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-1ß, 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.

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.

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-1ß, 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.

Effects of dietary Allium mongolicum Regel polysaccharide on growth, lipopolysaccharide-induced antioxidant responses and immune responses in Channa argus.

The present study evaluated the effects of dietary Allium mongolicum Regel polysaccharide (AMRP) on growth, lipopolysaccharide-induced antioxidant responses and immune responses in Channa argus. A basal diet was supplemented with AMRP at 0, 1, 1.5 or 2 g/kg feed for 56 days. After the 56 days feeding period, weight gain (WG), specific growth rate (SGR) and feed conversion ratio (FCR) were significantly increased or decreased (P < 0.05) by dietary AMRP, with the highest WG, SGR and the minimum FCR occurring in 1.5 g/kg AMRP group. Furthermore, AMRP supplementation conferred significant protective effects against LPS challenge by preventing alterations in the levels of complements 3 (C3) and complements 4 (C4), lysozyme, superoxide dismutase (SOD), glutathione-S-transferase (GST), interleukin-1ß (IL-1ß) and tumour necrosis factor-α (TNF-α) while regulating the expression of immune-related genes including heat shock protein 70 (HSP70), heat shock protein 90 (HSP90), SOD, GST, IL-1 and TNF-α. Finally, AMRP supplementation significantly increased serum total protein, albumin and globulin concentrations and reduced mortality after LPS challenge. Taken together, our results suggest that the administration of AMRP could attenuate LPS-induced negative effects in C. argus, with 1.5 g/kg considered a suitable dose.

Astaxanthin protects lipopolysaccharide-induced inflammatory response in Channa argus through inhibiting NF-κB and MAPKs signaling pathways.

The present study was conducted to evaluate the protective effects of astaxanthin against lipopolysaccharide (LPS)-induced inflammatory responses in Channa argus in vivo and ex vivo. Primary hepatocytes were exposed to different concentrations of LPS for 24 h to induce an inflammatory response, and the protective effects of astaxanthin against LPS-induced inflammation were studied ex vivo and in vivo. Hepatocytes exposed to LPS (5-20 µg mL-1) alone for 24 h resulted in a significant increase in lactate dehydrogenase release (LDH), Nitric oxide (NO) production and Malondialdehyde (MDA) content, 10 µg mL-1 LPS could induced inflammatory response in hepatocytes. Gene expression of TLR4, NFkBp65, MAPKp38, TNF-α, IL-6 and IL-1ß mRNA expression were also enhanced ex vivo (p < 0.05). In vivo test demonstrated that pretreatment with astaxanthin prevented the LPS-induced upregulation of pro-inflammatory cytokines TNF-α, IL-6 and IL-1ß. Besides, astaxanthin blocked the expression of Toll-like receptor 4 (TLR4) and then suppressed the phosphorylation of nuclear transcription factor-kappa B (NF-κB) p65 and degradation inhibitor of NF-κBα (IκBα). Further study showed that astaxanthin could suppress the phosphorylation of p38, extracellular signal-regulated kinase (ERK) and c-jun NH2-terminal kinase (JNK) in mitogen-activated protein kinase (MAPK) signal pathway. In conclusion, our results suggest that astaxanthin played an anti-inflammatory role by regulating TLR4 and the NF-κB and MAPK signaling pathways in C. argus.

Enhancement of secondary metabolites from Bacillus Licheniformis XY-52 on immune response and expression of some immune-related genes in common carp, Cyprinus carpio.

This study was undertaken to isolate active secondary metabolites from immunostimulatory Bacillus Licheniformis XY-52 and evaluate their activities at 0%, 0.5%, 1.0%, and 2.0% doses supplementation with feed on immune response in common carp at weeks 1, 2, and 3. By applying chromatography techniques and successive recrystallization, two purified metabolites were obtained and identified by spectral data (mass spectrometry and nuclear magnetic resonance) as: Cyclo-(Phe-Tyr) and Cyclo-(Phe-Gly). The results revealed that humoral innate immune parameters (lysozyme activity, phagocytic activity and bactericidal activity) were significantly (P < 0.05) increased after feeding on the two active compounds-supplemented diet. Furthermore, administration of the two active compounds significantly (P < 0.05) up regulated IL-1ß, Type 1 IFN, IFN g2b, IL10 and TNF-α gene expression. Heat shock protein 70 (HSP70) gene expression was significantly (P < 0.05) lower as compared to control group at the end of trial. Common carp fed with the two compounds had higher survival rates (69.3%) compared to the controls (32.0%) after challenged with the pathogen, Aeromonas hydrophila. The present study indicates that the two isolated active compounds could positively influence immune response and enhance disease resistance of common carp against A. hydrophila infection.