Carassius Auratus Gibelio Research Articles

Effects of Dietary Inosine 5'-Monophosphate Supplementation on the Growth Performance and Salinity and Oxidative Stress Resistance of Gibel Carp (Carassius auratus gibelio).

An 88-day feeding trial was conducted to evaluate the effects of dietary inosine 5'-monophosphate (5'-IMP) on the growth performance and salinity and oxidative stress resistance in the juvenile gibel carp CAS III (Carassius auratus gibelio; initial body weight: 7.48 g). Four isonitrogenous and isoenergetic diets containing exogenous 5'-IMP were formulated. P1, P2, P3 and P4 were diets containing 5'-IMP at four concentrations (0, 1, 2 and 4 g kg-1). The four diets were randomly allotted to triplicate tanks in a recirculating system. After the feeding trial, six fish per tank were netted randomly and placed into 12‱ saline water to test their response to salinity stress. The results indicated that the feed conversion rate was enhanced by dietary supplementation with 5'-IMP. The appetite, plasma neuropeptide Y level and feeding rate of the P3 group were lower than those in the control treatment group. Dietary supplementation with 5'-IMP improved the osmoregulatory adaptation of gibel carp under acute salinity stress. Six hours after the salinity stress treatment, in the dietary 5'-IMP treatment group, the plasma cortisol and K+ concentrations were lower and the Na+/K+-ATPase activity was greater than that in the control group. Dietary supplementation with 5'-IMP promoted the expression of the glucocorticoid receptors NKA-α1b and NKCC and retarded the expression of Hsp70 in P4-treated gill filaments and kidneys. Dietary supplementation with 5'-IMP resulted in a stable oxidative-stress-resistant phenotype characterized by increased levels of cellular antioxidants, including SOD, catalase, glutathione peroxidase, glutathione reductase and MPO. The above results of the current study demonstrate that supplementation of 5'-IMP can promote feed utilization and have positive influences on the salinity and oxidative stress resistance of gibel carp.

Vigour-related traits of gibel carp (Carassius gibelio): do they represent reproduction-associated costs facilitating the coexistence of asexual and sexual forms?

Vigour-related traits of gibel carp (Carassius gibelio): do they represent reproduction-associated costs facilitating the coexistence of asexual and sexual forms?

Effects of supplementing coated methionine in a high plant-protein diet on growth, antioxidant capacity, digestive enzymes activity and expression of TOR signaling pathway associated genes in gibel carp, Carassius auratus gibelio.

This study explored the impacts of supplementation of different levels of coated methionine (Met) in a high-plant protein diet on growth, blood biochemistry, antioxidant capacity, digestive enzymes activity and expression of genes related to TOR signaling pathway in gibel carp (Carassius auratus gibeilo). A high-plant protein diet was formulated and used as a basal diet and supplemented with five different levels of coated Met at 0.15, 0.30, 0.45, 0.60 and 0.75%, corresponding to final analyzed Met levels of 0.34, 0.49, 0.64, 0.76, 0.92 and 1.06%. Three replicate groups of fish (initial mean weight, 11.37 ± 0.02g) (20 fish per replicate) were fed the test diets over a 10-week feeding period. The results indicated that with the increase of coated Met level, the final weight, weight gain (WG) and specific growth rate initially boosted and then suppressed, peaking at 0.76% Met level (P< 0.05). Increasing dietary Met level led to significantly increased muscle crude protein content (P< 0.05) and reduced serum alanine aminotransferase activity (P< 0.05). Using appropriate dietary Met level led to reduced malondialdehyde concentration in hepatopancreas (P< 0.05), improved superoxide dismutase activity (P< 0.05), and enhanced intestinal amylase and protease activities (P< 0.05). The expression levels of genes associated with muscle protein synthesis such as insulin-like growth factor-1, protein kinase B, target of rapamycin and eukaryotic initiation factor 4E binding protein-1 mRNA were significantly regulated, peaking at Met level of 0.76% (P< 0.05). In conclusion, supplementing optimal level of coated Met improved on fish growth, antioxidant capacity, and the expression of TOR pathway related genes in muscle. The optimal dietary Met level was determined to be 0.71% of the diet based on quadratic regression analysis of WG.

A novel cell line established from skin tissue of gibel carp (Carassius gibelio) is susceptible to Carassius auratus herpesvirus infection

Frequent outbreaks of emerging infectious diseases in fish, such as Carassius auratus herpesvirus (CaHV) infection has caused great economic losses in China. However, the lack of a sensitive cell culture system has limited studies of CaHV. In the present study, a new cell line (gibel carp skin cell, GiCS) derived from gibel carp (Carassius gibelio) skin tissue was established to create a valuable tool for research of the virus. The GiCS cells consisted mainly of epithelial-like cells, which grew well at 25 °C in L-15 medium supplemented with 10–20% fetal bovine serum. Chromosomal analysis revealed that the skin cell line remained amphitriploid, with most chromosome counts being 156 (54%). The GiCS cells can be efficiently transfected and expressed exogenous genes. In particular, the GiCS cells showed high susceptibility to CaHV infection, which was confirmed by virus infection tests, detection of viral gene expression, and ultrastructural observation. To our knowledge, it is the first cell line that is highly permissive to CaHV infection. In addition, the cells also showed susceptibility to several aquatic animal viruses from different families including Iridoviridae, Rhabdoviridae, and Reoviridae. In conclusion, these results indicated that the establishment of the GiCS cell line is a significant advance that will be beneficial to future studies of CaHV and other aquatic animal viruses.

Effects of the Replacement of Dietary Fishmeal by the Blend of Tenebrio molitor Meal, Chlorella Meal, Clostridium Autoethanogenum Protein, and Cottonseed Protein Concentrate on Growth, Protein Utilization, and Intestinal Health of Gibel Carp (Carassius gibelio, CAS Ⅴ)

The trial was conducted to investigate the effects of the replacement of dietary fishmeal (FM) by the blend of Tenebrio molitor meal (TMM), Chlorella meal (CM), Clostridium autoethanogenum protein (CAP), cottonseed protein concentrate (CPC) on growth, protein utilization and intestinal health of gibel carp (Carassius gibelio, CAS Ⅴ). The FM-based diet was used as the control, and the blended proteins (TMM: CM: CAP: CPC) at ratios of 1 : 1:8 : 2 (BLEND A), 1 : 1:6 : 4 (BLEND B), and 1 : 1:4 : 6 (BLEND C) were used to replace FM at three levels (33%, 67%, 100%), respectively. The results showed that, compared to the control group, growth performance increased significantly when dietary FM was fully replaced by BLEND B (P&lt;0.05), while decreased by BLEND A (P&lt;0.05). The complete substitution of FM with BLEND B significantly upregulated the mRNA expression of intestinal proinflammatory cytokines, anti-inflammatory cytokines, and tight junction-related genes (P&lt;0.05), improving intestinal tissue morphology and health. And it also significantly increased intestinal trypsin activity (P&lt;0.05), upregulated the mRNA expression of amino acid sensory receptor-related and amino acid or peptide transport-related genes (P&lt;0.05), increased protein apparent digestibility coefficient (P&lt;0.05). The 100% substitution of FM with BLEND A significantly upregulated the mRNA expression of intestinal proinflammatory cytokines and downregulated the mRNA expression of anti-inflammatory cytokine il-10 (P &lt;0.05), reduced intestinal villus height (P&lt;0.05), and decreased protein apparent digestibility coefficient (P&lt;0.05). In conclusion, BLEND B could completely substitute dietary FM and was beneficial to the growth and health of gibel carp. Dietary digestible essential amino acids index (DEEAI) was found as an important indicator and should be higher than 79.5% to meet the maximum growth of fish.

Fish assemblages across a salinity gradient in the Zeeschelde estuary (Belgium)

Between 1991 and 2008 a total of 71 fish species was recorded in the brackish and fresh water zone of the Schelde estuary (Zeeschelde). The results were obtained from fish surveys from the cooling water filter screens of the power plant at Doel (between 1991 and 2008) and fyke net surveys along the length of the estuary between 1995 and 2008. Species abundance in the different salinity zones was analysed using the fyke net data only. The ten most abundant species represent 90.8% of the total number of individuals caught. In decreasing order of abundance: flounder (Platichthys flesus), roach (Rutilus rutilus), herring (Clupea harengus), eel (Anguilla anguilla), pike-perch (Sander lucioperca), sole (Solea solea), common goby (Pomatoschistus microps), seabass (Dicentrarchus labrax), three-spined stickleback (Gasterosteus aculeatus) and white bream (Blicca bjoerkna). With fyke nets 33 species were caught in the tidal freshwater zone, 43 species in the oligohaline zone and 59 species in the mesohaline zone. Each salinity zone is characterised by a typical fish assemblage, although some species are shared between all three salinity zones: e.g. three-spined stickleback (Gasterosteus aculeatus), Prussian carp (Carrasius gibelio), roach (Rutilus rutilus) and eel (Anguilla anguilla). Diadromous species occur in all zones and make up, on average up 22% of the species richness. Freshwater species comprise about 70% of the species in the tidal freshwater zone. In the oligohaline zone the contribution of the freshwater species to the species richness is less while marine migrants become more abundant. As expected, the contribution of marine migrants and estuarine species is higher in the mesohaline zone. The recent increase in species richness in the freshwater and oligohaline zone coincides with a remarkable increase in dissolved oxygen since 2007.

Fish fauna of lake Küçük Akgöl (Sakarya, Turkey)

This research was conducted to determine the ichthyofauna of lake Küçük Akgöl between March 2017 and March 2018. Sampling was conducted monthly and randomly using nets with different mesh sizes, fishing rods and fish scoops during field studies, resulting in a total of 99 fish samples collected. Through external morphology examinations based on traditional methods, it was determined that 9 fish species Alburnus alburnus, Blicca bjoerkna, Carassius gibelio, Rutilus rutilus, Scardinius erythrophthalmus, Esox lucius, Gambusia sp., Perca fluviatilis, Lepomis gibbosus) belonging to 5 families (Cyprinidae, Esocidae, Poecilidae, Percidae, Centrarchidae) inhabit lake Küçük Akgöl.

Betaine Alleviates High-Fat Diet Induced Excessive Lipid Deposition in Gibel Carp Hepatopancreas and L8824 Cells by Enhancing VLDL Secretion through HNF4α/MTTP Pathway.

Betaine, a methyl donor, plays a crucial role in lipid metabolism. Previous studies have shown that appropriate betaine supplementation in a high-fat diet reduces triglycerides (TG) of serum and hepatopancreas in fish. However, the underlying mechanism remains unclear. This study examined whether betaine can enhance the secretion of very low-density lipoprotein (VLDL) and sought to identify the specific mechanisms through which this enhancement occurs. A lipid accumulation model was established in gibel carp and L8824 cells using a high-fat diet and oleic acid, respectively. Different doses of betaine (1, 4, and 16 g/kg in the diet; 400 μmol in cell culture) were administered, and measurements were taken for lipid deposition, gene expression of HNF4α, MTTP, and ApoB, as well as the regulation of Mttp and Apob promoters by HNF4α. The results showed that betaine supplementation mitigated lipid droplet accumulation, TG levels, and VLDL production induced by the high-fat diet in gibel carp hepatopancreas and L8824 cells. Moreover, betaine not only increased VLDL content in the cell culture supernatant but also reversed the inhibitory effects of the high-fat diet on protein expression of MTTP, ApoB, and HNF4α in both gibel carp hepatopancreas and L8824 cells. Additionally, HNF4α exhibits transactivating activity on the promoter of Mttp in gibel carp. These findings suggest that betaine supplementation exerts its effects through the HNF4α/MTTP/ApoB pathway, promoting the assembly and secretion of VLDL and effectively reducing lipid accumulation in the hepatopancreas of farmed gibel carp fed a high-fat diet.

Features of the Biology of Alien Species Prussian Carp (Cyprinidae, Actinopterygii) from the Water Bodies of Armenia

Features of the Biology of Alien Species Prussian Carp (Cyprinidae, Actinopterygii) from the Water Bodies of Armenia

Cytogenetic Analysis of the Fish Genus Carassius Indicates Divergence, Fission, and Segmental Duplication as Drivers of Tandem Repeat and Microchromosome Evolution.

Fishes of the genus Carassius are useful experimental vertebrate models for the study of evolutionary biology and cytogenetics. Carassius demonstrates diverse biological characteristics, such as variation in ploidy levels and chromosome numbers, and presence of microchromosomes. Those Carassius polyploids with ≥150 chromosomes have microchromosomes, but the origin of microchromosomes, especially in European populations, is unknown. We used cytogenetics to study evolution of tandem repeats (U1 and U2 small nuclear DNAs and H3 histone) and microchromosomes in Carassius from the Czech Republic. We tested the hypotheses whether the number of tandem repeats was affected by polyploidization or divergence between species and what mechanism drives evolution of microchromosomes. Tandem repeats were found in tetraploid and hexaploid Carassius gibelio, and tetraploid Carassius auratus and Carassius carassius in conserved numbers, with the exception of U1 small nuclear DNA in C. auratus. This conservation indicates reduction and/or loss in the number of copies per locus in hexaploids and may have occurred by divergence rather than polyploidization. To study the evolution of microchromosomes, we used the whole microchromosome painting probe from hexaploid C. gibelio and hybridized it to tetraploid and hexaploid C. gibelio, and tetraploid C. auratus and C. carassius. Our results revealed variation in the number of microchromosomes in hexaploids and indicated that the evolution of the Carassius karyotype is governed by macrochromosome fissions followed by segmental duplication in pericentromeric areas. These are potential mechanisms responsible for the presence of microchromosomes in Carassius hexaploids. Differential efficacy of one or both of these mechanisms in different tetraploids could ensure variability in chromosome number in polyploids in general.

Immune response and apoptosis of gibel carp (Carassius auratus gibelio) gills to Chilodonella hexasticha infection: Insights from histopathological and multi-omics analyses

Gibel carp (Carassius auratus gibelio) is an important economically farmed fish in China. Chilodonella hexasticha parasitizes on the gills and fins of host fish, causing disruption to their normal respiration and movement, ultimately resulting in death of the fish. In this study, a combination of histopathological, immunohistochemical, transferase dUTP nick end labeling (TUNEL), multi-omics, and molecular approaches were employed to identify the immune reaction and cell apoptosis in gill tissue in response to C. hexasticha infection. Significant lamellae fusion, hyperplasia, hyperemia, necrosis, and desquamation of infected gibel carp gills were observed. In total, the expression of 3619 genes was higher, and 3143 lower, for gills in the infected group compared to the control group. Furthermore, 76 metabolites were significantly increased and 105 were significantly decreased in the infected group compared with the control group. From the qRT-PCR analysis results, immune system–related genes encoding IL-8, CXCL8a, and CXC11 were significantly up-regulated in infected gibel carp, while ZAP70 was significantly down-regulated. Immunohistochemical results also showed the down-regulated ZAP70 in the infected group. Apoptosis-related genes encoding CASP3 and Mcl-1b were up-regulated in response to C. hexasticha infection. These genes indicate the activation of CASP family–related apoptosis and Bim-mediated mitochondrial apoptotic pathways. TUNEL assays also revealed severe apoptosis in the infected group. Based on this study's results, it can be concluded that C. hexasticha infection leads to histopathological changes in the gills of infected fish, and induces both a significant immune response and apoptosis.

A Comparative Approach to Sustainable Fish Meal: Prussian carp meal (Carassius gibelio Bloch, 1782)

In this study, the usability of Prussian carp (Carassius gibelio) meal (PCM) as an alternative animal protein source in fish feeds was investigated by comparing anchovy (Engraulis encrasicholus) and sprat (Sprattus sprattus) meals with biochemical, fatty acid, amino acid and element compositions. Prussian carp were obtained by fishing and made into a meal (PCM), anchovy (AM), and sprat (SM) meals were taken from a commercial company. At the end of the study, the total, essential, and non-essential amino acid values of PCM were lower than AM and SM (P &lt; 0.05). The PUFA and Omega-6 values of PCM were higher than AM and SM; and lower than SFA, Omega-3, EPA, DHA, AI, FLQ values (P &lt; 0.05). According to the element analysis, the P and Ca values of the PCM were higher than the AM and SM (P &lt; 0.05), and the Na, K, Fe, Cu, Zn and Se values were lower. As a result of the study, it was concluded that PCM could be used in the feed sector in order to increase the sustainability of the fish meals used in feed production, reduce the foreign dependency on vegetable and fish meals, and reduce feed costs.

CyHV-2 infection triggers mitochondrial-mediated apoptosis in GiCF cells by upregulating the pro-apoptotic gene ccBAX

Apoptosis is a physiological cell death phenomenon, representing one of the fundamental physiological mechanisms for maintaining homeostasis in living organisms. Previous studies have observed typical apoptotic features in Carassius auratus gibelio caudal fin cell (GiCF) infected with Cyprinid herpesvirus 2 (CyHV-2), and found a significant up-regulation of ccBAX expression in these infected cells. However, the specific apoptotic mechanism involved remains unclear. In this study, we utilized the GiCF cell line to investigate the apoptotic mechanism during CyHV-2 infection. Immunofluorescence staining revealed translocation of ccBAX into mitochondria upon CyHV-2 infection. Flow cytometry analysis demonstrated that overexpression of ccBAX expedited virus-induced apoptosis, characterized by heightened mitochondrial depolarization, increased transcriptional levels of Cytochrome c (Cyto c) in both the cytoplasm and mitochondria, and augmented Caspase 3/7 enzyme activity. Bax inhibitor peptide V5 (BIP–V5), an inhibitor interfering with the function of Bax proteins, inhibited Bax-mediated apoptotic events through the mitochondrial pathway and attenuated apoptosis induced by CyHV-2. In this study, it was identified for the first time that CyHV-2 induces apoptosis via the mitochondrial pathway in GiCF cells, bridging an important gap in our understanding regarding cell death mechanisms induced by herpesvirus infections in fish species. These findings provide a theoretical basis for comprehending viral apoptotic regulation mechanisms and the prevention and control of cellular pathologies caused by CyHV-2 infection.

Quantitative and Qualitative Composition of the Peripheral Blood of Fish in the Gradient of Long-Term Radiation Exposure

The paper deals with analysis of hematological parameters of the common rudd (&lt;i&gt;Scardinius erythrophthalmus &lt;/i&gt;L.) and Prussian carp (&lt;i&gt;Carassius gibelio&lt;/i&gt; Bloch) from the most radionuclide-contaminated water bodies of the Chernobyl Exclusion Zone. Data on absolute and relative leukocyte composition and morphological disorders of erythrocytes in peripheral blood were obtained. The leukocyte fraction of both fish species similarly responded to the absorbed dose rate. In the doses' range of 5.1-54.1 &amp;mu;Gy/h, reactive changes of the compensatory nature were recorded with increase of the leukocytes content at the expense of lymphocyte and granulocyte fractions. Under the higher doses (up to 84.5 &amp;mu;Gy/h), hematopoiesis was damaged with sharp decrease of the leukocytes' content and significant changes in leukograms, which was also confirmed by the hematological indices' values. The morphological disorders in erythrocytes increased along with absorbed dose rate.

STUDY ON SOME TOXIC EFFECTS OF THE INSECTICIDE FENDONA 15 SC ON THE PRUSSIAN CARP (CARASSIUS GIBELIO, BLOCH, 1782)

Fendona 15 SC (15g/L alpha-cypermethrin formulation) is an insecticide with fast and reliable action against a broad range of insect pests. The toxicological effects of Fendona 15 SC (0,0002 ml/L water and 0,0004 ml/L water) upon prussian carp (Carassius gibelio, Bloch, 1782) recorded respiratory, haematological, biochemical and behavioral changes. The experiments were of acute and subchronic type and the semistatic test method was used. Data obtained from the toxicity tests were evaluated using the one-way analysis of variance (Anova) method.

An ichthyofaunal amendment with the length-weight relations and condition factors of some endemic and invasive freshwater fishes from Western Anatolia

In the scope of this study, fish fauna of Küçük Menderes River and its tributaries, updated with the comparison of the recent ichthyofaunal studies, as well as the length-weight relations (LWR) and condition factors (CF) were estimated for 7 freshwater fish species belonging to six families from the river basin: endemic Oxynoemacheilus eliasi, Cobitis fahireae; invasive, Carassius gibelio, Atherina boyeri, transloce Perca fluviatilis and the native Squalius fellowesii, Cyprinus carpio. The fish samples were collected with various fishnets and DC electro-fishing devices from six stations in 2018 and 2019. The LWR of the fishes was studied based on 379 specimens. The estimated values of parameter b ranged from 2.884 (A. boyeri) to 3.176 (C. fahireae). The coefficient of determination (R2) was changed between 0.792 to 0.980 for all sampling localities. In the study, Fulton’s condition factor ranged between 0.391 (S. fellowesii) to 3.080 (S. fellowesii); the relative condition factor ranged between 0.346 (O. eliasi) to 2.746 (S. fellowesii), respectively. This research is anticipated to contribute valuable insights for the conservation of the species, while also furnishing essential data to inform future fisheries management studies in the region.

A SHORT NOTE ON WATER QUALITY AND SOME BIODIVERSITY COMPONENTS IN GURBAN VALLEY, GIURGIU COUNTY

Several field trips were carried out in 2022 and 2023, aiming to investigate the water quality parameters, ichthyofaunal and floristic diversity in some areas of Gurban Valley, located in the protected area Natural Park Comana, Giurgiu County, southern Romania. Throughout the study period were identified fish specimens belonging to nine species: Prussian carp Carassius gibelio (Bloch, 1782); Gobio obtusirostris Valenciennes, 1842; Dnieper chub Petroleuciscus borysthenicus (Kessler, 1859); Roach Rutilus rutilus (Linnaeus, 1758); Danubian spined loach Cobitis elongatoides Băcescu &amp; Mayer, 1969; Belica Leucaspius delineatus (Heckel, 1843); Southern ninespine stickleback Pungitius platygaster (Kessler, 1859); European bitterling Rhodeus amarus (Bloch, 1782) and European mudminnow Umbra krameri Walbaum, 1792. A total of 147 captured specimens were measured, weighed and photographed. For the capture of fish, minnow traps and plankton nets were used, on the Gurban River, right tributary of the Neajlov River, Giurgiu County. The floristic inventory compiled so far included 58 plant species grouped into 31 families, with European, circumpolar, Eurasian, eurasiatic continental or cosmopolitan distribution. Related to physico-chemical characterization of water samples collected from four sampling points (SP), the results of laboratory analysis allowed to frame the water into quality classes and to evaluate if the water meets the requirements for aquatic organisms. Hence, on the basis of nitrite-nitrogen (N-NO2-) and nitrate-nitrogen (N-NO3-) water corresponds to Ist quality class, meanwhile chemical oxygen demand (COD), phosphate-phosphorus (P-PO43-) and ammonium-nitrogen (N-NH4+) allowed to associate water quality with IIIrd class. In addition, it has been found very significant correlations between electrical conductivity (EC) and total hardness (TH) with r=0.9230*** and between pH and TH with r=0.8821***, respectively.

Evolutionary mechanisms and practical significance of reproductive success and clonal diversity in unisexual vertebrate polyploids.

Unisexual reproduction is generally relevant to polyploidy, and unisexual vertebrates are often considered an evolutionary "dead end" due to the accumulation of deleterious mutations and absence of genetic diversity. However, some unisexual polyploids have developed strategies to avoid genomic decay, and thus provide ideal models to unveil unexplored evolutionary mechanisms, from the reproductive success to clonal diversity creation. This article reviews the evolutionary mechanisms for overcoming meiotic barrier and generating genetic diversity in unisexual vertebrates, and summarizes recent research advancements in the polyploid Carassius complex. Gynogenetic gibel carp (Carassius gibelio) is a unique amphitriploid that has undergone a recurrent autotriploidy and has overcome the bottleneck of triploid sterility via gynogenesis. Recently, an efficient strategy in which ploidy changes, including from amphitriploid to amphitetraploid, then from amphitetraploid to novel amphitriploid, drive unisexual-sexual-unisexual reproduction transition and clonal diversity has been revealed. Based on this new discovery, multigenomic reconstruction biotechnology has been used to breed a novel strain with superior growth and stronger disease resistance. Moreover, a unique reproduction mode that combines both abilities of ameiotic oogenesis and sperm-egg fusion, termed as ameio-fusiongensis, has been discovered, and it provides an efficient approach to synthesize sterile allopolyploids. In order to avoid ecological risks upon escape and protect the sustainable property rights of the aquaculture seed industry, a controllable fertility biotechnology approach for precise breeding is being developed by integrating sterile allopolyploid synthesis and gene-editing techniques. This review provides novel insights into the origin and evolution of unisexual vertebrates and into the attempts being made to exploit new breeding biotechnologies in aquaculture.

Сравнительная характеристика состояния внутренних органов серебряного карася (Carassius auratus gibelio) в возрастном аспекте

The histological results of the study of the organs of larvae and mature individuals of the silver crucian carp Carassius auratus gibelio (Bloch, 1782) caught in the reservoirs of the Volga River delta are presented. Analysis the internal organs state and tissues helps to identify physiological disorders and pathologies. Thanks to the histological method, it becomes possible to study the structure of the body at the cellular and tissue level, to determine the development of the pathological process and the degree of damage. For pathomorphological evaluation, the liver, gills, kidneys, spleen, intestines and pancreas were examined in silver crucian carp of different ages. It was established that representatives of this species of different ages had identical pathological changes in the organs, but the degree of their manifestation was different: there was a tendency to increase the intensity of the pathology with age. 4 types of major pathological changes associated with metabolic disorders, necrotic damage to cells and tissues, circulatory disorders of organs and signs of hyperplasia were found. Sexually mature individuals had a higher level of pathological manifestations. To a greater extent, the gills, which are in direct contact with the environment, were damaged. The liver of the studied fish also had significant damage. The most frequently reported liver pathology was lipoid degeneration (vacuolar degeneration). Kidneys, intestines and spleen were characterized by degenerative and necrotic disorders. In the spleen of adults, granulomatous inflammation was found, which indicates infectious diseases. The same types of morphological changes were found in larvae and mature individuals, which indicates the nonspecific nature of the identified pathologies, which, as a rule, are associated with the adaptation of the organism to the prevailing living conditions.

Структурні показники та динаміка промислових уловів риб дніпровських водосховищ

Purpose: to establish and analyze the dynamics of the species composition and amounts of commercial fish catches over the past 10 years in the context of assessing the overall efficiency of the fishery exploitation of Dnieper reservoirs. Methodology. As primary materials, data from official commercial fishery statistics and the results of field monitoring studies carried out by the Institute of Fisheries of the National Academy of Sciences on Dnieper reservoirs in the period of 2012‒2022 were used. The intensity of commercial fish harvest was assessed by the annual fishing mortality rate, which was defined as the difference between the total and natural mortality. The total mortality rate was determined graphically by the natural logarithms of the number of age groups in catches; natural mortality — based on the parameters of the von Bertalanffy equation. Statistical data processing was carried out in MS Excel. Findings. The dynamics of commercial catches in the cascade of Dnieper reservoirs in the last 10 years has been characterized by instability with a minimum of 8.9 thousand tons in 2013 and a maximum of 14.0 thousand tons in 2019. The majority of commercial catches was Prussian carp (28.2% of the total catch), common bream (21.1%), roach (20.5%) and silver bream (8.3%). The catch dynamics of all limited species had the same features — a growth in the period 2014‒2016, stabilization until 2019 and a further decrease, which was due to the determining influence of organizational factors. The distribution of fishing pressure by the objects of fishing does not fully correspond to the quantitative parameters of their ichthyomass; the average (2019‒2021) coefficients of annual fishing mortality were: pikeperch — 32.0%, common bream — 22.8%, roach — 24.2%, silver bream — 22.7%, Prussian carp — 19.0%. The maximum catches per unit effort of the gill net in the studied period were recorded for the Kamianske reservoir (348.9±73.4 kg), the lowest (152.0±44.5 kg) — for the Kaniv reservoir. The average fish catch per one gill net per cascade was 245.1±36.3 kg; a trend towards its growth during 2012‒2021 was observed. Originality. Original data on the modern dynamics of the amount and structure of commercial fish catches as a component of scientific support for fisheries exploitation of the Dnieper reservoirs were obtained. Practical value. It has been found that the fluctuations of fish catches in Dnieper reservoirs are largely determined by the influence of external (organizational) factors, which makes it possible to effectively manage the use of fish stocks. It is shown that for some species (in particular, pikeperch), the intensity of fishery exploitation exceeds the optimum, for others (Prussian carp, Black Sea sprat), on the contrary, an increase in the fishing pressure is possible.