Tissues Of Common Carp Research Articles

Seasonal variation of heavy metals in water and Cyprinus carpio L. from Umiam Lake reservoir of Meghalaya, India: Potential health risk assessment for human consumption.

The purpose of this study is to assess the seasonal variation of heavy metal concentration in water and fish tissues of common carp (Cyprinus carpio L.) from the Umiam Lake reservoir located in the Ri bhoi district of Meghalaya, India, and to elucidate the possible human health risk of ingesting fish captured from the contaminated lake. Results show significant (p < 0.05) seasonal differences of heavy metal concentrations in the water and different tissues of fish Cyprinus carpio L.. The total concentration of heavy metals in the water exceeds the WHO and BIS standards and thus poses a significant threat to the aquatic flora and fauna of the reservoir. The heavy metal concentrations in fish tissues were tissue-dependent, where the average concentration of heavy metals in all the tissues of Cyprinus carpio L. was in the order of Cr > Pb > Cu > Cd. In addition, the health risk assessment suggests that the heavy metals in the fish muscle from the Umiam Lake reservoir might have adverse effects on human. Therefore, the overall results of the study provide an understanding on the seasonal distribution of heavy metals in water, provide insight on their bioaccumulation in the fish tissues, and highlights the potential health risk for the local population of long-term fish consumption from Umiam Lake reservoir.

Identification of Isthmin-1 in common carp (Cyprinus carpio L.) and the effects on glucose metabolism in vivo and in vitro.

Isthmin-1 (Ism1) plays roles in glucose uptake in mammals as an adipokine. To investigate its role in the glucose metabolism of common carp (Cyprinus carpio. L), the Ism1 sequence was cloned, and its expression and distribution in tissues were detected. In addition, we prepared and purified the recombinant Ism1 protein using the E. coli expression system and assessed changes in the expression of key genes related to glucose metabolism through both in vivo injection experiments and primary hepatocyte experiments in vitro. The results revealed that the open reading frame of Ism1 was 1377 bp long, encoding 458 amino acids. Similarity analysis indicated that Ism1 exhibited a close evolutionary relationship with goldfish (Carassius auratus), sharing 98.35% amino acid similarity. Ism1 was expressed in all tissues of common carp, with the highest level observed in the heart, followed by the gill, head kidney, and hepatopancreas. Distinct patterns of Ism1 expression were identified during the oral glucose tolerance test and long-term high-carbohydrate and high-fat diet feeding experiments. In vivo studies demonstrated that the serum glucose concentration was reduced on treatment with Ism1, accompanied by a significant upregulation of mRNA levels for gk, hk, and pfk genes in hepatopancreas; conversely pepck and g6pase mRNA levels were significantly downregulated in the hepatopancreas under these conditions as well. Furthermore, our primary hepatocyte experiment confirmed that Ism1 could inhibit pepck and g6pase mRNA expression, while promoting gk, hk, and pfk mRNA expression levels. In conclusion, Ism1, in common carp, could participate in the glucose metabolism, which provides essential information for future studies on the function of Ism1.

Comparative analysis of the immune responses of CcIgZ3 in mucosal tissues and the co-expression of CcIgZ3 and PCNA in the gills of common carp (Cyprinus carpio L.) in response to TNP-LPS

Fish live in an aquatic environment rich in various microorganisms and pathogens. Fish mucosal-associated lymphoid tissue (MALT) plays a very important role in immune defence. This study was conducted to characterize the immune response mediated by CcIgZ3 in common carp (Cyprinus carpio.) and investigate the proliferating CcIgZ3+ B lymphocytes in gill. We determined the expression of CcIgZ3 in many different tissues of common carp following stimulation by intraperitoneal injection of TNP-LPS (2,4,6-Trinitrophenyl hapten conjugated to lipopolysaccharide) or TNP-KLH (2,4,6-Trinitrophenyl hapten conjugated to Keyhole Limpet Hemocyanin). Compared with TNP-KLH, TNP-LPS can induce greater CcIgZ3 expression in the head kidney, gill and hindgut, especially in the gill. The results indicate that the gill is one of the main sites involved in the immune response mediated by CcIgZ3. To examine the distribution of CcIgZ3+ B lymphocytes, immunohistochemistry (IHC) experiments were performed using a polyclonal antibody against CcIgZ3. The results indicated that CcIgZ3 was detected in the head kidney, hindgut and gill. To further examine whether CcIgZ3+ B lymphocytes proliferate in the gills, proliferating CcIgZ3+ B cells were analysed by immunofluorescence staining using an anti-CcIgZ3 polyclonal antibody and an anti-PCNA monoclonal antibody. CcIgZ3 and PCNA (Proliferating Cell Nuclear Antigen) double-labelled cells in the gills were located within the epithelial cells of the gill filaments of common carp stimulated with TNP-LPS at 3 dps and 7 dps, and relatively more proliferating CcIgZ3+ B cells appeared in the gills of common carp at 7 dps. These data imply that CcIgZ3+ B cells in the gills might be produced by local proliferation following TNP-LPS stimulation. In summary, compared with those in TNP-KLH, CcIgZ3 preferentially affects the gills of common carp following challenge with TNP-LPS. CcIgZ3+ B cells proliferate in the gills to quickly produce the CcIgZ3 antibody. In addition, CcIgZ3+ B cells can be activated to induce a strong immune response very early locally in the gill and produce the antibody CcIgZ3, which helps exert an immune-protective effect. These results suggest that an effective vaccine can be designed to promote production of the mucosal antibody CcIgZ3.

Assessing Seasonal Changes in Physicochemical Traits and Biochemical Profiles of Key Carp Species in Masani Barrage Lake and JLN Canal

Our thorough seasonal analysis of Masani Barrage Lake and JLN Canal in Rewari reveals the profound impact of seasonal changes on aquatic ecosystems. Both water bodies display distinct patterns in temperature, pH, salinity, and other parameters. The unique characteristics of lakes, with greater temperature fluctuations and nutrient cycling, contribute to differences in phytozooplankton and ecological dynamics compared to more regulated canals. Additionally, our study on common carp tissues shows clear seasonal variations in moisture, ash, protein, lipid, and fatty acid levels, indicating specific metabolic responses to environmental conditions. Understanding these nuances is crucial for grasping the diverse influences of these habitats on fish physiology, with lakes experiencing more significant variations than canals due to their larger and more open systems.

Bioinformatics studies and comparison of mRNA transcription of glutathione S-transferase gene in some tissues of common carp (Cyprinus carpio) and brown trout (Salmo trutta)

Bioinformatics has revolutionized the way we study gene expression and regulation, enabling researchers to analyze large-scale genomic data with unprecedented speed and precision. In this study, we use bioinformatics tools and methods to compare mRNA transcription of glutathione S-transferase (gstr) gene in two different fish species: common carp and brown trout. In this study, liver, intestine, muscle, brain, heart, eye, spleen, gill, kidney, stomach, ovary and testis samples were taken from male and female brown trout and common carp, and total RNA was isolated from each tissue to synthesize cDNA from these tissues. Then, the transcript amounts of the gstr gene were determined by qPCR from all tissue samples. Gene structures, conserved gene synteny design, phyogenetic tree analyzes and similarity-identity ratios with other vertebrates were determined. When the transcriptional differences between male and female tissues for the brown trout gstr gene were examined, it was seen that the intestine, gill, kidney, stomach, muscle and gonads were significantly higher in male fish (p&lt;0.05), but the differences between other tissues were not statistically significant. It has been determined that the highest gene expression was liver (p&lt;0.05) and brain, eye, spleen, kidney, heart and spleen tissues have significantly lower gstr gene expression than other tissues in both male and female in common carp. In addition, the in-silico analysis determined that the brown trout gstr gene shared the highest similarity and identity ratio with rainbow trout, and the common carp gstr gene shared the highest similarity and identity ratio with goldfish.

Spring Viremia of Carp Virus Infection Induces Carp IL-10 Expression, Both In Vitro and In Vivo.

Interleukin-10 (IL-10) is a pleiotropic cytokine with both immune enhancement and immunosuppression activities, but the main role is immunosuppression and anti-inflammatory ability. In order to use the immunosuppressive function of IL-10, many viruses, such as SARS-CoV-2, hepatitis B virus and EB virus, can evade the host's immune surveillance and clearance by increasing the expression of host IL-10. However, it has not been reported whether the aquatic animal infection virus can upregulate the expression of host IL-10 and the mechanisms are still unknown. Spring viremia of carp (SVC) is a fatal viral disease for many fish species and is caused by spring viremia of carp virus (SVCV). This disease has caused significant economic losses in the aquaculture industry worldwide. In this study, the expression of carp IL-10 with or without infection of SVCV in epithelioma papulosum cyprinid (EPC) cells, carp head kidney (cHK) primary cells and common carp tissues were analyzed using RT-PCR and ELISA. The results show that SVCV infection induced carp IL-10 mRNA and protein expression, both in vitro and in vivo. However, the upregulation of carp IL-10 by SVCV was hindered by specific inhibitors of the JAK inhibitor (CP-690550), STAT3 inhibitor (STA-21), NF-κB inhibitor (BAY11-7082) and p38 MAPK (mitogen-activated protein kinase) inhibitor (SB202190), but not JNK inhibitor (SP600125). Furthermore, the results demonstrated that JAK1, JAK2, JAK3, TYK2 and STAT5 played important roles in carp IL-10 production induced by SVCV infection. Taken together, SVCV infection significantly induced carp IL-10 expression and the upregulation trigged in JAK-STAT, NF-κB and p38MAPK pathways. To our knowledge, this is the first time that a fish infection virus upregulated the host IL-10 expression through the JAK-STAT, NF-κB and p38MAPK pathways. Altogether, fish viruses may have a similar mechanism as human or other mammalian viruses to escape host immune surveillance and clearance.

Study of the concentration level of heavy metals in water and some tissues of common carp, Carpinus carpio L. which is cultured in cages in the Euphrates River

The current study included measuring some chemical and physical properties of the water of the study area and estimating the concentration of three heavy elements (lead, copper, and zinc) in the tissues of the common carp (Gills, muscles, and viscera) of Cyprinus carpio L. Samples were collected from one of the private farms that raise fish in floating cages on the Euphrates River from 11/18/2022 to 4/18/2023. The study also included measuring water temperature, air, turbidity, electrical conductivity, total dissolved solids, pH And dissolved oxygen samples taken from the water were analyzed as well as samples taken from fish tissues on a monthly basis. The results of the study showed that the air temperature ranged between(6.8-10.2)C. Water temperature (17_33), turbidity (6.8_10.2), electrical conductivity (1.04_2.13), total dissolved solids (7752_18730) mg/l, and pH value (7.2_7.82) between neutral to lightly basic. The dissolved oxygen value ranged between (6.78 - 7.92) mg/l during the months of the experiment. The standard methods were used to estimate the concentration of heavy metals in water and tissues by flame atomic absorption spectrometer. The results showed that the highest total concentration of lead, copper and zinc was recorded in the water during the winter season (1.533, 2.300, 6.700) µg/L. Recorded in tissues for lead in the gills and viscera, the highest values were in spring (9.533, 6.500) µg/L, respectively. Copper recorded the highest value in the gills and viscera, respectively, and the concentrations were high in the autumn season (16.793, 18.723) µg/g dry weight, respectively. g dry weight respectively, the results showed that the accumulation of heavy elements was in the following order . &#x0D; Concentrations in the water are zinc &lt; copper &lt; lead&#x0D; And in the tissue as follows &#x0D; Gills &lt; muscle &lt; viscera lead &#x0D; gills &lt; viscera &lt; muscle copper &#x0D; Zinc gills &lt; muscle &lt; viscera&#x0D; Different densities were also studied to obtain the best culture density. Three densities (21_25_28 fish / m3) were used, with 500 fish for the first treatment, 900 fish for the second treatment, and 1100 fish for the third treatment, with an average weight of (120_140) g. Diet of Iranian origin was used for the three treatments. The results of the statistical analysis showed that there were significant differences during the months of the study, where the highest rate was in the month of March.

The role of CcPTGS2a in immune response against Aeromonas hydrophila infection in common carp (Cyprinus carpio)

Prostaglandin-endoperoxide synthase 2 (PTGS2), a crucial enzyme in prostaglandin synthesis, catalyzes the conversion of arachidonic acid to prostaglandins and plays a significant role in the inflammatory response. This investigation aimed to determine the regulatory role of PTGS2a in the innate immune response to bacterial infection in fish. To achieve this objective, the CcPTGS2a gene was identified and characterized in common carp (Cyprinus carpio), and its function in immune defense was investigated. According to the sequence and structural analysis results, CcPTGS2a had an open reading frame of 1806 bp that encoded 602 amino acids. It was estimated that the protein's theoretical molecular weight was 69.0 kDa, and its isoelectric point was 8.10. The structure of CcPTGS2a was observed to be conserved, with an epidermal growth factor domain and a peroxidase domain present. Moreover, the amino acid sequence of CcPTGS2a exhibited significant homology with the amino acid sequences of several fish species. CcPTGS2a mRNA was detected in the healthy tissues of common carp, with higher expression in the head kidney, spleen, gills, and liver. Following the challenges with Aeromonas hydrophila and lipopolysaccharide, CcPTGS2a mRNA showed unique geographic and temporal expression patterns, with significant increases detected in the head kidney, gills, spleen, and liver. Additionally, the recombinant CcPTGS2a protein exhibited detectable bacterial binding to various bacteria. As determined by subcellular localization analysis, CcPTGS2a was predominantly localized in the nucleus and cytoplasm. Furthermore, it was discovered that the overexpression of CcPTGS2a stimulated the up-regulation of ferroptosis-related genes and inflammatory cytokine mRNA expression in fish and EPC (Epithelioma papulosum cyprinid) cells while concurrently reducing the bacterial load of A. hydrophila. In contrast, the interference of CcPTGS2a decreased the mRNA expression of ferroptosis-related genes and inflammatory cytokines in fish and EPC cells and increased the bacterial load of A. hydrophila. Notably, A. hydrophila stimulation resulted in the up-regulation of CcPTGS2a protein expression in EPC cells. These results suggested that CcPTGS2a was involved in the immune response to bacterial infections in common carp.

Common carp as an ecological indicator of environmental pollution in reservoirs of southern Spain: inferring the environmental risks of anthropogenic activities.

Extraction and mineral processing, as well as the waste generated by old abandoned mining sites, are the main sources of contamination of water bodies and lands by potentially toxic elements (PTEs). The common carp (Cyprinus carpio Linnaeus 1758) has been reported to be a good ecological indicator of environmental pollution in water bodies. Hence, we evaluated the concentration of eleven PTEs (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn) in different tissues of common carp in two reservoirs of the province of Jaén, southern Spain: El Tranco de Beas (S1) and La Fernandina (S2). We also assessed the concentration of PTEs in water and sediment samples. We used inductively coupled plasma mass spectrometry for all the collected samples. We found high concentrations of As and Fe in water in the S2 reservoir, above the maximum limits allowed by the sanitary criteria in Spain; however, the analysis of sediments indicated low ecological risk in S1 and moderate ecological risk for As in S2. The concentration of PTEs in common carp was higher in the S2 reservoir, exceeding the permissible limits in the case of As, Cd, Pb, and Zn. As and Cd showed higher concentrations in the kidney; Cu, Fe, and Zn showed higher concentrations in the liver; and Pb and Mn presented higher concentrations in the gill and gill bone. There was a good correlation between the concentrations found in water/sediment samples and those in common carp, corroborating its usefulness as a good ecological indicator, allowing the detection of environmental pollution and inferring previous or current anthropogenic activities such as mining.

Total mercury content in selected tissues of common carp (Cyprinus carpio) pond farmed in the Czech Republic

The aim of this study was to evaluate the total mercury content in selected tissues (muscle, spleen, kidney, liver, scales, brain and gonads) of common carp (Cyprinus carpio). Thirty individuals of market carp caught in three ponds (Jaroslavicky, Strachotin, Vrkoc) located in the Morava River basin in the Czech Republic were used for this study. Total mercury was determined by atomic absorption spectrometry on AMA 254 device. The highest total mercury content was found in the muscle of carp (7.6 ± 2.8 µg·kg-1 in Jaroslavicky, 6.8 ± 2.3 µg·kg-1 in Vrkoc, and 12.9 ± 4.3 µg·kg-1 in Strachotin), followed by levels in caudal kidney, liver, spleen, and brain; the lowest mercury content was determined in gonads and scales. The comparison revealed that individual localities significantly differ in the mercury content in muscle, caudal kidney, liver and spleen samples. However, in all cases the values of the mercury content in muscle complied with the hygienic limit of up to 0.3 mg·kg-1, which means that mercury does not pose a risk to the consumers of these pond farmed fish and that the benefits of eating fish meat outweigh the potential risk in terms of mercury content.

Evaluation of establishment and maintenance of primary cell cultures from several strains of common carp (Cyprinus carpio L.).

As a surrogate for the whole organism, primary cultures and cell lines serve as valuable tools for investigating exogenous and endogenous cytopathy. Studying cell responsiveness to diseases and contaminants is considered a less demanding and more readily accessible research approach that minimizes animal distress and provides more specific data. In the current work, the authors established primary cultures from several different organs and tissues of common carp (Cyprinus carpio L.) for subsequent use in other applications. They investigated the technical challenges in obtaining successful and durable carp-derived tissue cultures. The trials indicate that the type of tissue grown, carp strain and fish age impact equally upon culturing success, as do the cultivating conditions. Cells from gill epithelia, head and trunk kidneys, spleen, skin, gonads and ocular tissue were successfully established and maintained for further use in in-vitro testing. The primary cultures were, therefore, used to investigate and assess pathogens and pollutants emerging in carp's environment.

Adverse Effects of Toxic Metal Pollution in Rivers on the Physiological Health of Fish.

Toxic metal pollution influences the lives of diverse aquatic organisms and humans who consume contaminated aquatic products. However, its potential impacts on aquatic organism health and, thus, ecological health, have been neglected in many regions. This research was carried out to contribute to filling that knowledge gap. Three freshwater fish species in the Nhue–Day River basin, Vietnam, have been chosen to study the bioaccumulation of metals (Zn, Cu, Pb, and Cd) in the tissues (livers, kidneys, gills) and their effects on fish physiological health (changes in the oxidative-GST activity, and physiological biomarkers-energy reserves, respectively) from 2013 to 2017. The extensive results revealed significant spatial and temporal variations in metal concentrations in tissues of common carp (Cyprinus carpio), silver carp (Hypothalmic molitrix), and tilapia (Oreochromis niloticus), and well correlated to their concentration in the water (p < 0.05). Fish bioaccumulated metals in the following order: Zn > Cu > Pb > Cd, with more in the kidneys and livers (spring and summer) than in other tissues. Metal accumulation in O. niloticus and C. carpio was higher than in H. molitrix. Biomarker responses (except for glycogen variation) were also higher during warm seasons. Changes in metal levels in water and fish tissues caused variations in biomarkers in the respective fish tissues, particularly in the livers, as demonstrated by significant correlations of metal concentrations in water and fish tissues to biochemical and physiological responses (p < 0.05). The findings suggest that metal pollution in the river basin adversely impacts the physiological health of both wild and cultured fish. Seasonal shifts in the levels of metal accumulation and biomarkers could be connected to species-specific differences in physiology and the levels of metals in environments. This biomarker set is simple but effective in assessing the impact of metal pollution on fish health and, hence, the aquatic ecosystem. This is one of the first biomonitoring studies to assist in designing better water management strategies for the Nhue–Day River basin.

Massive fish death associated with the toxic cyanobacterial Planktothrix sp. bloom in the Béni-Haroun Reservoir (Algeria).

In July 2017, a massive bloom of the potentially toxic cyanobacterial species Planktothrix sp. was observed in the Béni-Haroun Reservoir (Algeria), which was followed by a massive fish death. Many questions were raised in association with the role of cyanotoxins and the fish massive mortality. The objective of this paper is twofold: (1) to investigate the variability of physicochemical and cyanobacterial parameters (chlorophyll-a, phycocyanin, allophycocyanin, and microcystins) throughout the period of July 2017 to June 2018; and (2) to determine the free and total MC levels in viscera and muscle tissues of the common carp (Cyprinus carpio), which are found dead in the considered reservoir in October 2017. Our results showed microcystin (MC) concentrations in water samples (by the protein phosphatase PP2A assay) had reached 651.2ng MC-LR equiv./L. Total MC levels (free + bound) in the viscera and muscle tissues of sampled dead fish were at 960.24 and 438.54µg MC-LR equiv./kg dw, respectively. It is assumed that high concentrations of MC observed in the tissues of common carp induced a strong degradation of the visceral contents resulting in the complete lysis of the hepatopancreas, and presumably the massive fish death.

Structure of the lipopolysaccharide O-antigen of Aeromonas encheleia strain A4 representing the new PGO1 serogroup of aeromonads prevailing in Polish aquaculture

The structure of the O-specific polysaccharide (OPS) from Aeromonas encheleia strain A4 lipopolysaccharide was investigated. A. encheleia strain A4, classified into the new provisional serogroup PGO1 predominating among aeromonads in Polish aquaculture, was isolated from common carp tissues during an outbreak of MAI/MAS disease on a fish farm. The high-molecular-weight OPS fraction liberated from the lipopolysaccharide after mild acid hydrolysis followed by gel-permeation chromatography was studied with chemical methods, mass spectrometry, and one- and two-dimensional 1H and 13C NMR spectroscopy techniques. Inter-residue correlations were identified in 1H,13C-heteronuclear multiple-bond correlation (HMBC) and 1H,1H NOESY experiments. It was found that the O-specific polysaccharide of A. encheleia strain A4 consists of branched pentasaccharide repeating units with the following structure:→2)[α-d-Fucp3NRHb-(1→3)]-α-l-Rhap-(1→3)-β-l-Rhap-(1→4)-α-l-Rhap-(1→3)-β-d-QuipNAc-(1→

Activation of the NLRP1 inflammasome and its ligand recognition in the antibacterial immune response of common carp (Cyprinus carpio)

NLRP1 (NLR family pyrin domain containing 1) is the first member of NOD-like receptors (NLRs) which can form inflammasome and play critical roles in innate immunity and pathogenesis of various diseases. To date, many NLRs and inflammasome-related genes have been identified in teleost, however, the activation of NLRP1 inflammasome is only found in zebrafish, and the activator of fish NLRP1 is unclear. In the present study, the activation of CcNLRP1 inflammasome and its function in innate immune defence of common carp was investigated. The expression of CcNLRP1 was induced in immune-related tissues of common carp upon challenge with Edwardsiella tarda and Aeromonas hydrophila. The colocalization of CcNLRP1 and CcASC, ASC oligomerization, and interaction between CcNLRP1CARD and CcASC was observed in 293T, Hela and EPC cells, suggesting that the CcNLRP1 inflammasome was activated in common carp. Furthermore, we found that MDP may be the specific ligand of CcNLRP1, which can activate the CcNLRP1 inflammasome. Taken together, the present study identifies a new inflammasome in common carp, and is beneficial to the control of infectious diseases in carp farming.

Effect of secondary attack by Aeromonas hydrophila on the expression level of hif genes in common carp (Cyprinus carpio).

Hypoxia-inducible factors (hifs) are involved in infectious diseases inflammatory reactions, and immune regulation. Common carp, a representative allotetraploid species that has undergone genome-wide replication events, has important research value. In this study, common carp were infected twice with Aeromonas hydrophila. Liver tissues of common carp were collected at 4h, 12h, 24h, 48h, 3days, 7days post-first infection and 4h, 12h, 24h post-second infection. The mRNA levels of hif genes were determined at different time points. The hif2a-2, hif3a-2, hif3b-1 and hif3b-2 expression levels in the infected group were upregulated when compared with those in the control group, whereas the expression levels of other genes were downregulated after the second infection. This indicates that the effect of A.hydrophila infection on gene expression pattern is dependent on the host, pathogen, infected tissue and gene. Pressure analysis of the hif gene family revealed that the non-synonymous substitution to synonymous substitution ratio of 12 hif genes was <1, which indicated that they were in a state of purification and selection. Combined with the differences between copy genes, the polyclonal antibodies against Hif1b-1 and Hif1b-2 were successfully prepared in this study. Western blot analysis showed that the protein expression of Hif1b-1 and Hif1b-2 reached to the highest level 48h after the first infection. After the second A.hydrophila infection, the protein expression levels of Hif1b-1 and Hif1b-2 reached the highest levels at 4 and 48h, respectively. This may indicate that the Hif1b-1 and Hif1b-2 genes in common carp play an important role in the immune mechanism at the protein level. The findings of this study will lay the foundation for future studies on the immune regulatory function of common carp hif genes, which may aid in devising novel therapeutic strategies for common carp diseases, such as A.hydrophila infection.

A modified material‐saving method system for detecting and analysing fatty acids in fish using gas chromatography

A modified method system for the determination of fatty acids in micro fish samples was established, including lipid extraction, column selection, chromatographic condition optimization and data analysis. Firstly, we compared the methods of tissue disruption with freeze-drying and liquid nitrogen grinding, the amount of fresh sample can be less to 0.1–0.3 g by liquid nitrogen grinding. Then, in order to reduce the detection time of GC, we compared the performance of two GC columns and optimized gas chromatography conditions of HP-88. The recommended analysis time was 43 min with the speed of 1.4 ml/min and split ratio of 10:1 for HP-88. Besides, to analyse the composition and content of fatty acids accurately, we compared relative quantitative and semi-quantitative methods. Lastly, using the tissues of common carp (Cyprinus carpio) in different development periods as materials, we tested the effect of the method system. Taken together, in this study, a material-saving method system for measuring fatty acids in fish tissues was presented, which can be easily applied to the determination of fatty acid composition in small size fish and minor tissues in various aquatic organisms, and also provide technical support for the study of the lipid metabolic mechanism in aquatic animals.

Effect of copper on bioconcentration of benzotriazole ultraviolet stabilizers (BUVSs) in common carp (Cyprinus carpio)

Benzotriazole ultraviolet stabilizers (BUVSs) have received increasing attention as emerging contaminants. However, most of the existing relevant studies focused on the adverse ecological effect of BUVSs under their single exposure, information about the bioconcentration potential of BUVSs and their joint exposure with heavy metals remains scarce. In this study, we investigated the bioconcentration kinetics of 6 frequently reported BUVSs in four main tissues of common carp under different Cu concentration. The bioconcentration factors (BCFs) and half-lives (t1/2) in the fish tissues ranged from 5.73 (UV-PS in kidney) to 1076 (UV-327 in liver), and 2.19 (UV-PS in kidney) to 31.5 (UV-320 in liver) days, respectively. Under the effect of Cu, an increase in BCF values was observed, which is mainly due to the decreased depuration rate (k2). These results indicated that BUVSs accumulated in fish and that Cu can affect the bioconcentration of BUVSs. This study provides important insight into the co-exposure of heavy metal and BUVSs, contributing to the perfection of BUVSs risk assessment.

Content and distribution features of heavy metals in the tissue of &lt;i&gt;Cyprinus carpio&lt;/i&gt; L. in the Ural River basin

This paper discusses regional features of environmental pollution by heavy metals. The authors have studied the content of heavy metals in the water of the Ural River within the Republic of Bashkortostan (RB), Chelyabinsk and Orenburg Regions, as well as its right tributary, the Khudolaz River, located in the zone of influence of industrial enterprises of the city of Sibay and characterized by a high content of pollutants. It is noted that in the considered segment with a length of about 60 km downstream of the Ural River, a gradual decrease in the concentration of toxic elements is observed as a result of self-purification processes. Studies of the elemental composition of muscle tissue and scales of the common carp ( Cyprinus carpio L.), living in the Khudolaz River on the territory of the city of Sibay, showed high concentrations of heavy metals in them. Muscle tissue and scales accumulate heavy metals to varying degrees, which is due to the functional feature of these organs, their accumulative activity and the chemical properties of the metal itself. The greatest amount of Cu, Fe, Co accumulate in muscle tissue, while Zn, Mn - in scales. No similar pattern has been revealed for the accumulation of Ni and Pb. In muscle tissue, the elements are distributed as follows: Fe Zn Ni Mn = Co Cu Pb, in scales - Zn Fe Mn Co Ni Cu Pb. Fe, Zn predominate in both series of element distribution, while the lowest concentrations are characteristic of Pb. A correlation analysis has revealed a presence of a direct statistically significant relationship between the content of heavy metals in water and the tissues of common carp: strong - in muscles (r = 0,95-0,98) and medium - in scales (r = 0,34-0,55).

Evaluation of Behavioral Changes and Tissue Damages in Common Carp (Cyprinus carpio) after Exposure to the Herbicide Glyphosate.

Pesticides can induce changes in behavior and reduce the survival chance of aquatic organisms. In this study, the toxic effects of glyphosate suspension (Glyphosate Aria 41% SL, Tehran Iran) on behavior and tissues of common carp (Cyprinus carpio) were assessed. For this purpose, a 96 h LC50 of glyphosate suspension (68.788 mL·L−1) was used in the toxicity test. All individuals were divided into control and treatment groups with four replicates. Exposure operations were performed under two conditions: increasing concentration of suspension from 0 to 68.788 mL·L−1; then, decreasing to the first level. The swimming pattern was recorded by digital cameras during the test and tissue samples were collected at the end of the test. There were significant differences between the swimming pattern of treated individuals and control ones during both steps. The sublethal concentration of glyphosate led to hypertrophy, hyperplasia and hyperemia in the gill of fish. However, changes were obvious only after sampling. The exposed fish also displayed clinical signs such as darkening of the skin and increasing movement of the operculum. Moreover, glyphosate suspension affected swimming patterns of fish suggest that the swimming behavior test can indicate the potential toxicity of environmental pollutants and be used as a noninvasive, useful method for managing environmental changes and assessing fish health conditions by video monitoring.