Search

Cyprinid herpesvirus 2 (CyHV-2) has become a serious threat to the gibel carp Carassius auratus gibelio industry and has led to enormous losses worldwide. We have therefore developed an immunochromatographic strip (ICS) to enable rapid on-site detection of CyHV-2 by aquaculture facility staff. The ICS employs 2 monoclonal antibodies (MAbs 2C3-1E6 and 3H2-1G5) against the ORF25 protein, a CyHV-2 membrane protein, as the capture and detection antibodies, respectively. Indirect immunofluorescence assay (IIFA) and Western blotting of CyHV-2-infected fathead minnow cells indicated that the 2 MAbs could specifically bind CyHV-2 by recognizing ORF25 antigen. Sandwich ELISA showed that the detection limit of ORF25 protein halved when MAb 2C3-1E6 served as the capture antibody compared to MAb 3H2-1G5. The test for detecting purified CyHV-2 using the ICS could be completed in 10 min and the sensitivity was 1 µg ml-1. Sensitivity of the ICS remained stable following storage at 4, 25 and 37°C for 6 mo. Tissue homogenate from gibel carp with and without obvious gill hemorrhages was subjected to CyHV-2 detection using the ICS: the results were in good accordance with conventional PCR. Our ICS does not require highly trained technicians or specialized equipment, making it suitable for rapid diagnosis of CyHV-2 infection both in the laboratory and in the field.

Leucine has been reported to regulate key metabolic pathways, including growth, immunity and antioxidative defence. To study the effects of dietary leucine supplementation in a carbohydrate‐rich diet on juvenile gibel carp (Carassius auratus gibelio var. CAS III), an 8‐week feeding trial was conducted on gibel carp juveniles reared on an experimental wheat meal‐rich diet (40%) with varying leucine contents (0.87%, 1.23%, 1.68%, 2.10%, 2.41% and 2.83%). No significant changes in growth performance were observed regardless of leucine levels (p > 0.05). However, proper leucine levels (1.68% and 2.10%) could increase the accumulation of whole‐body crude protein and decrease the accumulation of crude lipid. Furthermore, significant liver tissue damage occurred at 1.23% and 1.68% dietary leucine levels, whereas 2.10% and 2.41% dietary leucine could improve the antioxidant capacity at the end of the 8‐week feeding trial. 1.68% and 2.10% dietary leucine levels could alleviate the hyperglycaemia caused by high carbohydrate intake after the 8‐week feeding trial, as well as the elevated glucose content after starvation, to maintain normal metabolic conditions. Supplementation with leucine could significantly downregulate IL‐1β, TNF‐α1, MyD88 and TIRAP mRNA levels during the 8‐week feeding trial and after starvation for 48 h. In conclusion, 2.10%–2.41% leucine contents in a carbohydrate‐rich diet could benefit muscle protein deposition, hyperglycaemia and hyperlipidaemia alleviation, and results in non‐specific immunity improvement.

Myxozoans usually have a complex life cycle involving indirect transmission between vertebrate and invertebrate hosts. The vertical transmission of these parasites in vertebrate hosts has not been documented so far. Here, we assessed whether the myxozoan parasite Myxobolus honghuensis is vertically transmitted in naturally infected allogynogenetic gibel carp Carassius auratus gibelio (Bloch). M. honghuensis infection of broodfish, fertilized eggs and laboratory-cultured progeny was monitored in 2018 and 2019. The presporogonic stage was microscopically observed in the pharynx of broodfish and their progeny. In situ hybridization confirmed the presence of M. honghuensis presporogonic stage in the pharynx of broodfish and progeny. Nested PCR results showed that M. honghuensis was present in tissues and eggs of broodfish, fertilized eggs and their corresponding progeny. The sequences obtained from broodfish and progeny showed 98.0-99.8% similarity with ITS-5.8S rDNA of M. honghuensis. This study provides molecular and light microscopy evidence for the transfer of M. honghuensis from broodfish to progeny via the eggs, but it is insufficient to assert that M. honghuensis can transmit vertically in naturally infected allogynogenetic gibel carp. This is the first record about vertical transfer of myxozoan in the vertebrate host.

В данной статье представлены результаты изучений морфофизиологического индекса сердца Carassius auratus gibelio, вылов которого производился в озере Кедровое, Краснотуранского района, Красноярского края, в летний период (июль). В статье проанализированы значения индекса сердца в зависимости от возраста и количества особей. Показатели различны для каждого возраста. Наибольшее значения индексов характерно для половозрелых особей., This article presents the results of studies of the morphophysiological index of the heart of Carassius auratus gibelio, which was caught in Lake Kedrovoye, Krasnoturansky district, Krasnoyarsk Territory, in the summer (July). The article analyzes the values of the heart index depending on the age and number of individuals. The indicators are different for each age. The highest index values are typical for sexually mature individuals.

В статье проанализированы половые и возрастные характеристики Carassius auratus gibelio. Вылов особей проводился на озере Кедровое Краснотуранского района Красноярского края в июле 2022 года. Было выловлено 33 экземпляра рыбы. В работе представлена зависимость количества и возраста исследуемых образцов карася серебряного, а также процентное соотношение выборки по возрасту. Отражено доминирующее преобладание самок над самцами., The article analyzes the sexual and age characteristics of Carassius auratus gibelio. The catch of individuals was carried out on Lake Kedrovoye, Krasnoturansky district, Krasnoyarsk Territory, in July 2022. 33 specimens of fish were caught. The paper presents the dependence of the number and age of the studied samples of silver carp, as well as the percentage of the sample by age. The dominant predominance of females over males is reflected.

В данной статье представлены морфологические параметры Carassius auratus gibelio, выловленного с озера Кедровое Краснотуранского района Красноярского края. Было рассмотрено и изучено 33 экземпляра рыбы. Был осуществлён биологический анализ выборок исследуемого вида рыбы. Производились следующие промеры: полная длина тела АВ, промысловая длина тела AD, общая масса тела. Отражена зависимость роста и веса рыбы от ее возраста. С увеличение возраста рыбы повышаются ее морфологические параметры. Все исследуемые образцы рыбы представленны самками., This article presents the morphological parameters of Carassius auratus gibelio, caught from Lake Kedrovoye, Krasnoturansky district, Krasnoyarsk Krai. 33 specimens of fish were examined and studied, and a biological analysis of samples of the fish species under study was carried out. The following measurements were made: total body length AB, commercial body length AD, total body weight. The dependence of the height and weight of the fish on its age is reflected. With an increase in the age of the fish, its morphological parameters increase. All the studied fish samples are represented by females.

Aflatoxin contamination of food and water is a serious problem worldwide. This study investigated the defensive ability of gibel carp exposed to aflatoxin B1 (AFB1) by challenging it with cyprinid herpesvirus 2 (CyHV-2) infection. The data showed that AFB1 exposure significantly increased the mortality of CyHV-2-infected gibel carp, and enhanced the viral load in the fish liver, kidney, and spleen. The oxidative-antioxidant balance suggested that AFB1 induced severe oxidative stress, including increased reactive oxygen species (ROS) and malondialdehyde (MDA) levels in the AFB1 exposed group, and the reduced activity of superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT) in the AFB1 exposed group. Meanwhile, the related expression of nuclear factor erythroid 2-related factor 2 (Nrf2), interferon regulatory factor 3 (IRF3) and the type 1 interferon (IFN1) were noticeably down-regulated, but caspase-1 was up-regulated, after exposure to AFB1, demonstrating that fish are unable to avoid the virus infection. It should be noted that the intestinal microbiota diversity and richness were lower in the AFB1 exposed group, and the composition of intestinal microbiota was affected by AFB1, resulting in the higher abundance of bacteria (such as Aeromonas and Bacteroides) and the lower abundance of potentially beneficial bacteria (such as Cetobacterium and Clostridium) in the AFB1 exposed group. This research provides insight into the possibility that AFB1 may increase the susceptibility of C. gibelio to CyHV-2 infection, and thus amplify the viral outbreak to endanger ecological safety in aquatic environment.

The article presents the results of long-term studies focusing on the population structure, seasonal distribution, migration and other characteristics of the populations of silver carp ( Carassius auratus gibelio Bloch, 1783) in the Azov estuaries. Taking into account the analysis of long-term statistical data of the Azov-Black Sea Territorial Administration of the Federal Fisheries Agency, as well as the results of the proper research on the 161st water body with a total area of more than 62.000 hectares, the commercial catch indices of Prussian carp for 2010-2016 are displayed. Estimation of fish abundance was carried out by direct accounting method based on the results of control fishing in estuaries with various fishing gears, taking into account their catch coefficient. The dynamics of stock indicators, recommended catch level and production of Prussian carp in the Azov estuaries for 2010-2016 has been traced. The main reasons affecting the state of stocks and effective development of the recommended catch of Prussian carp have been analyzed. In order to optimize and increase the efficiency of the fishing organizations of the Krasnodar Territory, Prussian carp stocks and the volumes of its recommended catch in various groups of Azov estuaries were calculated, forecasted indicators for its production for 2018 were given. It has been stated that in connection with a rather high total stock of the population, in the near future Prussian carp will remain the dominant component of the ichthyofauna of the Azov estuaries with the main fishing part concentrated in the Akhtarsk-Griven and the Chernoerkovsk-Sladkov groups of estuaries.

Cyprinid herpesvirus 2 (CyHV-2) infection results in huge economic losses in gibel carp (Carassius auratus gibelio) industry. In this study, we first constructed recombinant plasmids pcORF25 and pcCCL35.2 as DNA vaccine and molecular adjuvant against CyHV-2, respectively, and confirmed that both recombinant plasmids could be effectively expressed in vitro and in vivo. Then, the vaccination and infection experiments (n = 50) were set as seven groups. The survival rate (70%) in ORF25/CCL35.2 group was highest. The highest specific antibody levels were found in ORF25/CCL35.2 group in major immune tissues by qRT-PCR, and confirmed in serum by ELISA assay, antibody neutralization titer, and serum incubation-infection experiments. Three crucial innate immune indices, namely C3 content, lysozyme, and total superoxide dismutase (TSOD) activities, were highest in ORF25/CCL35.2 group in serum. pcORF25/pcCCL35.2 can effectively up-regulate mRNA expressions of some important immune genes (IL-1β, IL-2, IFN-γ2, and viperin), and significantly suppress CyHV-2 replication in head kidney and spleen tissues. The minimal tissue lesions can be seen in ORF25/CCL35.2 group in gill, spleen, and trunk kidney tissues by histopathological examination. The results indicated that the combination of DNA vaccine pcORF25 and molecular adjuvant pcCCL35.2 is an effective method against CyHV-2 infection, suggesting a feasible strategy for the control of fish viral diseases.

Using the example of Lake Krugloye (Mordovinskaya floodplain in the Saratov Reservoir), the changes in the physiological and biochemical parameters in two abundant fish species inhabiting the same biotopes have been comparatively analyzed. The fish under study are the aboriginal crucian carp (Carassius auratus gibelio) (Bloch, 1792) and the invasive Amur sleeper (Perccottus glenii) (Dybowski, 1877). The study reveals differences between the species in the patterns of the dynamics of body weight and contents of protein, fat, water, and caloric contents upon an increase in body length during various months of the active feeding period. Potential reasons for the differences and their consequences are discussed.

The present study examined the effect of dietary spirulina, Arthrospira platensis on growth performance, blood physiological indices, immune-related gene expressions and resistance of juvenile gibel carp against Aeromonas hydrophila infection. Four isonitrogenous (360 g kg−1) and isolipidic (90 g kg−1) diets were formulated with containing different levels of spirulina powder of 0 g (SP0, the control diet), 3.38 g (SP3.38), 6.76 g (SP6.76) and 13.52 g (SP13.52) per 100 g diet to replace 0%, 25%, 50% and 100% of fishmeal protein, respectively. And each diet was randomly assigned to triplicate tanks (150-L capacity per each) and each tank was stocked with 22 fish (15.37 ± 0.06 g). Fish were fed one of the tested diets up to satiation twice a day for 46 days. A challenge test was carried out after the feeding trial by injecting Aeromonas hydrophila intraperitoneally for 7 days. The results showed that fish growth, feeding rate in groups SP3.38 and SP6.76 were significantly higher than those of groups SP0 and SP13.52 (P

Aquaculture nutritional models play a vital role in the management of fish culture operations. This study reported a combined nutritional model constructed based on the data from several fish farms and published studies in order to predict the growth, feed requirement and waste output of gibel carp (Carassius auratus gibelio) and the web-based model service platform. This combined model comprised a growth model, a feed requirement model and waste (nitrogen and phosphorus) output model. The performance of different growth models and the growth trajectory of gibel carp were analyzed based on growth data obtained from two fish farms in Jingzhou, Ningbo (China) and published studies. The least squares method was used to optimize the growth coefficient within each growth stanza and to choose the best fit of growth model, which was the thermal-unit growth coefficient (TGC) model. Three growth stanzas of gibel carp in its life cycle were found by using TGC model, which were from first-feeding (1 g) to 13.5 g (Stanza 1); from 13.3 to 175.5 g (Stanza 2); and > 175.5 g (Stanza 3). Feed requirement of fish in different growth stages were determined by digestible energy requirement (DEreq), estimated based on the summary of recovered energy (RE), basal metabolism (HeE), heat increment of feeding (HiE), and urinary and branchial excretion (UE + ZE). Nutrient mass balance method was used to estimate waste output when the different growth stages of gibel carp was fed with different diets. The combined model was developed as a web-based service which could be obtained freely online. The design and implementation of the program which included three layers, i.e., front user side, application layer and data storage, were also reported in the current study. The user interface, functionalities of the application layer and database design were outlined. The service could be accessed by any browser and mobile device, providing a convenient tool for fishery management for farmers, farm managers and researchers in academia. The validation of the predicted body weight and feed conversion rate (FCR) showed that the current combined model has a great reference value in estimating the growth, feed requirement and waste discharge in gibel carp farms. The web-based model service could be an effective tool for benchmarking the growth performance, providing differentiated production, reducing feed waste, increasing economic benefits, and evaluating aquaculture pollution in different gibel carp culture operations.

The pharmacokinetics (PK) of cefquinome (CEQ) was studied in crucian carp (Carassius auratus gibelio) after single oral, intramuscular (i.m.), and intraperitoneal (i.p.) administration at a dose of 10 mg/kg body weight and following incubation in a 5 mg/L bath for 5 hr at 25°C. The plasma concentration of CEQ was determined using high-performance liquid chromatography (HPLC). PK parameters were calculated based on mean CEQ concentration using WinNonlin 6.1 software. The disposition of CEQ following oral, i.m., or i.p. administration was best described by a two-compartment open model with first-order absorption. After oral, i.m., and i.p. administration, the maximum plasma concentration (Cmax ) values were 1.52, 40.53, and 67.87 μg/ml obtained at 0.25, 0.23, and 0.35 hr, respectively, while the elimination half-life (T1/2β ) values were 4.68, 7.39, and 6.88 hr, respectively; the area under the concentration-time curve (AUC) values were 8.61, 339.11, and 495.06 μg hr/ml, respectively. No CEQ was detected in the plasma after bath incubation. Therapeutic blood concentrations of CEQ can be achieved in the crucian carp following i.m. and i.p. administration at a dosage of 10 mg/kg once every 2 days.

The prevalence of processes of the increase in abundance and changes in the sexual structure of Prussian carp populations in waterbodies differing dramatically in ecological properties and distant from each other (Lake Sevan and Rybinsk Reservoir) indicates the presence of global factors affecting climatic zones. The increase in environmental temperature due to global warming may be such a factor. Experimentally proven high thermophilicity and the thermal stability of Prussian carp, as well as its low sensitivity to hypoxia, provide some advantages for this species over many other fish inhabiting the same waterbodies.

Purpose. To determine the possibility of performing an express-evaluation of the toxicity of ammonia polluted waters based on ethological parameters of Carassius auratus gibelio (Bloch,1782) with the use «time sampling» method. Methodology. For biotesting in August 2017, water samples were taken from the Denishevsky reservoir of the Teteriv river and water supply network of the water service company, which were placed in aquaria (10 dm3) and a control and experimental groups of fish were formed according to the following scheme: control group – samples of settled (24 hours) clean tap water; experimental group D-1 – water samples from the Denishivsky reservoir with the total ammonia concentration of 1.5 mg/dm3; experimental group D-2 – samples of settled (24 hours) tap water with the total ammonia concentration of 1.5 mg/dm3. Test-objects were females of C. auratus gibelio, in which the parameters of typical and non-typical motor activity and feeding behavior were determined. Fish were exposed for 12 hours. For both experimental groups, water toxicity indexes were calculated in comparison with the control. Findings. In the studies, we showed the possibility of using the «time sampling» method for rapid assessment of the toxicity of polluted waters with ammonium concentration of 1.5 mg/dm3 based the ethological parameters of Prussian carp (C. auratus gibelio), which included the instantaneous fixation of the number of individuals preferring one or another act of behavior. It was shown that C. auratus gibelio females reacted on ammonia content by impairing the motor and feeding behavior. Settled tap water artificially pollution with ammonia (group D-2) appeared to be more toxic for fish than water polluted by natural way. Immobilization of individual fish in the group D-1 was 6.60% lower, while their survival rate was 11.11% hogher compared to the group D-1. Unlike fish of the experience groups, fish in the control group exhibited only single untypical ethological acts. The calculation based on the behavioral parameters of Prussian carp females demonstrated mainly medium (group D-1) and high (group D-2) levels of acute toxicity of experimental waters. Originality. For the first time, the express-evaluation of the toxicity of water with elevated ammonium content (1.5 mg/dm3) was carried out by observing the motor activity and feeding behavior of Prussian carp (C. auratus gibelio) by the «time sampling» method. Practical use. The results of the study are used for the rapid assessment of the toxicity of water of surface water sources of the Teteriv river.

Purpose. To provide the biological assessment of the silver Prussian carp (Carassius auratus gibelio (Bloch, 1782)) commercial stock of the Dnieper-Bug estuary in the conditions of the transformed Dnieper river flow. Methodology. During the analysis of the biological state of the Prussian carp commercial stock, the main attention was given to the dynamics of age and sexual structure, length-weight growth rate, absolute fecundity and condition factor. The basic data were collected during the work of control-observation stations of the Institute of Fisheries in the Dnieper-Bug estuary during the current century. The collection and processing of ichthyological materials were performed in accordance with the generally accepted methodologies. Findings. The analysis showed that during the current century, the age structure of the Prussian carp of the Dnieper-Bug estuary was the most labile among other commercial cyprinids. It was found that as a result of an increase in the right wing of the age series, there was a gradual increase of the mean weighted age of its commercial stock. At the beginning of studies (2001-2002), the core of the stock was formed by age-3-6 fish (up ); however in subsequent years, a displacement of dominant groups toward the dominance of age-4-7 fish (more than 80% of the total stock) was observed. At the same time, the relative number of age-3 fish (recruits) was at a relatively high level – up to 10.6%. The linear growth varied more intensively until the age-5, but it reduced with ageing and did not show high variability. The body weight most variable was in age-4 fish (Cv=9.62%). The noted insignificant deviations in the body weight growth rate of the right wing of the age series was due to stable predominance of females in the stock structure, which were characterized by a variability of the mean weight as a result of different development of gonads. The dynamics of the age-related changes in the condition factor indicated on a gradual decline Fulton condition factor from 3.47±0.22 in age-3 fish to 3.12±0.06 in age-6 fish. The highest variability of these indexes was typical for age-5 fish (Cv=10.9%; lim=2.46-3.89), that was related to the linear-weight growth and fecundity. With an increase in the age, the variableness of condition factor reduced substantially. Originality. The paper contains modern and significantly updated data on main biological characteristics of the Prussian carp commercial stock in the transformed conditions of the Dnieper-Bug estuary. Practical value. The obtained results are a scientific background for rational fishery optimization of commercial pressure on the representatives of valuable fish fauna of the Dnieper-Bug estuary. In current conditions, the presented information is actual enough from the point of view of the maintenance and support the biodiversity of valuable commercial species in natural water bodies of Ukraine.

The article studies the morphological characteristics, age, sex structure, fecundity and cytomorphological parameters of erythrocytes of Crucian carp ( Carassius auratus gibelio , Bloch, 1782) from both subwatersheds (Big and Small) of Lake Sevan. The analysis of cyto-morphological characteristics of nuclei and erythrocytes showed that the population of the Crucian carp from the lake is heterogeneous as a whole, and consists of individuals with small (diploid) and large nuclei and erythrocytes (subgroups I and II). In sampling taken from both subwatersheds of Lake Sevan occurrence of individuals with the smallest nuclei (diploid individuals) made 38.8%. Crucian carps with the largest nuclei of red blood cells (subgroup II) are noted among females more than among males, with a low percentage of occurrences - 17.5%. The ratios of the volumes of the nuclei of erythrocytes and the number of nucleoli in the nuclei of erythrocytes of Crucian carps can be indicating the existence of triploid individuals in Lake Sevan. The number of Crucian carps with the largest nuclei of red blood cells (subgroup II, possibly triploids) is 17.5% in both subwatersheds of Lake Sevan. During the spawning period males prevailed to females in Small Sevan (1.5 ♂:1 ♀) and females prevailed to males in Big Sevan (1 ♂:1.6 ♀), which is the result of different spawning conditions in different parts of the lake. The highest role in the catch had individuals at the age of 3+. It has been established that the Crucian carp from Lake Sevan with large nuclei of erythrocytes do not differ statistically from individuals with small nuclei for all studied plastic and meristic characteristics and absolute individual fecundity.

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.

Gibel carp Carassius auratus gibelio (Bloch), a commercially important freshwater-cultured fish in China, is threatened by myxosporeans, particularly Thelohanellus wuhanensis, Myxobolus honghuensis, M. wulii and M. turpisrotundus. Here, we developed a multiplex PCR assay for simultaneous detection of these 4 myxosporeans. The specific primers for each species were designed based on the 28S rDNA gene of T. wuhanensis, the ITS-5.8S rDNA of M. honghuensis and M. wulii, and the 18S rDNA gene of M. turpisrotundus. Specificity testing confirmed that the 4 primer sets have no cross-reactivity with other related myxosporean species tested. Detection limits of the multiplex PCR assay were 0.2, 0.3, 3.1 and 3.8 spores for T. wuhanensis, M. honghuensis, M. wulii and M. turpisrotundus, respectively. Following screening of 104 field samples, the analytical sensitivity of the present multiplex PCR assay was found to be similar to the sensitivity obtained by the singleplex PCR assays and was higher than that of microscopic examination. Moreover, Kappa analysis showed a strong agreement between the results of the singleplex and multiplex PCR assays, indicating that the developed multiplex PCR assay was an efficient approach for the diagnosis of the 4 myxosporeans infecting gibel carp.

This study was conducted to investigate the effects of dietary protease on growth performance, feed utilization, whole-body proximate composition, nutrient digestibility, intestinal and hepatopancreas structure of juvenile Gibel carp, Carassius auratus gibelio (mean weight 8.08 ± 0.18 g). Six diets were prepared, including a positive control diet (dietary protein 350 g/kg, PC), one negative control diet (dietary protein 33 g/kg, NC) and four protease supplementations diets, which were 75, 150, 300 and 600 mg/kg protease NC diet. After 12 weeks of diet feeding in indoor recycle aquarium tanks, no significant difference (p > .05) was found on growth performance between fish fed diet with 75–600 mg/kg protease and the PC group. Compared with the fish fed the NC diet, the specific growth rate of fish fed 300 mg/kg protease increased significantly (p .05) by the dietary treatment. Serum alkaline phosphatase and albumin were significantly affected by dietary protease (p .05). Foregut muscular thickness was thinner (p .05) by the dietary treatments. Based on the regression analysis of weight gain rate, the optimal dietary inclusion level of protease was 400 mg/kg in the diet for juvenile Carassius auratus gibelio.

A nine-week feeding experiment was conducted in flow-through system with gibel carp (43.8 +/- 0.2g) to study the effects of dietary available phosphorus (P) on growth, phosphorous digestibility and intestinal enzyme activities. Seven semipurified diets were formulated to contain 0.8 (the basal), 2.4, 3.6, 6.1, 7.4, 10.1 and 15.8g available phosphorus kg(-1) diet. The results showed that specific growth rate and feed efficiency increased with increasing dietary available P from 0.8 to 7.4g P kg(-1). Fish body ash increased with increasing dietary available P, while moisture, protein content or energy content had no difference. Total phosphorus waste discharging (TPW) increased with increased dietary phosphorous. Plasma glucose was higher in the fish fed with 7.4g kg(-1) P. Plasma triglycerides was lower in fish fed diets containing 6.1-10.1g kg(-1) P. No significant effects were observed in plasma P and Ca (p>.05). The activities of intestinal amylase, lipase and trypsin showed no difference, while AKP and Na+, K+-ATPase activities decreased with increasing dietary available P. In conclusion, based on the regression between specific growth rate (SGR), P retention efficiency, feed efficiency (FE) and dietary available P, the available P requirements for on-growing gibel carp were 10.69, 8.22 and 6.72g kg(-1), respectively.

The aim of the work was to determine the total cholesterol content in the meat of perch (Perca fluviatilis L.), Prussian carp (Carassius auratus gibelio), ruffe (Gymnocephalus cernua L.) and sander (Sander lucioperca L.) collected from Lake Gopło, Lake Góreckie and to compare the cholesterol content between females and males of ruffe caught in different seasons from Lake Gopło. The study involved 84 samples of fish meat. The cholesterol content was determined with the modified Liebermann-Burchardt colorimetric method using a Shimadzu spectrophotometer (UV-VIS-NIR-3100). As analyses indicated there were no statistically significant differences in the total cholesterol content in the meat of females and males of ruffe caught during spring (42.27 and 44.35 mg·100 g-1, respectively). The statistically significant differences were determined between individuals of females and males of ruffe collected in autumn from Lake Gopło. These values ranged from 48.95 mg·100 g-1 for females to 59.29 mg·100 g-1 for males. There were found no statistically significant differences in the total cholesterol content in the meat of perch collected from Lake Gopło (57.80 mg·100 g-1) and Lake Góreckie (61.45 mg·100 g-1). Analyses which concerned the total cholesterol content in the meat of four different fish species collected from Lake Gopło confirmed a statistically significant interspecies differences in the total cholesterol content. These values ranged from 52.77 mg·100 g-1 (in the meat of sander) to 61.12 mg·100 g-1 (in the meat of Pruscian carp).

A 12-week growth trial was conducted in a flow-through system to determine dietary selenium (Se) requirement for on-growing gibel carp (initial body weight: 76.2 +/- 0.05 g, mean +/- SEM). Selenomethionine was supplemented to the basal diet to formulate seven semi-purified diets containing 0.26, 0.58, 0.72, 1.14, 1.34, 1.73 and 2.09 mg Se kg(-1) diet. The results showed that plasma superoxide dismutase (SOD) activity significantly increased when fish were fed with 0.58 mg Se kg(-1) diet (P = 0.72 mg kg(-1) (P > 0.05). Whole-body and muscle Se concentrations were higher when fed with 1.34 mg Se kg(-1) diet (P = 1.34 mg kg(-1) (P > 0.05). In conclusion, based on broken-line regression of hepatic Se concentrations, hepatic SOD activity and hepatic T-AOC activity, dietary Se requirements for on-growing gibel carp was 0.73 mg kg(-1), 1.12 mg kg(-1) and 1.19 mg kg(-1) diet respectively.

Two 8-week growth trials were conducted in indoor recirculation system to evaluate the protein requirements for juvenile (3.70 ± 0.20 g) and pre-adult (85.2 ± 0.70 g) gibel carp, Carassius auratus gibelio var. CAS III. Six isoenergetic diets were formulated for each trial using fish meal and casein as protein sources, and protein level was 250–450 g kg−1 in Trial 1 and 200–450 g kg−1 in Trial 2. With the increasing dietary protein, feeding rate (FR) and feed conversion ratio (FCR) significantly decreased (P 0.05), while decreased after the maximum value in 350 g kg−1 in Trial 2 (P 0.05). Hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in both trials increased when dietary protein was above 400 g kg−1 (P

A 60-day feeding trial was conducted to evaluate the effects of different substitution levels (0 %, 20 %, 40 %, 60 %, 80 % and 100 %, named as G1, G2, G3, G4, G5 and G6, respectively) of fishmeal with soybean meal on growth, feed utilization, intestinal microbiota composition and immunity of Carassius auratus gibelio ♀ × Cyprinus carpio ♂ (13.2 ± 0.2 g). Quadratic regression analysis of fish responses including growth performance and feed utilization indicated that the maximum level of soybean meal inclusion varied significantly with the response being modeled. Generally, 95 %–100 % of most growth responses, i.e., weight gain rate and specific growth rate, could be obtained if substitution of fishmeal by soybean meal was limited to In conclusion, based on the results of the growth performance and feed utilization

A 63-day feeding trial was conducted to explore dietary yeast cell wall (YCW) on growth, immunity and disease resistance against Aeromonas hydrophila in gibel carp (Carassius auratus gibelio var. CAS Ⅲ) (initial body weight: 8.49 ± 0.27 g). Four isonitrogenous and isoenergetic diets were formulated to contain 0 % or 0.4 % three types of yeast cell wall (YCW) (termed as YCW0, YCW1, YCW2 or YCW3, respectively). Fish were randomly divided into 4 feeding groups in triplicates of 22 fish in each tank. Results showed that the highest final body weight was observed in fish fed YCW3 diet than the control (P 0.05). Dietary supplementation of YCW decreased condition factor, hepatosomatic index and viscerosomatic index (P 0.05). Hepatic IL-1β and TGF-β expressions were significantly down-regulated in the fish fed YCWs (P

Cyprinid herpesvirus 2 (CyHV-2), which infects goldfish and crucian carp causing high mortality, is an emerging viral pathogen worldwide. The genome of CyHV-2 is large and comprises double-stranded DNA, including several genes similar to cyprinid herpesvirus 1, ictalurid herpesvirus-1, cyprinid herpesvirus 3, and ranid herpesvirus-1. Genes of DNA viruses are expressed in three temporal phases: immediate-early (IE), early (E), and late (L) genes. Viral IE genes initiate transcription as soon as the virus enters the host, without viral DNA replication. IE gene products enable the efficient expression of E and L genes or regulate the host to initiate virus replication. In the present study, five IE genes of CyHV-2 were identified, including open reading frame (ORF)54, ORF121, ORF141, ORF147, and ORF155. Time course analysis and reverse transcription polymerase chain reaction confirmed five IE genes, thirty-four E genes, and thirty-nine L genes. In addition, all 150 ORFs identified in the CyHV-2 genome are transcribed, and are expressed in chronological order, similar to other herpesviruses. This study is the first to identify the IE genes of CyHV-2, which will provide more information for viral molecular characterization.

Purpose. To study the effect of рН values of the aquatic environment on the level of ectoparasite infestation, protein and lysozyme content in organs and serum of some cyprinid species in experimental conditions. Methodology. The objects of the study were yearlings of Cyprinus carpio, Carassius auratus gibelio and Pseudorasbora parva caught in ponds of fish farm “Nyvka” (Kiev region) in spring. Fish were kept in experimental conditions at neutral pH water (6.8-7.2) and a temperature of 17-18оC. To study the changes in the level of fish parasite infestation at different pH values, we used carp yearlings, as an object, the most infected with parasites. Fish were placed in aquariums with water pH of 5.0-5.5 (slightly acidic environment) and 8.5-9.0 (slightly alkaline environment) for 5 days. Thereafter, the ectoparasites were counted on fish body surface and gills. The protein content in serum and tissue extracts of organs (liver, kidney, spleen) of Carassius auratus gibelio and Pseudorasbora parva infected and uninfected ectoparasites, after holding them in slightly acidic or slightly alkaline environment for 8 days, was determined by Lowry’s method, while lysozyme content was determined by a diffusion method on agar. Findings. A comparative assessment of the number of ectoparasites (Ichthyophthirius multifiliis, Trichodina sp., Dactylogyrus sp., Gyrodactylus sp.) on fish body surface and gills, the content of protein and lysozyme in serum and organs at different pH values of aquatic environment has been presented. It was demonstrated that the number of ectoparasites on fish body surface and gills was significantly reduced when keeping the fish in both slightly acidic and slightly alkaline environments. In infected Carassius auratus gibelio, a reduction in the protein and lysozyme content in liver, kidney and serum was observed only in the neutral pH environment compared to uninfected individuals. In the slightly acidic or slightly alkaline environments with a significant reduction in the number of ectoparasites, the protein and lysozyme levels in fish serum and organs were not significantly different from those of non-infected individuals that were kept in water of corresponding pH values. In Pseudorasbora parva with low level of parasite infestation, we did not detect any changes in the protein and lysozyme levels in fish serum and organs in a neutral pH environment. The effect of different pH levels of water on the studied parameters of Pseudorasbora parva showed their significant changes. Originality. For the first time, we demonstrated the change in the level of ectoparasite infestation, protein and lysozyme contents in fish serum and organs (Cyprinus carpio, Carassius auratus gibelio, Pseudorasbora parva), which were kept in the slightly acidic or slightly alkaline aquatic environments. Practical value. The concentration of hydrogen ions, or an aqueous active reaction (pH), plays an important role in the life of fish, their development and in the predisposition to various diseases. The performed studies showed that infestation of fish with parasites can be significantly decreased when changing water pH. This leads to the recovery and restoration of fish normal physiological functions, the impairment of which causes the toxic effects of parasites.

The aim of the present pilot study was to apply a flow cytometric assay, the so-called OxyDNA test, to determine the level of oxidative DNA damage in fish spermatozoa exposed to different concentrations (0.01–10,000 mg/L) of cadmium. Milt was collected from three randomly selected Prussian carp (Carassius auratus gibelio) males. Oxidative DNA damage was assessed with the OxyDNA kit and using flow cytometry. The ratio of OxyDNA-positive events increased significantly at higher cadmium concentrations. The results indicate that direct contact of fish spermatozoa with cadmium-polluted water initiates genotoxic damage.

An 84-day growth trial was designed to investigate effects of dietary replacements fish oil with pork lard (PL) or rapeseed oil (RO) on growth and quality of gibel carp (Carassius auratus gibelio var. CAS III) (initial body weight: 158.2 ± 0.2 g), and responses of the fish refed fish oil (FO) diet. Three isonitrogenous (crude protein: 30%) and isolipid (crude lipid: 10%) diets were formulated containing 7.73% FO, PL or RO. Five experimental treatments including FO group (FO), PL group (PL), RO group (RO), group fed PL for 42 days and refed FO for 42 days (PL+rFO), RO and refed FO group (RO+rFO) was tested. At the end of first 42 days, the fish fed PL and RO had higher mortality than that of the control (P > 0.05). At the end of whole experiment, fish fed PL and RO showed higher plasma cortisol than FO fish (P 0.05). PL and RO diet decreased muscle EPA, DHA and n-3/n-6 ratio (P

Two trials were conducted to investigate protein requirements of juvenile (3.18g in Trial 1) and on-growing (87.1g in Trial 2) gibel carp, Carassius auratus gibelio var. CAS III. Six isoenergetic diets containing 250-500gkg(-1) dietary protein were formulated using soy protein concentrate (SPC) and casein as protein sources. The results showed that weight gain (WG) increased when dietary protein increased from 250 to 400gkg(-1) and decreased at 400 to 500gkg(-1) CP in Trial 1, while WG increased when dietary protein increased from 250 to 350gkg(-1) and kept constant at 350 to 500gkg(-1) CP in Trial 2. With increasing dietary protein, feed conversion ratio (FCR) decreased, while protein retention efficiency (PRE) decreased in Trial 1 and was not affected in Trial 2. Apparent digestibility coefficient of protein (ADC(p)) increased with increasing dietary protein in two trails. Trypsin activity increased with dietary protein in the juveniles and was not affected in on-growing fish. Hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities increased with dietary protein. Broken-line and quadratic regression of WG estimated that dietary protein requirements for maximum growth were about 402-427gkg(-1) for the juvenile and 337-418gkg(-1) for on-growing gibel carp.

Microelement (As, Cd, Cr, Cu, Ni, Pb, and Zn) concentrations were determined in the muscle, skin, gill, and liver tissues of Carassius auratus gibelio collected from subsidence pools at three different coal mines in the Huainan coalfield in China. The concentrations of elements in the water were within the allowable levels for raising fish. However, the higher levels of these metals in sediment may pose potential harm on fish. It was found that the concentrations of Cr, Ni, and Zn in all fish tissues were higher, while As, Cd, and Pb levels were relatively low. Microelement accumulation appeared to be more widespread in subsidence pools than that in natural water. Elements accumulated in fish tissues differently: the highest metal concentrations were generally found in the liver tissues of the fish analyzed, whereas the lowest were recorded in the muscles. The mean element concentrations in muscle tissue from C. auratus gibelio collected from subsidence pools (As, 0.16 mg/kg; Cd, 0.06 mg/kg; Cr, 6.21 mg/kg; Cu, 1.61 mg/kg; Ni, 3.88 mg/kg; Pb, 1.76 mg/kg; and Zn, 12.80 mg/kg dry weight) were far below the allowable limit of the hygienic standard in fish proposed by the Ministry of Health in China, suggesting that the fish were safe for human consumption. A health risk assessment also suggested there was no risk from the analyzed elements for inhabitants near the Huainan coalfield that consume fish.

Carassius auratus gibelio is an omnivore favored for its flavor and is commonly used as a benthic species in traditional pond polyculture. This study investigated the effects of common aquaculture stressors, such as high ammonia, high nitrite, high pH, and hypoxia on the aerobic metabolism of C. auratus gibelio. The results showed that the standard metabolic rate (SMR) was positively correlated with ammonia, nitrite, and pH, while the maximum metabolic rate (MMR) was negatively correlated with all four stressors. Thus, aerobic scope (AS) was reduced when C. auratus gibelio was exposed to high ammonia, high nitrite, high pH, and hypoxia. The peak of post-prandial O2 consumption was positively correlated with nitrite, pH, and the occurrence of the peak metabolic rate post-prandial was delayed in high ammonia, high nitrite, hypoxia, and high pH conditions. These findings indicated that, in experimental conditions, exposure to these environmental stressors can influence aerobic metabolism in C. auratus gibelio. With more energy required to maintain standard metabolic rates, less will be available for growth. While the C. auratus gibelio is one of the most hypoxia tolerance species, the reduction we observed in AS caused by stressors that commonly occur in ponds and in nature will likely affect growth in ponds and fitness in nature. These data have provided insight into the optimal, fitness-maximizing thresholds for these common stressors in this species of interest.

Tissue depletion of florfenicol (FF) and its metabolite florfenicol amine (FFA) was investigated in crucian carp (Carassius auratus gibelio) following administration of 10 mg/kg body weight (BW) daily for five consecutive days by oral gavage at water temperatures of 10 and 25 °C. Plasma and tissue samples, including muscle with skin in natural proportions, liver, and kidney, were collected from 10 fish per sampling point. The concentrations of FF and FFA in each sample were simultaneously determined using high performance liquid chromatography (HPLC) with fluorescence detection. Depletion profiles at different temperatures were estimated and withdrawal periods were calculated. FF was more rapidly eliminated at 25 °C, with apparent elimination half-life (t1/2λz) values ranging from 8.1 h in skin-on muscle to 9.74 h in plasma, than at 10 °C. In contrast, water temperature did not affect FF withdrawal. At 10 °C, the withdrawal periods were calculated as 2.81 and 2.83 days based on the maximum residue limit (MRL) of FF plus FFA and the tolerance of FFA both at 1 μg/g in skin-on muscle, respectively. At 25 °C, the corresponding withdrawal periods were calculated as 2.15 and 2.41 days, respectively. Each withdrawal period was rounded to the next day (3 days).

A 8 week growth trial of three feeding frequencies (2, 4 and 6 meals day(-1)) and three dietary protein levels (30%, 34% and 38%) was conducted to investigate the influence of feeding frequency and dietary protein level on growth, feed utilization, serum free essential amino acids (EAA) dynamics and nitrogen (N), phosphorus (P), carbon (C) retention in juvenile allogynogenetic gibel carp (Carassius auratus gibelio) 'CAS III'. The results showed that feeding frequency and dietary protein level increased feed intake (FI), specific growth rate (SGR) and feed efficiency (FE). SGR increased significantly with the increase in feeding frequency and dietary protein level. But, the increase in dietary protein level from 30% to 38% in group 6 meals day(-1) did not result in better growth. Compared with the group of 4 meals day(-1) 9 38%, the fish fed the diet containing 30% crude protein at 6 meals day(-1) obtained similar SGR but showed lower FIp (protein intake). Compared with 2 meals day(-1), NREs (nitrogen retention efficiency) of 4 and 6 meals day(-1) were relatively higher. PRE (phosphorus retention efficiency) and CRE (carbon retention efficiency) increased significantly with feeding frequency while TNW (total nitrogen waste output), TPW (total phosphorus waste output) and TCW (total carbon waste output) decreased significantly. Feeding frequency and dietary protein level increased trypsin activity. Serum free EAA concentrations varied more synchronously at 6 meals day(-1) than 2 meals day(-1). It could be concluded that increasing feeding frequency could improve growth by increasing feed intake and feed efficiency for juvenile gibel carp. The increase in feeding frequency showed protein-sparing effect.

The first data on the responses of tactile receptors of the tonic, phasic, and mixed types to mechanic stimulation of the surface of head skin of fish obtained by means of noninvasive recording of potentials are presented. The sensitivity of skin tactile receptors is the highest in the circumoral and gular zones, which reflects their functional role in foraging behavior.