Crucian Carp Carassius Auratus Gibelio Research Articles

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.

The antagonistic effect and protective efficacy of gram-positive probiotics Bacillus coagulans to newly identified pathogens Pseudomonas aeruginosa in crucian carp Carassius auratus gibelio

Pseudomonas aeruginosa is a common gram-negative pathogen belonging to the Aeromonas genus. In the present study, dominant bacteria were isolated from diseased crucian carp (Carassius auratus gibelio). The isolate was identified as P. aeruginosa based on biochemical identification and 16S rDNA sequencing. In the histological observation of diseased C. auratus, a large number of vacuoles and inflammatory infiltration appeared in the liver, the structure of intestinal villi was loose, and a large number of inflammatory cells and vacuoles were found in gill. Five virulence genes exoU, exoS, pcrV, exoT and exoY were identified in this P. aeruginosa isolate. Drug sensitivity testing showed that the isolate was susceptible to norfloxacin, ofloxacin and ciprofloxacin. The supernatant of Bacillus coagulans NJ3 exhibited a significant bactericidal effect on isolated P. aeruginosa based on the inhibition zone experiment. The accumulative mortality of C. auratus caused by P. aeruginosa infection could be significantly reduced by adding B. coagulans NJ3 into the aquaculture water. These results indicated that B. coagulans NJ3 could be used as probiotics to prevent the infections of P. aeruginosa in C. auratus. The present study provided a scientific basis for the identification of P. aeruginosa, and treatment for this pathogen infections in fish by using B. coagulans NJ3.

Long-term effects of three compound probiotics on water quality, growth performances, microbiota distributions and resistance to Aeromonas veronii in crucian carp Carassius auratus gibelio

Probiotics could promote the healthy growth of aquatic animals and have been widely used in aquaculture. However, the influence of high concentration compound probiotics on the aquatic animals has not been reported. In the present study, a compound probiotics was used in high-density culture of crucian carps under the condition of micro-water exchange. During nearly 7-weeks feeding experiment, the aquaculture water quality, growth performances, disease resistance and microbiota distributions of crucian carps were tested. Under the high concentrations of compound probiotics, the content of total ammonia nitrogen and nitrite were finally in a state of dynamic equilibrium. The body length and weight of crucian carps in the experimental group (E) was significantly higher than that in the recirculating group (R). The antioxidant enzymes in the intestines and gills of the E group including SOD, CAT, GSH and MDA, were significantly higher than those in R group. The mortality of crucian carps in E group was significantly lower after the immersion infection of Aeromonas veronii. The addition of compound probiotics significantly increased the number of microorganisms detected in the intestines and gills of crucian carps in E group. The bacteria including Firmicutes, Planctomycetes, Verrucomicrobiota at the phylum level in E group were higher than those in R group. At the genus level, these bacteria (Pirellula, Roseimicrobium, Malikia) were not only higher in E group water, but also significantly higher in the intestines and gills than R group. The results of present study systematically analyzed the impact of high-concentration probiotics on crucian carps breeding, and speculated genus Pirellula, Roseimicrobium, Malikia may be used as aquatic probiotics. The present study will provide a new idea for the green and sustainable development of aquaculture.

Bioaccumulation, histopathological and apoptotic effects of waterborne cadmium in the intestine of crucian carp Carassius auratus gibelio

Cadmium (Cd) is a highly toxic, nonessential heavy metal that has been associated with a variety of toxicological effects in both humans and animals. The main objective of this research was to investigate bioaccumulation, intestinal apoptosis, and digestive dysfunction effects of waterborne cadmium in the intestine of crucian carp Carassius auratus gibelio. Fish were exposed to 0, 100, and 500 μg/L waterborne Cd for 4 weeks, and the results showed that Cd accumulation in the intestine was significantly increased as Cd concentration increased. The intestinal structure was severely damaged, including mucosal fold length decreased, the rough endoplasmic reticulum underwent marked swelling and indistinct, and the intestinal microvilli transformed or nearly disappeared. The activities of intestinal apoptosis enzymes (Caspases 3, Caspases 8, and Caspases 9) and apoptosis rate of enterocyte cells were significantly elevated in 500 μg/L waterborne Cd group, activities of digestive enzymes (amylase and protease) were significantly decreased by 500 μg/L waterborne Cd. Overall, our results demonstrated that waterborne Cd exposure could increase Cd bioaccumulation in the intestine and destroy the intestinal digestibility of crucian carp, which in turn led to the occurrence of cell apoptosis.

A Noninvasive Electrophysiological Investigation of Tactile Sensitivity in Cyprinid Fish (Cyprinidae)

Tactile reception in cyprinid fish (silver crucian carp Carassius auratus gibelio and common carp Cyprinus carpio) was investigated by noninvasive recording of action potentials from the head skin in response to rhythmic tactile stimulation. Responses shaped as electric potentials following synchronously with changes in the pressure force on the skin were recorded using chloro-silver electrodes. It was shown that fish, like all terrestrial vertebrates, have phasic and tonic tactile receptors. Three main types of tactile responses were distinguished: (1) tonic responses as potential fluctuations repeating the dynamics of the tactile stimulus, (2) phasic responses as on-, off-, and on-off potentials, and (3) slow deflections from the resting potential. Compound responses comprising simultaneously different types of responses were also recorded. The response latency averaging 6.1 ms for tonic and 4.4 ms for phasic responses was clearly independent of the stimulus direction (switch-on, switch-off). The threshold level of tactile sensitivity in the perioral and gular head areas was 0.05–0.2 g/mm2. Tactile receptors on the silver crucian carp and common carp heads exhibited zonal distribution patterns, with sensory areas differing in their tactile sensitivity. Most sensitive areas were on the upper and lower lips, in the perilabial skin and the gular area on the ventral side of the head. Less sensitive areas were situated rostrally and ventrally to the eyeball. The areas situated dorsally and caudally to the eyeball proved to be insensitive to the applied tactile stimulation. In all sensory areas on the fish head, most intense responses were evoked by sliding tactile stimuli. The distribution specificity of tactile sensory areas meets their functional significance for fish feeding behavior.

Identification and characterization of novel type of RNAs, circRNAs in crucian carp Carassius auratus gibelio

Circular RNAs (circRNAs) with regulatory potency activity was identified from varieties of species. Crucian carp (Carassius auratus gibelio) is one of the most freshwater aquaculture species in China. Every year, huge economic damage to the farming was caused by the virus and bacterial infection. Until now, there is any information about circRNA reported from the Crucian carp. In this study, the expression pattern of circRNA in Crucian carp was investigated with transcriptomic analysis. The results showed that only 37 circRNAs were identified from the Crucian carp, and these circRNAs biogenesis was formed with canonical GU-AG splicing mechanism with unevenly distributed on the chromosomes. Wherein, most of the circRNAs were derived from the sense overlapping strategy. Reverse transcript PCR and Sanger sequencing data indicated that these circRNAs were existed authenticity in Crucian carp. The bioinformatics analysis indicated that circRNAs identified from the Crucian carp with potential miRNA sponge regulate the expression level of mRNAs. GO annotation and KEGG pathway analysis of these circRNAs showed that more than 20% circRNAs were related with catalytic activity and binding in the category of molecular function, and these circRNAs were enriched in 9 signaling pathways, such as, Wnt signaling pathway, MAPK signaling pathway, Ubiquitin mediated proteolysis et al. 220 mRNAs would be regulated by the circRNAs via miRNAs mediation. These target mRNAs were further analyzed with functional annotation and KEGG analysis. GO annotation analysis showed that several genes were related with function of nucleotide binding, transcription regulatory activity. KEGG pathway analysis showed that 5 genes were enriched in the pathway of Endocytosis. The circRNA-miRNA-mRNA regulation network indicated that one miRNA can link one or more circRNA and one or more mRNA. Overall, these results will not only help us to further understand the novel RNA transcripts in Crucian carp, but also provide the novel clue to investigate the interaction between host and pathogens from this novel circRNA molecule.

The metabolic responses of crucian carp blood to Cyprinid herpesvirus 2 infection

In recent years, Cyprinid herpesvirus 2 (CyHV-2) has severely affected the culture of crucian carp Carassius auratus gibelio, causing massive economic losses. However, the responses of crucian carp during infection with CyHV-2 have not been explored. In this study, physiological and biochemical indicators and enzyme activities of crucian carp before and after infection with CyHV-2 were analyzed. The number of white blood cells in the diseased fish was significantly increased. Compared to control group, red blood cell content, hemoglobin content, mean corpuscular volume, mean corpuscular hemoglobin content and mean corpuscular hemoglobin concentration in the experimental group were significantly decreased. In the diseased fish group, the levels of the glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase, alkaline phosphatase, lactate dehydrogenase and urea nitrogen in the blood were also significantly increased compared to the control group. In addition, the activity of serum total antioxidant capacity, acid phosphatase, glutathione-S transferase and catalase in diseased fish were significantly higher than in the control group. LC-Q/TOF-MS analysis platform was used in this study for the first time to detect changes in the serum metabolome of crucian carp infected with CyHV-2. A total of 79 differential metabolites have been identified. Significant increases in concentrations were found for several carbohydrates (glucose, mannose, ribose, etc.), fatty acids (pentadecanoic acid, arachidonic acid, palmitic acid, eicosapentaenoic acid, hydroxylic tetracarbonate alkenoic acid, linoleic acid and its derivatives) and most of the amino acids and their derivatives. However, guanine, cytosine, uridine and VB2 were significantly decreased. KEGG pathways enrichment showed that amino acid metabolism and lipid metabolism were severely influenced. The above results provide a theoretical basis for the infection mechanism of CyHV-2

TỔNG QUAN VỀ VIỆC SỬ DỤNG SELEN (Se) TRONG NUÔI TRỒNG THỦY SẢN

Effects of antibiotics usage in aquaculture on environment and human health has prompted the search for alternative products. Recently, the microelements in organic form have been used as alternative to antibiotics in aquaculture. Se is one of the microelements that have received heightened attention. This report reviews the role of Se in the culture of fishes (cobia Rachycentron canadum L., red sea bream Pagrus major, fingerling channel catfish Ictalurus punctatus, seabass Lates calcarifer, snubnose dart Trachinotus blochii, rainbow trout Oncorhynchus mykiss, common carp Cyprinus carpio L., Atlantic salmon parr Salmo salar, nile tilapia Oreochromis niloticus, african catfish Clarias gariepinus, Senegalese sole Solea senegalensis, grouper Epinephelus malabaricus, gilthead seabream Sparus aurata, Chinook salmon Oncorhynchus tshawytscha, fathead minnow Pimephales promelas, striped bass Morone saxatilis, bluegill Lepomis macrochirus, crucian carp Carassius auratus gibelio) and crustacean (giant freshwater prawn Macrobrachium rosenbergii, white shrimp Penaeus vannamei, marron Cherax cainii, crayfish Procambarus clarkii). Suggestion for further research on the application of Se in aquaculture is also included.

Identification and characterization of a type I interferon induced by cyprinid herpesvirus 2 infection in crucian carp Carassius auratus gibelio

Crucian carp (Carassius auratus gibelio) is a popular food fish in Asia, and cyprinid herpesvirus 2 (CyHV-2) is the only known viral pathogen for crucian carp. Type I interferon genes are induced up on host cell recognition of viral nucleic acids and well recognized for their crucial roles in providing local or systemic protection against the viruses in various organisms. In a transcriptome analysis to uncover differentially expressed genes in crucian carp in response to CyHV-2 challenge, a partial interferon transcript was identified to be significantly up-regulated in the kidney of infected fish, which was named as crucian carp IFNc (ccIFNc). The complete ORF of ccIFNc was further determined by RACE technique, which spanned over 546 bp and encoded a polypeptide containing 182 amino acids. Phylogenetic analysis revealed that ccIFNc clustered with known type I IFN genes from other aquatic organisms. Quantitative RT-PCR analysis demonstrated that ccIFNc was constitutively expressed in all investigated tissues with a comparably higher expression level in spleen, gill, kidney, and muscle. Following challenge with CyHV-2, the transcriptional levels of ccIFNc were dramatically up-regulated in all of the tested tissues, especially in the spleen and gill with increased folds of 436 and 158, respectively. The intramuscular (i.m.) injection of a eukaryotic expression plasmid encoding ccIFNc (pEGFP-cIFNc) resulted in increased ccIFNc expression and reduced the mortality after the CyHV-2 challenge significantly. In summary, our data suggested that the ccIFNc belongs to the type I interferon family with a potential role in countering CyHV-2 infection in crucian carp.

Genetic Diversity in Populations of Silver Crucian Carp Carassius auratus gibelio (Cyprinidae, Cypriniformes), Depending on the Type of Reproduction and Reservoir Size

This paper presents data on the polymorphism of inter simple sequence repeats of DNA in the silver crucian carp Carassius auratus gibelio in water bodies in the southern part of Western Siberia. The share of polymorphic ISSR-PCR bands in silver crucian carp populations from different lakes varied from 40 to 70%, and Nei’s gene diversity index varied from 0.16 to 0.25. The genetic diversity indices were lower in the populations that were largely represented by females than in bisexual ones. The highest levels of genetic polymorphism were revealed in populations with diploid–triploid complexes. The gene diversity index of the silver crucian carp population is positively correlated with the reservoir size (r = 0.90, p = 0.015; Rs = 0.74, p = 0.036).

Effects of inducers of cytochrome P450s on enrofloxacin N-deethylation in crucian carp Carassius auratus gibelio.

In this study with crucian carp (Carassius auratus gibelio), the effect on enrofloxacin (EF) and its metabolite ciprofloxacin (CF) and on the activity of cytochrome P450 1A (CYP1A) and cytochrome P450 3A (CYP3A) was estimated following the oral administration of rifampicin (RIF) (12mg/kg) and β-naphthoflavone (BNF) (12mg/kg), respectively. First, reversed-phase high-performance liquid chromatography (RP-HPLC) was used to detect the pharmacokinetics of EF with continual blood sampling. In RIF-treated, BNF-treated and control groups, the value of the CmaxCF/CmaxEF ratio was 4.41, 0.81 and 0.95, and the corresponding value of the AUC0-t-CF/AUC0-t-EF ratio was 3.69, 1.84 and 1.76, respectively. In the RIF-treated, BNF-treated and control groups, the MRT values of EF were 26.57, 27.45 and 30.88h, and the corresponding values for CF were 5.79, 35.18 and 38.11h, respectively. Based on these results for crucian carp, the accumulation and elimination of EF and CF in the RIF-treated group were more rapid than in BNF-treated and control groups. Second, liver microsomes were pretreated with the inducer of CYP1A for BNF and that of CYP3A for RIF, and then the enzymatic activities of CYP1A and CYP3A were measured, respectively. The activities of ethoxyresorufin-O-deethylation (EROD) and erythromycin-N-demethylation (ERND) increased significantly (P<0.05) for CYP1A and CYP3A, respectively. However, in further experiments on the formation of CF, the level of EF N-deethylation was significantly induced by RIF and inhibited by ketoconazole (KTZ) for CYP3A but had no influence for CYP1A, BNF and berberine chloride (BER). We concluded that CYP3A might be responsible for the N-deethylation of EF and because of this activity, could also serve as a toxicity biomarker in crucian carp.

ГЕНЕТИЧЕСКОЕ РАЗНООБРАЗИЕ ПОПУЛЯЦИЙ СЕРЕБРЯНОГО КАРАСЯ CARASSIUS AURATUS GIBELIO (CYPRINIDAE, CYPRINIFORMES) В ЗАВИСИМОСТИ ОТ ТИПА РАЗМНОЖЕНИЯ И РАЗМЕРА ВОДОЁМА

The paper presents data on the polymorphism of the interior simple sequence repeats of DNA in the silver crucian carp Carassius auratus gibelio from waterbodies in the Western Siberia. The proportion of the polymorphic ISSR-PCR bands in the silver crucian carp populations from different lakes varied from 40 to 70%, the rate of Nei’s gene diversity being 0.16 - 0.25. Genetic diversity indicators were lower in the populations primarily presented by females, as compared with bisexual ones. The highest levels of genetic polymorphism were revealed in the populations of diploid-triploid complexes. The gene diversity level of the silver crucian carp population positively correlates with the reservoir’s size (r = +0.90, p = 0.015; Rs = 0.74, p = 0.036).

Molecular Cloning and Expression Analysis of &lt;i&gt;Lysozyme C&lt;/i&gt; and &lt;i&gt;MHC class I&lt;/i&gt; from Crucian Carp &lt;i&gt;Carassius auratus gibelio&lt;/i&gt; in Response to Cyprinid Herpesvirus 2 Infection

Molecular Cloning and Expression Analysis of &lt;i&gt;Lysozyme C&lt;/i&gt; and &lt;i&gt;MHC class I&lt;/i&gt; from Crucian Carp &lt;i&gt;Carassius auratus gibelio&lt;/i&gt; in Response to Cyprinid Herpesvirus 2 Infection

Effect of Temperature Growth on Lysozyme and Protein Content in Several Freshwater Fishes, Infested and Not-infested by Ectoparasites

The effect of the water temperature growth from 15 to 25°Conthe infestation rate of fishes (carp Cyprinus carpio, crucian carp Carassius auratus gibelio, stone moroco Pseudorasbora parva, and bester Huso huso×Acipenser ruthenus) by ectoparasites, lysozyme and protein content in tissues and organs was investigated. Number of ectoparasites in all considered fishes at temperature growth to 25°C significantly reduced. Changes of lysozyme and protein content in blood plasma, kidneys and spleen of fishes were determined.

Effect of Trichlorfon on Hepatic Lipid Accumulation in Crucian Carp Carassius auratus gibelio

This study evaluated the toxic effects of the organophosphate pesticide trichlorfon on hepatic lipid accumulation in crucian carp Carassius auratus gibelio. Seventy-five fish were divided into five groups (each group in triplicate), and then exposed to 0, 0.5, 1.0, 2.0, and 4.0 mg/L of trichlorfon and fed with commercial feed for 30 d. At the end of the experiment, plasma and hepatic lipid metabolic biochemical status were analyzed. Triglyceride contents were significantly (P < 0.05) increased in liver but decreased in plasma after 1.0, 2.0, and 4.0 mg/L trichlorfon treatments. Plasma insulin contents were markedly (P < 0.05) increased when trichlorfon concentrations were 0.5, 1.0, and 4.0 mg/L. There were no significant differences in hepatic hormone-sensitive lipase contents between the trichlorfon-treated fish and the controls. Hepatic cyclic adenosine 3′, 5′-monophosphate, very-low-density lipoprotein, and apolipoprotein B100 contents were decreased in the fish when trichlorfon concentration was 2.0 mg/L. Furthermore, electron microscope observations showed rough endoplasmic reticulum dilatation and mitochondrial vacuolization in hepatocytes with trichlorfon exposure. On the basis of morphological and physiological evidence, trichlorfon influenced crucian carp hepatic pathways of lipid metabolism and hepatocellular ultrastructure, which resulted in lipid accumulation in the liver.

Металоакумулювальна здатність тканин карася сріблястого Carassius auratus gibelio залежно від історії експозиції in situ

The effect of copper (0.005 and 0.05 mg×L -1 ) and manganese ions (0.17 and 1.7 mg×L 1 ), thiocarbamate (Tatoo 9.1 and 91 ug×L -1 ) and tetrazine (Apollo, 2 and 10 ug×L -1 ) pesticides on metal content in the tissues of crucian carp Carassius auratus gibelio from two sites, relatively clean (Z) and polluted (B), under exposure during 14 days was studied. In fish from the clean site the copper, zinc, and manganese (in liver) concentration has been higher than in fish from polluted site, whereas cadmium, and manganese (in gills) concentration, was lower. The ratio of essential metals copper, zinc and manganese concentration to nonessential cadmium concentration was twofold higher in tissues of crucian carp from clean site. Significant effect both of site and exposure on the metal concent in the tissues of fish was proved. According to Principal Component Analysis, the difstinctions between the groups of animals from different aquatic bodies under the same substance effect independently of its concentration was proved. Dependence on the concentration of acting substance was revealed only for copper in the gibel carp from polluted site. The concentration of acting metal increased for copper after treatment by 0.005 mg×L -1 (in the giils of fish from group B) and for manganeze after the treatment by 0.17 mg×L -1 (in the liver of fish from group B) and 1.7 mg×L -1 (with exception of gills in fish from group B). The decreasing of the ratio of concentrations of copper, zinc and manganeze to concentration of cadmium was shown in the gills of fish from clean site under all exposures and after the effect of Apollo in all cases. Negative interrrelation was detected by the linear regression analysis for zinc and cadmium content in fish tissues. Keywords : Carassius auratus gibelio , copper, zinc, manganese, cadmium, pesticides.

Inhibition of CYP450 1A and 3A by berberine in crucian carp Carassius auratus gibelio

Berberine has long been considered as an antibiotic candidate in aquaculture. However, studies regarding its effects on drug-metabolizing enzymes in fish are still limited. In the present study, the effects of berberine on cytochrome P4501A (CYP1A) and CYP3A in crucian carp were investigated. Injection of different concentrations of berberine (0, 5, 25, 50, and 100mg/kg) inhibited the CYP1A mRNA expression, thereby inhibiting further the catalytic activity of CYP1A-related ethoxyresorufin-O-deethylase (EROD). Furthermore, both CYP1A expression and EROD activity were further inhibited with increasing berberine concentrations. In addition, the CYP3A expressions at both the mRNA and the protein levels were downregulated by higher berberine concentrations. The catalytic activity of CYP3A-related erythromycin N-demethylase (ERND) was also inhibited by berberine at a dose of no less than 25mg/kg. Moreover, at the berberine concentration exceeding 25mg/kg, the inhibition of CYP3A expression and ERND activity increased with increasing berberine concentrations. In vitro experiments were also performed. When berberine was pre-incubated with the crucian carp liver microsomes, it competitively inhibited the corresponding EROD activity with the IC50 of 11.7μM. However, the ERND activity was slightly inhibited by berberine with the IC50 of 206.4μM. These results suggest that, in crucian carp, berberine may be a potent inhibitor to CYP1A, whereas the CYP3A inhibition needs a higher concentration of berberine.

Adaptive mechanisms of distribution and population dynamics of Carassius auratus gibelio in the Ponto-Caspian region (with reference to the Azov basin)

Historically, from the beginning of the 20th century until the beginning of the 21st century, an attempt was made to discern the major adaptive mechanisms that determine the distribution and population dynamics of the silver crucian carp Carassius auratus gibelio (Bloch, 1782) in the Ponto-Caspian region at various stages of freshwater and coastal marine ecosystem functioning with reference to the Azov basin (including introduction of Carassius auratus gibelio from the Amur basin into natural waterbodies of this region as well as rapid development of pond fish farming with introduction of Carassius auratus gibelio as an additional object of aquaculture). Until the middle of the 20th century, Carassius auratus gibelio was a secondary component of freshwater and lagoon ichthyocenoses of the Azov basin. Its populations were represented by the gynogenetic form. At present, owing to transformation of the genetic structure and domination of the bisexual form of Carassius auratus gibelio, the dependence controlling reproduction of the formerly prevalent unisexual-female form by direct connection with abundance and spawning dates of related cyprinid species disappeared. In 1980–1998, there was a quantitative outbreak and area expansion of Carassius auratus gibelio in the Azov basin owing to freshened waters of the Taganrog and Temryuk bays of the Sea of Azov. Owing to multiple spawning, a broad food spectrum, and high resistance to pollutants, Carassius auratus gibelio actively colonizes new biotopes vacated by former major components of ichthyocenoses of the Azov basin. At present, catches of Carassius auratus gibelio definitely belong to the top three semifreshwater fish of the Russian part of the Azov basin. In the years of the outbreak, Carassius auratus gibelio living in the Temryuk Bay makes, under favorable hydrological conditions, extensive spawning migrations via the Kerch Strait along the Black Sea coast of Taman Peninsula.

Etiology and pathology of epidermal papillomas in allogynogenetic crucian carp Carassius auratus gibelio (f%%FONT_ERR%%) × Cyprinus carpio var. singuonensis (m%%FONT_ERR%%)

Allogynogenetic crucian carp Carassius auratus gibelio (female) x Cyprinus carpio var. singuonensis (male) is one of the main freshwater aquaculture species in China. In recent years, epidermal papillomas have been observed on the scales, fins and opercula of adult fish in many fish farms in the Chongming county of Shanghai, China. The disease appears in the late autumn of the first year and becomes more severe in winter. It gradually regresses in the late spring or summer of the second year, as water temperature increases. Our study revealed that the disease pathogen was likely to be a herpes-like virus, as indicated by enveloped viral particles in the cytoplasm, empty capsids in the nucleus and a virus-like morphology of the pathogen. The size of the enveloped herpes-like virus was 118.18 +/- 10.53 (SD) nm (n = 22) and its nucleocapsid was 78.64 +/- 7.74 nm (n = 22) in diameter. Histopathological examination of tumours revealed that both epithelial and stromal cells proliferated to form papillomas. The nuclei of epithelial tumour cells were irregular in shape and in size. Most of the mucous cells were located in clusters near the middle of each papilloma. Cytoplasmic organelles were sparse in tumour cells. Numerous granulocytes and lymphocytes infiltrated into the tumour tissue. There were no inclusion bodies in the cytoplasm and nuclei of tumour cells. The lesions only occurred in adult allogynogenetic crucian carp, even though they were cultured together with other fish species. There was marked variation in incidence: in some ponds, only a few fish were affected, while the incidence was up to 90% in other ponds.

Inheritance of microsatellite DNA in bisexual gynogenesis complex of Fangzheng silver crucian carp, Carassius auratus gibelio (Bloch)

Five gynogenetic progeny groups of silver crucian carp Carassius auratus gibelio were produced and sex ratios (males:total progeny) of each of the progeny groups were analysed. About 110 males and 366 females were genotyped at 15 microsatellite loci for comparison with their parents to (1) verify the gynogenesis status of Fangzheng C. auratus gibelio, (2) detect the incorporation of paternal genetic material into the offspring and (3) study the possible association of genetic exchange at microsatellite loci with the existence of sex. The sex ratios in progenies of five groups were highly variable, but all had significant female bias. The sex ratio ranged from 0 to 0·37. Significant differences in the sex ratio within and between groups were also found. Microsatellite genotyping at 15 loci showed that 100 and 97% of the progeny shared the same genotype with the mother in four groups and in one group, respectively, confirming that gynogenesis is the general mechanism of reproduction in C. auratus gibelio. However, 0·63% of all offspring did show incorporation of paternal genetic material. No single loci tested were associated with the occurrence of male progeny, indicating unknown genetic mechanisms for sex determination in C. auratus gibelio.