Glutamate attenuates lipopolysaccharide-induced oxidative damage and mRNA expression changes of tight junction and defensin proteins, inflammatory and apoptosis response signaling molecules in the intestine of fish

Acute low temperature and lipopolysaccharide differentially modulated the innate immune and antioxidant responses in a subtropical fish, the pacu (Piaractus mesopotamicus)

Exogenous factors such as low water temperature can be stressful and elicit negative immune system effects, especially for fish, which are ectothermic. Stress and immune responses require energy overload, which can affect the cellular redox balance, causing oxidative damage. These overall responses impair the animal's health and negatively affect fish farming. To evaluate indicators of stress, immune and antioxidant systems, and oxidative stress responses in fish during thermal challenge, the present study reduced the water temperature from 29.5 °C to 16 °C and then inoculated pacu (Piaractus mesopotamicus) with lipopolysaccharide (LPS) from Escherichia coli. Our results revealed that acute exposure to low water temperature itself increased blood glucose, impaired the serum lysozyme concentration and increased GSH-Px activity. There was an interaction effect between low temperature and LPS inoculation. After LPS inoculation, leukocytes were initially activated (3 h); glucose levels increased (3 h); GST activity initially decreased (3 h) but then increased (6 h); SOD, CAT and GSH-Px activities decreased; and lysozyme activity remained depressed in fish subjected to cold shock. The results showed that thermal and immunological challenges impaired the maintenance of leucocyte activation and compromised the pacu oxidant response. The overall response of pacu to thermal challenge indicates that the species proved to be acutely sensitive to a drop in water temperature, reducing its ability to maintain homeostasis, especially when subjected to immunological challenge.

Effects of dietary salidroside on intestinal health, immune parameters and intestinal microbiota in largemouth bass (Micropterus salmoides)

The largemouth bass has become one of the economically fish in China, according to the latest China Fishery Statistical Yearbook. The farming scale is constantly increasing. Salidroside has been found in past studies to have oxidative stress reducing and immune boosting properties. In this study, the addition of six different levels of salidroside supplements were 0、40、80、120、160 and 200 mg/kg. A 56-day feeding trial was conducted to investigate the effects of salidroside on the intestinal health, immune parameters and intestinal microbiota composition of largemouth bass. Dietary addition of salidroside significantly affected the Keap-1β/Nrf-2 pathway as well as significantly increased antioxidant enzyme activities resulting in a significant increase in antioxidant capacity of largemouth bass. Dietary SLR significantly reduced feed coefficients. The genes related to tight junction proteins (Occludin, ZO-1, Claudin-4, Claudin-5) were found to be significantly upregulated in the diet supplemented with salidroside, indicating that salidroside can improve the intestinal barrier function (p < 0.05). The dietary administration of salidroside was found to significantly reduce the transcription levels of intestinal tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) (p < 0.05). Furthermore, salidroside was observed to reduce the transcription levels of intestinal apoptosis factor Bcl-2 associated death promoter (BAD) and recombinant Tumor Protein p53 (P53) (p < 0.05). Concomitantly, the beneficial bacteria, Fusobacteriota and Cetobacterium, was significantly increased in the SLR12 group, while that of pathogenic bacteria, Proteobacteria, was significantly decreased (p < 0.05). In conclusion, the medium-sized largemouth bass optimal dosage of salidroside in the diet is 120mg/kg-1.

Moringa oleifera leaf polysaccharide regulates fecal microbiota and colonic transcriptome in calves

This study investigated the effects of Moringa oleifera polysaccharide on growth performance indicators, serum biochemical indicators, immune organ indicators, colonic morphology, colonic microbiomics and colonic transcriptomics in newborn calves. 21 newborn calves were randomly divided into three groups of 7 calves per treatment group: control group (no Moringa oleifera polysaccharide addition); low-dose group (Moringa oleifera polysaccharide 0.5 g/kg); and high-dose group (Moringa oleifera polysaccharide 1 g/kg). This trial used gavage to feed MOP to calves. The test lasted 8 weeks. Calves were humanely electroshocked on the last day of the trial and slaughtered afterwards. Thymus, spleen, blood and colonic contents were collected for further testing. The results of this trial showed that MOP significantly increased the body weight of newborn calves and reduced the rate of calf diarrhea, thus promoting calf growth. Fecal scores showed a linear decrease with the addition of MOP. In terms of serum biochemistry, feeding MOP significantly increased serum ALB levels in a linear fashion. In terms of serum antioxidants, feeding MOP linearly increased CAT and T-AOC levels and decreased MDA concentrations, and in terms of serum immunity, feeding MOP linearly increased IgA, IgG, and IgM levels. At the same time, MOP regulated the abundance of Firmicutes and Bacteroidetes in the intestinal tract of calves, which reduced the occurrence of diarrhea. In addition, moringa polysaccharide could regulate genes related to inflammatory signaling pathways such as MAPK signaling pathway, TGF-beta signaling pathway, PI3K-Akt signaling pathway and TNF signaling pathway in calves' intestine to reduce the occurrence of intestinal inflammation. In conclusion, MOP can be used as a novel ruminant additive for the prevention of enteritis in calves.

Alleviative effect of poly-β-hydroxybutyrate on lipopolysaccharide-induced oxidative stress, inflammation and cell apoptosis in Cyprinus carpio

In this study, the alleviative effects of poly-β-hydroxybutyrate (PHB) in bioflocs on oxidative stress, inflammation and apoptosis of common carp (Cyprinus carpio) induced by lipopolysaccharide (LPS) were evaluated. Common carp were irregularity divided into 5 groups and fed five diets with 0 % (CK), 2 %, 4 %, 6 % and 8 % PHB. After 8-week feeding trial, LPS challenge was executed. Results showed that appropriate level of PHB enhanced serum immune function by reversing LPS-induced the decrease of C3, C4, IgM, AKP, ACP and LZM in serum, alleviated LPS-induced intestinal barrier dysfunction by decreasing the levels of 5-HT, D-LA, ET-1 and DAO in serum, increasing ZO-1, Occludin, Claudin-3 and Claudin-7 mRNA, improving intestinal morphology. Moreover, dietary PHB reversed LPS-induced the decrease of AST and ALT in hepatopancreas, while in serum exhibited the opposite trend. Suitable level of PHB reversed LPS-induced the reduction of GSH-PX, CAT, T-SOD and T-AOC in intestines and hepatopancreas, whereas MDA showed the opposite result. PHB alleviated LPS-induced the decrease of Nrf2, HO-1, CAT, SOD and GSH-PX mRNA, the increase of Keap1 mRNA. Appropriate level of PHB alleviated LPS-induced inflammation and apoptosis by up-regulating TGF-β, IL-10 and Bcl-2 mRNA, down-regulating NF-κB, TNF-α, IL-6, Bax, Caspase-3, Caspase-8 and Caspase-9 mRNA. Furthermore, PHB inhibited activation of NLRP3 inflammasomes by reducing the levels of NLRP3, Caspase-1, ASC, IL-1β and IL-18 mRNA and protein. In addition, the increases of dietary PHB linearly and quadratically affected LPS-induced adverse effects on common carp. Summary, this study suggested that appropriate level of dietary PHB alleviated LPS-induced oxidative stress, inflammation, apoptosis and the activation of NLRP3 inflammasome in common carp. And the appropriate level of PHB in common carp diets was 4 %.

The role of amino acid metabolism in inflammatory bowel disease and other inflammatory diseases

Inflammation is a characteristic symptom of the occurrence and development of many diseases, which is mainly characterized by the infiltration of inflammatory cells such as macrophages and granulocytes, and the increased release of proinflammatory factors. Subsequently, macrophage differentiates and T cells and other regulated factors exhibit anti-inflammatory function, releasing pro- and anti-inflammatory factors to maintain homeostasis. Although reports define various degrees of metabolic disorders in both the inflamed and non-inflamed parts of inflammatory diseases, little is known about the changes in amino acid metabolism in such conditions. This review aims to summarize amino acid changes and mechanisms involved in the progression of inflammatory bowel disease (IBD) and other inflammatory diseases. Since mesenchymal stem cells (MSCs) and their derived exosomes (MSC-EXO) have been found to show promising effects in the treatment of IBD and other inflammatory diseases,their potential in the modulation of amino acid metabolism in the treatment of inflammation is also discussed.

Difenoconazole disrupts carp intestinal physical barrier and causes inflammatory response via triggering oxidative stress and apoptosis

As a common fungicide, difenoconazole (DFZ) is widespread in the natural environment and poses many potential threats. Carp makes up a significant proportion of China's freshwater aquaculture population and are vulnerable to the DFZ. Therefore, this study investigated the effects of DFZ (0.488 mg/L and 1.953 mg/L) exposure for 4 d on the intestinal tissues of carp and explored the mechanisms. Specifically, DFZ exposure caused pathological damage to the intestinal tissues of carp, reducing the expression levels of intestinal tight junction proteins, and leading to damage to the intestinal barrier. In addition, DFZ exposure activated the NF-κB signaling pathway, increasing the levels of pro-inflammatory factors (TNF-α, IL-1β, IL-6) and decreasing the levels of anti-inflammatory factors (IL-10, TGF-β1). As disruption of the intestinal barrier is closely linked to oxidative stress and apoptosis, we have conducted research in both areas for this reason. The results showed that DFZ exposure elevated reactive oxygen species in carp intestines, decreased antioxidant enzyme activity, and suppressed the expression of oxidative stress-related genes. TUNEL results showed that DFZ induced the onset of apoptosis. In addition, the expression levels of apoptosis-related genes and proteins were examined. Western blotting results showed that DFZ could upregulate the protein expression levels of Bax, Cytochrome C and downregulate the protein levels of Bcl-2. qPCR results showed that DFZ could upregulate the transcript levels of Bax, Caspase-3, Caspase-8 and Caspase-9 and downregulate the transcript levels of Bcl-2 transcript levels. This suggests that DFZ can induce apoptosis of mitochondrial pathway in carp intestine. In conclusion, DFZ can induce oxidative stress and apoptosis in carp intestine, leading to the destruction of intestinal physical barrier and the occurrence of inflammation. Our data support the idea that oxidative stress and apoptosis are important triggers of pesticide-induced inflammatory bowel illness.

Effects of Dietary Lactic Acid Supplementation on the Activity of Digestive and Antioxidant Enzymes, Gene Expressions, and Bacterial Communities in the Intestine of Common Carp, Cyprinus carpio

The present study investigated the effects of dietary lactic acid (LA) supplementation on the growth performance, intestinal digestive/antioxidant enzymes' activities, gene expression, and bacterial communities in common carp, Cyprinus carpio. Four diets were formulated to contain 0 g/kg LA (control), at 2.5 g/kg LA (2.5LAC), 5 g/kg LA (5LAC), and 10 g/kg LA (10LAC) and offered to the fish over a period of 56 days. The results showed that dietary 5 g/kg LA supplementation improved growth performance and feed efficiency in the fish. All LA treatments exhibited significant elevations in the intestinal trypsin and chymotrypsin activities, whereas the intestinal lipase, amylase, and alkaline phosphatase activities exhibited significant elevations in the 5LAC and 10LAC treatments. All LA treatments exhibited significant elevations in the intestinal heat shock protein 70, tumor necrosis factor-alpha, interleukin-1 beta, and defensin gene expressions, and the highest expression was observed in the 5LAC treatment. Additionally, dietary LA treatment significantly increased the lysozyme expression and Lactobacillus sp. population in the intestine of the fish, and the highest values were observed in the 5LAC and 10LAC treatments. Aeromonas sp. and Vibrio sp. populations decreased in the LA treatments, and the lowest Aeromonas sp. population was observed in the 10LAC treatment. The intestinal mucin2 and mucin5 expressions, and the hepatic reduced glutathione content, significantly increased, whereas hepatic glutathione peroxidase, glutathione reductase, and malondialdehyde significantly decreased in the 5LAC and 10LAC treatments. In conclusion, dietary 5 g/kg LA is recommended for common carp feeding to improve growth rate, antioxidant capacity, and intestinal health.

Evaluation of the Anticancer Activity and Mechanism Studies of Glycyrrhetic Acid Derivatives toward HeLa Cells

In this paper, a series of glycyrrhetic acid derivatives 3a–3f were synthesized via the esterification reaction. The cytotoxicity of these compounds against five tumor cells (SGC-7901, BEL-7402, A549, HeLa and B16) and normal LO2 cells was investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The results showed that compound 3a exhibited high antiproliferative activity against HeLa cells (IC50 = 11.4 ± 0.2 μM). The anticancer activity was studied through apoptosis, cloning, and scratching; the levels of the intracellular ROS, GSH, and Ca2+; and the change in the mitochondrial membrane potential, cell cycle arrest and RNA sequencing. Furthermore, the effects of compound 3a on gene expression levels and metabolic pathways in HeLa cells were investigated via transcriptomics. The experimental results showed that this compound can block the cell cycle in the S phase and inhibit cell migration by downregulating Focal adhesion kinase (FAK) expression. Moreover, the compound can reduce the intracellular glutathione (GSH) content, increase the Ca2+ level and the intracellular ROS content, and induce a decrease in the mitochondrial membrane potential, further leading to cell death. In addition, it was also found that the mechanism of compounds inducing apoptosis was related to the regulation of the expression of mitochondria-related proteins B-cell lymphoma-2 (Bcl-2), Bcl-2-Associated X (Bax), and the activation of the caspase proteins. Taken together, this work provides a help for the development of glycyrrhetinic acid compounds as potential anticancer molecules.

Dietary glutamate enhances intestinal immunity by modulating microbiota and Th17/Treg balance-related immune signaling in piglets after lipopolysaccharide challenge

The purpose of this study was to explore the effects of glutamate on piglet growth performance and intestinal immunity function, and to further elucidate its mechanism. In a 2 × 2 factorial design involving immunological challenge (lipopolysaccharide (LPS) or saline) and diet (with or without glutamate), twenty-four piglets were randomly assigned to four groups, each with 6 replicates. Piglets were fed with a basal or glutamate diet for 21 d before being injected intraperitoneally with LPS or saline. Piglet's intestinal samples were collected 4 h after injection. Results showed that glutamate increased daily feed intake, average daily gain, villus length, villus area, and villus length to crypt depth ratio (V/C), and decreased the crypt depth (P < 0.05). Furthermore, glutamate increased the mRNA expression of forkhead box P3 (FOXP3), a signal transducer and activator of transcription 5 (STAT5) and transforming growth factor beta, while decreasing the mRNA expression of RAR-related orphan receptor c and STAT3. Glutamate increased interleukin-10 (IL-10) mRNA expression while decreasing the mRNA expression of IL-1β, IL-6, IL-8, IL-17, IL-21, and tumor necrosis factor-α. At the phylum level, glutamate increased the Actinobacteriota abundance and Firmicutes-to-Bacteroidetes ratio while decreasing Firmicutes abundance. At the genus level, glutamate improved the abundance of beneficial bacteria (e.g., Lactobacillus, Prevotellaceae-NK3B31-group, and UCG-005). Furthermore, glutamate increased the concentrations of short-chain fatty acids (SCFAs). Correlation analysis revealed that the intestinal microbiota is closely related to Th17/Treg balance-related index and SCFAs. Collectively, glutamate can improve piglet growth performance and intestinal immunity by modulating gut microbiota and Th17/Treg balance-related signaling pathways.

Gut Microbial Perturbation and Host Response Induce Redox Pathway Upregulation along the Gut-Liver Axis during Giardiasis in C57BL/6J Mouse Model

Apicomplexan infections, such as giardiasis and cryptosporidiosis, negatively impact a considerable proportion of human and commercial livestock populations. Despite this, the molecular mechanisms of disease, particularly the effect on the body beyond the gastrointestinal tract, are still poorly understood. To highlight host-parasite-microbiome biochemical interactions, we utilised integrated metabolomics-16S rRNA genomics and metabolomics-proteomics approaches in a C57BL/6J mouse model of giardiasis and compared these to Cryptosporidium and uropathogenic Escherichia coli (UPEC) infections. Comprehensive samples (faeces, blood, liver, and luminal contents from duodenum, jejunum, ileum, caecum and colon) were collected 10 days post infection and subjected to proteome and metabolome analysis by liquid and gas chromatography-mass spectrometry, respectively. Microbial populations in faeces and luminal washes were examined using 16S rRNA metagenomics. Proteome-metabolome analyses indicated that 12 and 16 key pathways were significantly altered in the gut and liver, respectively, during giardiasis with respect to other infections. Energy pathways including glycolysis and supporting pathways of glyoxylate and dicarboxylate metabolism, and the redox pathway of glutathione metabolism, were upregulated in small intestinal luminal contents and the liver during giardiasis. Metabolomics-16S rRNA genetics integration indicated that populations of three bacterial families-Autopobiaceae (Up), Desulfovibrionaceae (Up), and Akkermanasiaceae (Down)-were most significantly affected across the gut during giardiasis, causing upregulated glycolysis and short-chained fatty acid (SCFA) metabolism. In particular, the perturbed Akkermanasiaceae population seemed to cause oxidative stress responses along the gut-liver axis. Overall, the systems biology approach applied in this study highlighted that the effects of host-parasite-microbiome biochemical interactions extended beyond the gut ecosystem to the gut-liver axis. These findings form the first steps in a comprehensive comparison to ascertain the major molecular and biochemical contributors of host-parasite interactions and contribute towards the development of biomarker discovery and precision health solutions for apicomplexan infections.

Oxidative stress and immune response of hepatopancreas in Chinese mitten crab Eriocheir sinensis under lipopolysaccharide challenge

Chinese mitten crab (Eriocheir sinensis; H. Milne Edwards, 1853) is one of the important farmed crustaceans in China. Lipopolysaccharide (LPS), as a harmful factor, is prone to occur during the farming process of crabs. Aiming to test the hypothesis that damage degrees of the hepatopancreas in E. sinensis is correlated to LPS concentrations, in this study, E. sinensis were injected with LPS (50 μg/kg, and 500 μg/kg) and analyzed for the activity of antioxidant and immune-related enzymes, immune-related gene expression, and histopathological of hepatopancreas. As result, the hepatopancreas of E. sinensis immune-related genes, i.e., Dorsal, HSP90, Toll2, TLRs, Tube, and proPO, were significantly affected by LPS challenge. Among immune-related genes, Dorsal and proPO might play key roles in combating the LPS challenge. The activity of CAT gradually decreased with the increase of time, and the total antioxidant capacity was decreased after LPS challenge, indicating the inhibition of LPS on the antioxidant system. Interestingly, the decreasing trend of AKP and ACP activity suggested the immune system of crabs was affected by LPS challenge. The hepatopancreas section showed that the damage degree of hepatopancreas was different under the challenge of LPS with different concentrations, and the damage degree was proportional to the concentration. Our findings provide useful information for understanding the mechanism of hepatopancreas injury of E. sinensis induced by LPS infection.

Pasture intake protects against commercial diet-induced lipopolysaccharide production facilitated by gut microbiota through activating intestinal alkaline phosphatase enzyme in meat geese

Introduction

Diet strongly affects gut microbiota composition, and gut bacteria can influence the intestinal barrier functions and systemic inflammation through metabolic endotoxemia. In-house feeding system (IHF, a low dietary fiber source) may cause altered cecal microbiota composition and inflammatory responses in meat geese via increased endotoxemia (lipopolysaccharides) with reduced intestinal alkaline phosphatase (ALP) production. The effects of artificial pasture grazing system (AGF, a high dietary fiber source) on modulating gut microbiota architecture and gut barrier functions have not been investigated in meat geese. Therefore, this study aimed to investigate whether intestinal ALP could play a critical role in attenuating reactive oxygen species (ROS) generation and ROS facilitating NF-κB pathway-induced systemic inflammation in meat geese.

Methods

The impacts of IHF and AGF systems on gut microbial composition via 16 sRNA sequencing were assessed in meat geese. The host markers analysis through protein expression of serum and cecal tissues, hematoxylin and eosin (H&E) staining, localization of NF-қB and Nrf2 by immunofluorescence analysis, western blotting analysis of ALP, and quantitative PCR of cecal tissues was evaluated.

Results and Discussion

In the gut microbiota analysis, meat geese supplemented with pasture showed a significant increase in commensal microbial richness and diversity compared to IHF meat geese demonstrating the antimicrobial, antioxidant, and anti-inflammatory ability of the AGF system. A significant increase in intestinal ALP-induced Nrf2 signaling pathway was confirmed representing LPS dephosphorylation mediated TLR4/MyD88 induced ROS reduction mechanisms in AGF meat geese. Further, the correlation analysis of top 44 host markers with gut microbiota showed that artificial pasture intake protected gut barrier functions via reducing ROS-mediated NF-κB pathway-induced gut permeability, systemic inflammation, and aging phenotypes. In conclusion, the intestinal ALP functions to regulate gut microbial homeostasis and barrier function appear to inhibit pro-inflammatory cytokines by reducing LPS-induced ROS production in AGF meat geese. The AGF system may represent a novel therapy to counteract the chronic inflammatory state leading to low dietary fiber-related diseases in animals.

Melatonin ameliorates imidacloprid-induced intestinal injury by negatively regulating the PGN/P38MAPK pathway in the common carp (Cyprinuscarpio)

Imidacloprid (IMI), one of the most frequently used neonicotinoid insecticides in agriculture, is resided in surface water worldwide and poses a threat to aquatic organisms. Melatonin (MT) provides effective protection against insecticide-induced toxicity, nevertheless, the toxic effects and whether MT attenuates intestinal injury caused by IMI exposure in the common carps remains poorly explored. Previous studies have reported adverse effects of IMI exposure on intestinal health status. Therefore, we first demonstrated that IMI altered the composition and function of the intestinal microbiota, destroying the integrity of intestinal ultrastructure, increasing intestinal permeability. Meanwhile, metagenomic sequencing and ELISA kits results hypothesized that peptidoglycan (PGN) is an IMI-triggered intestinal microbial metabolite. Subsequently, we thus further elucidated that IMI induced an increase in intestinal tight junction permeability by inducing PGN secretion in vitro model. MT addition dramatically attenuated IMI-induced intestinal toxicity by remitting PGN synthesis and thus resecuring tight junction permeability, thereby reducing intestinal injury. SB203580 was supplied as a P38MAPK inhibitor to alleviate the increased permeability of tight junctions induced by IMI/PGN. Therefore, these findings confirmed that MT protects against IMI-induced intestinal injury by negatively regulating PGN/P38MAPK pathway to antagonize the increased tight junction permeability.

Molecular characterization of adenosine monophosphate deaminase 1 and its regulatory mechanism for inosine monophosphate formation in triploid crucian carp

Inosine monophosphate (IMP) is the main flavoring substance in aquatic animal, and adenosine monophosphate deaminase1 (AMPD1) gene is a key gene in IMP formation. At present, the research on the mechanism of AMPD1 regulating IMP formation in aquatic animal is still blank. In this study, in order to study the mechanism of AMPD1 regulating IMP formation in fish, the full open reading frame (ORF) of AMPD1 which was 2160bp was obtained for the first time in triploid crucian carp (Carassius auratus). It encoded 719 amino acids with a molecular mass of 82.97 kDa, and the theoretical isoelectric point value was 6.31. The homology analysis showed that the homology of triploid crucian carp and diploid Carassius auratus was the highest, up to 99%. And the phylogenetic tree showed that triploid crucian carp was grouped with diploid Carassius auratus, Culter alburnus, and Danio rerio. And real-time fluorescence quantitative results showed that AMPD1 was expressed specifically in muscle of triploid crucian carp (p < 0.05). The results of detection the localization of AMPD1 in cells indicated that the AMPD1 was mainly localized in cytoplasm and cell membrane. Further, we examined the effects of glutamate which was the promotor of IMP formation on the expression of AMPD1 and the formation of IMP in vivo and in vitro experiments, the results showed that 3% glutamate and 2 mg/ml glutamate could significantly promote AMPD1 expression and IMP formation in triploid crucian carp muscle tissue and muscle cells (p < 0.05). Then we inhibited the expression of AMPD1 in vivo and in vitro experiments, we found the formation of IMP in muscle tissue and muscle cells of triploid crucian carp all were inhibited and they affected the gene expression of AMPK-mTOR signaling pathway. The all results showed that AMPD1 mediated glutamate through AMPK-mTOR signaling pathway to regulate the formation of fish IMP.

Hexavalent Chromium Exposure Induces Intestinal Barrier Damage via Activation of the NF-κB Signaling Pathway and NLRP3 Inflammasome in Ducks

Hexavalent chromium [Cr(VI)] is a dangerous heavy metal which can impair the gastrointestinal system in various species; however, the processes behind Cr(VI)-induced intestinal barrier damage are unknown. Forty-eight healthy 1-day-old ducks were stochastically assigned to four groups and fed a basal ration containing various Cr(VI) dosages for 49 days. Results of the study suggested that Cr(VI) exposure could significantly increase the content of Cr(VI) in the jejunum, increase the level of diamine oxidase (DAO) in serum, affect the production performance, cause histological abnormalities (shortening of the intestinal villi, deepening of the crypt depth, reduction and fragmentation of microvilli) and significantly reduced the mRNA levels of intestinal barrier-related genes (ZO-1, occludin, claudin-1, and MUC2) and protein levels of ZO-1, occludin, cand laudin-1, resulting in intestinal barrier damage. Furthermore, Cr(VI) intake could increase the contents of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-18 (IL-18) but decrease the activities of total superoxide dismutase (T-SOD), catalase (CAT), and glutathione reductase (GR), as well as up-regulate the mRNA levels of TLR4, MyD88, NF-κB, TNFα, IL-6, NLRP3, caspase-1, ASC, IL-1β, and IL-18 and protein levels of TLR4, MyD88, NF-κB, NLRP3, caspase-1, ASC, IL-1β, and IL-18 in the jejunum. In conclusion, Cr(VI) could cause intestinal oxidative damage and inflammation in duck jejunum by activating the NF-κB signaling pathway and the NLRP3 inflammasome.

Effects of exposure to cadmium (Cd) and selenium-enriched Lactobacillus plantarum in Luciobarbus capito: Bioaccumulation, antioxidant responses and intestinal microflora

Cadmium (Cd) is a dangerous pollutant with multiple toxic effects on aquatic animals, and it exists widely in the environment. Selenium (Se) is a biologically essential trace element. Interactions between heavy metals and selenium can significantly affect their biological toxicity, although little is known about the mechanism of this antagonism. Lactobacillus is one of the dominant probiotics, given that a certain dose promotes host health. In this study, we evaluated the protective effect of a dietary probiotic supplementation, Se-enriched Lactobacillus plantarum (L. plantarum), on the bioaccumulation, oxidative stress and gut microflora of Luciobarbus capito exposed to waterborne Cd. Fish were exposed for 28 days to waterborne Cd at 0.05 mg/L and/or dietary Se-enriched L. plantarum. Exposure to Cd in water leads to Cd accumulation in tissues, oxidative stress and significant changes in gut microflora composition. Adding Se-enriched L. plantarum to the diet can reduce the accumulation of Cd in tissues, enhance the activity of antioxidant enzymes, and reverse changes in intestinal microbial composition after Cd exposure. The results obtained indicate that Se-enriched L. plantarum provides significant protection against the toxicity of Cd by inhibiting bioaccumulation. Selenium reduced oxidative stress by increasing the activity of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and malondialdehyde (MDA). Se-enriched L. plantarum can reduce the increase in the number of pathogenic Aeromonas caviae bacteria in the intestine caused by Cd stress and increase the number of Gemmobacter to regulate the microbial population. The results of this study show that Se-enriched L. plantarum dietary supplements can effectively protect Luciobarbus capito against Cd toxicity at subchronic levels.

Effects of dietary tryptophan on muscle growth, protein synthesis and antioxidant capacity in hybrid catfish Pelteobagrus vachelli♀ × Leiocassis longirostris♂

The present study evaluated effects of dietary supplementation with tryptophan (Trp) on muscle growth, protein synthesis and antioxidant capacity in hybrid catfish Pelteobagrus vachelli♀ × Leiocassis longirostris♂. Fish were fed six different diets containing 2·6 (control), 3·1, 3·7, 4·2, 4·7 and 5·6 g Trp/kg diet for 56 d, respectively. Results showed that dietary Trp significantly (1) improved muscle protein content, fibre density and frequency of fibre diameter; (2) up-regulated the mRNA levels of PCNA, myf5, MyoD1, MyoG, MRF4, IGF-I, IGF-II, IGF-IR, PIK3Ca, TOR, 4EBP1 and S6K1; (3) increased phosphorylation levels of AKT, TOR and S6K1; (4) decreased contents of MDA and PC, and increased activities of CAT, GST, GR, ASA and AHR; (5) up-regulated mRNA levels of CuZnSOD, CAT, GST, GPx, GCLC and Nrf2, and decreased Keap1 mRNA level; (6) increased nuclear Nrf2 protein level and the intranuclear antioxidant response element-binding ability, and reduced Keap1 protein level. These results indicated that dietary Trp improved muscle growth, protein synthesis as well as antioxidant capacity, which might be partly related to myogenic regulatory factors, IGF/PIK3Ca/AKT/TOR and Keap1/Nrf2 signalling pathways. Finally, based on the quadratic regression analysis of muscle protein and MDA contents, the optimal Trp requirements of hybrid catfish (21·82-39·64 g) were estimated to be 3·94 and 3·93 g Trp/kg diet (9·57 and 9·54 g/kg of dietary protein), respectively.

Ginsenoside Rg1 Mitigates Porcine Intestinal Tight Junction Disruptions Induced by LPS through the p38 MAPK/NLRP3 Inflammasome Pathway

Inflammation leads to porcine tight junction disruption of small intestinal epithelial cells, resulting in intestinal dysfunction. Herein, we established lipopolysaccharide (LPS)-induced in-vivo and in-vitro inflammatory models. The results revealed that LPS induced tight junction disruption in IPEC-J2 cells by downregulating tight-junction-related protein zonula occludens-1 (ZO-1), occludin and claudin-1 expression, while ginsenoside Rg1 rescued such inhibition and abrogated the upregulated expression of phosphorylation p38 MAPK. The p38 MAPK inhibitor (SB203580) showed a similar effect with Rg1 and attenuated the LPS-induced inhibition of ZO-1, occludin and claudin-1 expression, which is consistent with the reduced expression of NLRP3 inflammasome and IL-1β. Furthermore, the specific inhibitors of NLRP3 and IL-1β result in increased expression of tight-junction-related protein, demonstrating that p38 MAPK signaling was associated with Rg1 suppression of tight junction disruption. Besides, LPS treatment decreased the expression of ZO-1, occludin and claudin-1 through p38 MAPK signaling, and caused abnormal morphological changes in murine ileum. Meanwhile, Rg1 attenuated the decreased expression of ZO-1, occludin and claudin-1 and partially alleviated LPS-induced morphological changes in murine ileum. In summary, these findings characterized a novel mechanism by which Rg1 alleviates LPS-induced intestinal tight junction disruption by inhibiting the p38 MAPK-mediated NLRP3 inflammasome pathway.

Effects of Water Extract from Artemisia argyi Leaves on LPS-Induced Mastitis in Mice

Simple Summary

Mastitis is a common disease in dairy cows. On the one hand, it will reduce milk yield and milk quality of dairy cows, thus increasing the cost of animal husbandry, and, on the other hand, it will influence the health of infected animals and even human beings. Generally speaking, because mastitis is caused by pathogenic microorganisms, antibiotic treatment is commonly used. However, antibiotic resistance of microorganisms caused by wrongful use of antibiotics and antibiotic residues after treatment has become an urgent problem to be solved. Chinese herbal medicines are pure natural substances, and many of them have antibacterial, anti-inflammatory, or immune-enhancing effects. In this experiment, Artemisia argyi (A. argyi) was selected as the research object to construct the cell model of cow mastitis. Studies have found that A. argyi extract can play a positive role in the regulation of inflammation, which is rich in organic acids and flavonoids. Therefore, A. argyi extract may be a potential treatment for mastitis.

Abstract

In the context of the unsatisfactory therapeutic effect of antibiotics, the natural products of plants have become a research hotspot. Artemisia argyi (A. argyi) is known as a traditional medicine in China, and its extracts have been reported to have a variety of active functions, including anti-inflammatory. Therefore, after establishing the mouse mastitis model by lipopolysaccharide (LPS), the effects of A. argyi leaves extract (ALE) were evaluated by pathological morphology of the mammary gland tissue, gene expression, and serum oxidation index. Studies have shown that ALE has a restorative effect on LPS-induced mammary gland lesions and significantly down-regulated the rise of myeloperoxidase (MPO) induced by LPS stimulation. In addition, ALE played a positive role in LPS-induced oxidative imbalance by restoring the activities of glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) and preventing the increase in nitric oxide (NO) concentration caused by the over-activation of total nitric oxide synthase (T-NOS). Further analysis of gene expression in the mammary gland showed that ALE significantly down-regulated LPS-induced up-regulation of inflammatory factors IL6, TNFα, and IL1β. ALE also regulated the expression of MyD88, a key gene for toll-like receptors (TLRs) signaling, which, in turn, regulated TLR2 and TLR4. The effect of ALE on iNOS expression was similar to the effect of T-NOS activity and NO content, which also played a positive role. The IκB gene is closely related to the NF-κB signaling pathway, and ALE was found to significantly alleviate the LPS-induced increase in IκB. All of these results indicated that ALE may be considered a potential active substance for mastitis.

Sodium butyrate alleviates LPS-induced kidney injury via inhibiting TLR2/4 to regulate rBD2 expression

Defensins represent an integral part of the innate immune system to ward off potential pathogens. The study used a rat model to investigate mechanisms by which sodium butyrate (NaB) regulates β-defensin to inhibit lipopolysaccharide (LPS)-induced nephrotoxicity. We found that NaB alleviated LPS-induced renal structural damage, as judged by reduced renal lesions and improved glomerular vascular structure. In addition, elevated levels of indicators of kidney damage creatinine and blood urine nitrogen, inflammatory mediators TNF-α, and IL-6 dropped after NaB administration. Rat β-defensin 2 (rBD2), as estimated by mRNA level, was significantly higher in LPS-treated kidneys, whereas the changes of rBD2 reduced in NaB-treated kidneys. In addition, NaB alleviated LPS-induced increase in TLRs mRNA expression. Mechanistically, the present study indicates that NaB has nephroprotective activity resulting from modulation of TLR2/4 to regulate rBD2 expression hence curbing inflammation. PRACTICAL APPLICATIONS: In practice, adding NaB to diet can improve animal performance. Our results suggest that dietary supplementation of NaB increases animal feed intake and improves the body's defense ability to relieve inflammation caused by bacteria. Especially in the age of resistance prohibition, sodium butyrate can partially replace antibiotics to induce the expression of body defensin. It may become a health care product to enhance the body's immunity.

Glutamate attenuates lipopolysaccharide induced intestinal barrier injury by regulating corticotropin-releasing factor pathway in weaned pigs

Objective

The purpose of this study was to evaluate the protection of glutamate (GLU) against the impairment in intestinal barrier function induced by lipopolysaccharide (LPS) stress in weaned pigs.

Methods

Twenty-four weaned pigs were divided into four treatments containing: i) non-challenged control, ii) LPS-challenged control, iii) LPS+1.0% GLU, and iv) LPS+2.0% GLU. On day 28, pigs were treated with LPS or saline. Blood samples were collected at 0, 2, and 4 h post-injection. After blood samples collection at 4 h, all pigs were slaughtered, and spleen, mesenteric lymph nodes, liver and intestinal samples were obtained.

Results

Dietary GLU supplementation inhibited the LPS-induced oxidative stress in pigs, as demonstrated by reduced malondialdehyde level and increased glutathione level in jejunum. Diets supplemented with GLU enhanced villus height, villus height/crypt depth and claudin-1 expression, attenuated intestinal histology and ultrastructure impairment induced by LPS. Moreover, GLU supplementation reversed intestinal intraepithelial lymphocyte number decrease and mast cell number increase induced by LPS stress. GLU reduced serum cortisol concentration at 4 h after LPS stress and downregulated the mRNA expression of intestinal corticotropin-releasing factor signal (corticotrophin-releasing factor [CRF], CRF receptor 1 [CRFR1], glucocorticoid receptor, tryptase, nerve growth factor, tyrosine kinase receptor A), and prevented mast cell activation. GLU upregulated the mRNA expression of intestinal transforming growth factor β.

Conclusion

These findings indicate that GLU attenuates LPS-induced intestinal mucosal barrier injury, which is associated with modulating CRF signaling pathway.

Polysaccharide from dandelion enriched nutritional composition, antioxidant capacity, and inhibited bioaccumulation and inflammation in Channa asiatica under hexavalent chromium exposure

Taraxacum mongolicum polysaccharide (TMP) exhibits anti-inflammatory and antioxidant activity, making it an attractive candidate for aquatic-product-safety applications. Here, this study was aimed to investigate the effects of dietary TMP on the growth, nutritional composition, antioxidant capacity, bioaccumulation and inflammation in Channa asiatica under hexavalent chromium stress. The C. asiatica was randomly distributed into five groups: The first group served as the blank control group (CK), the subsequent groups were fed TMP-supplemented feed (0, 0.5, 1.0 and 2.0 g/kg), respectively, and exposed to waterborne Cr⁶⁺ for 28 days. Our results indicated that the TMP effectively increased (P < 0.05) C. asiatica muscle flavour amino acid, total free amino acids, monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), and EPA + DHA contents, enhanced positively antioxidant enzyme activity (GPX, SOD, CAT, T-AOC), reduced oxidative stress parameters (MDA, PC), and up-regulated antioxidant-related genes mRNA expression. Meanwhile, the appropriate amount of TMP supplementation also inhibited the bioaccumulation of Cr⁶⁺ in tissues and alleviated the inflammatory response (P < 0.05). Furthermore, sensory evaluation implied that the overall score of sashimi and cooked fillet in the 2.0 g/kg TMP group was the highest in the experimental group, second only to CK. In brief, these results elucidate that TMP-supplemented diets excellently ameliorated the growth, enriched nutritional composition and antioxidant capacity, and inhibited bioaccumulation and inflammation in C. asiatica exposed to waterborne Cr⁶⁺.

Response mechanism of ♀ Epinephelus fuscoguttatus × ♂ Epinephelus lanceolatus under low-temperature and waterless stresses using TMT proteomic analysis

♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatus, a hybrid grouper created from artificial breeding, has been widely developed over the past decades. However, the study focusing on lukewarm high-protein-content fish species using advanced techniques has rarely been reported. In this work, the TMT (tandem mass tag)-assisted technique was employed to explore its differentially expressed proteins and response mechanisms under low-temperature dormant and waterless stresses. Our findings suggest that 162 and 258 differentially expressed proteins were identified under low-temperature dormant and waterless stresses, respectively. The waterless preservation treatment further identifies 93 differentially expressed proteins. The identified proteins are categorized and found to participate in lipid metabolism, glycometabolism, oxidative stress, immune response, protein and amino acid metabolism, signal transduction, and other functions. Accordingly, the factors that affect the response mechanisms are highlighted to provide new evidences at protein level.

Protective effects of dietary icariin on lipopolysaccharide-induced acute oxidative stress and hepatopancreas injury in Chinese mitten crab, Eriocheir sinensis

To investigate the effects of dietary icariin (ICA) supplementation on acute oxidative stress and hepatopancreatic injury induced by lipopolysaccharide (LPS) injection in Eriocheir sinensis, an 8-week feeding trial of crabs was conducted using 4 diets with different supplementation levels of ICA (0, 50, 100, and 200 mg/kg diet weight, respectively), and then challenged with LPS of 400 μg/kg body weight for 6 h. Results showed that 100 mg/kg ICA supplementation increased the antioxidant capacity, reduced the stress-related indicators in haemolymph, strengthen the mitochondrial membrane potential, and reduce apoptosis compared to the single LPS-treated crabs. The expressions of apoptosis-related genes and proteins were also evaluated to further understand the effects of dietary ICA pretreatment on LPS-induced cell apoptosis. As a result, dietary 100 mg/kg diet weight ICA pre-addition significantly down-regulated the expression of HSP60, HSP70, Caspase 3c, Caspase 8, Caspase 3, Caspase 9, P38, and Bax (P < 0.05), and alleviated the suppressed expression of PI3K, AKT, MEK, and Bcl-2 (P < 0.05) in crabs challenged with LPS. Overall, this research reveals that ICA supplementation of 100 mg/kg diet weight could enhance the resistance to oxidative damage and apoptosis in E. sinensis facing LPS challenge.

In vitro study of sodium butyrate on soyasaponin challenged intestinal epithelial cells of turbot (Scophthalmus maximus L.) refer to inflammation, apoptosis and antioxidant enzymes

The study is aimed to investigate the protective effect and potential mechanisms of sodium butyrate (NaBT) on soyasaponins (SA) induced intestinal epithelial cells (IECs) injury in vitro. The primary IECs of turbot were developed and treated with 0.4, 1 and 4 mM NaBT in the presence of 0.4 mg/mL SA for 6 h to explore the protective effects of NaBT. The results showed that the addition of NaBT significantly down-regulated gene expression of inflammatory cytokine TNF-α, IL-1β and IL-8, pro-apoptosis relevant gene BAX, caspase-3, caspase-7 and caspase-9 induced by SA, while up-regulated anti-apoptosis gene Bcl-2. SA stimulation did not induce reactive oxygen species production, but elevated gene expression of antioxidant enzyme heme oxygenase-1 and superoxide dismutase. Moreover, the gene expression of those antioxidant enzyme was further up-regulated in NaBT groups. Furthermore, NaBT supplementation decreased the acid phosphatase and alkaline phosphatase activities and suppressed phosphorylation of p38 and c-Jun N-terminal kinase (JNK). In conclusion, NaBT could mitigate SA-induced inflammation and apoptosis and elevate gene expression of antioxidant enzymes on IECs of turbot and p38 and JNK signaling pathway participated in those processes.

Comparative analysis of erythrocyte hemolysis, plasma parameters and metabolic features in red crucian carp (Carassius auratus red var) and triploid hybrid fish following Aeromonas hydrophila challenge

Aeromonas hydrophila can pose a great threat to survival of freshwater fish. In this study, A. hydrophila challenge could promote the erythrocyte hemolysis, increase free hemoglobin (FHB) level and generate malondialdehyde (MDA) production in plasma but decrease the levels of total antioxidant capacity (T-AOC), total superoxide dismutase (SOD), catalase (CAT), alkaline phosphatase (ALP) and lysozyme (LZM) of red crucian carp (RCC, 2 N = 100) and triploid hybrid fish (3 N fish, 3 N = 150) following A. hydrophila challenge. Elevated expression levels of heat shock protein 90 alpha (HSP90α), matrix metalloproteinase 9 (MMP-9), free fatty acid receptor 3 (FFAR3), paraoxonase 2 (PON2) and cytosolic phospholipase A2 (cPLA2) were observed in A. hydrophila-infected fish. In addition, A. hydrophila challenge could significantly increase expressions of cortisol, leucine, isoleucine, glutamate and polyunsaturated fatty acids (PUFAs) in RCC and 3 N, while glycolysis and tricarboxylic acid cycle appeared to be inactive. We identified differential fatty acid derivatives and their metabolic networks as crucial biomarkers from metabolic profiles of different ploidy cyprinid fish subjected to A. hydrophila infection. These results highlighted the comparative metabolic strategy of different ploidy cyprinid fish against bacterial infection.

Effects of dietary Astragalus Propinquus Schischkin polysaccharides on growth performance, immunological parameters, antioxidants responses and inflammation-related gene expression in Channa argus

The present study investigated the effects of dietary Astragalus Propinquus schischkin polysaccharides on growth, immune responses, antioxidants responses and inflammation-related genes expression in Channa argus. Channa argus were randomly divided into 5 groups and fed 5 levels diets of A. propinquus schischkin polysaccharides (0, 250, 500, 1000 and 2000 mg/kg) for 56 days. The results showed, dietary A. propinquus schischkin polysaccharides addition can increase the final body weight, weight gain and specific growth rate, decrease the feed conversion ratio of Channa argus. And dietary A. propinquus schischkin polysaccharides supplementation can increase the levels of serum superoxide dismutase, catalase, glutathione peroxidase, lysozyme, complement 3, complement 4, immunoglobulin M and alkaline phosphatase, decrease the levels of serum malondialdehyde, cortisol, aspartate aminotransferase and glutamic-pyruvic transaminase. Furthermore, dietary A. propinquus schischkin polysaccharides can decrease the gene expression levels of interleukin-1β, interleukin-, tumor necrosis factor-α and nuclear factor-κB, increase the gene expression levels of glucocorticoid receptor in liver, spleen, kidney, intestine. To sum up, dietary A. propinquus schischkin polysaccharides can accelerate growth, enhance immune responses and antioxidants responses, regulate inflammation-related genes expression in Channa argus and the optimum amount is 1000 mg/kg.

Toxic effects of hexavalent chromium (Cr6+) on bioaccumulation, apoptosis, oxidative damage and inflammatory response in Channa asiatica

The objective of this study was to evaluate the toxic effects of Cr⁶⁺ on bioaccumulation, digestion, immunity, oxidative stress, apoptosis and inflammation-related genes in Channa asiatica. The fish was exposed to waterborne Cr⁶⁺ concentrations (0, 0.5, 1.0 and 2.0 mg/L) for 28 and 56 days. Our results demonstrated that the accumulation of Cr⁶⁺ in tissues increased in a concentration-dependent manner, and the content in tissue was liver > gill > gut > muscle. Meanwhile, Cr⁶⁺ exposure led to a remarkable suppression of digestion, immunity and antioxidant capacity in C. asiatica. Inversely, MDA and PC content were positively correlated with Cr⁶⁺ exposure concentration. Furthermore, the expression of genes went up with the increase of waterborne Cr⁶⁺ concentration. Among them, HSP90, NF-κB and TNF-α have a sharp increase. These results elucidate that waterborne Cr⁶⁺ exposure may induce bioaccumulation, inhibit digestion and immunity, promote oxidative stress and up-regulate the expression of apoptosis and inflammation-related genes in C. asiatica.

Bioflocs attenuate Mn-induced bioaccumulation, immunotoxic and oxidative stress via inhibiting GR-NF-κB signalling pathway in Channa asiatica

Manganese (Mn) is a relatively common element in aquatic ecosystems and can be bio-concentration, but the mechanism of manganese poisoning on fish health is unclear. Here, this study's objective was to evaluate the potential mechanisms of bioflocs in ameliorating Mn-induced toxicity in Channa asiatica. Three hundred sixty juveniles were randomly divided into 12 tanks. Four C:N ratios in triplicate tanks were tried: C/N = 7.6:1 with a commercial diet (control), C/N 10:1, C/N 15:1 and C/N 20:1, and the bio-accumulation, immunotoxic, oxidative stress, GR-NF-κB related genes expression and intestinal histomorphology were assessed in three different periods after Mn exposure (0 h, 48 h and 96 h). The results showed that bioflocs had a significant protective effect on Mn poisoning by preventing alterations in bio-accumulation levels, LSZ, AKP, C3, C4 and IgM, of which the C/N 15:1 group had the best relief effect. Furthermore, bioflocs also assisted in the recovery of liver T-SOD, CAT, GPX and T-AOC levels while decreasing the content of MDA. Moreover, C/N 15:1 group significantly down-regulated the expression level of NF-κB, TNF-α, IL-1β and IL-8 and up-regulated significantly IκBα, GR, HSP70 and HSP90 expression levels considerably (P < 0.05). From the intestinal section, the C/N 15:1 group resistance was the best one, and there was no difference between C/N 20:1 group and control group. These results revealed that administration of bioflocs (C/N 15:1) has the potential to combat Mn toxicity in C. asiatica, and the specific pathway may be GR-NF-κB.

Bioflocs attenuates lipopolysaccharide-induced inflammation, immunosuppression and oxidative stress in Channa argus

The regulation of C/N in aquaculture water is an important means of environmental regulation, of which the most common is bioflocs technology (BFT). Here, an eight-week feeding experiment and a lipopolysaccharide (LPS) challenge test were proceed to investigate the growth, oxidative stress, immunosuppression and GR-NF-κB related genes expression of Channa argus rearing in the BFT. Four groups were set, the control group was a basic diet (C/N = 7.6:1), and the other three groups were adjusted by glucose, which was C/N 10: 1, C/N 15: 1 and C/N 20:1, respectively. And we detected the two-stage test indexes of C. argus before and after the LPS challenge. The results showed that the bioflocs of C/N 15:1 group significantly (P < 0.05) promoted the growth performance. Similarly, the trend of immune enzyme activity was the same before and after LPS challenge, but decreased after challenge (except AKP and IgM). The best group is still treatment C/N 15:1. Liver and intestine SOD, CAT, GPX, ASA and T-AOC levels of juveniles in treatment C/N 15:1 were markedly increased (P < 0.05) compared to control before and after the LPS challenge. Simultaneously, the content of MDA in control group was considerably higher than that in treatment C/N 15:1 (P < 0.05). Furthermore, C/N 15:1 group significantly down-regulated the expression level of pro-inflammatory factors (NF-κB, TNF-α, IL-1β and IL-8), and up-regulated IκBα, GR, HSP70 and HSP90 expression levels considerably (P < 0.05). Also, intestinal morphology appeared injury in control group, while intestinal integrity was better in treatment C/N 10:1 and C/N 15:1 after challenge. Taken together, these upshot indicated that bioflocs could enhance growth and alleviate C. argus from LPS-induced oxidative stress, immunosuppression and inflammation through restraining GR-NF-κB signaling pathway. The best C/N ratio for alleviating LPS is 15:1.

The anti-inflammatory effect of ent-kaur-15-en-17-al-18-oic acid on lipopolysaccharide-stimulated RAW264.7 cells associated with NF-κB and P38/MAPK pathways

Ent-kaur-15-en-17-al-18-oic acid (LL-3) was demonstrated that it can inhibit LPS-induced nitric oxide (NO) production and macrophage migration, maintain homeostasis of oxidative stress, including increased mitochondrial membrane potential (MMP), decreased levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and maintenance of superoxide dismutase (SOD) and glutathione (GSH) activities and inhibit oxidative stress-induced P38 and nuclear factor κB (NF-κB) pathways to decrease inducible nitric oxide synthase (iNOS), cyclooxygense-2 (COX-2), and tumour necrosis factor (TNF)-α mRNA expressions without marked cytotoxicity. These findings revealed that LL-3 could serve as a candidate lead compound for further studying anti-inflammatory therapies.[Formula: see text].

Vitamin D3 mitigates lipopolysaccharide-induced oxidative stress, tight junction damage and intestinal inflammatory response in yellow catfish, Pelteobagrus fulvidraco

The present study explored the possible mitigative effects of vitamin D₃ (VD₃) on lipopolysaccharide (LPS)-induced intestinal oxidative stress, inflammatory response and tight junction damage in yellow catfish, Pelteobagrus fulvidraco. Herein, four experimental groups were established by injecting yellow catfish with NaCl, LPS, VD₃ or LPS plus VD₃. The results showed that LPS induced oxidative stress and that exogenous VD₃ mitigated the adverse effects of LPS. Additionally, LPS suppressed the activity of antioxidant enzymes (Cat, Sod and Gr) and upregulated the mRNA expression of proinflammatory cytokines (Tnf-α, Il-1β, Il-8). Furthermore, the mRNA expression of "fencing" tight junctions (Claudin-1, Claudin-5, Occludin, Zo-1) was downregulated, while that of "pore-forming" tight junctions (Claudin-2, Claudin-12) was upregulated, however no effect on apoptosis genes was observed (p53, Bax, Caspase-3 and Caspase-9). These LPS-induced effects were significantly reversed by pretreatment with VD₃. Taken together, this study suggests that exogenous VD₃ substantially alleviates LPS-induced intestinal inflammation by upregulating antioxidant activity, suppressing inflammation and promoting fencing tight junctions in the intestine.

Molecular and functional characterization of a mitochondrial glutathione reductase homolog from redlip mullet (Liza haematocheila): Disclosing its antioxidant properties in the fish immune response mechanism

Glutathione reductase (GSHR) is a biologically important enzyme involved in the conversion of oxidized glutathione (GSSG) into its reduced form, reduced glutathione (GSH), with the catalytic activity of NADPH. Most animals and aquatic organisms, including fish, possess high levels of this enzyme system to neutralize oxidative stress in cells. The current study was conducted to broaden our knowledge of GSHR in fish by identifying a mitochondrial isoform of this enzyme (LhGSHRm) in redlip mullet, Liza haematocheila, and clarifying its structure and function. The complete open reading frame of LhGSHRm consists of 1527 base pairs, encoding 508 amino acids, with a predicted molecular weight of 55.43 kDa. Multiple sequence alignment revealed the conservation of important amino acids in this fish. Phylogenetic analysis demonstrated the closest evolutionary relationship between LhGSHRm and other fish GSHRm counterparts. In tissue distribution analysis, the highest mRNA expression of LhGSHRm was observed in the gill tissue under normal physiological conditions. Following pathogenic challenges, the LhGSHRm transcription level was upregulated in a time-dependent manner in the gill and liver tissues, which may modulate the immune reaction against pathogens. rLhGSHRm showed considerable glutathione reductase activity in an enzyme assay. Further, the biological activity of rLhGSHRm in balancing cellular oxidative stress was observed in both disk diffusion and DPPH assays. Collectively, these results support that LhGSHRm has profound effects on modulating the immune reaction in fish to sustain precise redox homeostasis.

Toxic effects of waterborne lead (Pb) on bioaccumulation, serum biochemistry, oxidative stress and heat shock protein-related genes expression in Channa argus

Lead (Pb) is a harmful metal element for aquatic animals. The aim of this study was to determine waterborne Pb exposure on oxidative stress, serum biochemistry and heat shock proteins (HSPs) genes expression in Channa argus. Fish were randomly divided into four groups and the Pb concentrations were 0, 50, 200, and 800 μg/L, respectively. The results showed that the accumulation of Pb was detected in the gill, intestine, liver and muscle following exposure to Pb. Pb accumulation content in tissues was gill > intestinal > liver > muscle. With the increased of Pb exposure concentrations, the levels of catalase (CAT), glutathione peroxidase (GPx), lysozyme (LZM) and immunoglobulin M (IgM) significantly decreased. Serum biochemistry, oxidative stress parameters and HSPs gene expression were all enhanced with the increase following Pb expose concentration. Our results suggest that waterborne Pb exposure can induce Pb accumulation, oxidative stress and immune response in C. argus.

Amelioration of hexavalent chromium-induced bioaccumulation, oxidative stress, tight junction proteins and immune-related signaling factors by Allium mongolicum Regel flavonoids in Ctenopharyngodon idella

Chromium (Cr) is the most common heavy metal and that becomes toxic when present at higher concentrations in aquatic environments. Allium mongolicum Regel flavonoids (AMRF) has been documented to possess detoxification, antioxidant and anti-inflammatory properties. The aim of this study was to explore the potential of dietary AMRF and Cr exposure on bioaccumulation, oxidative stress, and immune response in Ctenopharyngodon idella. After acclimation, 360 fish were randomly distributed into six groups. The fish were fed with diets supplemented with Cr and/or AMRF for 4 weeks (28 days), the Cr concentrations were 0, 120, and 240 mg/kg and the concentrations of AMRF were 0 or 40 mg/kg, respectively. The results shown that Cr accumulation in the kidney, liver, spleen, intestine and gill were significantly increased following Cr exposure, dietary AMRF supplementation attenuated the increased in Cr accumulation. Dietary AMRF supplementation significantly reduced the levels of malondialdehyde (MDA) and protein carbonyl (PC) in liver, spleen and gill compared with the same Cr dose groups. When fish were supplemented with AMRF significantly increased lysozyme activity (LZM), complement 3 (C3) in kidney and intestine compared with the same Cr dose groups. Serum glutamic oxalate transaminase (GOT) and glutamic pyruvate transaminase (GPT) were significantly increased following exposure to Cr. Dietary AMRF supplementation significantly decreased GOT and GPT activity in the serum. In addition, AMRF supplementation can decrease the expression of inflammatory (NF-κB p65, TNF-α and IL-1β) and increased the expression of tight junction proteins (occludin and ZO-1) following Cr exposure in C. idella. These results indicate that AMRF has the potential to alleviate the effects of Cr toxicity in C. idella.

Effect of dietary isoleucine on skin mucus barrier and epithelial physical barrier functions of hybrid bagrid catfish Pelteobagrus vachelli × Leiocassis longirostris

The study investigated the effects of dietary isoleucine (Ile) on skin mucus barrier and epithelial physical barrier functions of hybrid bagrid catfish Pelteobagrus vachelli × Leiocassis longirostris. A total of 630 fish (33.11 ± 0.09 g) were fed semi-purified isonitrogenous diets containing 5.0 (control), 7.5, 10.0, 12.5, 15.0, 17.5, and 20.0 g Ile kg ^-1 diet for 8 weeks. The results indicated that dietary Ile increased (P < 0.05) in skin (1) mucus protein content and antimicrobial activity against three gram-negative bacteria (Aeromonas hydrophila, Escherichia coli, and Yersinia ruckeri) and two gram-positive bacteria (Streptococcus agalactiae and Staphylococcus aureus), (2) mucus lysofew information is available about the influencezyme (LZM), acid phosphatase (ACP), and alkaline phosphatase (AKP) activities, and complement 3 and 4 (C3 and C4) and immunoglobulin M (IgM) contents, (3) intelectin 1 (intl1), intelectin 2 (intl2), c-type-lysozyme (c-LZM), g-type-lysozyme (g-LZM), and β-defensin mRNA levels. Dietary Ile decreased (P < 0.05) reactive oxygen species (ROS), malondialdehyde (MDA), and protein carbonyl (PC) contents, and up-regulated (P < 0.05) CuZnSOD, GST, GPX1a, muc5ac, muc5b, zonula occludens-1 (ZO-1), zonula occludens-2 (ZO-2), occludin, and claudin 3 mRNA levels in skin. These results indicated that Ile improved skin mucus barrier function via increasing mucus protein, C3 and C4, and IgM contents and antibacterial factors activities, and promoted epithelial physical barrier function via decreasing skin antioxidant damage and improving tight junction structure in hybrid bagrid catfish.

Effectiveness of the guava leaf extracts against lipopolysaccharide-induced oxidative stress and immune responses in Cyprinus carpio

The anti-inflammatory activity of the guava leaf extracts (GLE) against LPS-induced inflammatory responses in fish macrophage cell lines is well documented. Here, we evaluated the effects of dietary GLE on LPS-induced oxidative stress, immune responses, and glucocorticoid receptor-related gene expression in Cyprinus carpio. Basal diet was supplemented with 0 (control), 100, 150, 200, or 250 mg kg^-1 GLE for eight weeks. Highest (p < 0.05) weight gain rate was obtained in fish group supplemented with 200 mg kg^-1 of GLE. The results showed that superoxide dismutase, glutathione-S-transferase, glutathione peroxidase, glutathione reductase, lysozyme, and complement C3 decreased, while malondialdehyde level increased in the liver and spleen upon LPS-challenge. Dietary GLE supplementation (especially 200 or 250 mg kg^-1) alleviated LPS-induced changes. Similarly, GLE (150-250 mg kg^-1) reversed LPS-induced alteration of serum biochemical parameters such as alkaline phosphatase, aspartate transaminase, alanine transaminase, and myeloperoxidase. LPS treatment markedly induced increased the mRNA levels of TNF-α, IL-1β, and NF-κB p65 in both the liver and kidney tissues; however, GLE pre-treatment attenuated LPS-induced elicitation of TNF-α, IL-β, and NF-κB p65. Moreover, dietary GLE supplementation significantly increased the expression of HSP70 and HSP90, and glucocorticoid receptor in the liver and kidney after LPS challenge. Thus, GLE attenuated LPS-induced inflammation response by up-regulating glucocorticoid receptor-related gene expression in carp. Finally, GLE supplementation reduced carp mortality after LPS-challenge. These results suggest that dietary supplementation with 200 mg kg^-1 GLE is adequate for effectively attenuating LPS-induced oxidative stress and immune-suppressive effects in C. carpio.

Impacts of Amino Acids on the Intestinal Defensive System

The intestine interacts with a diverse community of antigens and bacteria. To keep its homeostasis, the gut has evolved with a complex defense system, including intestinal microbiota, epithelial layer and lamina propria. Various factors (e.g., nutrients) affect the intestinal defensive system and progression of intestinal diseases. This review highlights the current understanding about the role of amino acids (AAs) in protecting the intestine from harm. Amino acids (e.g., arginine, glutamine and tryptophan) are essential for the function of intestinal microbiota, epithelial cells, tight junction, goblet cells, Paneth cells and immune cells (e.g., macrophages, B cells and T cells). Through the modulation of the intestinal defensive system, AAs maintain the integrity and function of the intestinal mucosa and inhibit the progression of various intestinal diseases (e.g., intestinal infection and intestinal colitis). Thus, adequate intake of functional AAs is crucial for intestinal and whole-body health in humans and other animals.

Administration of commensal Shewanella sp. MR-7 ameliorates lipopolysaccharide-induced intestine dysfunction in turbot (Scophthalmus maximus L.)

This study was designed to evaluate whether the administration of commensal Shewanella sp. MR-7 (MR-7) could ameliorate lipopolysaccharide (LPS)-induced intestine dysfunction in turbot. Fish (body weight: 70.00 ± 2.00 g) were randomly divided into three groups including the control group treated with dough, the LPS group treated with dough plus LPS, and the LPS+MR-7 (LMR) group treated with dough plus LPS and MR-7. These three groups with 24 fish each were force-fed with 1 g dough daily for 7 continuous days. The results revealed that MR-7 administration ameliorated LPS-induced intestinal injury, showing higher intestinal villus and microvillus height. Further results showed that MR-7 could inhibit LPS-induced activation of TLR-NF-κB signaling thus maintaining the normal expression levels of cytokines and finally ameliorate the intestinal inflammatory response in turbot. Compared with the LPS group, LMR group had less goblet cells and lower mucin-2 expression level. Moreover, MR-7 restored LPS-induced down-regulation of tight junction protein-related gene expression (zonula occluden-1, occludin, tricellulin and claudin-3). Further investigations indicated that MR-7 partially counteracted LPS-induced changes in gut microbiota composition, enhanced the beneficial bacteria Lactobacillus and reduced the Pseudomonas, thus maintaining the overall microbiota balance. Taken together, the administration of MR-7 could effectively restore LPS-induced intestine function disorder in turbot by ameliorating inflammatory response, mucosal barrier dysfunction and microbiota dysbiosis.

Effect of sub-chronic exposure to selenium and astaxanthin on Channa argus: Bioaccumulation, oxidative stress and inflammatory response

Selenium (Se) is the most common micronutrient and that becomes toxic when present at higher concentrations in aquatic environments. Astaxanthin (AST) has been documented to possess antioxidant and anti-inflammatory properties. The aim of this study was to explore the potential of dietary AST and Se exposure on oxidative stress, and inflammatory response in Channa argus. After acclimation, 540 fish were randomly distributed into nine groups housed in twenty-seven glass tanks. The fish were exposed for 8 weeks to waterborne Se at 0, 100 and 200 μg L^-1 or dietary AST at 0, 50 and 100 mg kg^-1. The results shown that Se accumulation in the kidney, liver, spleen, intestine and gill were significantly increased following Se exposure, dietary 50 and 100 mg kg^-1 AST supplementation decreased the accumulation of Se in the kidney, liver, spleen, and intestine. In addition, AST supplementation can decrease oxidative stress and inflammatory response in the liver and spleen following exposure to waterborne Se. These results indicate that AST has the potential to alleviate the effects of Se toxicity in C. argus.

Combination of Glutamine and Ulinastatin Treatments Greatly Improves Sepsis Outcomes

Background

Sepsis is one of the most dangerous syndromes, has extremely high mortality, and is caused by the body’s extreme responses to an infection. The pathogenesis of sepsis is very complex and remains largely unknown and thus the treatments for sepsis are limited. Here, we evaluated the treatment results of two potential drugs, glutamine and ulinastatin, on sepsis.

Methods

CLP rat model was used to study sepsis. Gastrostomy was performed to deliver the drugs. Flow cytometry was employed to measure CD4 and CD8 levels. May–Grünwald–Giemsa staining was used to count the numbers of monocytes and neutrophils in the blood. ELISA assay was performed to assess the levels of PCT, IL-6, TNFα, and IL-1β.

Results

Sepsis was successfully induced with the standard CLP rat model. Both glutamine and ulinastatin treatments greatly improved the outcomes of sepsis, but the combination of both treatments had the maximum therapeutic effect. Mechanistically, PCT, IL-6, TNFα, and IL-1β levels were significantly diminished following glutamine and ulinastatin treatments, suggesting an inhibition of inflammatory responses. Further, CD4 and CD4/CD8 ratio, and the numbers of monocytes and neutrophils were greatly up-regulated by glutamine and ulinastatin, indicating an enhanced immunity.

Conclusion

Glutamine and ulinastatin treatments largely mitigate sepsis shock by suppressing the inflammatory responses of the body and strengthening the immune system. Combination of these two drugs could serve as a potential treatment for sepsis.

In vitro immune function in laboratory-reared age-0 smallmouth bass (Micropterus dolomieu) relative to diet

Smallmouth bass (Micropterus dolomieu) are used as an indicator species in environmental monitoring and assessment studies. However, laboratory-based studies for methods development and effector assessment are limited for this species. Nutrition, a known modulator of teleost physiological responses including immune function, is a critical knowledge-gap sometimes overlooked in the design of laboratory studies. We report the results from a study evaluating a commercially available artificial pelleted diet for bass and live feed (fathead minnows). Following a six-month diet-acclimation period, age-0 smallmouth bass were assessed using morphometric measures, histologic and immune-function end points using conventional methods, miniaturized cell isolation and assay methods as well as imaging flow cytometry. Fish on the two diets did not significantly differ in length, weight, or condition factor, indicating that growth was similar in the two groups. Histologic examination revealed relatively higher levels of macrophage aggregates and accumulation of ceroid/lipofuscin in the spleen as well as hepatocyte changes in the pellet-fed group. Leukocytes from the pellet-fed group exhibited significantly elevated bactericidal activity and significantly depressed mitogen response compared to fish fed live feed. Following exposure to a known inducer of inflammatory responses, bacterial lipopolysaccharide, responses including the transition of leukocytes to an apoptotic/necrotic condition differed significantly based on diet. Histologic findings were consistent with the occurrence of diet-related oxidative stress in the pellet-fed fish. Oxidative stress can be induced by multiple factors including environmental pollutants. For a diet to be useful in laboratory-based studies, it cannot elicit response that could also be induced by experimental treatments. To do so greatly complicates the detection of experimental effects. Until an artificial diet is developed for smallmouth bass that does not produce potentially confounding conditions for laboratory-based studies, use of a live feed appears to be the best option.

Dietary choline supplementation attenuated high-fat diet-induced inflammation through regulation of lipid metabolism and suppression of NFκB activation in juvenile black seabream (Acanthopagrus schlegelii)

The present study aimed to investigate whether dietary choline can regulate lipid metabolism and suppress NFκB activation and, consequently, attenuate inflammation induced by a high-fat diet in black sea bream (Acanthopagrus schlegelii). An 8-week feeding trial was conducted on fish with an initial weight of 8·16 ± 0·01 g. Five diets were formulated: control, low-fat diet (11 %); HFD, high-fat diet (17 %); and HFD supplemented with graded levels of choline (3, 6 or 12 g/kg) termed HFD + C1, HFD + C2 and HFD + C3, respectively. Dietary choline decreased lipid content in whole body and tissues. Highest TAG and cholesterol concentrations in serum and liver were recorded in fish fed the HFD. Similarly, compared with fish fed the HFD, dietary choline reduced vacuolar fat drops and ameliorated HFD-induced pathological changes in liver. Expression of genes of lipolysis pathways were up-regulated, and genes of lipogenesis down-regulated, by dietary choline compared with fish fed the HFD. Expression of nfκb and pro-inflammatory cytokines in liver and intestine was suppressed by choline supplementation, whereas expression of anti-inflammatory cytokines was promoted in fish fed choline-supplemented diets. In fish that received lipopolysaccharide to stimulate inflammatory responses, the expression of nfκb and pro-inflammatory cytokines in liver, intestine and kidney were all down-regulated by dietary choline compared with the HFD. Overall, the present study indicated that dietary choline had a lipid-lowering effect, which could protect the liver by regulating intrahepatic lipid metabolism, reducing lipid droplet accumulation and suppressing NFκB activation, consequently attenuating HFD-induced inflammation in A. schlegelii.

IRW and IQW Reduce Colitis-Associated Cancer Risk by Alleviating DSS-Induced Colonic Inflammation

Background and Objective

Bioactive peptides exert great influence in animals and human health by targeting gastrointestinal tracts. The colitis model of mice was induced by dextran sulfate sodium (DSS). Thirty-two 8-week-old mice weighing 23 g on average were randomly assigned to four groups of 8 each: mice fed basal diet (CON), mice fed basal diet with 5% DSS (DSS), mice fed 0.03% IRW with 5% DSS (IRW-DSS), and mice fed 0.03% IRW with 5% DSS (IQW-DSS). After an adaptation period of 3 days, on day 8, all mice were slaughtered. Serum samples were collected to determine the level of amino acids; colonic tissue was quick-frozen for the determination of gene expression.

Methods

The aim of this study was to assess the ability of two kinds of peptides (IRW and IQW) to repair intestinal inflammatory in the DSS-induced model in accordance with serum amino acids and intestinal inflammatory factors.

Results

The results demonstrated that the addition of IRW and IQW had a mitigating effect on DSS-induced intestinal inflammation. The level of Asp decreased in the serum of mice supplemented with IRW-DSS (P < 0.05), and IQW enhanced the level of Leu, but lowered the level of Ser (P < 0.05). IQW and IRW addition reduced the level of TNF-α and IL-17 (P < 0.05). No other significant effects were observed.

Conclusions

The present study demonstrated that intracolic administration of IRW and IQW might be a novel option for preventing inflammatory bowel disease via regulating the level of serum amino acid and enhancing the intestinal immune defense.

Effect of sub-chronic exposure to selenium and Allium mongolicum Regel flavonoids on Channa argus: Bioaccumulation, oxidative stress, immune responses and immune-related signaling molecules

Selenium (Se) is a micronutrient that becomes toxic when present at higher concentrations in fish tissues. Allium mongolicum Regel flavonoids (AMRF) have been documented to possess antioxidant, immunoenhancement and anti-inflammation properties. The aim of this study was to investigate the protective effects and potential mechanisms of dietary supplementation of AMRF and Se exposure on oxidative stress, immune responses and immune-related genes expression in Channa argus. A total of 480 C. argus were randomly divided into eight groups housed in twenty-four 200 L glass aquarium (3 tanks per group, 20 fish per tank). The fish were exposed for 56 days to waterborne Se at 0, 50, 100 and 200 μg/L and/or dietary AMRF at 40 mg/kg. The result indicated that AMRF exerted significant protective effects by preventing alterations in the levels of bioaccumulation, malondialdehyde, lysozyme, complement C3 and immunoglobulin M. AMRF also assists in the elevation of catalase and glutathione peroxidase in the liver and spleen while regulating the expression of immune-related genes including NF-κB p65, IκB-α, TNF-α, IL-1β, IL-8, HSP70, HSP90, and glucocorticoid receptor after 56 days of Se exposure. Our results suggest that administration of AMRF (40 mg/kg) has the potential to combat Se toxicity in C. argus.

Hydrolyzed wheat gluten alleviates deoxynivalenol-induced intestinal injury by promoting intestinal stem cell proliferation and differentiation via upregulation of Wnt/β-catenin signaling in mice

Disintegration of the intestine caused by deoxynivalenol (DON), which is a fungal metabolite found in cereal grain-based human and animal diets, triggers severe intestinal inflammatory disease. Hydrolyzed wheat gluten (HWG) can promote the development of intestine. Therefore, HWG was administered orally to male mice on 1-14 days, and DON was administered to them on 4-11 days. Feed, water intake and body weight were recorded all over the experimental period. Blood samples were collected then the mice were sacrificed to collect the jejunum for crypt isolation and culture. The intestinal morphology was observed by electron microscopy, and Western blotting was used to investigate intestinal stem cell (ISC) proliferation and differentiation, as well as the primary regulatory mechanism of the Wnt/β-catenin signaling. The results showed that HWG increased the average daily gain and average daily water intake of mice under DON-induced injury conditions, and increased the jejunum weight, villous height in the jejunum, and promoted jejunal crypt cell expansion. The DON-induced decrease in Wnt/β-catenin activity, the expression of Ki67, PCNA and KRT20 were rescued by HWG in the jejunum, crypt and enteroid, as well as the number of goblet cells and Paneth cells. Furthermore, HWG increased jejunum diamine oxidase (DAO) activity. In conclusion, HWG alleviates DON-induced intestinal injury by enhancing ISC proliferation and differentiation in a Wnt/β-catenin-dependent manner.

The development of antioxidant system in the intestinal tract of broiler chickens

The gastrointestinal tract is the site for the uptake of nutrients from the external environment. We hypothesized that the antioxidant system in the intestinal tract has a vital protective role from the oxidative damage induced by oxidants in foods. The aim of this study was to investigate the development of the antioxidant system in the intestine of chickens. The activity and gene expression of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and the content of the non-enzymatic substance glutathione (GSH) were measured in the duodenum, jejunum, and ileum of chickens at 1, 3, 7, 11, 14, 21, 35, and 42 d of age. The results showed that the small intestinal tract had relatively higher SOD activity and GSH concentration and lower CAT and GSH-Px activities, compared with those of other visceral organs. CAT and GSH-Px activities and GSH concentration showed a decreasing trend with age, whereas SOD activity was not significantly influenced by age. The gene expression of SOD1, SOD2, and GSH-Px7 showed a dramatic decrease from 3 d of age. The results indicated that SOD and GSH were highly expressed in the first week of age after hatching. To conclude, the results suggest that SOD and GSH play a vital protective role in the small intestine after hatching, which contributes to rapid development of the intestine.