Baicalin enhances antioxidant, inflammatory defense, and microbial diversity of yellow catfish (Pelteobagrus fulvidraco) infected with Aeromonas hydrophila.

Introduction: The aim of this research was to clarify the mechanism through which baicalin exerts its inhibitory effects on Aeromonas hydrophila infection. Methods: The antibacterial efficacy of baicalin was assessed by determining its minimum inhibitory concentration (MIC) against A. hydrophila. Various parameters, including the growth curve, cell wall integrity, biofilm formation, AKP content, and morphological alterations of A. hydrophila, were analyzed. In vivo experiments involved the administration of A. hydrophila 4 h postintraperitoneal injection of varying doses of baicalin to induce infection, with subsequent monitoring of mortality rates. After a 3 d period, liver, spleen, and intestinal tissues were harvested to evaluate organ indices, antioxidant and immune parameters, as well as intestinal microbial composition. Results: The findings indicated that baicalin treatment resulted in the disruption of the cell wall of A. hydrophila, leading to the loss of its normal structural integrity. Furthermore, baicalin significantly inhibited biofilm formation and facilitated the release of intracellular proteins (P < 0.05). In vivo, baicalin enhanced the survival rates of yellow catfish infected with A. hydrophila. Compared to the control group, the liver index of yellow catfish was elevated, while the spleen and intestinal indices were reduced in the baicalin-treated group (P < 0.05). Additionally, baicalin at an appropriate dosage was found to increase levels of SOD, GSH, CAT, ACP, and AKP in yellow catfish (P < 0.05), while simultaneously decreasing MDA accumulation and the mRNA expression of inflammatory markers such as Keap1, IL1, IFN-γ, and TNF-α, (P < 0.05). Moreover, baicalin significantly enhanced the operational taxonomic unit (OTU) count in A. hydrophila-infected yellow catfish (P < 0.05), restoring the abundance of Barnesiellaceae, Enterobacteriaceae, Plesiomonas, and UBA1819 (P < 0.05). Discussion: In summary, baicalin demonstrates the potential to improve the survival rate of yellow catfish subjected to A. hydrophila infection, augment antioxidant and immune responses, mitigate inflammation, and enhance intestinal microbial diversity.

Gut microbiota and serum metabolome reveal the mechanism by which TCM polysaccharides alleviate salpingitis in laying hens challenged by bacteria.

This paper aimed to evaluate the effect of 3 kinds of TCM polysaccharides instead of antibiotics in preventing salpingitis in laying hens. After feeding the laying hens with Lotus leaf polysaccharide, Poria polysaccharide, and Epimedium polysaccharide, mixed bacteria (E. coli and Staphylococcus aureus) were used to infect the oviduct to establish an inflammation model. Changes in antioxidant, serum immunity, anti-inflammatory, gut microbiota, and serum metabolites were evaluated. The results showed that the 3 TCM polysaccharides could increase the expression of antioxidant markers SOD, GSH, and CAT, and reduce the accumulation of MDA in the liver; the contents of IgA and IgM in serum were increased. Decreased the mRNA expression of TLR4, NFκB, TNF-α, IFN-γ, IL1ß, IL6, and IL8, and increased the mRNA expression of anti-inflammatory factor IL5 in oviduct tissue. 16sRNA high-throughput sequencing revealed that the 3 TCM polysaccharides improved the intestinal flora disturbance caused by bacterial infection, increased the abundance of beneficial bacteria such as Bacteroides and Actinobacillus, and decreased the abundance of harmful bacteria such as Romboutsia, Turicibacter, and Streptococcus. Metabolomics showed that the 3 TCM polysaccharides could increase the content of metabolites such as 3-hydroxybutyric acid and isobutyl-L-carnitine, and these results could alleviate the further development of salpingitis. In conclusion, the present study has found that using TCM polysaccharides instead of antibiotics was a feasible way to prevent bacterial salpingitis in laying hens, which might make preventing this disease no longer an issue for breeding laying hens.

Lotus leaf extract can attenuate salpingitis in laying hens by inhibiting apoptosis.

This study aimed to determine whether the lotus leaf extract (LLE) had the effect of treating salpingitis in laying hens. First, the salpingitis model was established by the method of bacterial infection. Differential genes between salpingitis and healthy laying hens were identified by transcriptome sequencing, and GO and KEGG enrichment analyses were performed. Groups of treatment of antibiotics and LLE were established to verify the feasibility of the lotus leaf extract in treating salpingitis. Furthermore, the active component and pharmacological effects of LLE were identified using the UPLC-Q-TOF-MS and network pharmacology technique. At last, the mechanism of LLE treating salpingitis was further evaluated by DF-1 cells infected with bacteria. The results showed that LLE significantly reduced the levels of TLR4 and IFN-γ (P < 0.05), accelerated the levels of IgA and IgG (P < 0.05), regulated the levels of SOD and MDA (P < 0.05) in laying hens with salpingitis. A total of 1,874 differential genes were obtained according to the transcriptome sequencing. It was revealed a significant role in cell cycle and apoptosis by enrichment analysis. In addition, among the 28 components identified by UPLC-Q-TOF-MS, 20 components acted on 58 genes, including CDK1, BIRC5, and CA2 for treating salpingitis. After bacterial infection, cells were damaged and unable to complete the normal progression of the cell cycle, leading to cell cycle arrest and further apoptosis formation. However, with the intervention of LLE, bacterial infection was resisted. The cells proliferation was extensively restored, and the expression of NO was increased. The addition of LLE significantly decreased cell apoptosis. The G1 phase increased, the S phase and the G2 phase decreased in the model group; after the intervention of LLE, the G1 phase gradually returned to the average level, and G2 and S phases increased. The mRNA expression levels of BIRC5, CDK1, and CA2 were consistent with the predicted results in network pharmacology. At the same time, the mRNA expression levels of Caspase-3 and Caspase-7 were reduced after added with LLE. The mRNA expression levels of TNF-α, TRADD, FADD, Caspase-8, Caspase-10, and Caspase-9 (P < 0.05), which would inhibit death receptor activation and decrease the apoptotic cascade, were upregulated after bacterial infection. However, the results in LLE groups were downregulated (P < 0.05). Meanwhile, the mRNA expression levels of BCL-2 in LLE groups were increased significantly compared with it in model group (P < 0.05). Notably, LLE administration inhibited apoptosis and regulated the cell cycle distribution in the salpingitis induced by bacterial infection. These results indicated that the LLE attenuated bacterial-induced salpingitis by modulating apoptosis and immune function in laying hens.

Nuciferine Regulates Immune Function and Gut Microbiota in DSS-Induced Ulcerative Colitis.

Nuciferine, a major aporphine alkaloid obtained from the leaves of Nelumbo nucifera, exhibits anti-cancer and anti-inflammatory properties; however, its protective effects against inflammatory bowel diseases (IBD) has never been explored. In this study, an ulcerative colitis (UC) model was established in BALb/c mice by the continuous administration of 5% dextran sulfate sodium (DSS) in drinking water for 1 week. From day 8 to day 14, the DSS-treated mice were divided into a high-dose and a low-dose nuciferine treatment group and were intraperitoneally injected with the corresponding dose of the drug. Body weight loss, disease activity index (DAI), and colon length were measured. Histological changes were observed using hematoxylin and eosin staining. T lymphocyte proliferation was assessed by MTT assay. The ratio of CD3+, CD4+, CD8+, Th1, Th2, Th17, and Treg cells were estimated by flow cytometry. Finally, 16S rRNA sequencing was performed to compare the composition and relative abundance of the gut microbiota among the different treatment groups. The results showed that nuciferine treatment led to a significant improvement in symptoms, such as histological injury and colon shortening in mice with DSS-induced UC. Nuciferine treatment improved the Th1/Th2 and Treg/Th17 balance in the DSS-induced IBD model, as well as the composition of the intestinal microflora. At the phylum level, compared with the control group, the abundance of Firmicutes and Actinobacteriota was decreased in the model group, whereas that of Bacteroidetes increased. Meanwhile, at the genus level, compared with the control group, the numbers of the genera Lachnospiraceae_Clostridium, Bilophila and Halomonas reduced in the model group, while those of Bacteroides, Parabacteroides, and Paraprevotella increased. Notably, nuciferine administration reversed this DSS-induced gut dysbiosis. These results indicated that nuciferine modulates gut microbiota homeostasis and immune function in mice with DSS-induced UC.

Effects of sulfated ß-glucan from Saccharomyces cerevisiae on growth performance, antioxidant ability, nonspecific immunity, and intestinal flora of the red swamp crayfish (Procambarus clarkii).

The aim of this study was to examine the combined effects of sulfated ß-Glucan from Saccharomyces cerevisiae (sGSC) on growth performance, antioxidant ability, nonspecific immunity, and intestinal flora of the red swamp crayfish (Procambarus clarkii). Four experimental diets (sGSC25, sGSC50, sGSC100 and sGSC200) with different levels of sGSC (0.025%, 0.05%, 0.1% and 0.2% in diet, respectively) were fed to juvenile crayfish (average weight: 2.5 ± 0.5 g) for 8 weeks. The control diet was given with 2000 mg/kg GSC (GSC200 group). The based control diet was given without sGSC or GSC (blank group). Each group had 3 parallel test pools, 20 crayfish were reared in each pool. At the end of the growth trial, adding dietary 0.025%-0.1% sGSC could significantly improve the growth performance, antioxidant capacity and immunity of crayfish. Compared with GSC, sGSC had a better effect at lower concentration. Higher concentration of sGSC (>0.1%) would cause some side effects. sGSC also could improve the structure of the intestinal flora and optimize the function of the flora. sGSC would increase the abundances of probiotics such as Hafnia and Acinetobacter, and decreases the abundances of maleficent bacteria such as Enterobacteriaceae. Higher concentration of sGSC (>0.1%) would increase the abundance of Aeromonas. To conclude, 0.025%-0.1% sGSC can be used as a supplement in crayfish feed to increase growth, immunity, and antioxidant capacity and improve the structure of intestinal flora. These results provided a theoretical basis for the application of sGSC instead of GSC in crayfish breeding. It will be necessary to further study the optimal concentration of sGSC in feed additives in different growth stages of crayfish in the future.