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The effect of baicalin methyl ester (BME) on the regulation of mice intestinal barrier in the inflammatory response was studied in vivo and in vitro. Thirty six C57/BL mice were randomly divided into six groups (n = 6): control group; LPS group (LPS 3.5 mg/kg given intraperitoneal [ip] on day 7 of the study only), PBS group, and three BME groups (low: 50 mg/kg; medium: 100 mg/kg; high: 200 mg/kg) orally dosed with BME for 7d and LPS ip on day 7. All mice were sacrificed on day 8, and jejunum tissue collected for histopathology (H&E and PAS staining), protein expression of pro-inflammatory factors (TNF-α, IL-6, IL-8, IFN-γ) by ELISA, and intestinal tight junction proteins (ZO-1, occludin, claudin-1 and claudin-4) by Western Blot. Compared with the control group, LPS significantly increased the serum cytokines DAO (p < 0.01) and DLA (p < 0.01), upregulated the expression of pro-inflammatory factors, MLCK proteins (p

Breast infection is the primary etiology of mastitis in dairy cows, leading to a reduction in the quality of dairy products and resulting in substantial economic losses for animal husbandry. Although antibiotic treatment can eliminate the pathogenic microorganisms that induce mastitis, it cannot repair the inflammatory damage of mammary epithelial cells and blood milk barrier. Mas1 is a G protein-coupled receptor, and its role in lipopolysaccharide (LPS) -induced inflammatory injury to mammary epithelial cells has not been studied. LPS treatment of EpH4 EV cells led to a significant downregulation of Mas1 transcript levels, which attracted our great interest, suggesting that Mas1 may be an important target for the treatment of mastitis. Therefore, this study intends to verify the role of Mas1 in the inflammatory injury of EpH4 EV cells by gene overexpression technology and gene silencing technology. The findings demonstrated that the overexpression of the Mas1 gene effectively reversed the activation of the nuclear factor-κB/mitogen-activated protein kinase (NF-κB/MAPK) signaling pathways induced by LPS, while also suppressing the upregulation of pro-inflammatory mediators. Furthermore, overexpression of the Mas1 gene reversed the downregulation of zonula occludens 1 (ZO-1), Occludin, and Claudin-3 caused by LPS, suggesting that Mas1 could promote to repair the blood-milk barrier. However, the silencing of the Mas1 gene using siRNA resulted in a contrasting effect. These results indicated that Mas1 alleviated the inflammatory injury of mammary epithelial cells induced by LPS.

【Objective】The key target genes related to late pregnancy, lactation and fecundity in muscle tissue of Holstein cattle were screened, with a view to providing a theoretical basis for further study of gene function.【Method】The dataset GSE62159 from the GEO database on gene expression and fecundity in the muscle of Holstein cattles during late pregnancy, early lactation, and mid lactation were selected. The weighted gene co-expression network analysis (WGCNA) method was used for gene co- expression analysis, and the obtained modules were associated with late pregnancy, mid lactation and fecundity traits. The genes with connectivity in the top 30 of each module were selected as the Hub genes. The module was analyzed by protein-protein interaction (PPI) network with String website. The gene with the top 30 node connection degree value in PPI network was selected as the core gene, and intersected with Hub gene to obtain the key target genes related to different physiological periods and fecundity in the muscle.【Result】A total of 13 modules were obtained, of which the Green and Blue modules were related to late pregnancy and mid-lactation periods respectively, and the Magenta module was related to fecundity. The functional enrichment analysis of genes in each target module showed that the main functions of genes related to the late pregnancy were substance metabolism, energy metabolism, protein synthesis and secretion, body response to oxidative stress and neurodegeneration; the functions of genes related to mid-lactation included maintenance of stem cell population, protein synthesis and secretion, antigen processing and presentation and occurrence of many diseases; while those related to fecundity included angiogenesis, intrauterine embryonic development and actin filament binding, etc. Three key genes related to late pregnancy, one key gene related to mid-lactation and eight key genes related to fecundity were screened in the muscle of Holstein cattle.【Conclusion】The genes related to and late pregnancy in the muscle of Holstein cattle were identified as EIF5A, ACO2 and EEF1G, and the gene related to mid-lactation as EIF4A2, and the genes related to fecundity as ITGB1, MYH9, TLN1, CAV1, COL4A1, COL4A2, FLNA and HSPG2.

Siraitia grosvenorii has anti-inflammatory, antioxidant, and immune-regulating effects, while macrophages play an important role in reducing inflammation. However, it is still unclear whether Siraitia grosvenorii extract (SGE) is effective in reducing inflammation by regulating macrophages. This study investigated the regulatory effect of SGE on macrophage polarization in a lipopolysaccharide (LPS)-induced intestinal inflammation model after establishing the model in vitro and in vivo. The results from the in vivo model showed that, compared with the LPS group, SGE significantly improved ileal morphology, restored the ileal mucosal barrier, and reduced intestinal and systemic inflammation by increasing CD206 and reducing iNOS proteins. In the in vitro model, compared with the LPS group, SGE significantly reduced the expression of iNOS protein and cytokines (TNF-α, IL-1β, and IFN-γ) while significantly increasing the protein expression of CD206 in RAW264.7 cells. In conclusion, SGE can alleviate intestinal inflammation, protect the mucus barrier, and block the systemic immunosuppressive response by increasing M2 macrophages.

Inflammatory bowel disease (IBD) is becoming an increasingly serious health problem in humans and animals. Probiotics can inhibit the development of IBD. Due to the specificity of the strains, the function and mechanism of action of different strains are still unclear. Here, a DSS-induced colitis mouse model was utilized to investigate the ability and mechanism by which Lacticaseibacillus casei IB1 alleviates colitis. Treatment with L. casei IB1 improved DSS-induced colitis in mice, as indicated by increased body weight, colon length, and goblet cell numbers and decreased disease activity index (DAI), proinflammatory factor (TNF-α, IL-1β, and IL-6) levels, and histopathological scores after intake of IB1. IB1 supplementation also improved the expression of tight junction proteins and inhibited the activation of the MAPK and NF-κB signaling pathways to alleviate intestinal inflammation. In addition, IB1 rebalanced the intestinal microbial composition of colitis mice by increasing the abundance of Faecalibaculum and Alistipes and decreasing the abundance of Bacteroides and Escherichia_Shigella. In summary, L. casei IB1 showed great potential for relieving colitis by regulating the microbiota and restoring the epithelial barrier. It can be used as a potential probiotic for the prevention and treatment of UC in the future.

Goats, versatile creatures selectively bred for various purposes, have become pivotal in shaping the socioeconomic landscape, particularly in rural and economically challenged areas. Their remarkable ability to withstand and adapt to extreme heat has proven invaluable, allowing them to flourish and reproduce in even the harshest climates on Earth. Goat farming has emerged as a reliable and sustainable solution for securing food resources. However, despite its significance, the goat-producing industry has received less attention than other ruminants. Despite goats’ inherent resilience to heat, their productivity and reproductive performance suffer under high ambient temperatures, leading to heat stress. This presents a significant challenge for goat production, necessitating a comprehensive multidisciplinary approach to mitigating the adverse effects of heat stress. This review aims to explore the diverse impacts of heat stress on goats and propose effective measures to address the sector’s challenges. By understanding and addressing these issues, we can enhance the resilience and sustainability of goat farming, ensuring its continued contribution to food security and socioeconomic development.

Reproduction in goats is a highly complex and dynamic process of life regulation, involving coordinated regulation from various aspects such as central nervous system regulation, reproductive system development, oocyte maturation, and fertilized egg development. In recent years, researchers have identified numerous genes associated with goat reproductive performance through high-throughput sequencing, single-cell sequencing, gene knockout, and other techniques. However, there is still an urgent need to explore marker genes related to goat reproductive performance. In this study, a single-cell RNA sequencing dataset of oocytes (GSE136005) was obtained from the Gene Expression Omnibus (GEO) database. Weighted Gene Co-expression Network Analysis (WGCNA) was utilized to identify modules highly correlated with goat litter size. Through gene function enrichment analysis, it was found that genes within the modules were mainly enriched in adhesive junctions, cell cycle, and other signaling pathways. Additionally, the top 30 hub genes with the highest connectivity in WGCNA were identified. Subsequently, using Protein–Protein Interaction (PPI) network analysis, the top 30 genes with the highest connectivity within the modules were identified. The intersection of hub genes, key genes in the PPI network, and differentially expressed genes (DEGs) led to the identification of the RPL4 gene as a key marker gene associated with reproductive capacity in goat oocytes. Overall, our study reveals that the RPL4 gene in oocytes holds promise as a biological marker for assessing goat litter size, deepening our understanding of the regulatory mechanisms underlying goat reproductive performance.

Although numerous studies have shown that the hypothalamic–pituitary–adrenal axis plays a vital role in the response to environmental stress by mediating the production of a series of hormones, the mechanism underlying these effects has not been elucidated. This study used proteomics techniques to investigate the differentially expressed proteins (DEPs) in the pituitary glands of pigs and to elucidate the potential changes in the immune–neuroendocrine system under heat stress (HS). In total, 2517 peptides corresponding to 205 proteins were detected. A comparison of the expression patterns between HSs and healthy controls revealed 56 DEPs, of which 31 were upregulated and 25 were downregulated. Ingenuity pathway analysis (IPA) was used to reveal the subcellular characteristics, functional pathways, regulatory networks, and upstream regulators of the identified proteins. The results showed that these differentially expressed proteins were involved in intercellular communication, interactions, apoptosis, nervous system development, functions, abnormalities and other functions, and in the regulatory network. Moreover, the upstream regulators of the differentially expressed proteins were mainly transcriptional regulators, hormones, and cytokines. Thus, the functional network and pathway analyses could provide insights into the complexity and dynamics of HS–host interactions and may accelerate our understanding of the mechanisms underlying HS.

Exposure to vomitoxin (DON) can negatively impact the intestinal health of livestock and poultry, leading to compromised nutrient absorption and utilization, resulting in slowed growth and reduced production efficiency. In this study, we synthesized carbonated chitosan montmorillonite intercalation complexes (CCM) through solution precipitation. The successful formation of intercalation complexes was confirmed by examining functional groups and surface features using infrared spectroscopy and scanning electron microscopy. To assess the impact of CCM on DON-infected mice, we established an experimental mouse model of jejunal inflammation induced by DON infection. We analyzed the effects of CCM on blood biochemical and conventional indices, jejunal inflammatory factors, pathological changes, and the expression of proteins in the MAPK pathways in DON-infected mice. Our results indicate that CCM effectively mitigates the adverse effects of DON on growth performance, jejunal injury, and the inflammatory response in mice. CCM supplementation alleviated the negative effects of DON infection on growth performance and reduced intestinal inflammation in mice. Moreover, CCM supplementation successfully inhibited the activation of the mitogen-activated protein kinase (MAPK) signaling pathway induced by DON. These findings suggest that the mitigating effect of CCM on DON-induced inflammatory injury in the murine jejunum is closely linked to the regulation of the MAPK signaling pathway.

ABSTRACT: Goose astroviruses (GoAstVs) are causative agents that account for fatal infection of goslings characterized by visceral urate deposition, resulting in severe economic losses in major goose-producing regions in China since 2017. In this study, we sought to unravel the intrinsic properties associated with adaptation and evolution in the host environment of GoAstVs. Consistent results from phylogenetic analysis and correspondence analysis performed on the codon usage patterns (CUPs) reveal 2 clusters of GoAstVs, namely, GoAstV-1 and GoAstV-2. However, multiple similar compositional characteristics were found, despite the high divergence between GoAstV-1 and GoAstV-2. Studies on the base composition of GoAstVs reveal an A/U bias, indicating a compositional constraint, while natural selection prevailed in determining the CUPs in the virus genome based on our neutrality plot analysis, reflecting high adaptive pressure to fit the host environment. Codon adaptation index (CAI) analysis revealed a higher degree of fitness to the CUPs of the corresponding host for GoAstVs than avian influenza virus and betacoronaviruses, which may be a favorable factor contributing to the high pathogenicity and wide distribution of GoAstVs in goslings. In addition, GoAstVs were less adapted to ducks and chickens, with significantly lower CAI values than to geese, which may be a reason for the different prevalence of GoAstVs among these species. Extensive investigations on dinucleotide distribution revealed a significant suppression of the CpG and UpA motifs in the virus genome, which may facilitate adaptation to the host's innate immune system by evading surveillance. In addition, our study reported the trends of increasing fitness to the host's microenvironment for GoAstVs through increasing adaptation to host CUPs and ongoing reduction of CpG motifs in the virus genome. The present analysis deepens our understanding of the basic biology, pathogenesis, adaptation and evolutionary pattern of GoAstVs, and contributes to the development of novel antiviral strategies.

Abstract Background As a kind of flavonoid, baicalin (C21H18O11) is extracted from Scutellaria baicalensis Georgi, the extract of which can be added to animal feed in China. Objectives The present review will describe the current understanding of the pharmacological effects of baicalin in the regulation of inflammation, oxidative stress anti‐virus and anti‐tumour responses. Methods We highlight emerging literature that the application in livestock health and performance, the biological activities, the molecular mechanisms and the dosage forms of baicalin by analysing and summarising the main points of the cited literatures. Results It is found that baicalin can improve the functions of multiple physiological systems. Baicalin has a strong anti‐inflammatory effect by regulating TLR4‐NFκB‐MAPK signalling pathway; it also can reduce oxidative stress by regulating Nrf2–Keap1 pathway; it can inhabit many kinds of virus such as influenza virus, respiratory virus, hepacivirus and others; it can also inhibit the growth of tumour cells by blocking the cell cycle or inducing apoptosis; and new dosage forms such as cationic solid lipid nanoparticles, cyclodextrin inclusion complexes or nanocrystalline can be applied to improve the deficiency of baicalin. Conclusions In summary, these studies have elucidated a comprehensive report on the anti‐inflammatory, anti‐oxidant, anti‐virus and anti‐tumour of baicalin, these findings thus indicated that baicalin can be used effectively to the field of animal production in future when the appropriate dosage form is determined.

Abstract Background Infectious bovine rhinotracheitis (IBR) caused by bovine alphaherpesvirus 1 (BoHV-1) is one of the most important contagious diseases in bovine. This is one of the most common infectious disease of cattle. This has led to high economic losses in the cattle farming industry. BoHV-1 can potentially be transmitted via semen during natural or artificial insemination (AI). Therefore, testing methods for the early diagnosis of BoHV-1 infection are urgently needed for international trade of ruminant semen. In this study, we developed a novel droplet digital PCR (ddPCR) assay for the detection of BoHV-1 DNA in semen samples. Results The ddPCR results showed that the detection limit was 4.45 copies per reaction with high reproducibility. The established method was highly specific for BoHV-1 and did not show cross-reactivity with specify the organisms (BTV, BVDV, Brucella, M . bovis). The results of clinical sample testing showed that the positivity rate of ddPCR (87.8%) was higher than that of qPCR (84.1%). Conclusions The ddPCR assay showed good accuracy for mixed samples and could be a new added diagnostic tool for detecting BoHV-1.

The minor constituent found in Acanthus ilicifolius Linnaeus, 4-hydroxy-2 (3H) benzoxazolone alkaloid (HBOA), has a range of versatile applications. Herein, a quick and straightforward method for extracting HBOA from A. ilicifolius Linnaeus was proposed. HBOA was used as a template, whereas methacrylic acid, ethylene glycol dimethacrylate, and acetonitrile were used as functional monomers, cross-linkers, and porogens, respectively. Molecularly imprinted polymers (MIPs) were synthesized by precipitation polymerization, and their adsorption isotherms, dynamics, and selective binding ability were characterized and analyzed. The results showed that the adsorption amount of the template was 90.18 mg/g. The MIPs were used as solid-phase extraction fillers and actual sample extraction columns, with a linear range of 0–100 μg/L, average recovery of 78.50–101.12%, and a relative standard deviation of 1.20–3.26%. The HBOA concentrations in the roots, stems, and leaves were 1,226, 557, and 205 μg/g, respectively. In addition, MIP–SPE was successfully used in isolating and purifying HBOA from different parts of A. ilicifolius Linnaeus, indicating its effectiveness in extracting and determining HBOA in other herbs.

Echinococcosis is a parasitic disease caused by the metacestodes of Echinococcus spp. The disease has a long latent period and is largely underdiagnosed, partially because of the lack of effective early diagnostic approaches. Using liquid chromatography-mass spectrometry, we profiled the serum-derived extracellular vesicles (EVs) of E. multilocularis-infected mice and identified three parasite-origin proteins, thioredoxin peroxidase 1 (TPx-1), transitional endoplasmic reticulum ATPase (TER ATPase), and 14-3-3, being continuously released by the parasites into the sera during the infection via EVs. Using ELISA, both TPx-1 and TER ATPase were shown to have a good performance in diagnosis of experimental murine echinococcosis as early as 10 days post infection and of human echinococcosis compared with that of control. Moreover, TER ATPase and TPx-1 were further demonstrated to be suitable for evaluation of the prognosis of patients with treatment. The present study discovers the potential of TER ATPase and TPx-1 as promising diagnostic candidates for echinococcosis.

The pathological mechanisms of gastrointestinal disorders, including inflammatory bowel disease (IBD), in pigs are poorly understood. We report the induction of intestinal inflammation in heat-stressed (HS) pigs, fecal microbiota transplantation from pigs to mice, and explain the role of microorganisms in IBD. 24 adult pigs were subjected to HS (34 ± 1 °C; 75–85% relative humidity for 24h) while 24 control pigs (CP) were kept at 25 ± 3°C and the same humidity. Pigs were sacrificed on days 1, 7, 14, 21. Colonic content microbiome analyses were conducted. Pseudo-germ-free mice were fed by gavage with fecal microbiota from HS-pigs and CP to induce pig-like responses in mice. From 7 d, HS-pigs exhibited fever and diarrhea, and significantly lower colonic mucosal thickness, crypt depth/width, and goblet cell number. Compared with each control group, the concentration of cortisol in the peripheral blood of HS pigs gradually increased, significantly so on days 7, 14, and 21 (P < 0.01). While the concentration of LPS in HS pigs' peripheral blood was significantly higher on days 7, 14 (P < 0.01), and 21 (P < 0.05) compared with that of the control group. The colonic microbiome composition of HS-pigs was different to that of CP. By day 14, opportunistic pathogens (e.g., Campylobacterales) had increased in HS-pigs. The composition of the colonic microbiome in mice administered feces from HS-pigs was different from those receiving CP feces. Bacteroides were significantly diminished, Akkermansia were significantly increased, and intestinal damage and goblet cell numbers were higher in mice that received HS-pig feces. Moreover, we verified the relevance of differences in the microbiota of the colon among treatments. Heat stress promotes changes in gut microbiome composition, which can affect the colonic microbial structure of mice through fecal microbiota transplantation; the molecular mechanisms require further investigation. This study enhanced our understanding of stress-induced inflammation in the colon and the increase in diarrhea in mammals subjected to prolonged HS. Our results provide useful information for preventing or ameliorating deficits in pig production caused by prolonged exposure to high temperatures.

Baicalin is a natural plant extract with anti-inflammatory and anti-oxidant activities. However, the molecular mechanism of baicalin on oxidative stress in IPEC-J2 cells exposed to LPS remains to be unclear. In this study, LPS stimulation significantly increased Toll-like receptor 4, tumor necrosis factor-α, and interleukins (IL-6 and IL-1β) expression in IPEC-J2 cells, and it activated the nuclear factor (NF-κB) expression. While, baicalin exerted anti-inflammatory effects by inhibiting NF-κB signaling pathway. LPS stimulation significantly increased the levels of the oxidative stress marker MDA, inhibited the anti-oxidant enzymes catalase and superoxide dismutase, which were all reversed by baicalin pre-treatment. It was found that baicalin treatment activated the nuclear import of nuclear factor-erythroid 2 related factor 2 (Nrf2) protein, and significantly increased the mRNA and protein expression of its downstream anti-oxidant factors such as heme oxygenase-1 and quinone oxidoreductase-1, which suggested that baicalin exerted anti-oxidant effects by activating the Nrf2-HO1 signaling pathway. Thus, pretreatment with baicalin inhibited LPS - induced oxidative stress and protected the normal physiological function of IPEC-J2 cells via NF-κB and Nrf2–HO1 signaling pathways.

Tea tree oil (TTO) exhibits a potent antioxidant, antibacterial, and anti-inflammatory activity and is commonly used in skincare products. However, it is not clear whether TTO can protect gut barrier damage in inflammatory bowel disease (IBD) patients. Herein, we report the impact of terpinen-4-ol (TER, the primary constituent of TTO), on lipopolysaccharide (LPS)-induced intestinal epithelial cell barrier function impairment in intestinal porcine epithelial cell lines (IPEC-J2) and dextran sulfate sodium (DSS)-induced IBD in mice. TER protected against LPS-induced damage in IPEC-J2 cells in vitro and attenuated DSS-induced colitis in vivo. Added TER promoted the tight junction (TJ) proteins expressing in vitro and in vivo and attenuated the LPS-induced upregulation of ERK phosphorylation in IPEC-J2 cells. However, when an inhibitor of ERK phosphorylation was added, TER did not promote the expression of TJ protein, denoting that the ERK signaling pathway mediates the upregulation of TJ proteins. Our data may propose the potential application of TER in treating IBD.

The choice of carrier material is critical in the study of natural drug release preparations and glycosylated magnetic molecularly imprinted materials. The stiffness and softness of the carrier material affect the efficiency of drug release and the specificity of recognition. The dual adjustable aperture-ligand in molecularly imprinted polymers (MIPs) provides the possibility of individualized design for sustained release studies. In this study, a combination of paramagnetic Fe3O4 and carboxymethyl chitosan (CC) was used to enhance the imprinting effect and improve drug delivery. A combination of tetrahydrofuran and ethylene glycol was used as a binary porogen to prepare MIP-doped Fe3O4-grafted CC (SMCMIP). Salidroside serves as the template, methacrylic acid acts as the functional monomer, and ethylene glycol dimethacrylate (EGDMA) serves as the crosslinker. Scanning and transmission electron microscopy were used to observe the micromorphology of the microspheres. The structural and morphological parameters of the SMCMIP composites were measured, including the surface area and pore diameter distribution. In an in vitro study, we found that the SMCMIP composite had a sustained release property of 50% after 6 h of release time in comparison to the control SMCNIP. The total amounts of SMCMIP released at 25 °C and 37 °C were 77% and 86%, respectively. In vitro results showed that the release of SMCMIP followed Fickian kinetics, meaning that the rate of release is dependent on the concentration gradient, with diffusion coefficients ranging from 3.07 × 10−2 cm2/s to 5.66 × 10−3 cm2/s. The results of cytotoxicity experiments showed that the SMCMIP composite did not have any harmful effects on cell growth. The survival rates of intestinal epithelial cells (IPEC-J2) were found to be above 98%. By using the SMCMIP composite, drugs may be delivered in a sustained manner, potentially leading to improved therapeutic outcomes and reduced side effects.

Herein, we assessed the anti-inflammatory and intestinal barrier protective effects of butyrolactone-I (BTL-1), derived from the coral-derived endophytic fungus (Aspergillus terreus), using the LPS-induced IPEC-J2 inflammation model and the DSS-induced IBD model in mice. In IPEC-J2 cells, pretreatment with BTL-I significantly inhibited TLR4/NF-κB signaling pathway and JNK phosphorylation, resulting in the decrease of IL-1β and IL-6 expression. Interestingly, BTL-1 pretreatment activated the phosphorylation of ERK and P38, which significantly enhanced the expression of TNF-α. Meanwhile, BTL-1 pretreatment upregulated tight junction protein expression (ZO-1, occludin, and claudin-1) and maintained intestinal barrier and intestinal permeability integrity. In mice, BTL-1 significantly alleviated the intestinal inflammatory response induced by DSS, inhibited TLR4/NF-κB signaling pathway, and MAPK signaling pathway, thus reducing the production of IL-1, IL-6, and TNF-α. Further, the expression of tight junction proteins (ZO-1, occludin, and claudin-1) was upregulated in BTL-1 administrated mice. Therefore, it has been suggested that butyrolactone-I alleviates inflammatory responses in LPS-stimulated IPEC-J2 and DSS-induced murine colitis by TLR4/NF-κB and MAPK signal pathway. Thereby, BTL-1 might potentially be used as an ocean drug to prevent intestinal bowel disease.

Heat stressed pigs show typical characteristics of inflammatory bowel disease (IBD). However, little is known about the pathogenesis of heat stress (HS)-induced IBD in pigs. In this study, we determined the effects of HS on colon morphology, intestinal microbiota diversity, transcriptome genes (transcripts), and short chain fatty acids (SCFAs) metabolism in pigs. In addition, the correlation among these parameters was analyzed by weighted gene co-expression network analysis. Results showed that the liver and kidney functions related to blood biochemical indexes were partially changed in pigs under HS. Furthermore, the levels of diamine oxidase and D-lactic acid were significantly increased, whereas the levels of secretory immunoglobulin A were decreased. The integrity of colonic tissue was damaged under HS, as bleeding, lymphatic infiltration, and villi injury were observed. The concentrations of SCFAs in the colon, such as acetic acid and butyric acid, were decreased significantly. In addition, the composition of colon microbiota, such as decrease in Lactobacillus johnsonii, Lactobacillus reuteri and increase in Clostridium sensu stricto 1 of day 7 and 14 while under HS. These changes were associated with changes in the concentration of SCFAs and biochemical indexes above mentioned. Differentially expressed genes were enriched in the nucleotide-binding oligomerization domain-like receptor signaling pathway, Th17 cell differentiation, and IBD pathway, which were also associated with the changes in SCFAs. Thus, the structure, diversity of intestinal microorganisms, and changes in the levels of SCFAs in colon of heat stressed pigs changed significantly, contributing to the activation of immune response and inflammatory signal pathways and causing abnormal physiological and biochemical indexes and intestinal mucosal damage. These results highlight the interconnections between intestinal microbiota, SCFAs, and immune response and their role in the pathogenesis of stress induced IBD therapy.

Immune stress markedly affects the immune function and growth performance of livestock, including poultry, resulting in financial loss to farmers. It can lead to decreased feed intake, reduced growth, and intestinal disorders. Studies have shown that pathogen-induced immune stress is mostly related to TLR4-related inflammatory signal pathway activation, excessive inflammatory cytokine release, oxidative stress, hormonal disorders, cell apoptosis, and intestinal microbial disorders. This paper reviews the occurrence of immune stress in livestock, its impact on immune function and growth performance, and strategies for immune stress prevention.