membrane protein of Akkermansia muciniphila, alleviates high-fat diet (HFD)-induced hepatic lipid accumulation and modulates gut microbiota in fish; however, its mechanism and mediators remain unknown. Using zebrafish model, this study aims to determine the mechanism by which Amuc_1100 reduces HFD-induced hepatic lipid accumulation through modulation of gut microbiota.

In main study, 1-month-old zebrafish were fed a low-fat diet (LFD), HFD, or HFD supplemented with 0.01% Amuc_1100 (AM0.01) for 4 weeks. Body weight gain, hepatic lipid accumulation, microbial translocation, and gut microbiota composition were evaluated. In parallel, larvae at 5 d post-fertilization were fed the same diets for 7 d and analyzed by Oil Red O staining. In validation experiments, germ-free (GF) zebrafish received microbiota transplants from donor fish fed HFD or AM0.01. Antibiotics (ABS)-treated zebrafish were fed LFD, HFD, or AM0.01 for 4 weeks. Intestinal protein interacting with Amuc_1100 was identified via pull-down and co-immunoprecipitation, and its role was confirmed using protein-protein interaction (PPI) inhibitor BV02 and gene knockdown. Data were analyzed by Student's t-test or one-way ANOVA.

Compared with HFD group, zebrafish in AM0.01 group showed lower body weight gain, reduced hepatic lipid accumulation, and decreased microbial translocation (P < 0.05). AM0.01 feeding increased Bacillus abundance while reducing Acinetobacter, Plesiomonas and Aeromonas abundances relative to HFD (P < 0.05). GF zebrafish colonized with microbiota from AM0.01-fed donors showed less hepatic lipid accumulation than those receiving microbiota from HFD-fed donors (P < 0.05). In contrast, ABS-treated zebrafish showed no significant difference in hepatic triacylglycerol content between HFD and AM0.01 groups (P > 0.05). Using pull-down assays with intestinal proteins from LFD-fed zebrafish, we identified 14-3-3β/α-A as an interacting protein of Amuc_1100. When 14-3-3β/α-A PPI was inhibited by BV02, Amuc_1100 failed to alter the HFD-induced gut microbiota profile in 1-month-old zebrafish (P > 0.05). Moreover, either BV02 treatment or 14-3-3β/α-A knockdown abolished the protective effect of Amuc_1100 against hepatic lipid accumulation in conventional and GF zebrafish (P < 0.05).

Amuc_1100 reduces hepatic lipid accumulation by modulating gut microbiota through intestinal 14-3-3β/α-A, highlighting its potential as a therapeutic target.

The overuse of antibiotics in both veterinary and human medicine has resulted in the emergence of antibiotic-resistant bacteria, prompting a search for effective alternatives. Antimicrobial peptides (AMPs) are short, often cationic, peptide-based molecules with antimicrobial and immunomodulatory activity, which makes them promising alternatives to conventional antibiotics in poultry production.

From a prior machine-learning-guided screen of 875 candidate AMPs against a wide bacterial panel, 62 exhibited activity against avian pathogenic Escherichia coli (APEC) and low in vitro hemolytic and cytotoxic activity. We selected three lead AMPs from this list (named TeRu4, TeBi1, and PeNi4), and evaluated their in vitro and in vivo efficacy, safety, and immunomodulatory potential for use in poultry farming. In animal experiments, AMPs were administered via in ovo injection on d 18 of embryonic development. In APEC challenge trials, yolk sacs were inoculated with APEC post-hatch to assess early chick mortality, while in pen trials, birds were raised in a commercial production setting for 35 d. For challenged birds, TeBi1 (10 μg/egg) significantly reduced culture-positive rates for APEC in the air sac and pericardium, increased body weight by 50% and reduced cytokine transcript levels by 10%-30% on d 7 post hatch. In HD11 chicken macrophage-like cultured cells, TeRu4 (16 μg/mL) suppressed lipopolysaccharide (LPS)-induced pro-inflammatory cytokine transcript levels. In pen trials, TeRu4 (20 μg/egg) increased the survival probability of female birds by 4.9%, while TeBi1 (20 μg/egg) increased the survival probability of all birds by 4.4%, by d 35. Gene expression analysis revealed AMP- and sex-specific cytokine responses. In pen trials, no significant differences were observed in mean weights, feed conversion ratio (FCR), and flock uniformity on d 35. By integrating high-throughput in ovo automation with large-scale commercial pen trials, this study provides a systematic translational bridge from in silico AI discovery to field-relevant poultry production interventions.

These findings demonstrate that TeBi1 and TeRu4 are promising antibiotic alternatives that improve survival, modulate immune responses, and maintain normal growth performance in broiler chickens in this experimental setting.

The regulatory effects of glucose absorption at different sites (rumen vs. small intestine) on lipid metabolism exhibit significant variation in beef nutrition. This study aimed to investigate the regulatory pathways of rumenprotected or unprotected glucose on lipid metabolism through the rumen-jejunum axis in Xinjiang Brown cattle.

Thirty Xinjiang Brown cattle (females) with similar initial weight (410 ± 22.4 kg) were randomly assigned to 3 treatment groups (n = 10 animals per group). The experimental groups were fed a basal diet with the following daily supplements per head: 150 g palmitate coating (CON group), 150 g palmitate coating plus 150 g rumen-unprotected glucose (RUG group), and 300 g rumen-protected glucose (containing 50% glucose; RPG group). The experiment lasted for 70 d. Supplementation with both rumen-unprotected glucose and rumen-protected glucose increased chest width (P = 0.001), chest girth (P = 0.013), abdominal girth (P = 0.002), backfat thickness (P = 0.041), omental fat weight (P = 0.047), as well as serum concentrations of insulin (P < 0.001), glucagon-like peptide-1 (P < 0.001), and 5-hydroxytryptamine (P < 0.001), while decreasing the content of deoxycholic acid (P < 0.001) in the jejunum. The inclusion of rumen-unprotected glucose resulted in a trend toward higher intramuscular fat (IMF) (P = 0.064) in the longissimus thoracis, along with significant increases in C14∶0 (P = 0.042), C15∶0 (P = 0.014), and marbling score (P = 0.048), as well as significant reductions in drip loss (P = 0.022) and shear force (P = 0.041). These changes were accompanied by significant increases in dry matter intake (P = 0.001), ruminal concentrations of acetate (P = 0.022) and propionate (P = 0.011). The rumen-protected glucose supplementation elevated serum glucose (P < 0.001) level, while enhancing digestibility of ether extract (P = 0.027) and neutral detergent fiber (P = 0.027). Neither rumen-unprotected glucose nor rumen-protected glucose affected the alpha diversity and beta diversity of ruminal and jejunal microbiota (P > 0.05), but the differential bacterial biomarkers were either positively or negatively correlated with chest girth, abdominal girth, marbling score, backfat thickness, and deoxycholic acid (P < 0.05).

Rumen-unprotected glucose supplementation enhances IMF deposition and meat quality attributes through microbial volatile fatty acid-driven metabolic reprogramming.

High levels of zinc oxide (ZnO) and copper sulfate are widely used as alternative growth promoters in postweaning pig diet. However, excessive exposure to these metals may drive co-selection for heavy metal (HMR) and antibiotic resistance (AMR). Nursery diets also contain abundant iron to offset the low bioavailability of plant-derived iron, yet how dietary iron influence gut dysbiosis and microbial resistance in postweaning pigs remains unclear. This exploratory study examined the effects of dietary iron and metal-based growth promoters on the fecal resistome of postweaning pigs using shotgun metagenomics and whole-genome sequencing (WGS).

Fifty weanling pigs were stratified and randomly assigned to five dietary treatments for 24 d. Experimental diets included a control diet (Con) containing 25, 139, and 141 mg/kg of Cu, Fe, and Zn, respectively, a low-iron diet (LFe, 19 mg Fe/kg), a high-iron diet (HFe, 1,219 mg Fe/kg), a high-copper diet (HCu, 257 mg Cu/kg), and a high-zinc diet (HZn, 2,631 mg Zn/kg, including 2,490 mg Zn/kg from ZnO). All pigs were orally administered with F18 enterotoxigenic Escherichia coli (ETEC) on d 13-16. Metagenome sequencing were performed on d 24 fecal DNA (n = 24) to identify HMR genes (BacMet Predicted database) and AMR genes (CARD database). Functional annotation was performed using HUMAnN3. Whole genome sequencing (WGS) was conducted on 120 E. coli isolates from fecal cultures on d 1, 12, and 24, and AMR and virulence genes were identified from contig assemblies using ABRicate.

Dietary metal treatments significantly altered β-diversity of HMR genes compared with Con, with HZn differing from both HCu and LFe (P < 0.05). Fecal iron levels correlated with sodB (ρ = 0.64, P = 0.075), an iron-containing superoxide dismutase, while fecal copper levels correlated with pcoC (ρ = 0.66, P = 0.075), a plasmid-mediated copper resistance gene. Across metagenomes, 172 AMR genes were identified, dominated by glycopeptide and tetracycline resistance. While dietary iron had minimal effects on fecal AMR profile, HZn induced the largest shifts in resistome, including increases of ant(9)-la, conferring aminoglycoside resistance on mobile genetic elements, and adeF, encoding a multidrug efflux pump (P < 0.05). Functional profiling revealed enrichment of carbohydrate metabolism pathways in HZn group (P < 0.05). WGS of E. coli isolates showed distinct AMR profiles under HZn on d 24 and distinct virulence profile under LFe on d 12, exhibiting increased prevalence of exotoxin and T3SS genes (P < 0.05).

Dietary iron restriction enhanced E. coli virulence genes, whereas excessive ZnO induced the most pronounced changes in the gut resistome and microbial metabolism, highlighting a risk for AMR co-selection and marked influence on gut microbiota.