We aimed to investigate the role of capsaicin (CAP) in modulating lipopolysaccharide (LPS)-induced hepatic and intestinal inflammation, oxidative stress, and its colonic microflora in mice. Thirty healthy male Kunming mice with similar body weights were randomly assigned to three groups: the control group (CON), the LPS group, and the CAP group, with ten mice in each group. The CON and the LPS groups received a daily dose of normal saline, respectively, while the CAP group received an equivalent dose of CAP. On the 28th day of the experiment, the LPS and the CAP groups were intraperitoneally injected with LPS, while the CON group was injected with an equal volume of normal saline. The results lead to the following conclusions. Compared to the LPS group, CAP improved the loss of hepatic lobular structure and significantly increased the duodenal villus length and ratio of villus length to crypt depth. CAP increased hepatic and colon interleukin-10 (IL-10) and decreased IL-6, IL-1β, and tumor necrosis factor (TNF-α) levels. CAP also increased hepatic catalase (CAT), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) expression, and decreased malondialdehyde (MDA) levels. CAP significantly increased the relative abundances of Mucispirillum, Helicobacter, Prevotellaceae-UCG-001, Colidextribacter, unclassified-f-Oscillospiraceae, and Odoribacter, some of which were closely related to hepatic and colonic immune and oxidative markers. CAP also decreased the overall content of short-chain fatty acids, except for propionic acid. Overall, CAP can regulate the colon microbiota and exert anti-inflammatory and antioxidant effects. Whether CAP exerts its anti-inflammatory and antioxidant effects by modulating the colonic microflora, mainly Mucispirillum spp. and Helicobacter spp., requires further investigation.

Calf intestines are colonized by rich and complex microbial communities, playing a crucial role in animal physiology, metabolism, nutrition, and immune function. In this study, we provide insight into the composition of fecal microbial bacteria and fungi, respectively, as well as the cross-kingdom interactions. We investigated the intestinal microbiota of different breeds of calves by characterizing the bacterial and fungal communities in the rectal feces of Holstein calves and German Simmental × Holstein cross F1 generation (GXH) using 16S rRNA and ITS amplicon sequencing techniques. PICRUSt2 (version 2.2.0) were used to determine microbial diversity and function and explore the reasons why Holstein calves are more susceptible to diarrhea. The results revealed no significant difference in the diversity of fecal microbiota among the groups (p > 0.05). We identified Firmicutes, Bacteroidetes, and Proteobacteria as the dominant bacterial phyla in the fecal bacterial communities of the two breeds of calves. Ascomycota and Basidiomycota play important roles in the fungal community but differ in relative abundance. Bacteroides was the dominant genus at the group level for calf fecal microbiota in both breeds. The relative abundance of Prevotella, Escherichia-Shigella, Peptostreptococcus, and Butyricicoccus was higher in Holstein calves, and the relative abundance of Faecalibacterium, Megamonas, Butyricicoccus, and Alloprevotella was lower than GXH group. Aspergillus and Cladosporium were the dominating genera of fecal fungi in both groups of calves. LEfSe analysis revealed 33 different bacteria and 23 different fungi between the two groups, with more differential strains found in GXH. In addition, the feces fungi-bacteria interkingdom interactions varied among breeds. Thus, the composition and structure of bacterial and fungal communities in calf feces varied by breed, indicating a potential association between breed and microbial communities. We also found differences in the network between bacterial–fungal kingdoms. We explain the reasons for Holstein calves being more prone to diarrhea. This indicated that breed makes differences in calf diarrhea rates by influencing gut microbial composition and interactions.

This study evaluated the inhibitory activity of quercetin at sub-inhibitory concentrations on quorum-sensing (QS) molecules in vitro and the effects of dietary supplementation with quercetin (for 24 consecutive days) on enterotoxigenic Escherichia coli (ETEC)-induced inflammatory and oxidative stress responses in weaned piglets. The piglets were fed one of three diets: the basal diet (Con), ETEC challenge (K88) after the basal diet, or ETEC challenge (quercetin + K88) after the basal diet supplemented with 0.2% quercetin. In vitro experiments revealed that 5 mg/mL quercetin exhibited the strongest QS inhibitory activity and reduced pigment production by Chromobacterium violaceum ATCC12472 by 67.70%. In vivo experiments revealed that quercetin + K88 significantly increased immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) levels in the serum, ileum mucosa, and colon mucosa; increased glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) levels in the serum, liver, and colon mucosa; and decreased cluster of differentiation 3 (CD3) and cluster of differentiation 8 (CD8)activity in the serum compared with K88 alone. Quercetin + K88 significantly alleviated pathological damage to the liver and spleen and upregulated antioxidant genes (nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1(HO-1), CAT, SOD, and glutathione s-transferase (GST)). Inducible nitric oxide synthase (iNOS) and kelch-like ech-associated protein 1 (Keap1), which cause oxidative damage to the liver and spleen, were significantly downregulated. The acetic acid content in the cecum was significantly increased, and the E. coli count and QS signal molecule autoinducer-2 (AI-2) yield were significantly reduced. In conclusion, 0.2% dietary quercetin can alleviate ETEC-induced inflammation and oxidative stress in weaned piglets.

Early weaning disrupts gut microbiota homeostasis and increases oxidative stress and inflammation in calves, thus negatively affecting their growth performance and health. Resveratrol is a polyphenol with antioxidant and anti-inflammatory properties that modulates gut microbiota and metabolites. In the present study, we investigated the effects of resveratrol on growth performance, immune function, antioxidant capacity, gut microbiota, and metabolic pathways in early-weaning calves. Thirty-six newborn Simmental × Holstein F₁ generation female calves were randomly assigned to one of 3 treatment groups: conventional weaning at 63 d of age (CON), early weaning at 49 d of age (EW), or early weaning at 49 d of age with 2 g/d resveratrol supplementation from d 7 to d 49 (EWR). The results revealed that the final BW, ADG, and feed efficiency were greater in the EWR group than in the CON group, and diarrhea incidence was significantly reduced. The EWR treatment decreased the concentrations of the proinflammatory cytokine IL-1β and the oxidative damage product malondialdehyde. Meanwhile, resveratrol supplementation increased the anti-inflammatory cytokine IL-4, catalase, and the total antioxidant capacity in early-weaning calves, which were not significantly different from CON group. In addition, EWR increased the abundance of Parabacteroides, Eubacterium_coprostanoligenes_group, Christensenella, and Ruminococcaceae, as well as increased concentration of butyric acid, valeric acid, isobutyric acid, isovaleric acid, and total branched short-chain fatty acids. Metabolomic analysis revealed that resveratrol significantly enhanced the tryptophan metabolic pathway. Correlation analysis suggested that Parabacteroides was closely related to the modulatory effects of resveratrol in early-weaning calves through its involvement in tryptophan metabolism. In conclusion, dietary resveratrol supplementation improves growth performance and reduces diarrhea in early-weaning calves by alleviating inflammation and oxidative stress, modulating gut microbiota, and enhancing microbial tryptophan metabolism.

Salvia sclarea L. extract contains various bioactive components such as flavonoids and fatty acids, exhibiting anti-inflammatory, antioxidant, and antibacterial properties. This study aimed to investigate the effects of Salvia sclarea L. extract on the gut microbiota and serum metabolome in lambs. Sixty 2-month-old Chinese Merino female lambs (body weight 20 ± 2 kg) were randomly assigned to five groups. The control (CK) group received the basal diet only, while the treatment groups received the basal diet supplemented with 0.04 mL/kg (CL1), 0.08 mL/kg (CL2), 0.12 mL/kg (CL3), and 0.16 mL/kg (CL4) of Salvia sclarea L. extract, respectively. The results showed that Firmicutes, Bacteroidetes, Spirochaetes, and Proteobacteria were identified as the dominant phyla across all groups (>90%). Compared with the CK group, CL1 and CL2 groups significantly reduced the relative abundance of Tenericutes (decreased by 38.2% and 32.9%, respectively, p < 0.05); the relative abundance of Patescibacteria in the CL1 group was significantly lower (decreased by 55.2%, p < 0.05). At the genus level, Ruminococcaceae constituted a substantial proportion, including Ruminococcaceae UCG-005, UCG-010, UCG-014, and NK4A214 group. STAMP analysis revealed that Klebsiella was significantly enriched in CL2, CL3, and CL4 groups compared to the CK group (p < 0.05). Correlation analysis between microbiota and immune indices showed that Christensenellaceae R-7 group was significantly negatively correlated with TNF-α (p < 0.05); Ruminococcaceae UCG-005 was significantly negatively correlated with IFN-γ (p < 0.05) and showed a negative correlation trend with immunoglobulins (IgA, IgG, IgM). Conversely, Ruminococcaceae UCG-014 was significantly positively correlated with IL-4 (p < 0.05) but showed a negative correlation trend with IgM. Untargeted metabolomics analysis identified 8, 18, 25, and 20 differential metabolites in CL1, CL2, CL3, and CL4 groups, respectively. Notably, 3-hydroxy-7-methoxyflavone and Gamma-Glu-Cys were significantly upregulated across all treatment groups. KEGG pathway enrichment analysis indicated that these differential metabolites were primarily involved in nucleotide metabolism, fatty acid biosynthesis, and oxidative stress-related pathways. Further Spearman correlation analysis revealed significant associations between gut microbiota and differential metabolites. Specifically, g_Klebsiella was significantly positively correlated with 3-Hydroxycapric acid and 3-hydroxy-7-methoxyflavone (p < 0.05). In conclusion, Salvia sclarea L. extract modulates host energy metabolism by regulating nucleotide metabolism and fatty acid biosynthesis, and enhances immune function by alleviating oxidative stress, through the remodeling of gut microbiota and serum metabolome.