Effect of dietary oridonin supplementation on growth performance, gut health, and immune response of broilers infected with Salmonella pullorum

Ingestion of Artemisia argyit essential oil combats Salmonella pullorum infections by altering gut microbiota composition in chicks

Pullorum disease, caused by Salmonella pullorum (S. pullorum), is a highly contagious illness affecting the poultry industry. Emerging evidence suggests that Artemisia argyit essential oil can influence the composition of gut microbes in the host, thereby promoting overall health. However, the specific mechanisms by which Artemisia argyit essential oil modulates gut microbiota to combat S. pullorum infection remains unclear. This study explored the effectiveness of various doses of Artemisia argyit essential oil in preventing S. pullorum infection in chicks. Our findings indicate that consuming this essential oil can mitigate the intestinal mucosal barrier damage and excessive inflammatory response caused by S. pullorum, as well as reverse the weight loss seen in infected chicks. Additionally, chicks that received faecal microbiota transplantation (FMT) from the gut microbiota of Artemisia argyit essential oil donors exhibited notable recovery from S. pullorum infections. This suggests that the observed protection may be linked to the modulation of gut microbiota. Furthermore, 16S rRNA sequencing revealed an increased abundance of Lactobacillus reuteri (L. reuteri), which along with the activation of Wnt/β-catenin pathways, played critical roles in the enhanced health of S. pullorum-infected chicks treated with Artemisia argyit essential oil. In summary, these findings highlight that the dietary inclusion of Artemisia argyit essential oil promotes the intestinal enrichment of L. reuteri, offering a promising strategy for the treatment and prevention of pullorum disease in chicks.

Gallnut tannic acid alleviates gut damage induced by Salmonella pullorum in broilers by enhancing barrier function and modulating microbiota

Pullorum disease (PD) is a bacterial infection caused by Salmonella pullorum (S. pullorum) that affects poultry. It is highly infectious and often fatal. Antibiotics are currently the mainstay of prophylactic and therapeutic treatments for PD, but their use can lead to the development of resistance in pathogenic bacteria and disruption of the host's intestinal flora. We added neomycin sulfate and different doses of tannic acid (TA) to the drinking water of chicks at 3 days of age and infected them with PD by intraperitoneal injection of S. pullorum at 9 days of age. We analyzed intestinal histopathological changes and the expression of immune-related genes and proteins by using the plate smear method, histological staining, real-time fluorescence quantitative PCR, ELISA kits, and 16S rRNA Analysis of intestinal flora. The results demonstrate that S. pullorum induces alterations in the immune status and impairs the functionality of the liver and intestinal barrier. We found that tannic acid significantly ameliorated S. pullorum-induced liver and intestinal damage, protected the intestinal physical and chemical barriers, restored the intestinal immune barrier function, and regulated the intestinal flora. Our results showed that TA has good anti-diarrhoeal, growth-promoting, immune-regulating, intestinal barrier-protecting and intestinal flora-balancing effects, and the best effect was achieved at an additive dose of 0.2%.

Effect of glutamine on the systemic innate immune response in broiler chickens challenged with Salmonella pullorum

BACKGROUND

The objective of this study was to evaluate the effects of glutamine on the growth performance and systemic innate immune response in broiler chickens challenged with Salmonella pullorum. A total of 600 one-day-old Arbor Acres broiler chickens were assigned randomly to 6 dietary treatments with 10 replicates for a 21-day feeding experiment. The experimental treatments were as follows: the control treatment (birds fed the basal diet), the Gln1 treatment, and the Gln 2 treatment (birds fed the basal diet supplemented with 0.5%, and 1.0% Glutamine, respectively). At 3 d of age, half of the birds from each treatment were challenged oral gavage with 2.0 × 104 CFU/mL of S. pullorum suspension (1.0 mL per bird) or an equivalent amount of sterile saline alone, which served as a control.

RESULTS

The results showed that S. pullorum infection had adverse effects on the average daily feed intake, average daily gain, and feed conversion ratio of broiler chickens compared with those of the CON treatment on d 7, decreased the spleen and bursa of fabricius relative weights (except on d 21), serum immunoglobulin A (IgA),immunoglobulin G (IgG), and immunoglobulin M (IgM) concentrations, and spleen melanoma differentiation-associated gene 5 (MDA5) and laboratory of genetics and physiology gene 2 (LGP2) mRNA expression levels, and increased the mRNA expression levels of spleen Nodinitib-1 (NOD1), Toll-like receptors 2,4 (TLR2, TLR4), DNA-dependent activator of IFN-regulatory factors (DAI), mitochondrial antiviral-signaling protein (MAVS), P50, P65, and RelB on d 4, 7, 14, and 21. Supplementation with Gln improved the relative weights of the spleen and bursa of Fabricius (except on d 21), increased the serum IgA, IgG, and IgM concentrations and the mRNA expression levels of spleen MDA5 and LGP2, and decreased the mRNA expression levels of spleen NOD1, TLR2, TLR4, DAI, MAVS, P50, P65, and RelB of S. pullorum-challenged broiler chickens.

CONCLUSION

These results indicate that Gln might stimulate the systemic innate immune responses of the spleen in broiler chickens challenged with S. pullorum.

Oridonin Inhibits Mycobacterium marinum Infection-Induced Oxidative Stress In Vitro and In Vivo

Prior to the COVID-19 pandemic, tuberculosis (TB) was the leading cause of death globally attributable to a single infectious agent, ranking higher than HIV/AIDS. Consequently, TB remains an urgent public health crisis worldwide. Oridonin (7a,20-Epoxy-1a,6b,7,14-tetrahydroxy-Kaur-16-en-15-one Isodonol, C₂₀H₂₈O₆, Ori), derived from the Rabdosia Rrubescens plant, is a natural compound that exhibits antioxidant, anti-inflammatory, and antibacterial properties. Our objective was to investigate whether Ori's antioxidant and antibacterial effects could be effective against the infection Mycobacterium marinum (Mm)-infected cells and zebrafish. We observed that Ori treatment significantly impeded Mm infection in lung epithelial cells, while also suppressing inflammatory response and oxidative stress in Mm-infected macrophages. Further investigation revealed that Ori supplementation inhibited the proliferation of Mm in zebrafish, as well as reducing oxidative stress levels in infected zebrafish. Additionally, Ori promoted the expression of NRF2/HO-1/NQO-1 and activated the AKT/AMPK-α1/GSK-3β signaling pathway, which are both associated with anti-inflammatory and antioxidant effects. In summary, our results demonstrate that Ori exerts inhibitory effects on Mm infection and proliferation in cells and zebrafish, respectively. Additionally, Ori regulates oxidative stress by modulating the NRF2/HO-1/NQO-1 and AKT/AMPK-α1/GSK-3β signaling pathways.

Protective effect and possible mechanism of arctiin on broilers challenged by Salmonella pullorum

This study was aimed to investigate the effects of dietary arctiin (ARC) supplementation (100, 200, and 400 mg/kg) on the growth performance and immune response of broilers after a Salmonella pullorum (S. pullorum) challenge, and we conducted in vitro antibacterial test to explore the bacteriostatic mechanism of ARC. The in vivo trial was randomly assigned to six groups: noninfected control (NC) group and positive control (PC) group received a basal diet; TET group, received a basal diet supplemented with 100 mg/kg chlortetracycline; ARC100, ARC200, and ARC400 groups received a basal diet containing 100, 200, and 400 mg/kg ARC, respectively. From days 14 to 16, all birds (except the NC group) were infected with 1 mL (1 × 108 CFU per mL) fresh S. pullorum culture by oral gavage per day. In vivo results showed that dietary supplementation of 200 mg/kg ARC significantly increased average daily gain (P < 0.05) and decreased feed-to-gain ratio of broilers vs. the PC group during days 15 to 28 after being challenged with S. pullorum (P < 0.05). The jejunal crypt depth (CD) was decreased by supplementing 100 or 200 mg/kg ARC in diets compared with PC birds at day 19 (P < 0.05). The jejunal villi height (VH) was increased by supplementing 100, 200, or 400 mg/kg ARC in diets compared with PC birds at day 28 (P < 0.05). Besides, dietary supplementation of 200 mg/kg ARC increased the jejunal VH to CD ratio than the PC group both at days 19 and 28 (P < 0.05). Notably, the broilers had lower serum lipopolysaccharide and diamine oxidase levels in the ARC100 and ARC200 groups at day 28 than those in the PC group (P < 0.05). Furthermore, in comparison to PC birds, the birds in ARC groups (100, 200, and 400 mg/kg) had higher serum contents of IgM and IL-10, and the birds in the ARC200 group had higher serum contents of IgA at day 19 (P < 0.05). At day 28, the birds in ARC groups (100, 200, and 400 mg/kg) had lower serum contents of IL-8, and the birds in the ARC200 group had lower serum contents of IFN-γ compared with PC birds (P < 0.05). The in vitro experiment showed that ARC significantly inhibited the biofilm formation and adhesion of S. pullorum (P < 0.05). Metabonomics analysis revealed that ARC can restrain the formation of the biofilm by affecting a variety of metabolic pathways of S. pullorum. Therefore, dietary supplementation of 200 mg/kg ARC might be a potential way to substitute antibiotics to control S. pullorum infection in broilers.

Investigation of the Potential of Heterophil/Lymphocyte Ratio as a Biomarker to Predict Colonization Resistance and Inflammatory Response to Salmonella enteritidis Infection in Chicken

Salmonella causes significant economic loss to the poultry industry and represents a real threat to human health. The region of difference 21 (ROD21) pathogenicity island removal is a genetic mechanism by which Salmonellaenteritidis (SE) invades the intestinal epithelium and induces systemic infection in mice. The heterophil/lymphocyte (H/L) ratio reflects the chicken’s robustness and immune system status. The H/L ratio is considered a disease resistance trait, and it could be used as a marker for selecting Salmonella resistance in live chickens. However, the association of the H/L ratio with Salmonella resistance and the inflammatory response remains to be elucidated. Moreover, the kinetics of ROD21 excision in the intestine and immune organs of chickens is unknown. Therefore, this study aimed to investigate the bacterial load, the ROD21 excision, the IL-1β, IL-8, and INF-γ blood serum concentration kinetics, and the association with the H/L ratio in chicken at 1, 3, 7, and 21 days post-SE infection. The results showed a significant correlation between the H/L ratio and the bacterial load in the ileum and caecum at 7 dpi. The ROD21 pathogenicity island absolute and relative excision in the caecum were positively correlated at 1 dpi but negatively correlated at 7 dpi with the H/L ratio. However, in the liver, we found the opposite tendency. The association of the H/L ratio with IL-1β, IL-8, and INF-γ blood serum concentrations showed that a low H/L ratio is correlated with increased IL-1β and INF-γ at 21 dpi. This study confirmed that the H/L ratio is associated with robustness and Salmonella-resistance in chicken. The methodology used in this study can separate individuals into susceptible and resistant and can help in the selection and breeding of Salmonella-resistant chickens.

Oridonin Alters Hepatic Urea Cycle via Gut Microbiota and Protects against Acetaminophen-Induced Liver Injury

Acetaminophen (APAP) hepatotoxicity is the leading cause of acute liver failure in the western world. Oridonin (OD), which is the major active ingredient of the traditional Chinese medicine Rabdosia rubescens, reportedly exerts anti-inflammatory and antioxidative effects. Here, we first find that OD protects against APAP-induced hepatotoxicity. The results of hepatic tissue-associated RNA-seq and metabolomics showed that the protective effects of OD were dependent upon urea cycle regulation. And such regulation of OD is gut microbiota partly dependent, as demonstrated by fecal microbiota transplantation (FMT). Furthermore, using 16S rRNA sequencing, we determined that OD significantly enriched intestinal Bacteroides vulgatus, which activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway to regulate redox homeostasis against APAP by urea cycle. In conclusion, our study suggests that the Bacteroides vulgatus-urea cycle-Nrf2 axis may be a potential target for reducing APAP-induced liver injury, which is altered by OD.

Supplemental magnolol or honokiol attenuates adverse effects in broilers infected with Salmonella pullorum by modulating mucosal gene expression and the gut microbiota

BACKGROUND

Salmonella pullorum is one of the most harmful pathogens to avian species. Magnolol and honokiol, natural compounds extracted from Magnolia officinalis, exerts anti-inflammatory, anti-oxidant and antibacterial activities. This study was conducted to evaluate the effects of dietary supplemental magnolol and honokiol in broilers infected with S. pullorum. A total of 360 one-day-old broilers were selected and randomly divided into four groups with six replicates: the negative control group (CTL), S. pullorum-infected group (SP), and the S. pullorum-infected group supplemented with 300 mg/kg honokiol (SPH) or magnolol (SPM).

RESULTS

The results showed that challenging with S. pullorum impaired growth performance in broilers, as indicated by the observed decreases in body weight (P < 0.05) and average daily gains (P < 0.05), along with increased spleen (P < 0.01) and bursa of Fabricus weights (P < 0.05), serum globulin contents, and the decreased intestine villus height and villus/crypt ratios (P < 0.05). Notably, supplemental magnolol and honokiol attenuated these adverse changes, and the effects of magnolol were better than those of honokiol. Therefore, we performed RNA-Seq in ileum tissues and 16S rRNA gene sequencing of ileum bacteria. Our analysis revealed that magnolol increased the α-diversity (observed species, Chao1, ACE, and PD whole tree) and β-diversity of the ileum bacteria (P < 0.05). In addition, magnolol supplementation increased the abundance of Lactobacillus (P < 0.01) and decreased unidentified Cyanobacteria (P < 0.05) both at d 14 and d 21. Further study confirmed that differentially expressed genes induced by magnolol and honokiol supplementation enriched in cytokine-cytokine receptor interactions, in the intestinal immune network for IgA production, and in the cell adhesion molecule pathways.

CONCLUSIONS

Supplemental magnolol and honokiol alleviated S. pullorum-induced impairments in growth performance, and the effect of magnolol was better than that of honokiol, which could be partially due to magnolol's ability to improve the intestinal microbial and mucosal barrier.

Oridonin: A Review of Its Pharmacology, Pharmacokinetics and Toxicity

Oridonin, as a natural terpenoids found in traditional Chinese herbal medicine Isodon rubescens (Hemsl.) H.Hara, is widely present in numerous Chinese medicine preparations. The purpose of this review focuses on providing the latest and comprehensive information on the pharmacology, pharmacokinetics and toxicity of oridonin, to excavate the therapeutic potential and explore promising ways to balance toxicity and efficacy of this natural compound. Information concerning oridonin was systematically collected from the authoritative internet database of PubMed, Elsevier, Web of Science, Wiley Online Library and Europe PMC applying a combination of keywords involving "pharmacology," "pharmacokinetics," and "toxicology". New evidence shows that oridonin possesses a wide range of pharmacological properties, including anticancer, anti-inflammatory, hepatorenal activities as well as cardioprotective protective activities and so on. Although significant advancement has been witnessed in this field, some basic and intricate issues still exist such as the specific mechanism of oridonin against related diseases not being clear. Moreover, several lines of evidence indicated that oridonin may exhibit adverse effects, even toxicity under specific circumstances, which sparked intense debate and concern about security of oridonin. Based on the current progress, future research directions should emphasize on 1) investigating the interrelationship between concentration and pharmacological effects as well as toxicity, 2) reducing pharmacological toxicity, and 3) modifying the structure of oridonin-one of the pivotal approaches to strengthen pharmacological activity and bioavailability. We hope that this review can provide some inspiration for the research of oridonin in the future.

Effects of a probiotic-fermented herbal blend on the growth performance, intestinal flora and immune function of chicks infected with Salmonella pullorum

Salmonella pullorum is a highly pathogenic bacteria in poultry industry. However, antibiotics were restricted in many countries because of the increasing risk of antibiotic resistance, Therefore, an environmental friendly and effective alternative strives to be developed. This study investigated the benefit of a probiotic-fermented herbal blend on the growth performance and gut microbiota of newborn broilers infected with S. pullorum. A total of 120 one-day-old dwarf male chicks were randomly allotted to 4 treatment groups, each including 5 replicates of 6 chicks: negative control (NC), positive control (PC), herbal blend (HB), and probiotic-fermented herbal blend (PF). All birds (n = 90), except for those in the NC, were infected with S. pullorum (1.69 × 108 CFU) on day 1. On day 11, body weight (BW), mortality, tissue pathology, cecal colony counts, immune organ indices, cecal mucosa secretory immunoglobulin A (sIgA) concentrations, and cecal cytokine mRNA expression levels were investigated. No mortality was observed after the PF treatment, and less pathological condition was in the ileum, cecum, and liver of HB and PF. BW, average daily gain and average daily feed intake were significant higher in the HB group compared to the PC and were the highest in the PF (P < 0.05). HB treatment significantly increased cecal populations of Lactobacilli, and decreased cecal populations of Escherichia coli and Salmonella, but results were more pronounced in the PF group (P < 0.05). Both HB and PF treatments increased cecal mucosa sIgA compared with the PC (P < 0.05). Tumor necrosis factor alpha and interferon gamma were lowest (P < 0.05) and interleukin 4 was the highest (P < 0.05) in PF, which exhibited similar levels to the NC group. PF treatment significantly improved the development of the thymus and bursa in S. pullorum-infected chicks. In conclusion, PF treatment prevented death, improved growth performance, regulated intestinal flora and enhanced immune ability of in S. pullorum-infected with chicks.

Effect of Dietary Tryptophan on Growth, Intestinal Microbiota, and Intestinal Gene Expression in an Improved Triploid Crucian Carp

Tryptophan (Trp) has received increasing attention in the maintenance of intestinal function. In this study, improved triploid crucian carp (ITCC) fed diets containing 6.35 g kg⁻¹ Trp had higher average daily gain (ADG) and improved villus height (VH) and crypt depth (CD) in the intestine compared to the control group. To elucidate the potential mechanisms, we used RNA sequencing (RNA-seq) to investigate changes in the intestinal transcriptome and 16S rRNA gene sequencing to measure the intestinal microbiota in response to 6.35 g kg⁻¹ Trp feeding in ITCC. Dietary Trp altered intestinal gene expression involved in nutrient transport and metabolism. Differentially expressed transcripts (DETs) were highly enriched in key pathways containing protein digestion and absorption and the AMPK signaling pathway. 16S rRNA sequencing showed that 6.35 g kg⁻¹ Trp significantly increased the abundance of the genus Cetobacterium, and the Firmicutes/Bacteroidetes ratio at the phylum level (P < 0.05). In addition, bacterial richness indices (Simpson index) significantly increased (P < 0.05) community evenness in response to 6.35 g kg⁻¹ Trp. In conclusion, appropriate dietary Trp improves the growth performance, and influences the intestinal flora of ITCC. This study might be helpful to guide the supply of dietary exogenous Trp in ITCC breeding.

Enrofloxacin Shifts Intestinal Microbiota and Metabolic Profiling and Hinders Recovery from Salmonella enterica subsp. enterica Serovar Typhimurium Infection in Neonatal Chickens

Enrofloxacin is an important antibiotic used for prevention and treatment of Salmonella infection in poultry in many countries. However, oral administration of enrofloxacin may lead to the alterations in the microbiota and metabolome in the chicken intestine, thereby reducing colonization resistance to the Salmonella infection. To study the effect of enrofloxacin on Salmonella in the chicken cecum, we used different concentrations of enrofloxacin to feed 1-day-old chickens, followed by oral challenge with Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium). We then explored the distribution pattern of S. Typhimurium in cecum contents in vivo and analyzed the microbial community structure of cecum contents using microbial 16S amplicon sequencing. Untargeted metabolomics was used to explore the gut metabolome on day 14. Faecalibacterium and Anaerostipes, which are closely related to the chicken intestinal metabolome, were screened using a multi-omics technique. The abundance of S. Typhimurium was significantly higher in the enrofloxacin-treated group than in the untreated group, and S. Typhimurium persisted longer. Moreover, the cecal colony structures of the three groups exhibited different characteristics, with Lactobacillus reaching its highest abundance on day 21. Notably, S. Typhimurium infection is known to affect the fecal metabolome of chickens differently. Thus, our results suggested that enrofloxacin and Salmonella infections completely altered the intestinal microbiota and metabolism of chickens.IMPORTANCE In this study, we examined the effects of S. Typhimurium infection and enrofloxacin treatment on the microbiota and metabolite synthesis in chicken cecum, in order to identify target metabolites that may promote S. Typhimurium colonization and aggravate inflammation and to evaluate the important microbiota that may be associated with these metabolites. Our findings may facilitate the use of antibiotics to prevent S. Typhimurium infection.

Effects of a probiotic on the growth performance, intestinal flora, and immune function of chicks infected with Salmonella pullorum

This study investigated the effects of a Lactobacillus paracasei KL1 and Lactobacillus plantarum subsp. plantarum Zhang-LL mixed probiotic on Salmonella-caused pullorosis in chicks. A total of 120 1-day-old Nongda no.3 dwarf chicks were randomly assigned to 4 treatments, with 6 replicates of 5 birds each. The treatments were blank group, Salmonella pullorum-infected group, probiotic treatment group, and probiotic prevention (PP) group. All birds (n = 90) except those in the blank group were infected with S. pullorum on day 4. On day 14, the BW, ADG, mortality, pathology of tissue, cecum colony count, immune organ indices, cecal mucosa secretory IgA, and cytokines were investigated. The results showed that the chicks infected with S. pullorum were depressed and their BW reduced. The PP group had the highest ADG and lowest mortality rate (0%), whereas the S. pullorum-infected group had 37.50% mortality rate and lowest ADG. Pathologic sections showed that the probiotic treatment group had minor lesions but the PP group had no lesions in the ileum, cecum, and liver. Cecal Lactobacillus counts was the highest (P < 0.05) and Salmonella and Escherichia coli counts were the lowest (P < 0.05) in the PP group; Compared with the S. pullorum-infected group, the thymus and spleen indexes of the probiotic treatment group increased (P < 0.05), but they were unaffected (P > 0.05) in the bursa of Fabricius, whereas in the PP group, all the immune organs were increased (P < 0.05).Cecal mucosa secretory IgA and IL-4 were the highest (P < 0.05) and tumor necrosis factor α and interferon gamma were the lowest (P < 0.05) in the PP group; In summary, the Lactobacillus KL1 and L. plantarum Zhang-LL mixed probiotic effectively reduced the mortality of pullorosis in chicks, promoted the growth performance, regulated the balance of the intestinal flora, improved the immune function, resisted pullorosis disease, completely prevented chicks from pullorosis after infection, and reduced economy loss in the poultry industry.

Transcriptome Analysis of the Cecal Tonsil of Jingxing Yellow Chickens Revealed the Mechanism of Differential Resistance to Salmonella

Salmonella is one of the most common food-borne pathogens. It can be transmitted between chickens, as well as to people by contaminated poultry products. In our study, we distinguished chickens with different resistances mainly based on bacterial loads. We compared the cecal tonsil transcriptomes between the susceptible and resistant chickens after Salmonella infection, aiming to identify the crucial genes participating in the antibacterial activity in the cecal tonsil. A total of 3214 differentially expressed genes (DEGs), including 2092 upregulated and 1122 downregulated genes, were identified between the two groups (fold change ≥ 2.0, padj < 0.05). Many DEGs were mainly involved in the regulation of two biological processes: crosstalk between the cecal tonsil epithelium and pathogenic bacteria, such as focal adhesion, extracellular-matrix-receptor interaction, and regulation of the actin cytoskeleton and host immune response including the cytokine-receptor interaction. In particular, the challenged resistant birds exhibited strong activation of the intestinal immune network for IgA production, which perhaps contributed to the resistance to Salmonella infection. These findings give insight into the mRNA profile of the cecal tonsil between the two groups after initial Salmonella stimulation, which may extend the known complexity of molecular mechanisms in chicken immune response to Salmonella.

Supplemental Plant Extracts From Flos lonicerae in Combination With Baikal skullcap Attenuate Intestinal Disruption and Modulate Gut Microbiota in Laying Hens Challenged by Salmonella pullorum

Dietary inclusions of baicalin and chlorogenic acid were beneficial for intestinal health in pigs. Nevertheless, it is unknown whether these plant-derived products had protection for intestine against bacterial challenge in chickens. This study was aimed at evaluating the potential mitigating effects of plant extracts (PE) from Flos lonicerae combined with Baikal skullcap (the active components are chlorogenic acid and baicalin) on intestinal disruption and dysbacteriosis induced by Salmonella pullorum in laying hens. A total of 216 41-week-old layers were randomly divided into 3 groups (6 replicates per group): negative control (NC), S. pullorum-infected positive control (PC), and the S. pullorum-infected group with supplementation of PE at 1000 mg/kg. All birds except those in NC were challenged with S. pullorum at the end of 4 weeks of the experiment. S. pullorum challenge impaired (P < 0.05) the production performance (egg production, feed intake, and feed efficiency) of laying hens, increased (P < 0.05) serum endotoxin content and frequency of Salmonella-positive organs, as well as up-regulated (P < 0.05) ileal expression of pro-inflammatory cytokines including IFNG, TNFA, IL8, and IL1B, whereas PE addition reversed (P < 0.05) these changes and increased (P < 0.05) ileal IL10 expression. Supplemental PE moderated ileal microbiota dysbiosis in challenged birds, characterized by a reduced abundance of Firmicutes along with increased abundances of Bacteroidetes (Bacteroides), Deferribacteres and several butyrate-producers such as Prevotellaceae, Faecalibacterium, Blautia, Butyricicoccus, Lachnoclostridium, and Olsenella, which may assist with energy harvesting and boost anti-inflammatory capacity of host. The decreased abundance of Firmicutes with the increased abundance of Bacteroidetes caused by PE addition had positive correlations with the decreased expression of ileal pro-inflammatory cytokines. The increased abundances of Bacteroidetes (Bacteroides) and Prevotellaceae following PE addition were also positively correlated with the improvement of performance (egg production and feed intake) of laying hens. Collectively, supplemental PE from Flos lonicerae in combination with Baikal skullcap alleviated S. pullorum-induced intestinal disruption and performance impairment in laying hens, which could be at least partially responsible by the modulation of gut microbial composition.