Dietary Astragalus polysaccharides ameliorates the growth performance, antioxidant capacity and immune responses in turbot (Scophthalmus maximus L.)

Insights into the molecular mechanisms, structure-activity relationships and application prospects of polysaccharides by regulating Nrf2-mediated antioxidant response

The occurrence and development of many diseases are closely related to oxidative stress. In this context, accumulating evidence suggests that Nrf2, as the master switch of cellular antioxidant signaling, plays a central role in controlling the expression of antioxidant genes. The core molecular mechanism of polysaccharides treatment of oxidative stress-induced diseases is to activate Keap1/Nrf2/ARE signaling pathway, promote nuclear translocation of Nrf2, and up-regulate the expression of antioxidant enzymes. However, recent studies have shown that other signaling pathways in which polysaccharides exert antioxidant effects, such as PI3K/Akt/GSK3β, JNK/Nrf2 and NF-κB, have complex crosstalk with Keap1/Nrf2/ARE, may have direct effects on the nuclear translocation of Nrf2. This suggests a new strategy for designing polysaccharides as modulators of Nrf2-dependent pathways to target the antioxidant response. Therefore, in this work, we investigate the crosstalk between Keap1/Nrf2/ARE and other antioxidant signaling pathways of polysaccharides by regulating Nrf2-mediated antioxidant response. For the first time, the structural-activity relationship of polysaccharides, including molecular weight, monosaccharide composition, and glycosidic linkage, is systematically elucidated using principal component analysis and cluster analysis. This review also summarizes the application of antioxidant polysaccharides in food, animal production, cosmetics and biomaterials. The paper has significant reference value for screening antioxidant polysaccharides targeting Nrf2.

Effects of Plant Polysaccharides Combined with Boric Acid on Digestive Function, Immune Function, Harmful Gas and Heavy Metal Contents in Faeces of Fatteners

The experiment aimed to investigate the effects of plant polysaccharides combined with boric acid on digestive function, immune function and harmful gas and heavy metal contents in the faeces of fatteners. For this study, 90 healthy crossbred fatteners were selected and randomly divided into five groups: the control group was fed with a basal diet (Con); experimental group I was fed with basal diet + 40 mg/kg boric acid (BA); experimental group II was fed with basal diet + 40 mg/kg boric acid + 400 mg/kg Astragalus polysaccharides (BA+APS); experimental group III was fed with basal diet + 40 mg/kg boric acid + 200 mg/kg Ganoderma lucidum polysaccharides (BA+GLP); and experimental group IV was fed with basal diet + 40 mg/kg boric acid + 500 mg/kg Echinacea polysaccharides (BA+EPS). Compared with Con, the average daily gain (ADG), the trypsin activities in the duodenum and jejunum, the IL-2 levels in the spleen, the T-AOC activities and GSH-Px contents in the lymph node of fattening were increased in the BA group (p < 0.05), but malondialdehyde content in the lymph and spleen, and the contents of NH3, H2S, Hg, Cu, Fe and Zn in the feces and urine were decreased (p < 0.05). Compared with the BA, the ADG, gain-to-feed ratio (G/F), the trypsin and maltase activities in the duodenum and jejunum were increased in the BA+APS (p < 0.05), and the T-SOD activities in the spleen and T-AOC activities in the lymph node were also increased (p < 0.05), but the H2S level was decreased in the feces and urine (p < 0.05). Compared with the BA, the ADG, G/F and the trypsin and maltase activities in the duodenum were increased in the BA+GLP and BA+EPS (p < 0.05), the activities of maltase and lipase in the duodenum of fatteners in the BA+GLP and the activities of trypsin, maltase and lipase in the BA+EPS were increased (p < 0.05). Gathering everything together, our findings reveal that the combined addition of boric acid and plant polysaccharides in the diet of fatteners synergistically improved their growth performance and immune status. That may be achieved by regulating the activity of intestinal digestive enzymes, improving the antioxidant function and then promoting the digestion and absorption of nutrients. Furthermore, the above results reduce the emission of harmful gases and heavy metals in feces and urine.

Astragalus polysaccharide: implication for intestinal barrier, anti-inflammation, and animal production

Intestine is responsible for nutrients absorption and plays a key role in defending against various dietary allergens, antigens, toxins, and pathogens. Accumulating evidence reported a critical role of intestine in maintaining animal and human health. Since the use of antibiotics as growth promoters in animal feed has been restricted in many countries, alternatives to antibiotics have been globally investigated, and polysaccharides are considered as environmentally friendly and promising alternatives to improve intestinal health, which has become a research hotspot due to its antibiotic substitution effect. Astragalus polysaccharide (APS), a biological macromolecule, is extracted from astragalus and has been reported to exhibit complex biological activities involved in intestinal barrier integrity maintenance, intestinal microbiota regulation, short-chain fatty acids (SCFAs) production, and immune response regulation, which are critical for intestine health. The biological activity of APS is related to its chemical structure. In this review, we outlined the source and structure of APS, highlighted recent findings on the regulation of APS on physical barrier, biochemical barrier, immunological barrier, and immune response as well as the latest progress of APS as an antibiotic substitute in animal production. We hope this review could provide scientific basis and new insights for the application of APS in nutrition, clinical medicine and health by understanding particular effects of APS on intestine health, anti-inflammation, and animal production.

Dietary Supplementation of Astragalus membranaceus Extract Affects Growth Performance, Antioxidant Capacity, Immune Response, and Energy Metabolism of Largemouth Bass (Micropterus salmoides)

The present study investigated the effects of Astragalus membranaceus extract (AME) on growth performance, immune response, and energy metabolism of juvenile largemouth bass (Micropterus salmoides). Seven diets containing 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, and 0.6% AME (Con, AME0.1, AME0.2, AME0.3, AME0.4, AME0.5, and AME0.6 groups) were formulated and fed to M. salmoides for 8 weeks. Final body weight (FBW), feed intake (FI), weight gain (WG), and specific growth rate (SGR) were all significantly higher in AME0.4 group than in Con group (P < 0.05). Feed conversion rate (FCR) was significantly improved in AME0.5 group compared with Con group (P < 0.05). Whole-body crude protein contents were significantly increased in AME0.2 group (P < 0.05). Whole-body crude lipid contents were significantly lower in AME0.2 and AME0.3 groups, while muscle lipid was upregulated by dietary AME (P < 0.05). Hepatic malondialdehyde (MDA) contents were significantly lowered in AME0.3 and AME0.4 groups, and catalase (CAT) activities were significantly increased in AME0.1 and AME0.2 groups (P < 0.05). Plasma aspartate aminotransferase (AST) level was significantly lowered in AME0.5, and AME0.6 groups, and alanine aminotransferase (ALT) level was lowered in AME0.5 groups (P < 0.05). Plasma triglyceride was declined in AME0.6 group, and glucose was decreased by 0.3%-0.5% AME (P < 0.05). Significantly higher hepatocyte diameter, lamina propria width, and submucosal layer thickness were recorded in AME0.6 groups, while the longest villi height was obtained in AME0.2 and AME0.3 groups (P < 0.05). The mRNA expression levels of insulin-like growth factor 1 (igf1) revealed the growth-promoting effect of AME. The anti-inflammatory and antiapoptotic effects of AME were demonstrated by transcription levels of interleukin 8 (il-8), tumor necrosis factor-alpha (tnf-a), caspase, B-cell lymphoma-xl (Bcl-xl), bcl-2 associated x (Bax), and bcl-2-associated death protein (Bad). The transcription levels of lipid metabolism and gluconeogenesis related genes, including acetyl-CoA carboxylase alpha (acc1), fatty acid synthase (fasn), fatty acid binding protein 1 (fabp1), phosphoenolpyruvate carboxykinase 2 (pepck2), and glucose-6-phosphatase catalytic subunit 1a (g6pc), were reduced by AME treatment, while the levels of glycolysis-related genes, including glucokinase (gck) and pyruvate kinase (pk), were the highest in AME0.2 and AME0.3 groups (P < 0.05). According to polynomial regression analysis of SGR, WG, FCR, whole-body crude lipid, MDA, and ALT, the optimal AME supplementation level was estimated to be 0.320%-0.429% of the diet. These results provided insights into the roles of AME in regulating immunity and metabolism, which highly indicated its potential as immunostimulants and metabolic regulators in diverse aquatic animals.

Astragalus polysaccharide protects experimental colitis through an aryl hydrocarbon receptor-dependent autophagy mechanism

BACKGROUND AND PURPOSE

Disruption of intestinal barriers plays a vital role in the pathogenesis of colitis. The aryl hydrocarbon receptor (AhR) is a recognition sensor that mediates intestinal immune homeostasis and minimizes intestinal inflammation. Astragalus polysaccharide (APS) exerts pharmacological actions in colitis; however, the mechanism has not been elucidated. We investigated whether APS protects through AhR-dependent autophagy.

EXPERIMENTAL APPROACH

The symptoms of dextran sulfate sodium (DSS)-induced colitis in mice involving intestinal barrier function and inflammatory injury were evaluated after APS administration. Intestinal-specific Becn1 conditional knockout (Becn1 cKO) mice were constructed and compared with wild-type mice. Autophagy and the effects of APS were investigated after the deactivation of AhRs. The relationship between APS-induced AhRs and autophagic Becn1 was investigated using a dual-luciferase reporter system and chromatin immunoprecipitation (ChIP)-quantitative polymerase chain reaction assay. Caco-2 cells were used to investigate inflammatory responses and AhR-dependent autophagy.

KEY RESULTS

APS improved intestinal barrier function in inflammatory injury in colitis mice. APS triggered autophagic flow; however, knockout of Becn1 in the gut increased susceptibility to colitis, leading to diminished epithelial barrier function and severe intestinal inflammation, impairing the protective effects of APS. Mechanistically, APS-triggered autophagy depends on AhR expression. Activated AhR binds to the promoter Becn1 to operate transcription of genes involved in anti-inflammation and intestinal barrier repair, while deactivation of AhR correlated with intestinal inflammation and the therapeutic function of APS.

CONCLUSIONS AND IMPLICATIONS

APS protects colitis mice by targeting autophagy, especially as the AhR stimulates the repair of damaged intestinal barrier functions.

Soluble non-starch polysaccharides in fish feed: implications for fish metabolism

Because of their unique glycosidic bond structure, non-starch polysaccharides (NSP) are difficult for the stomach to break down. NSP can be classified as insoluble NSP (iNSP, fiber, lignin, etc.) and soluble NSP (sNSP, oligosaccharides, β-glucan, pectin, fermentable fiber, inulin, plant-derived polysaccharides, etc.). sNSP is viscous, fermentable, and soluble. Gut microbiota may catabolize sNSP, which can then control fish lipid, glucose, and protein metabolism and impact development rates. This review examined the most recent studies on the impacts of various forms of sNSP on the nutritional metabolism of various fish in order to comprehend the effects of sNSP on fish. According to certain investigations, sNSP can enhance fish development, boost the activity of digestive enzymes, reduce blood sugar and cholesterol, enhance the colonization of good gut flora, and modify fish nutrition metabolism. In-depth research on the mechanism of action is also lacking in most studies on the effects of sNSP on fish metabolism. It is necessary to have a deeper comprehension of the underlying processes by which sNSP induce host metabolism. This is crucial to address the main issue of the sensible use of carbohydrates in fish feed.

Effects of three different plant-derived polysaccharides on growth performance, immunity, antioxidant function, and cecal microbiota of broilers

BACKGROUND

This study investigated the effects of dietary plant polysaccharides on growth performance, immune status and intestinal health in broilers. We randomly divided 960 one-day-old Arbor Acres broiler chicks into four groups. The control (CON) group was fed a basal diet, and the remaining groups were fed a basal diet supplemented with 1000 mg kg-1 Ginseng polysaccharide (GPS), Astragalus polysaccharide (APS), or Salvia miltiorrhiza polysaccharide (SMP) for 42 days.

RESULTS

Dietary supplementation with SMP significantly increased body weight (BW) at 21 and 42 days of age, average daily gain (ADG) and average daily feed intake (ADFI) during the starter and whole experimental period, decreased the concentrations of interleukin-1 beta (IL-1β), tumor necrosis factor α (TNF-α) and malondialdehyde (MDA), increased the levels of interleukin-4 (IL-4) and interleukin-10 (IL-10) and catalase (CAT) activity in the serum (P < 0.05). GPS, APS, and SMP supplementation increased serum levels of immunoglobulins, activities of glutathione peroxidase (GSH-Px), total superoxide dismutase (T-SOD) and total antioxidant capacity (T-AOC), and cecal concentrations of acetic acid and propionic acid of broilers (P < 0.05). Furthermore, high-throughput sequencing results showed that the relative abundance of Firmicutes was decreased while the relative abundance of Bacteroidota, Alistipes, and Prevotellaceae_NK3B31_group were increased (P < 0.05) in the GPS, APS, and SMP groups compared with the CON group.

CONCLUSION

Dietary GPS, APS, and SMP supplementation could improve growth performance, enhance immune function by increasing serum immunoglobulin and regulating cytokines, improve antioxidant function by increasing serum antioxidant enzyme activity, increase volatile fatty acid levels and improve the microbial composition in the cecum of broilers. Dietary SMP supplementation had the optimal effect in this study. © 2023 Society of Chemical Industry.

The attenuating effects of synbiotic containing Cetobacterium somerae and Astragalus polysaccharide against trichlorfon-induced hepatotoxicity in crucian carp (Carassius carassius)

This study aimed to investigate the hepatotoxic effects of trichlorfon on crucian carp (Carassius carassius) and the attenuating effects of a synbiotic combination of Cetobacterium somerae and Astragalus polysaccharide on hepatotoxicity. Results showed that trichlorfon did indeed induce hepatotoxicity in crucian carp and the synbiotic reversed this hepatotoxicity caused by trichlorfon. The synbiotic increased TC, TG, LDL-C, ALT and AST levels and decreased serum HDL-C levels caused by trichlorfon. H&E and Oil Red O staining demonstrated that the synbiotic ameliorated liver damage and abnormal lipid accumulation. The activity of antioxidant enzymes (T-SOD, CAT, GSH-Px) in the liver was also enhanced by the administration of the synbiotic. The supplementation of the synbiotic also increased the level of short-chain fatty acids in the intestine. In addition, the synbiotic balanced the gut microbial composition, leading to a reduction in the abundance of potentially pathogenic bacteria and an increase in the abundance of bacteria producing short-chain fatty acids. In conclusion, these findings indicate that trichlorfon can induce hepatotoxicity in crucian carp, whereas synbiotics can regulate gut microbiota, promote the growth of beneficial bacteria and increase the production of SCFAs, and alleviate trichlorfon-induced liver injury.

Effects of dietary chloroquine on fish growth, hepatic intermediary metabolism, antioxidant and inflammatory responses in turbot

Autophagy is a conserved cellular self-digestion process and is essential for individual growth, cellular metabolism and inflammatory responses. It was responsive to starvation, pathogens infection and environmental stress. However, the information on the regulation of autophagy in fish hepatic intermediary metabolism, antioxidant system, and immune responses were limited. In the present study, turbot with inhibited autophagy flux was built by dietary chloroquine. The hepatic metabolic response, antioxidant enzymes and immune responses were explored. Results showed that dietary chloroquine induced the expression of Beclin 1, SQSTM and LC-3II, and effectively inhibited autophagy flux. Autophagy dysfunction depressed fish growth and feed utilization, while it induced clusters of liver lipid droplets. The genes involved in lipolysis and fatty acid β-oxidation, as well as the lipogenesis-related genes in chloroquine group were depressed. The phosphorylation of AMPK was activated in chloroquine group, and the genes involved in glycolysis were induced. The hepatic content of malonyldialdehyde and the activities of SOD and CAT were induced when autophagy was inhibited. The content of Complement 3, Complement 4 and Immunoglobulin M, as well as the activity of lysozyme in plasma were depressed in chloroquine group. Dietary chloroquine induced the expression of toll-like receptors and stimulated the expression of myd88 and nf-κb p65, as well as the pro-inflammatory cytokines, such as tnf-α and il-1β. The expression of anti-inflammatory cytokine tgf-β was depressed in the chloroquine group. Our results would extend the knowledge on the role of autophagy in teleost and assist in improving fishery production.

Early Molecular Immune Responses of Turbot (Scophthalmus maximus L.) Following Infection with Aeromonas salmonicida subsp. salmonicida

Turbot aquaculture production is an important economic activity in several countries around the world; nonetheless, the incidence of diseases, such furunculosis, caused by the etiological agent A. salmonicida subsp. salmonicida, is responsible for important losses to this industry worldwide. Given this perspective, this study aimed to evaluate early immune responses in turbot (S. maximus L.) following infection with A. salmonicida subsp. salmonicida. For this, 72 fish were individually weighed and randomly distributed into 6 tanks in a circulating seawater system. For the bacterial challenge, half of the individuals (3 tanks with 36 individuals) were infected using a peritoneal injection with the bacterial suspension, while the other half of individuals were injected with PBS and kept as a control group. Several factors linked to the innate immune response were studied, including not only haematological (white blood cells, red blood cells, haematocrit, haemoglobin, mean corpuscular volume, mean cell haemoglobin, mean corpuscular haemoglobin concentration, neutrophils, monocytes, lymphocytes, thrombocytes) and oxidative stress parameters, but also the analyses of the expression of 13 key immune-related genes (tnf-α, il-1β, il-8, pparα-1, acox1, tgf-β1, nf-kB p65, srebp-1, il-10, c3, cpt1a, pcna, il-22). No significant differences were recorded in blood or innate humoral parameters (lysozyme, anti-protease, peroxidase) at the selected sampling points. There was neither any evidence of significant changes in the activity levels of the oxidative stress indicators (catalase, glutathione S-transferase, lipid peroxidation, superoxide dismutase). In contrast, pro-inflammatory (tnf-α, il-1β), anti-inflammatory (il-10), and innate immune-related genes (c3) were up-regulated, while another gene linked with the lipid metabolism (acox1) was down-regulated. The results showed new insights about early responses of turbot following infection with A. salmonicida subsp. salmonicida.

Astragalus polysaccharide improves the growth, meat quality, antioxidant capacity and bacterial resistance of Furong crucian carp (Furong carp♀ × red crucian carp♂)

To evaluate the functional effects of APS (Astragalus polysaccharide) on Furong crucian carp, APS-supplemented diets (0.00 %, 0.05 %, 0.10 % and 0.15 %) were prepared and utilized in feeding experiment. The results showed that the 0.05 % APS group has the highest weight gain rate and specific growth rate, and the lowest feed coefficient rate. In addition, 0.05 % APS supplement could improve muscle elasticity, adhesiveness and chewiness. Moreover, the 0.15 % APS group had the highest spleen-somatic index and the 0.05 % group had the maximum intestinal villus length. 0.05 % and 0.10 % APS addition significantly increased T-AOC and CAT activities while MDA contents decreased in all APS groups. The plasma TNF-α levels in all APS groups significantly increased (P<0.05), and the 0.05 % group showed the highest TNF-α level in spleen. In APS addition groups, the tlr8, lgp2 and mda5 gene expressions were significantly elevated, while xbp1, caspase-2 and caspase-9 expressions decreased in uninfected and A. hydrophila-infected fish. Finally, higher survival rate and slower disease outbreak rate were observed in APS-supplemented groups after being infected by A. hydrophila. In conclusion, Furong crucian carp fed by APS-supplemented diets possesses elevated weight gain rate and specific growth rate, and improved meat quality, immunity and disease resistance.

Dietary flaxseed (Linum usitatissimum) oil supplementation affects growth, oxidative stress, immune response, and diseases resistance in rainbow trout (Oncorhynchusmykiss)

This paper describes the effects of flaxseed (Linum usitatissimum) oil (FSO) as a feed additive on growth performance, oxidative stress, immunity, and disease resistance in rainbow trout (Oncorhynchus mykiss). Four-hundred-and-twenty rainbow trout individuals (mean weight: 25.66 ± 1.33 g) were fed with different doses of FSO (0.5, 1, and 1.5%) ad libitum two times a day for 9 weeks. At the end of the feeding, growth performance was evaluated and the fish were challenged with two different bacteria (Yersinia ruckeri and Aeromonas hydrophila). At the end of the 3rd, 6th, and 9th weeks, blood and tissue samples were collected from 9 fish per treatment to evaluate innate immune response, cytokine gene expression levels, antioxidant enzyme activities and lipid peroxidation levels, and digestive enzyme activities. Determination of haematological parameters and histological examination was also carried out to evaluate the general health status of the fish. Results showed that the final weight and specific growth rate of fish supplemented with FSO increased significantly (p < 0.05). FSO-supplemented fish showed higher resistance to Y. ruckeri infection than the control group (p < 0.05). However, survival rates of all groups in A. hydrophila challenge test were similar (p > 0.05). Among the investigated innate immune response parameters, the potential killing activity of phagocytes, myeloperoxidase activity, and lysozyme activity increased in the FSO-supplemented groups (p < 0.05). Almost all cytokine gene expression levels in the experimental groups up-regulated especially after 9 weeks of feeding in the head kidney and intestine (p < 0.05). Similarly, superoxide dismutase and catalase activities were found to be significantly higher in the FSO group than in the control (p < 0.05) whereas, the lipid peroxidation levels drastically declined as a result of the FSO supplementation (p < 0.05). These results suggest that FSO can improve growth, enhance immune response, and lower oxidative damage in rainbow trout when supplemented at the rates of 0.5-1.5% for 9 weeks.

Bidirectional and persistent immunomodulation of Astragalus polysaccharide as an adjuvant of influenza and recombinant SARS-CoV-2 vaccine

Respiratory viral infections, such as coronavirus disease of 2019 (COVID-19) and influenza, cause significant morbidity and mortality and have become a worldwide public health concern with tremendous economic and societal burdens. Vaccination is a major strategy for preventing infections. However, some new vaccines have an unmet need for impairing responses in certain individuals, especially COVID-19 vaccines, despite ongoing vaccine and adjuvant research. Here, we evaluated the effectiveness of Astragalus polysaccharide (APS), a bioactive polysaccharide extracted from the traditional Chinese herb Astragalus membranaceus as an immune adjuvant to regulate the efficacy of influenza split vaccine (ISV) and recombinant severe acute respiratory syndrome (SARS)-Cov-2 vaccine in mice. Our data indicated that APS as an adjuvant can facilitate the induction of high levels of hemagglutination inhibition (HAI) titer and specific antibody immunoglobulin G (IgG) and confer protection against the lethal challenge of influenza A viruses, including increased survival and amelioration of weight loss in mice immunized with the ISV. RNA sequencing (RNA-seq) analysis revealed that the NF-κB and Fc gamma R-mediated phagocytosis signaling pathways are essential for the immune response of mice immunized with the recombinant SARS-Cov-2 vaccine (RSV). Another important finding was that bidirectional immunomodulation of APS on cellular and humoral immunity was observed, and APS-adjuvant-induced antibodies persisted at a high level for at least 20 weeks. These findings suggest that APS is a potent adjuvant for influenza and COVID-19 vaccines, and has the advantages of bidirectional immunoregulation and persistent immunity.

The positive effects of postbiotic (SWF concentration®) supplemented diet on skin mucus, liver, gut health, the structure and function of gut microbiota of common carp (Cyprinus carpio) fed with high-fat diet

Postbiotics are an emerging research interest in recent years, which shows that metabolites, lysate extracts, cell wall components and even culture supernatants of probiotics can also exhibit significant prebiotic effects. In this study postbiotic stress worry free concentration® (SWFC) were prepared from the composition of culture supernatant of Cetobacterium somerae and Lactococcus lactis. The positive effects of SWFC supplemented diets on the growth performance, skin mucus, liver and gut health, and intestinal microbiota profile of Cyprinus carpio fed with high fat diets were investigated. 180 C. carpio with an average body weight of (3.01 ± 0.01) g were selected and randomly divided into three groups. They were fed with one of the three experimental diets supplemented with SWFC of 0 (control), 0.2 and 0.3 g/kg for 98 days, afterwards indexes were detected. The results revealed that, addition of SWFC had no significant effect on growth performance of C. carpio, while it can improve the health of the fish remarkably. In addition, SWFC improved mucosal C3, T-AOC, SOD activities, and decreased lipid peroxidation product MDA level, which were notably better than those in the control group (P < 0.05). In terms of the liver health systems, C. carpio fed on the diet supplemented with 0.2 g/kg of SWFC, showed significant improvement of the liver injured by HFD and reduce the contents of serum ALT and AST, and liver TAG (P < 0.05; P < 0.01). The expression of inflammation-related and lipid synthesis genes revealed that SWFC0.2 group could noteworthy enhance antioxidant capacity, reduced the expression of pro-inflammatory factors (TNF-α, IL-1β) and lipid synthesis genes (ACC, FAS, PPAR-β, PPAR-γ), and up-regulated the expression of anti-inflammatory factors (TGF-β). Additionally, intestinal morphology arose inflammatory cell infiltration, while intestinal integrity was better in SWFC groups compared with the control. Furthermore, the contents of serum LPS and LBP were remarkably lower in the SWFC0.2 group compared with the control (P < 0.01). The mRNA expression of genes related to gut health indicated that SWFC supplementation noteworthy up-regulated the expression of antioxidant (Nrf2, CAT, GPX), immune (Hepcidin, IL-10) and tight junction protein-related (ZO-1, Occludin). Simultaneously, the results of GF-zebrafish showed that the relative expression of anti-inflammatory genes (IL-1β, TGF-β) and antioxidant related genes (Nrf2, HO-1) were significantly up-regulated in SWFC groups. Data on intestinal microbiota profile verified that, at the phylum level, the abundance of Fusobacteria was remarkably elevated in the SWFC groups (P < 0.05), whereas the abundance of Firmicutes was declined noteworthy in SWFC0.2 and SWFC0.3 compared to the control group (P < 0.05; P < 0.01) respectively. At the genus level, the abundance of Cetobacterium in the SWFC groups were notably higher than those in the control group (P < 0.05), while the Vibrio content in the SWFC groups was significantly decreased (P < 0.05). PCoA result indicated that the intestinal microflora of SWFC0.2 group was abundant and diverse. Our results elucidate that dietary supplementation of SWFC protects C. carpio from HFD induced inflammatory response and oxidative stress, ameliorate skin mucus, liver and gut health, and improve the gut microbiota balance. Therefore, SWFC could be considered as an improving-fish-health additive, when supplemented to aquatic animal feed. With regards to how SWFC regulates the immunity and inflammatory responses and which signal transductions are involved remains unclear and more scientific evidences are needed to address these issues.

Potential role of plant polysaccharides as immunostimulants in aquaculture: a review

Aquaculture is one of the primary food-producing sectors in the world that ensures human nourishment. However, aqua farmers are facing serious problems due to disease out breaks and development of antimicrobial resistance. Until now, chemical or antibiotic based strategies has been applied to control disease related concern in aquaculture. Frequent usage of antibiotics in feed or usage of disinfectant to overcome the disease may end up with negative impacts to the environment and human. Utilization of plant derived polysaccharides has been drastically increased due to their effective roles and could serve as a best replacement for chemical agents and antibiotics. In addition, plant derived compounds and plant extracts was utilized to improve the immunity, intestinal health and growth performance of aquaculturable organisms. In addition, large number of plant-based polysaccharides was utilized as immunostimulants in aquaculture. Hence, this review aims to highlight the multifunctional properties of plant-based polysaccharides in aquaculture. Moreover, advantages and different concentration of plant polysaccharides as a feed additives in aquaculture sector has been discussed herein.

Immune-enhancing effects of Astragalus polysaccharides and Ganoderma lucidum polysaccharides on Vibrio harveyi flgJ DNA vaccine in grouper

Astragalus polysaccharides (APS) and Ganoderma lucidum polysaccharides (GLP) have been shown to possess strong immunoregulatory properties in aquatic animals. In this study, the fragment containing Vibrio harveyi flgJ gene was ligated into pcDNA3.1(+) vector and pcDNA3.1(+)-flgJ was constructed as DNA vaccine. APS and GLP were used as DNA vaccine adjuvants to evaluate the immunoregulatory effect by intramuscular injection to pearl gentian grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatus). The results showed that pcDNA3.1(+)-flgJ combined with APS or GLP could significantly up-regulate the innate and adaptive immune response in fish, including serum-specific antibody titres, catalase and lysozyme activities. At the same time, DNA vaccine combined with APS or GLP significantly up-regulated the expression levels of CD8α, IgM, IL-1β, MHC-Iα, MyD88 and TLR3 genes in thymus, head kidney, spleen and liver of pearl gentian grouper in comparison with those of the pFlgJ group. After 42 days post-vaccination, V. harveyi was used to challenge pearl gentian grouper by intraperitoneal injection. The relative percentage of survival (RPS) of pFlgJ, pFlgJ +APS, pFlgJ +GLP and pFlgJ+APS+GLP groups were 69%, 81%, 77% and 88%, respectively. These results suggested APS and GLP were potential adjuvants for DNA vaccine against V. harveyi infection in pearl gentian grouper.

Dietary Supplementation of Sophora flavescens Root Extract Improved the Growth Performance, Antioxidant Capacity, Innate Immunity, and Disease Resistance against Edwardsiella tarda Challenge in Turbot (Scophthalmus maximus)

The impacts of dietary supplementation with graded levels of Sophora flavescens root extract (SFE) on growth performance, antioxidant capacity, immune status, and resistance against Edwardsiella tarda challenge in Scophthalus maximus were investigated in this study. In all, 600 turbot (initial body weight: 8.38 ± 0.07 g) were randomly distributed in 12 tanks with 50 fish per tank and fed four experimental diets supplemented with 0, 0.05%, 0.1%, or 0.2% SFE (named as: SFE0, SFE0.05, SFE0.1, and SFE0.2, respectively), for 56 days. The results showed that 0.1% and 0.2% SFE supplementation have significantly increased the FBW, WGR, SGR, and PER of turbot, while decreased the FCR of turbot (p < 0.05). Dietary SFE supplementations have significantly increased the activities of plasma SOD, CAT, GPx, T-AOC, GST and LZM, decreased plasma MDA contents in turbot under normal or challenge condition (p < 0.05). Meanwhile, SFE addition dramatically enhanced the hepatic mRNA expression of antioxidant parameters (including Nrf2, Keap1, SOD, CAT, Trx2, GST and GR) during the normal condition. mRNA levels of NF-κB p65, IκBα, TNF-α, TGF-β, and IL-10 in the liver of fish were notably up-regulated by SFE treatment during normal condition (p < 0.05), while the transcription of IL-1β was down-regulated by SFE whenever under normal or challenge condition. 0.1% and 0.2% SFE administration have significantly increased the survival rate of turbot against E. tarda challenge (p < 0.05). In conclusion, dietary SFE supplementation improved the growth performance, antioxidant activity and disease resistance of turbot, and SFE could be a potential feed additive for turbot.

Astragalus polysaccharides protect against inactivated Vibrio alginolyticus-induced inflammatory injury in macrophages of large yellow croaker

As an effective immunostimulant, Astragalus polysaccharides (APS) have been widely used in fish aquaculture, however, their action mechanisms remain poorly understood. In the present paper, the inflammatory macrophage model of large yellow croaker (Larimichthys crocea) was constructed by using formalin-inactivated Vibrio alginolyticus. Inactivated V. alginolyticus could cause cellular damage of primary head kidney macrophages (PKM) by decreasing cell activity and inducing reactive oxygen species (ROS) production and cell apoptosis. When PKM were pretreated with APS, the depressed cell activity induced by inactivated V. alginolyticus was significantly improved, and ROS overproduction and cell apoptosis were inhibited. Then the protection mechanism of APS was investigated by transcriptome analysis. After treated with inactivated V. alginolyticus, the expression of immune-related genes (TLR5s, TLR13, Clec4e, IKK, IκB, BCL-3, NF-κB2, REL, IL-1β, and IL-6) and pyroptosis-related genes (caspase-1, NLRP3, and NLRC3) in PKM were significantly up-regulated. However, APS pretreatment reversed the up-regulation of most of the above-mentioned genes, where TLR5s, BCL-3, REL, caspase-1, NLRP12, IL-1β, and IL-6 were significantly down-regulated compared with inactivated V. alginolyticus-treated group. These results suggested that APS could protect large yellow croaker PKM against inactivated V. alginolyticus-induced inflammatory injury, and may exert their protection effects by activating NF-κB and pyroptosis signaling pathways. These findings therefore advance our understanding of the immune regulation mechanism of APS in fish, and facilitate the application of APS in prevention and control of fish bacteriosis.

Effects of white mustard (Sinapis alba) oil on growth performance, immune response, blood parameters, digestive and antioxidant enzyme activities in rainbow trout (Oncorhynchusmykiss)

A study was conducted to evaluate the effects of dietary supplementation of white mustard (Sinapis alba) oil (WMO) on growth performance, immune responses, digestive and antioxidant enzyme activities in juvenile rainbow trout (Oncorhynchus mykiss). For this purpose, fish (initial weight: 25.77 ± 0.13 g) were divided into four experimental groups in triplicate and fed ad libitum twice a day with diets containing WMO at 0 (control), 0.5, 1, and 1.5% of diet for 9 weeks. Three fish from each tank (n:9 per treatment) were sampled on 21st, 42nd, and 63rd days for further analyses. At the end of the feeding period, fish were challenged with Aeromonas hydrophila and Yersinia ruckeri in two separate experimental setups. Results showed that final weight, weight gain, and specific growth rate were significantly increased in all experimental groups compared to the control. Feed conversion ratio was similar among treatments. Respiratory burst and potential killing activity decreased in all experimental groups compared to the control (P < 0.05). Lysozyme and myeloperoxidase activities were elevated in all experimental groups at the end of the experiment compared to the control (P < 0.05). Cytokine gene expressions in the head kidney and intestine were elevated in all experimental groups compared to that of the control in general (P < 0.05). Hematological responses of the experimental fish groups were similar to that of the control (P > 0.05). Pepsin and trypsin levels decreased in all experimental groups (P < 0.05). In terms of antioxidant enzyme activities, significant improvement in liver superoxide dismutase, catalase, and glutathione s-transferase activities in all treatment groups were determined (P < 0.05). In addition, a significant decline in liver lipid peroxidation levels was recorded in all treated groups at all sampling times compared to the control (P < 0.05). At the end of this feeding trial, no significant differences (P > 0.05) were observed in survival against A. hydrophila among experimental groups compared to the control (P > 0.05). However, increased survival against Y. ruckeri was determined in experimental fish groups (P < 0.05). This study suggests that white mustard oil had a favorable effect on the overall health and growth of rainbow trout.

Tolerance Assessment of Atractylodes macrocephala Polysaccharide in the Diet of Largemouth Bass (Micropterus salmoides)

Atractylodes macrocephala polysaccharide (AMP) can enhance antioxidant defense and anti-inflammation, as the tolerance levels of AMP in aquaculture is important for additive utilization. However, the tolerance dose of AMP is unknown. We assess the tolerance levels of AMP in juvenile largemouth bass (3.38 ± 0.11 g) by feeding them a 0, 400, 4000, or 8000 mg/kg AMP supplemented diet for 10 weeks. The 400 mg/kg AMP dose increased growth performance. The Nrf2/Keap1 signaling pathway was activated, as indicated by Keap1 and Nrf2 protein levels in the liver. Enhanced activity of antioxidant enzymes (SOD, GPx), together with increased mRNA levels of antioxidant genes (sod, gpx) and decreased accumulation of reactive oxygen species (ROS) and MDA, was found in the liver, implying the antioxidant effect of AMP. Nutrient absorption was enhanced by AMP, as reflected by the increased length of intestinal villi and microvilli. However, 4000 and 8000 mg/kg AMP induced oxidant stress, as indicated by increased plasma ALT and AST content and decreased mRNA levels of antioxidant genes (sod, gpx) in the liver and intestinal tissues. Inflammatory reactions were also induced by high doses of AMP, as reflected by enhanced levels of pro-inflammatory cytokines (tnfα, nfκb) in the liver, intestinal, and kidney tissues and inhibited levels of anti-inflammatory cytokines (tgfβ, iκb). Histological analysis reveals inflammatory cell infiltration and tissue damage. Thus, the safe tolerance margin of AMP supplement for largemouth bass was 400–4000 mg/kg.

Preventing effect of astragalus polysaccharide on cardiotoxicity induced by chemotherapy of epirubicin: A pilot study

To assess the clinical effect of astragalus polysaccharide in preventing cardiotoxicity induced by chemotherapy of epirubicin. Two hundred forty-eight patients with breast cancer or malignant lymphoma were randomly divided into the experimental group (EG) (n = 124) and the control group (CG) (n = 124). The EG received chemotherapy regimen containing anthracycline epirubicin and astragalus injection, while CG received only chemotherapy regimen containing anthracycline epirubicin. We detected myocardial function (cardiac troponin I [cTnI], creatine kinase isoenzyme [CK-MB], left ventricular ejection fraction [LVEF], and the ratio of mitral annular diastolic peak velocity to atrial systolic velocity [E/A]) and incidences of cardiotoxicity to assess cardiac function, they were compared at before the first treatment course (T1), end of the second course (T2) and 6-month follow-up. We also detected proinflammatory cytokines (IL-6 and TNF-α), reactive oxygen species and antioxidant enzymes, glutathione peroxidase (GPx), and superoxide dismutase (SOD) aimed to discover potential mechanism. There were no statistical significances in differences of LVEF and E/A between 2 groups (P > .05) at T1 and T2, while levels of LVEF and E/A of EG were significant higher than those of the CG at 6 month follow-up, with statistically significant differences (P < .05). At T1, there were no statistical significances in differences of cTnI and CK-MB between 2 groups (P > .05); at T2 and 6 months follow-up, the cTnI, and CK-MB levels of EG was significantly lower than those of the CG, with statistically significant differences (P < .05). The incidence of cardiotoxicity of EG was 15% (17/113), which was significant lower than that of the CG (60%, 66/110), with statistically significant difference (P < .05). Moreover, the level of TNF-α, GPx, and SOD did not show significant difference (P > .05). The data in this pilot study suggested that astragalus polysaccharide may be an effective therapy for preventing cardiotoxicity induced by chemotherapy of epirubicin. Furthermore, larger, placebocontrolled, perspective studies are needed to assess the efficacy of astragalus injection treatment for preventing cardiotoxicity induced by chemotherapy of epirubicin.

The effective components of herbal medicines used for prevention and control of fish diseases

The increasing demand for fish consumption has promoted the rapid development of fish aquaculture. With the continuous expansion of culture scale and the deterioration of culture environment, various diseases have broken out frequently, leading to huge economic losses to fish farming. Antibiotics and chemicals are common options to prevent and control of fish diseases, but their use is now restricted or even banned due to serious problems such as drug residues, pathogen resistance, and environmental pollution. Herbs and their extracts have increasingly become promising supplements and alternatives, because of their effectiveness, safety, environmental friendliness and less drug resistance. The application of herbal medicines in prevention and control of fish diseases is mainly attributed to the powerful immune enhancement, antioxidation or direct anti-pathogenic efficacies of their effective components, including mainly polyphenols, polysaccharides, saponins, flavonoids, alkaloids, and essential oils. Recently these herbal active ingredients have been extensively studied for their efficacies in prevention and control of viral, bacterial, parasitic, and fungal diseases in fish. In the present paper, we comprehensively summarize the research progress of the active ingredients of herbal medicines used for prevention and control of fish diseases, especially of their action mechanisms, and highlight the potential application of the herbal medicines in fish aquaculture.

Immunosuppressive Effects of Thallium Toxicity in Nile Tilapia Fingerlings: Elucidating the Rescue Role of Astragalus membranaceus Polysaccharides

This study evaluated the immunotoxic effects of thallium (Tl) in Nile tilapia fingerlings and the recovery role of dietary Astragalus membranaceus polysaccharides (ASs). An 8-week experiment was designed where 180 fishes were randomly and equally assigned in triplicates into the six groups: the control group (CNT) was reared in unpolluted water and fed a commercial diet, two groups were fed a well-balanced commercial diet plus 1.5 and 3.0 g AS/kg diet (AS0.15 and AS0.30), respectively, the fourth group was exposed to a sublethal dose of Tl (41.9 μg l^-1) [equal to 1/10 of 96-h lethal concentration 50 (LC50)], and the last two groups were fed 0.15 and 0.3% AS, respectively, and concurrently exposed to Tl (41.9 μg l^-1) (AS0.15+Tl and AS0.30+Tl). Fish hematobiochemical parameters, serum immunity [nitric oxide, total immunoglobulin M (IgM) levels, and lysozyme activity], transcription of hepatic interferon-γ (IFN-γ), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α), and resistance to Aeromonas hydrophila (A. hydrophila) were assessed. Hematobiochemical parameters and serum immune indices were significantly decreased in the fish group exposed to sublethal Tl concentration compared to the CNT group. Furthermore, Tl exposure significantly induced overexpression of IL-1β, TNF-α, and IFN-γ genes (4.22-, 5.45-, and 4.57-fold higher, respectively) compared to CNT values. Tl exposure also increased the cumulative mortality (%) in Nile tilapia challenged with A. hydrophila. Remarkably, the groups fed AS0.15+Tl and AS0.30+Tl significantly ameliorated all the aforementioned parameters, but did not reach CNT values. Our findings suggest the possible immunomodulating roles of dietary AS in recovering the immunotoxic effects of Tl in Nile tilapia. We can conclude that dietary AS would be useful for maintaining the immunity of Nile tilapia fingerlings.

The growth performance, body composition and nonspecific immunity of white shrimps (Litopenaeus vannamei) affected by dietary Astragalus membranaceus polysaccharide

The aim of this study was to investigate the effects of Astragalus membranaceus polysaccharide (AMP) on the growth performance, body composition and non-specific immune index of white shrimps (Litopenaeus vannamei). AMP was used to replace 0 (control), 10, 30, and 50 g kg^-1 of the cellulose in the basic diet to formulate four kinds of test feeds. Sixplicate groups of shrimps with an average weight of 0.51 ± 0.03 g were fed with one of diets four times daily. Dietary 50 and 30 g kg^-1 of AMP increased body weight gain, feed efficiency, body protein, superoxide dismutase activity, catalase activity, acid phosphatase activity, lysozyme, disease resistance ability against Vibrio alginolyticus and decreased body lipid level of shrimps compared with those of the control group. However, a high level of AMP (50 g kg^-1) did not improve the efficiency of AMP on the growth performance, body composition and non-specific immune index of shrimps further compared to moderate level of AMP (30 g kg^-1). The results demonstrated that AMP with appropriate dose could promote the growth of shrimps and improve their disease resistance.

Evaluation of the effects of Astragalus polysaccharides as immunostimulants on the immune response of crucian carp and against SVCV in vitro and in vivo

This experiment was conducted to evaluate the immunomodulatory effect and antiviral activity of Astragalus polysaccharides (APS) in crucian carp and epithelioma papulosum cyprinid (EPC) cells. Two diets containing 0 and 2 g/kg, APS were fed crucian carp for 56 days. The results showed that supplementation with APS significantly upregulated the immune-related indices including the levels of IgM, the activities of LZM, AKP and ACP, and the contents of C3 and C4. At the same time, compared with the CK group, adding APS to the feed significantly upregulated the expression of IL-8, IL-10, IL-1β, IFN-α, IFN-γ, MyD88, TGF-β and TNF-α in the spleen, kidney, liver and intestine of crucian carp. In addition, when the crucian carp were injected with SVCV, the survival rates of fish in the APS group and the control group were 48.87% and 13.76%, respectively. These results indicated that dietary APS could improve the resistance of crucian carp against SVCV infection. APS also significantly decreased viral titer and inhibited apoptosis induced by SVCV in EPC cells. These results indicated that APS could stimulate the immune response of crucian carp and improve the abilities of crucian carp and EPC cells to resist SVCV infection.

Effects of Dietary Inositol Supplementation on Growth, Digestive Performance, Antioxidant Capacity, and Body Composition of Golden Pompano (Trachinotus ovatus)

A 56-day culture experiment was performed to evaluate effects of inositol supplementation on growth, digestive performance, antioxidant capacity, and body composition of golden pompano (Trachinotus ovatus). Five experimental diets (D1, D2, D3, D4, and D5) supplemented with 0, 150, 300, 600, and 1,200 mg kg⁻¹ inositol were formulated, respectively. Triplicate groups of 300 fish with an initial weight of (18.78 ± 0.21 g) and 15 seawater cages were used in the feeding experiment. Results indicated that the final body weight (FBW), weight gain rate (WGR), specific growth ratio (SGR), and condition factor (CF) in fish fed with D3–D5 diets were significantly higher than those fed the D1 and D2 diets, and the highest values were detected in D3 diet treatment. The whole-body composition was not significantly affected by different experimental diets. Fish fed with D3-D5 diets showed higher activities of amylase (AMS), lipase (LPS), and superoxide dismutase (SOD), and significantly higher than those fed with D1 and D2 diets. In contrast, fish fed with D3–D5 diets showed lower MDA content and significantly lower than those fed with D1 and D2 diets. The mRNA level of glutathione reductase (GR) in fish fed with D3 and D4 diets was significantly higher than those fed with D1, D2, and D5 diets. Likewise, the mRNA level of catalase (CAT) significantly increased in the dietary inositol groups compared with the D1 group. In conclusion, the supplement of inositol not less than 300 mg kg⁻¹ in the diet is indispensable to maintain the rapid growth and promote antioxidative capacity of T. ovatus.

Astragalus membranaceus polysaccharides modulate growth, hemato-biochemical indices, hepatic antioxidants, and expression of HSP70 and apoptosis-related genes in Oreochromis niloticus exposed to sub-lethal thallium toxicity

A 60-day experiment was performed to assess the efficacy of dietary Astragalus membranaceus polysaccharides (ASP) in attenuation of sub-lethal thallium (Tl) toxicity in Nile tilapia. Six experimental groups (in triplicates) were designed where a fish group was raised in clean water and fed basal diet and served as control (CONT), two groups were fed the basal diet supplemented with 0.15% and 0.30% ASP (ASPL and ASPH), Tl-intoxicated group exposed to 1/10 of 96-h LC50 (= 41.9 μg/L), and two other groups were fed 0.15% and 0.30% ASP and concomitantly exposed to 41.9 μg Tl/L (ASPL-Tl and ASPH-Tl). At the end of the experiment, fish behavioral responses, clinical signs, survivability, growth, whole-body composition, intestinal digestive enzymes, serum biochemical parameters, hepatic antioxidative biomarkers, and transcription of stress and apoptosis genes were assessed. Results showed that the whole-body composition, intestinal α-amylase and protease enzymes, serum AST and blood urea levels, and hepatic GSH were not significantly different among groups (P > 0.05). The Tl-intoxicated fish group was off food, had darkened skin, showed restlessness and hyperexcitability, and high mortalities. FBW, WG, SGR and FI were significantly decreased alongside increase FCR in the Tl-exposed group. Tl exposure caused significant increases (P < 0.05) in intestinal lipase enzyme and serum indices such as ALT, creatinine, total cholesterol, triglycerides, glucose, and cortisol levels. Moreover, a significant decreases in hepatic CAT and SOD enzyme activities and significant increases in hepatic MDA contents were also noticed (P < 0.05). Furthermore, Tl exposure induced significant upregulation of hepatic HSP70 and apoptosis-related genes (p53 and caspase 3). Interestingly, dietary supplementation with ASP in ASPL-Tl and ASPH-Tl groups modulated the parameters mentioned above but still not reached the CONT values. Altogether, this study suggests that ASP could be beneficial in the modulation of sub-lethal Tl toxicity effects in Nile tilapia. Additionally, we can conclude that using natural feed supplements such as ASP in aquafeed might be necessary for maintaining the overall health performances of Nile tilapia.

Effects of dietary Glycyrrhiza polysaccharide on growth, serum biochemistry, immunity, and egg laying in quail

This study was conducted to evaluate the effects of dietary supplementation with Glycyrrhiza polysaccharide (GCP) on growth performance, serum biochemistry, immunity, and egg laying in female quail. 300 1-day-old female quail were sorted into four dietary treatments with five replicate cages of 15 birds each. The basic diet in the four treatment groups was supplemented with 0, 500, 1000 and 1500 mg/kg GCP, and the experiment continued for 80 days. Results showed that dietary supplementation with GCP significantly (p < 0.05) increased average daily gain in a dose-dependent fashion, and decreased (p < 0.05) the feed-to-gain ratio and mortality. The relative weights of the thymus and bursa of Fabricius increased (p < 0.05) linearly with increasing dose of GCP from 0 to 1500 mg/kg on day 20. GCP birds showed higher serum levels of protein, glucose, immunoglobulin A and immunoglobulin M, but lower serum triglycerides (p < 0.05) on day 50. GCP increased (p < 0.05) average laying rate and average egg weight linearly from days 60 to 80, whereas feed to egg ratio was decreased (p < 0.05). Taken together, these results revealed that GCP could improve growth performance, serum biochemistry, immunity, and egg laying in female quail. Therefore, GCP may be a potential replacement for antibiotic growth promoters in poultry.

Immunostimulant Bathing Influences the Expression of Immune- and Metabolic-Related Genes in Atlantic Salmon Alevins

Disease resistance of fish larvae may be improved by bath treatment in water containing immunostimulants. Pattern recognition receptors, such as TLR3, TLR7, and MDA5, work as an "early warning" to induce intracellular signaling and facilitate an antiviral response. A single bath of newly hatched larvae, with Astragalus, upregulated the expression of IFNα, IFNc, ISG15, MDA5, PKR, STAT1, TLR3, and TLR7 immune genes, on day 4 post treatment. Similar patterns were observed for Hyaluronic acid and Poly I:C. Increased expression was observed for ISG15, MDA5, MX, STAT1, TLR3, TLR7, and RSAD2, on day 9 for Imiquimod. Metabolic gene expression was stimulated on day 1 after immunostimulant bath in ULK1, MYC, SLC2A1, HIF1A, MTOR, and SIX1, in Astragalus, Hyaluronic acid, and Imiquimod. Expression of NOS2 in Poly I:C was an average fourfold above that of control at the same timepoint. Throughout the remaining sampling days (2, 4, 9, 16, 32, and 45 days post immunostimulant bath), NOS2 and IL1B were consistently overexpressed. In conclusion, the immunostimulants induced antiviral gene responses, indicating that a single bath at an early life stage could enable a more robust antiviral defense in fish. Additionally, it was demonstrated, based on gene expression data, that cell metabolism was perturbed, where several metabolic genes were co-regulated with innate antiviral genes.

NLRP3 inflammasome is involved in the mechanism of mitigative effect of selenium on lead-induced inflammatory damage in chicken kidneys

Lead (Pb) is a kind of widespread toxic environmental pollutant which can cause harm to organisms. Selenium (Se) has the property of mitigating Pb toxicity through decreasing oxidative stress and inflammation caused by Pb. Nucleotide-binding domain, leucine-rich-containing family, and pyrin-domain containing-3 (NLRP3) inflammasome involve in inflammation process. However, the effect of NLRP3 inflammasome in heavy metal-caused animal damage remains unknown. This research aimed to explore the mechanism of mitigative role of Se on Pb-caused renal inflammatory injury in chickens. One-week-old male chickens were provided a standard diet and drinking water, a standard diet added with 1 mg kg^-1 of Se and drinking water, a standard diet and drinking water added with 350 mg L^-1 Pb, and a standard diet added with 1 mg kg^-1 Se and drinking water added with 350 mg L^-1 Pb. On the 4th, 8th, and 12th weeks, serum was used to measure creatinine (CREA) and uric acid (UA) contents, and kidneys were used to measure Se and Pb concentrations, histological structure, oxidative stress indicators, relative expressions of cytokines, and inflammatory factors. The results showed that Pb accumulated, Se concentration decreased, CREA and UA contents increased, and renal injury occurred in Pb-treated chicken kidneys. Excess Pb increased MDA content and the expressions of IL-1β, IL-6, IL-17, NLRP3, caspase-1, NF-κB, COX-2, TNF-α, and PTGEs and decreased GSH content, GPx and SOD activities, and IFN-γ expression in the chicken kidneys. Se administration alleviated the aforementioned changes. In addition, toxic effect of Pb on the chicken kidneys was time-dependent. NLRP3 inflammasome, caspase-1, and IL-1β may be sensitive indicators in Pb-induced chicken kidney inflammatory damage. In conclusion, NLRP3 inflammasome took part in antagonistic role of Se against Pb-caused inflammation via changing oxidative stress indicators, cytokines, and inflammation-related genes in the chicken kidneys.

MiR-196-5p involvement in selenium deficiency-induced immune damage via targeting of NFκBIA in the chicken trachea

Dietary selenium (Se) deficiency can induce multifarious immune injury in tissues, accompanied by inflammation and a decreased expression of selenoproteins. The results of previous studies indicated that these issues are associated with Se-mediated microRNAs involved in immune regulation, although the specific mechanisms associated with these interactions have not been reported in the trachea of chickens. To explore the effects of Se deficiency in the trachea of chickens and the role of miR-196-5p, we established correlational models of tracheal injury in chickens. One hundred broilers were divided into four groups, including a control group (C group), a Se deficient group (L group), a lipopolysaccharide (LPS)-induced control group (C + LPS group) and a LPS-induced Se deficient group (L + LPS group). Light microscopy observations indicated that the infiltration of inflammatory cells was the major histopathological change caused by Se deficiency. Furthermore, ultrastructural observation of the tracheal epithelium and ciliary showed typical inflammatory signs owing to Se deficiency. We determined the targeting relationship between miR-196-5p and NFκBIA by bioinformatics analysis. In the case of Se deficiency, the changes were detected as follows: 19 selenoproteins showed different degrees of decrease (p < 0.05). Significant inhibition of both antimicrobial peptides and immunoglobulin production were observed (p < 0.05). IκB-α (NFκBIA) expression degraded with the increasing miR-196-5p (p < 0.05), and the NF-κB pathway was activated. Thereafter, we can see a significant increase in the mRNA levels of inflammatory cytokines-related genes (tumor necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, prostaglandin E (PTGE), interleukin (IL)-1β, IL-6) and protein expression of NF-κB/iNOS pathway-related genes (NF-κB, iNOS, TNF-α, COX-2) (p < 0.05). The release of IL-2, interferon (IFN)-γ inhibited (p < 0.05) and the secretion of IL-4, IL-6 increased, suggesting the imbalance of Th1/Th2 (Th, helper T cell) cytokines. Compared to the control, the mRNA and protein expression levels of the anti-inflammatory system components with antioxidant activity (PPAR-γ/HO-1) were in an inhibitory state (p < 0.05). Antioxidases (SOD, CAT, GSH-Px) activities were suppressed. The activities of the peroxide markers (MDA, H₂O₂) were enhanced (p < 0.05). In addition, Se deficiency had a positive effect on the pathological changes of inflammation and the exceptional immunity in LPS-treated groups (p < 0.05). The results confirmed the relationship between miR-196-5p and NFκBIA in chickens, revealing that Se deficiency causes respiratory mucosal immune dysfunction via the miR-196-5p-NFκBIA axis, oxidative stress and inflammation. Moreover, Se deficiency exacerbates the inflammatory damage stimulated by LPS. Our work provides a theoretical basis for the prevention of tracheal injury owing to Se deficiency and can be used as a reference for comparative medicine. Furthermore, the targeted regulation of miR-196-5p and NFκBIA may contribute to the protection of the tracheal mucosa in chickens.

Protective potency of Astragalus polysaccharides against tilmicosin- induced cardiac injury via targeting oxidative stress and cell apoptosis-encoding pathways in rat

Tilmicosin (Til) was purposed to be used in the treatment of a wide range of respiratory diseases in livestock. However, undesirable adverse effects, cardiac toxicity, in particular, may be associated with Til therapy. In the present study, the response of adult rats administered Til subcutaneously at different doses (10, 25, 50, 75, and 100 mg/kg b.w.; single injection) was evaluated. Astragalus polysaccharide (AP) at two doses (100 and 200 mg/kg b.w.; intraperitoneally) was investigated for its potential to counteract the cardiac influences, involving the oxidative stress-induced damage and apoptotic cell death, elicited by the Til treatment at a dose of 75 mg/kg b.w. in rats. Til induced mortalities and altered the levels of the biomarkers for the cardiac damage, particularly in the rats treated with the doses of 75 and 100 mg/kg b.w.; similarly, morphological alterations in cardiac tissue were seen at all studied doses. AP was found to cause a significant (P ˂ 0.05) decline in the levels of impaired cardiac injury markers (troponin, creatine phosphokinase, and creatine phosphokinase-MB), improvement in the antioxidant endpoints (total antioxidant capacity), and attenuation in the oxidative stress indices (total reactive oxygen species, 8-hydroxy-2-deoxyguanosine, lipid peroxides [malondialdehyde], and protein carbonyl), associated with a significant (P ˂ 0.05) modulation in the mRNA expression levels of the encoding genes (Bcl-2, Bax, caspase-3, P53, Apaf-1, and AIF), related to the intrinsic pathway of apoptotic cell death in the cardiac tissue. AP administration partially restored the morphological changes in the rat's heart. The highest protective efficacy of AP was recorded at a dose level of 200 mg/kg b.w. Taken together, these results indicated that AP is a promising cardioprotective compound capable of attenuating Til-induced cardiac impact by protecting the rat cardiac tissue from Til-induced apoptosis when administered concurrently with and after the Til injection.