Response Of Common Carp Research Articles

CcPTGS2a-like gene-mediated NF-κB/ERK signaling regulation in the common carp (Cyprinus carpio)

Prostaglandin-endoperoxide synthase 2 (PTGS2), a common biological macromolecule, is pivotal for innate immunity and pathogen recognition. In this study, we identified and characterized a CcPTGS2a-like gene in the common carp (Cyprinus carpio) with an open reading frame (ORF) of 1821 bp and epidermal growth factor and peroxidase domains. Our multiple sequence analysis revealed high homology between the amino acid sequence of CcPTGS2a-like and those of its homologs in other fish. CcPTGS2a-like mRNA and protein expressions were significantly upregulated in the spleen, head kidney, liver, and gill tissues upon exposure to Aeromonas hydrophila stimulation. CcPTGS2a-like protein recognized the conserved bacterial surface components and exhibited detectable bacterial binding activity. CcPTGS2a-like overexpression before exposure to A. hydrophila notably enhanced the survival rate of common carp, concomitant with decreased bacterial burden. The NF-κB/ERK signaling pathway initiated the immune response in common carp upon infection with A. hydrophila. CcPTGS2a-like overexpression or interference in the head kidney and Epithelioma papulosum cyprinid cells could modulate the p–NF–κB (p-p-65), p-IκBα, and p-ERK1/2 levels as well as the IL-1β and IL-6 mRNA expression. These results indicated potential CcPTGS2a-like involvement in the immune response of the common carp to bacterial infections through the NF-κB/ERK signaling pathway.

Stressing out-carp edema virus induces stress and modulates immune response in common carp.

Carp edema virus (CEV) is a fish poxvirus that primarily infects the gills of common carp. CEV causes koi sleepy disease (KSD), which is highly contagious and can result in mortality of up to 100%. In the present study, we analyzed the stress and immune responses during KSD in two strains of common carp with different resistance to CEV: susceptible koi and resistant Amur sazan. Experiments were performed at two temperatures: 12°C and 18°C. In the case of koi carp, we also analyzed the effect of supplementation of 0.6% NaCl into tank water, which prevents mortality of the CEV-infected fish (salt rescue model). We found that CEV-infected koi kept at 18°C had the highest viral load, which correlated with the most severe histopathological changes in the gills. CEV infection resulted in the activation of stress response reflected by the upregulated expression of genes involved in stress response in the stress axis organs and increased levels of cortisol and glucose in the blood plasma. These changes were the most pronounced in CEV-infected koi kept at 18°C. At both temperatures, the activation of antiviral immune response was observed in koi kept under freshwater and NaCl conditions upon CEV infection. Interestingly, a clear downregulation of the expression of adaptive immune genes was observed in CEV-infected koi kept under freshwater at 18°C. CEV induces a stress response and modulates adaptive immune response in koi, and this is correlated with the level of viral load and disease development.

Regulation of NF-κB signaling by NLRC (NLRC3-like) gene in the common carp (Cyprinus carpio)

Among teleost NLRs, NLR-C subfamily is a large group of proteins that were teleost-specific and evolution analysis showed that NLR-Cs are most likely to evolve from NLRC3 gene (thus also called as NLRC3Ls). Presently, although there have been rich studies investigating teleost NLRC3 and NLRC3L, the data on the regulatory mechanism was limited. In this study, immune regulation of inflammatory signaling pathway mediated by common carp NLRC3L gene (CcNLRC) has been investigated. Confocal microscopy analysis showed that CcNLRC was located in cytoplasm, and in HEK293T cells, dual-luciferase reporter assay showed the regulation of NF-κB signaling by CcNLRC, in which CcNLRC could alter/decrease RIPK2-induced activation of NF-κB. These results indicated that CcNLRC may function as a negative NLR in the regulation of inflammatory response in common carp. Our data will allow to gain more insights into the molecular mechanism of teleost specific NLR (NLRC3L).

Exposure to benzo(a)pyrene interfered with cell composition and immune ability of common carp (Cyprinus carpio) intestine through inducing cell heterogeneous responses

The intricate heterogeneity of fish intestinal cell types response to environmental stressors has remained largely unaddressed due to previous technological limitations. Emerging single-cell sequencing technology (scRNA-seq), derived from the 2010s, may be a key breakthrough in this area, which could accurately obtain the transcriptome of each cell. In this context, common carp (Cyprinus carpio), which takes the intestine as the main immune organ, was selected as the test subject in this study. The study, mainly based on single-cell sequencing technology and supplemented by gas chromatography mass spectrometry (GC/MS), histological sectioning techniques and transcriptome analysis, revealed the detailed heterogeneity responses of intestinal cells in common carp after benzo(a)pyrene (B[a]P) exposure. Our findings showed a dose-dependent effect on B[a]P accumulation within the common carp intestine as the B[a]P concentration increased. B[a]P exposure led to mucous lamina propria edema and confluent intestinal villi. The high concentration group exhibited uneven and adherent intestinal villi, an abnormal decrease in mucosal epithelial cells, vacuolation, and an anomalously widened base thickness.In the intestinal atlas, an increased proportion of T_cells and a decreased proportion of ECs were identified as the most significant features. These changes primarily affected the intestine by impairing development processes and boosting immunocompetence. A comprehensive analysis of the heterogeneous responses of ECs and T_cells to B[a]P exposure revealed that the lysosome-phagosome pathway, strengthened by the “Lysosome” pathway in the EC1 subset and the “Phagosome” pathway in T_cell 2 subset, might be one of the most critical defense mechanisms within the common carp's intestine. In conclusion, our research presents the first description of the intestinal atlas and the heterogeneous responses in common carp following B[a]P exposure. Our findings enrich the understanding of the impact of polyaromatic hydrocarbons, exemplified by B[a]P, on cyprinidae fish.

Effects of Multispecies Probiotic Combination on Growth Performance, Biochemical Indices, and Non-specific Immune Responses in Common Carp (Cyprinus carpio)

Background: Probiotic bacteria as an alternative to antibiotics are necessary for aquaculture due to the prevalence of recurrent diseases. Objectives: This study investigated the effect of a probiotic combination, including endogenous bacteria such as Lactobacillus plantarum, Lactobacillus bulgaricus, Lactobacillus acidophilus, and Lactobacillus rhamnosus, on the health status of common carp. Methods: The probiotic combination was added to carp basal diets in three treatments, 1 to 3, each containing 106 CFU g-1, 107 CFU g-1, and 108 CFU g-1 probiotic combination, respectively. A fourth group (group 4) was used as a control and received no probiotic treatment for six months. After 3 months, the fish’s growth performance, biochemical indices, and innate immune responses were evaluated. Results: The growth indices, such as the daily growth rate, specific growth rate, condition conversion factor, condition factor, and protein efficiency, significantly improved in treatments 2 and 3 compared to the other groups (P < 0.05). Investigation of complement, lysozyme, and serum bactericidal activity showed that probiotic treatments positively affected the immune system of common carp, with treatments 2 and 3 demonstrating a greater effect (P < 0.05). Biochemical factors were also investigated, showing decreased cholesterol and triglyceride levels in the probiotic treatment group. Moreover, the probiotic treatments resulted in a significant reduction in the activity of liver enzymes AST and ALP compared to the control group (P < 0.05). Conclusions: A probiotic combination with concentrations of 5 × 107 CFU g-1 and 5 × 108 CFU g-1 of food can positively impact common carp’s growth performance, immune system, and biochemical parameters. As no significant difference was seen between the two concentrations, the lower one is recommended.

Effect of Beneficial Colonization of Bacillus coagulans NRS 609 on Growth Performance, Intestinal Health, Antioxidant Capacity, and Immune Response of Common Carp (Cyprinus carpio L.)

This study is aimed at exploring the effects of Bacillus coagulans NRS 609 on the growth performance, intestinal health, antioxidant activity, and immune response in common carp (Cyprinus carpio L.) by colonizing the intestinal tract with the beneficial strain. Gavage B. coagulans with GFP-tag at 109 CFU/mL into common carp for 7 days. Results indicated that B. coagulans were maintained in the intestine for at least 14 days. Four groups fed B. coagulans at different levels of inclusion, including 0 (CK), 1 × 10 7 (A), 1 × 10 8 (B), and 1 × 10 9 (C) CFU/g of feed for 8 weeks. Experimental groups showed significantly better growth performance than the control ( P < 0.05 ). The treatment groups had higher digestive enzyme activity, villus height, and muscle thickness than the control ( P < 0.05 ). Supplementation with B. coagulans also altered the composition of the intestinal flora. In addition, an enhancement of the antioxidant enzyme and a reduction of malondialdehyde in the liver were observed with the addition of B. coagulans ( P < 0.05 ). Moreover, the cytokines of IL-1β and IL-12, IL-10, and TGF-β, significant upregulation in experimental groups ( P < 0.05 ). Based on the results, the optimal level of B. coagulans was 107 CFU/g in diets for common carp.

Dietary gallic acid influences serum enzymatic parameters and immunological responses in Cyprinus carpio exposed to crowding stress

Application of dietary feed additives is an excellent approach to improve fish health status under different stressful condition. The current study investigated the roles of different level of dietary gallic acid (GA) on growth performances, biochemical indices, digestive enzymes activity, antioxidant status and immunological responses in common carp (Cyprinus carpio) subjected to crowding stress. Fish were fed with the control diet (0 mg/kg GA) and four graded levels of GA (150, 300, 450 and 600 mg/kg) for 60 days each with three replicates. Moreover, fish were challenged with crowding stress for six hours. The results revealed significant improvement in growth performances, immune indices in common carp fed with dietary GA in comparison to the control diet. The study also demonstrated significant improvement feed utility through enhanced activities of digestive enzymes (amylase, lipase and protease) by dietary GA provision. Moreover, dietary GA noticeably enhanced the antioxidant status of common carp by improving superoxide dismutase, catalase, glutathione peroxidase, and lowering malondiadehyde specially after exposure to crowding stress. Considering these results, the current study reveals that dietary GA at the concentration of 450 mg/kg can successfully improve growth performances, biochemical indices, digestive enzymes activity, antioxidant status and immunological responses in common carp.

Interaction analysis of TRIM proteins and innate immunity mediators of common carp (Cyprinus carpio L.) to evaluate its affinity for ubiquitination and innate immune response

Common carp (Cyprinus carpio L.) is considered the most important aquaculture piscine specie. The continuous exposure of this specie to pathogens, including viruses and bacteria, impact its growth and production. The role of tripartite motifs (TRIM) protein in higher mammals has been investigated and a lot of information is available that demonstrates the function of these proteins in diverse cellular mechanisms including antiviral responses. Fish species do not possess a specialized adaptive immune response as seen in mammals and information related to TRIM proteins is very limited. Therefore, understanding the function of TRIMs is a very important area of research. PPIs play a key role in determining the functions of target proteins. In this study, the outcome of interactions among TRIM proteins of Common carp with important innate immunity mediators is investigated. The TRIM proteins are activated as a response to viral infection and are classified on C-terminal domains. TRIMs including, TRIM3, 9, 21, 23, 25, 33, 37, and 82 contain discrete C-terminal domains that are included in this study. Some important mediators including RIG-I, MDA5, cGAS, STING, and TBK1 are selected in this study for their interactions with TRIMs by using computational approaches. These innate immunity mediators are very important in sensing viral infections. They also induce different signaling pathways that trigger cytokine production and activate downstream signaling pathways. A total of forty interactions are performed and the results suggest that TRIM proteins interact selectively with the mediators. The results further hypothesized the binding affinity, important residues, and regions of these proteins involved in interactions that can modulate different cellular activities. In most of the interactions, the residues present in the BBC and coiled-coil domains are predominantly involved in making contact with their interacting partners. The binding affinity and interacting profile proposed that the coil-coil region is very important for attachment to perform the catalytic activity of the TRIM proteins. The findings of this study will open new avenues in better understanding the molecular mechanisms associated with innate immunity and antiviral responses in Common carp against viral infections.

Quercetin Application for Common Carp (Cyprinus carpio): I. Effects on Growth Performance, Humoral Immunity, Antioxidant Status, Immune-Related Genes, and Resistance against Heat Stress.

This study was done to evaluate the effect of different quercetin levels on growth performance, immune responses, antioxidant status, serum biochemical factors, and high-temperature stress responses in common carp (Cyprinus carpio). A total number of 216 common carp with an average weight of 27.21 ± 53 g were divided into 12 tanks (four treatments × three replications) and fed 0 mg/kg quercetin (T0), 200 mg/kg quercetin (T1), 400 mg/kg quercetin (T2), and 600 mg/kg quercetin (T3) for 60 days. There were significant differences in growth performance, and the highest final body weight (FBW), weight gain (WG), specific growth rate (SGR), and feed intake (FI) were observed in T2 and T3 (P < 0.05). Different quercetin levels significantly increased complement pathway activity (ACH50) and lysozyme activity both before and after heat stress (P < 0.05). Catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) were significantly increased in fish exposed to heat stress, but fish fed with a supplemented diet with quercetin showed the lowest levels both before and after heat stress (P < 0.05). Superoxide dismutase (SOD) levels were significantly enhanced in fish fed diets supplemented with quercetin in both phases (P < 0.05). Different quercetin levels led to a significant decrease in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) before and after the challenging test (P < 0.05). Glucose and cortisol levels were significantly higher in the control group compared to the other treatments in both phases (P < 0.05). The expression of glutathione peroxidase (GPx) and lysozyme was markedly upregulated in fish fed with quercetin-supplemented diets (P < 0.05). No marked effects were observed for growth hormone (GR) and interleukin-8 (IL8) (P > 0.05). In conclusion, dietary quercetin supplementations (400-600 mg/kg quercetin) improved growth performance, immunity, and antioxidant status and increased tolerance to heat stress.

Hepatopancreas toxicity and immunotoxicity of a fungicide, pyraclostrobin, on common carp

Pyraclostrobin (PYR), a strobilurin fungicide, has been widely used to control fungal diseases, posing potential risk to aquatic organisms. However, the toxic effects of PYR to fish remained largely unknown. In this study, common carp (Cyprinus carpio L.) was exposed to environmentally relevant levels of PYR (0, 0.5 and 5.0 μg/L) for 30 days to assess its chronic toxicity and potential toxicity mechanism. The results showed that long-term exposure to PYR induced hepatopancreas damage as evident by increased in serum transaminase activities (AST and ALT). Moreover, PYR exposure remarkably enhanced the expressions of hsp70 and hsp90, decreased the levels of antioxidant enzymes and biomarkers and promoted the reactive oxygen species (H2O2 and O2‐) and MDA contents in carp hepatopancreas. PYR exposure also upregulated apoptosis-related genes (bax, apaf-1, caspase-3 and caspase-9) and reduced anti-apoptosis gene bcl-2 in fish hepatopancreas. Moreover, PYR exposure altered the expressions of inflammatory cytokines (IL-1β, IL-6, TNF-α and TGF-β) in the serum and hepatopancreas and the level of NF-κB p65 in the hepatopancreas. Further research indicated that PYR exposure markedly changed the levels of immune parameters (LYZ, C3, IgM, ACP and AKP) in the serum and/or hepatopancreas, indicating that chronic PYR exposure also has immunotoxicity on fish. Additionally, we found that PYR exposure upregulated p38 and jnk MAPK transcription levels, suggesting that MAPK may be play important role in PYR-induced apoptosis and inflammatory response in the hepatopancreas of common carp. In summary, PYR exposure induced oxidative stress, triggered apoptosis, inflammatory and immune response in common carp, which can help to elucidate the possible toxicity mechanism of PYR in fish.

Research Article: The effects of the water-soluble fraction of diesel (WSFD) on behavioral, biochemical, and growth response in common carp (Cyprinus carpio)

Research Article: The effects of the water-soluble fraction of diesel (WSFD) on behavioral, biochemical, and growth response in common carp (Cyprinus carpio)

The importance of CXC-receptors CXCR1-2 and CXCR4 for adaptive regulation of the stress axis in teleost fish

In an ever-changing environment, an adaptive stress response is the pivotal regulatory mechanism to maintain allostasis. Physiologic responses to stressors enable to overcome potential threat. Glucocorticoid effects can be considered compensatory and adaptive, however prolonged or excessive glucocorticoid secretion can be also maladaptive and detrimental. Therefore, it must be tightly regulated. Apart from the essential hormonal feedback regulation, evidence accrues that cytokines, e.g., proinflammatory interleukin 1β (IL-1β), also play an important regulatory role in the stress axis.Here we focused on the potential role of CXC chemokines (CXCL8 and CXCL12) and their receptors (CXCR1, 2 and 4) in the regulation of the stress response in common carp. We studied changes in gene expression of CXC chemokines and CXCRs in the stress axis organs (hypothalamus-pituitary gland-head kidney) upon 11 h of restraint stress and we established how CXCR blocking affects the activation of the stress axis and the synthesis/conversion of cortisol.During restraint stress, gene expression of the majority of the proinflammatory CXCL8 and homeostatic CXCL12 chemokines and their receptors was upregulated in the stress axis organs. Inhibition of CXCR1-2 and CXCR4 differentially affected the expression of genes encoding stress-related molecules: hormones, binding proteins, receptors as well as expression of genes encoding IL-1β and its receptor. Moreover, we observed that CXC chemokines, via interaction with their respective CXCRs, regulate gene expression of molecules involved in cortisol synthesis and conversion and consistently affect the level of cortisol released into the circulation during the stress response.We revealed that in fish, CXC chemokines and their receptors are important regulators of the stress response at multiple levels of the stress axis, with particularly pronounced effects on steroidogenesis and cortisol conversion in the head kidney.

EFFICIENCY OF SYNBIOTIC AS FEED ADDITIVES ON GROWTH PERFORMANCE, SURVIVAL RATE AND HEALTH STATUS IN COMMON CARP CHALLENGED WITH SAPROLEGNIA SPP.

The present study was conducted to investigate the effects of Synbiotic (combination of probiotic and prebiotic) as feed additive on growth performance, survival rate and immune response against Saprolegnia spp. in common carp. A total of 100 C. carpio fingerlings, weighing 49.55–50.50 g were randomly distributed into five treatment groups in duplicate, fishes were fed with different concentrations as follows: (T1) 0.5 %, (T2)1.0 % ,(T3) 1.5 % and (T4 ) 2% as well as the control group were fed basal diet without any addition of synbiotic. Results showed significant increase (P&lt; 0.05) in all growth parameters (i.e. final weight, DWG, RGR, SGR (%), FCR, FCE) compared with the control group. The highest values were observed in fish fed on the diet containing 2% and 1.5% synbiotic. Also, survival rate recorded highest value (100%) in treatment supplemented with synbiotic 2% compared with control group (75%), suggesting that the high level (2%) improve growth rate and survival rate. At the end of experimental period six fish were randomly selected from each treatment and control (C) + for challenge test in a viable fungal suspension (1×105 live zoospores/ml) of Saprolegnia spp. Considerable changes have been observed in the mean values of WBCs. Respiratory burst activity showed significant increased in all synbiotic diet compared to C+ group. These results can be considered as a beneficial dietary for improving the growth rate and immune response in common carp.

Genome-wide mining of gpx gene family provides new insights into cadmium stress responses in common carp (Cyprinus carpio)

Glutathione peroxidase (Gpx) is an important member of antioxidant enzymes, which can play a vital role in metabolizing reactive oxygen species (ROS) and in maintaining cell homeostasis. In order to study the evolutionary dynamics of gpx gene family in allotetraploid fish species, we identified a total of 14 gpx genes in common carp Cyprinus carpio, while 9 gpx genes were discovered in the diploid progenitor-like species Poropuntius huangchuchieni. Comparative genomic analysis and phylogenetic analysis revealed that the common carp gpx genes had significant expansion and were divided into five distinct subclades. Exon-intron distribution patterns and conserved motif analysis revealed highly conserved evolutionary patterns. Transcript profiles suggested that different gpx genes had specific patterns of regulation during early embryonic development. In adult tissues, gpx genes had a relatively broad expression distribution, most of which were highly expressed in the gills, intestines, and gonads. RT-qPCR studies showed that most gpx genes were downregulated during the initial cd2+ treatment stage. Dietary supplementation of Bacillus coagulans at different concentrations (Group 2 of 1.0 × 107 cfu/g, Group 3 of 1.0 × 108 cfu/g, and Group 4 of 1.0 × 109 cfu/g) induced different regulatory responses of gpx subclades. This result suggested that the appropriate concentration of B. coagulans can improve gpx gene expression when exposed to heavy metal cadmium treatment, which may play a vital role in the resistance to oxidative stress and immune responses. This study has expanded our understanding of the functional evolution of the gpx gene family in common carp.

EFFECTS OF EXTRACTS OF STOCHEOSPERMUM MARGINATUM AND ULVA LACTUCA ON THE HAEMATOLOGICAL AND IMMUNOLOGICAL PARAMETERS ON AEROMONAS HYDROPHILA INFECTED CYPRINUS CARPIO

Objective: Marine algae are the rich source of natural products with pharmacological and biological activities. In the present study the seaweeds Stocheospermum marginatum and Ulva lactuca extracts were used as a immuno stimulants of non-specific immune response in common carp were studied.&#x0D; Methods: The seaweeds Stocheospermum marginatum and Ulva lactuca chosen for the study and were extracted with ethanol. The fishes common carp (Cyprinus carpio) (weight 10±5g)] were divided into five groups. They were infected with A. hydrophila (1.6 × 104 CFU/fish). The infected fishes were injected with seaweeds extracts (0.30 mg) suspended in saline solution. One group was injected only saline (control) and one group was injected with ciprofloxacin (0.30 mg) (standard) suspended in saline. The experiment was carried out for 28 d. In every seven days interval the fishes were injected with seaweed extract and blood parameters of RBC, WBC, HB, Ht, MCV, MCH, and MCHC were recorded.&#x0D; Results: RBC was recorded on 28th day in group 3 (2.86±0.11×106 cells/mm3) followed by group 4 (2.13±0.04×106 cells/mm3). Similarly the WBC values also increase from initial day to final day.&#x0D; The phagocytic assay was same on 28th day in group 3 and group 4 (58.89±1.68). The lysozyme activity was more in group 3 on 28th day 1285±90.92 but the lowest activity recorded in group 4on 28th day 1205±34.35. The respiratory burst activity was higher in group 3 on 28th day 0.184±0.012. Overall results group 3 had the best activity when compared to others.&#x0D; Conclusion: From this study we can understand that the fish injected with seaweed extracts Stocheospermum marginatum and Ulva lactuca seweed as a good immunostimulant. The seaweeds Stoechospermum marginatum had alkaloids, phenol, quinone, saponin, steroid and terpenoid. Ulva lactuca containedalkaloids, sugar, flavenoid, phenol, quinone, steroid and terpenoid. These secondary metabolites were responsible for the immunostumilant activity.

Cytokines Studied in Carp (Cyprinus carpio L.) in Response to Important Diseases

Cytokines belong to the most widely studied group of intracellular molecules involved in the function of the immune system. Their secretion is induced by various infectious stimuli. Cytokine release by host cells has been extensively used as a powerful tool for studying immune reactions in the early stages of viral and bacterial infections. Recently, research attention has shifted to the investigation of cytokine responses using mRNA expression, an essential mechanism related to pathogenic and nonpathogenic-immune stimulants in fish. This review represents the current knowledge of cytokine responses to infectious diseases in the common carp (Cyprinus carpio L.). Given the paucity of literature on cytokine responses to many infections in carp, only select viral diseases, such as koi herpesvirus disease (KHVD), spring viremia of carp (SVC), and carp edema virus disease (CEVD), are discussed. Aeromonas hydrophila is one of the most studied bacterial pathogens associated with cytokine responses in common carp. Therefore, the cytokine-based immunoreactivity raised by this specific bacterial pathogen is also highlighted in this review.

Trichlorfon exposure in common carp (Cyprinus carpio L.) leads to oxidative stress, neurotoxicity, and immune responses

Organophosphorus insecticides, which are widely used to control parasitic infections, could accumulat in the environment and organisms, and their potential toxicity is a great concern. In this study, common carp (Cyprinus carpio L.) was exposed to different concentrations of trichlorfon (0, 0.1, 0.5, and 1.0 mg/L) for 28 days. The oxidative stress in brain and liver, the neurotransmitter contents in brain, and immune responses were investigated. Results revealed more severe oxidative stress effects in liver than in brain, including significant suppressive activities of superoxide dismutase, glutathione peroxidase, and total antioxidant capacity (T-AOC); reduced glutathione content; and increased reactive oxygen species and malondialdehyde contents in liver. Meanwhile, only the T-AOC activity decreased in the brain of trichlorfon-exposed groups. For neurotransmitters, the contents of 5-hydroxyindoleacetic acid, choline, and acetylcholine were all reduced after trichlorfon exposure. In the immune responses, alkaline phosphatase activity significantly decreased, while the lysozyme content significantly increased upon exposure to trichlorfon. Meanwhile, trichlorfon significantly increased the contents of inflammatory cytokines, namely, tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-12, and transforming growth factor β, and significantly decreased the IL-10 content. Moreover, histological observations showed increased numbers of melano-macrophage centers in the head kidney and spleen of exposed common carp. Taken together, the results demonstrated that trichlorfon induced more severe oxidative stresses in liver than in brain, with the presence of neurotoxicity. Trichlorfon could also affect the immune responses in common carp.

The response of common carp (Cyprinus carpio) to insonified bubble curtains.

Acoustic bubble curtains have been marketed as relatively low cost and easily maintained behavioural deterrents for fisheries management. Their energy efficiency can be improved by reducing air flow and exploiting bubble resonance. In a series of three flume experiments, we: (1) investigated the reactions of carp to a low air flow bubble curtain, (2) compared the effectiveness of resonant versus non-resonant insonified bubble curtains (for the same volume flux of gas injected through the nozzles) to deter passage, and determined the stimuli responsible for eliciting deterrence, and (3) included the effect of visual cues generated by the bubble curtain. This study showed that bubble curtains with a higher proportion of resonant bubbles deterred carp relatively better. Passage rejection was likely influenced by multiple cues at distances within a body length of the fish- specifically the rate of change in both particle motion and flow velocity caused by rising bubbles. All acoustic bubble curtains were less effective in the presence of daylight, suggesting that vision plays an important role at mediating carp reactions. We discuss the importance of ascertaining the bubble size distribution, in addition to the gas flow rate and aperture size, when characterising acoustically active bubble curtains.

Cyprinus carpio TRIF Participates in the Innate Immune Response by Inducing NF-κB and IFN Activation and Promoting Apoptosis.

TRIF, an important adaptor downstream of Toll-like receptor signaling, plays a critical role in the innate immune response. In this study, the full-length coding sequence of TRIF from common carp (Cyprinus carpio L.) was cloned and characterized. Bioinformatics analysis showed that common carp TRIF exhibited a conserved TIR domain and had the closest relationship with grass carp TRIF. Expression analysis revealed that TRIF was constitutively expressed in the examined tissues of common carp, with the highest expression in the spleen and the lowest expression in the head kidney, and could be upregulated under Aeromonas hydrophila and poly(I:C) stimulation in vivo and under poly(I:C), LPS, PGN, flagellin, and Pam3CSK4 stimulation in vitro. Laser confocal microscopy showed that common carp TRIF colocalized with the Golgi apparatus. A luciferase reporter assay showed that carp TRIF elicited the activity of ifn-1 and nf-κb through the C-terminal domain. Additionally, crystal violet staining and qPCR assays revealed that carp TRIF inhibited the replication of SVCV in epithelioma papulosum cyprini (EPC) cells. Then, the signaling downstream of carp TRIF was investigated. Coimmunoprecipitation and Western blotting analysis demonstrated that carp TRIF interacted with TBK1 and augmented the expression of TRAF6 and phosphorylation of TBK1. Overexpression of carp TRIF significantly enhanced the expression of interferon-stimulated genes and inflammatory cytokines. Furthermore, flow cytometric (FCM) analysis suggested that carp TRIF induced apoptosis through the activation of caspase-8. In summary, our study indicated that TRIF plays an essential role in the innate immune responses of common carp against bacterial and viral infection.

Modulatory effects of laurel-leaf cistus (Cistus laurifolius) ethanolic extract on innate immune responses and disease resistance in common carp (Cyprinus carpio)

Medicinal herbs are used for growth promotion, disease control and other health benefits in aquaculture industry. Here, we examined the effect of dietary laurel-leaf cistus (Cistus laurifolius) ethanolic extract on growth performance, digestive enzyme activity, haematological profile and nonspecific immune responses in common carp (Cyprinus carpio). In addition, resistance against Aeromonas hydrophila infection was examined. Common carp was fed diets containing 0 (Control), 0.1 (CL0.1), 0.5 (CL0.5) and 1 (CL1) g kg−1 laurel-leaf cistus extract for 45 days. After 30 days, superoxide anion production (SAP) increased in CL0.1 and CL0.5 fish groups and at the end of the study all experimental fish groups had higher SAP compared to that of the control (P ˂ 0.05). Lysozyme activity (LA) was elevated in CL0.5 and CL1 treated groups on 30th day (P < 0.05), and this increase was only observed in C0.1 fish group at the end of study compared to control (P ˂ 0.05). Myeloperoxidase activity was significantly increased in CL0.5 and CL1 fish groups at the end of study. IL-1βgene expression was significantly increased in treated fish in a dose-depended manner. Similar results were observed for transcription of IL-6 and IL-8 (P < 0.05). Anti-inflammatory cytokines, IL-10 and TGF-β were highly up-regulated in the intestine and head kidney of CL treated fish groups compared to control (P < 0.05). At the end of experiment, significantly higher final body weight, weight gain, and specific growth rate were obtained in CL0.1 treated fish group compared to control. However, growth was negatively affected in CL1 fish group (P < 0.05). CL1 fish group had also a significantly higher FCR. Amylase activity was significantly increased in all experimental fish groups compared to control (P ˂ 0.05). Trypsin activity was decreased in CL0.1 and CL1 fish groups (P ˂ 0.05). WBC and RBC were significantly increased (P ˂ 0.05) in CL0.5 and CL1 fish groups, whereas haemoglobin, haematocrit, mean cell, mean cell haemoglobin contents were no significantly changed among control and treatment groups. Result of challenge test with A. hydrophila exhibited that survival rate in all treatment groups was significantly higher than that of control. These findings demonstrated that laurel-leaf cistus at 0.1 g kg−1 can be a suitable candidate for growth promotion, immune system induction and infection control in fish.