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Common carp, Cyprinus carpio, is a global invasive species illegally introduced into the Groenvlei system, South Africa, in the 1990s for recreational angling. To manage this population effectively, basic information is needed on its biology including growth and reproduction. This study examined the growth trends of C. carpio using otolith growth zone deposition rates which were validated using a chemical mark–recapture experiment (n = 16). From a total of 140 C. carpio, length-at-age was best described using the Von Bertalanffy growth model for males and females. The average lengths-at-50% maturity were estimated at 314 mm FL (males) and 262 mm FL (females). Compared with other South African C. carpio populations, the Groenvlei population is relatively fast growing and long lived, with the oldest female aged 20 years and the oldest male aged 18 years, likely facilitated by relatively favourable environmental conditions at Groenvlei. Data from this study provide a baseline at the commencement of C. carpio management interventions at Groenvlei and an opportunity to monitor changes in population dynamics facilitated by these efforts. [ABSTRACT FROM AUTHOR]

Background Result Conclusion Elevated potentially toxic elements (PTEs) in aquatic products could threaten the health of ordinary consumers. Levels of chromium (Cr), arsenic (As), lead (Pb), and mercury (Hg) in Cyprinus carpio in karst plateau freshwater Lake, Caohai Lake, China were quantified using inductively coupled plasma mass spectrometry (ICP‐MS) and evaluated using a risk method with Monte Carlo simulation.Levels of Cr, As, Pb, and Hg in muscle tissue were substantially lower than those in viscera. The maximum concentration of muscle‐bound Cr, As, Pb, and Hg were less than the standard references set by Chinese Food Codex (GB 2762‐2022). The levels of Cr, As, Pb, and Hg in muscle tissue were independent of fish weight and length. The hazard index of all investigated elements in muscle tissue were less than one for adults and children, whereas the target hazard quotients of muscle‐bound PTEs for children were higher than those for adults. Results indicated that exposure duration was the largest contributor to the hazard quotient of Cr, As, and Hg, whereas the concentration of Pb in muscle was the most sensitive factor affecting the variation in hazard quotient of Pb.There is no risk related to the normal intake of muscle‐bound Cr, Pb, As and Hg with the consumption of Cyprinus carpio. A better definition of the probability distribution for exposure duration and PTEs concentration could result in a more accurate hazard quotient. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Lipid oxidation significantly contributes to muscle deterioration, with heme protein oxidation playing a crucial role in this process. This study investigated the inhibition of heme protein oxidation by Maillard reaction products (MRPs) using a washed muscle model combining washed carp with myoglobin (Mb). Protein oxidation products, protein texture, and lipid oxidation levels were assessed. Results showed that metmyoglobin (MetMb) is a primary driver of lipid oxidation in meat, likely due to Mb oxidation, exposing hydrophobic groups that bind to lipids. MRPs at concentrations of 0.5% and 1% effectively inhibited Mb oxidation. Specifically, treatment with 1% MRPs reduced MetMb formation by 15.38%, protein carbonyl content by 6.53%, hydroxyl radical content by 20.37%, protein aggregation by 40.81%, and particle size by 36.95% during later storage stages, thereby preserving Mb stability. In the Mb‐mediated oxidation model, 1% MRPs inhibited the formation of primary and secondary oxidative metabolites by 59.47% and 68.19%, respectively, while maintaining muscle tissue texture integrity. Practical Application: The antioxidation of Maillard reaction products (MRPs) improves the stability of common carp. By inhibiting the autoxidation of myoglobin and lipid, MRPs help preserve the texture and color of fish muscle while extending its shelf life. This study provides a valuable reference for effectively controlling lipid oxidation in refrigerated fish products and enhancing their overall quality. [ABSTRACT FROM AUTHOR]

[Display omitted] • The dilution effect was test using the goldfish-monogenean system. • Low competence hosts were necessary for a dilution effect. • The non-competent hosts did not result in dilution effect. • Host schooling behavior played a key role in restricting the dilution effect. High species diversity in a community may reduce the risk of infectious disease, termed the dilution effect. However, the generality of the dilution effect in different disease systems remains controversial as both host competence and behaviors of hosts may play roles in dilution or amplification of disease. Using the goldfish (Carassius auratus)-monogenean ectoparasite (Gyrodactylus kobayashii) system, effects of host competence and schooling behavior on parasite transmission were investigated while holding focal host density constant. Following competency tests of 12 fish species as potential hosts for the parasite, infection by G. kobayashii was determined on fins of goldfish mixed with each of three different species based on their level of host competence, including Prussian carp, Carassius gibelio (low competence), grass carp, Ctenopharyngodon idellus (non-competent), swordtail, Xiphophorus helleri (non-competent), and the four species combined. Compared with mean abundance (85.8 ± 25.1) on goldfish in the control group, the mean abundance on goldfish decreased significantly when paired with 10 Prussian carp (30.0 ± 16.5), but did not differ significantly when paired with 10 swordtail (70.0 ± 22.2), 10 grass carp (116.1 ± 33.2), or the multi-species of three Prussian carp, four grass carp and three swordtail (75.9 ± 30.8) during the 11-day experiment. The parasite was also found on the Prussian carp in the Prussian carp group and the multi-species group at a mean abundance of 7.1 and 10.9, respectively. Video recording showed that the school of goldfish mixed well with the Prussian carp, while they maintained separation from the grass carp and swordtail when mixed together. The distance between goldfish increased, and swimming speed and contact time decreased with the additional of other fish species for all groups. The results suggested that the presence of a low-competence host in sufficient numbers was a necessary condition for a dilution effect due to encounter reduction, and the dilution effect may also be enhanced by changes in schooling behavior of goldfish in the presence of low competence hosts. However, the presence of non-competent hosts did not result in any dilution effect owing to the specialist nature of the parasites and the lack of mixing with schools of goldfish. [ABSTRACT FROM AUTHOR]

The common carp is one of the most economically valuable freshwater fish worldwide and its aquaculture can be severely affected by the koi sleepy disease (KSD)/carp edema virus disease (CEVD). This study explores a natural outbreak of CEVD in a pond containing both clinically healthy and diseased fish of various origins exposed to the virus. We investigated mRNA expression of genes associated with known antiviral immune mechanisms, such as type I interferon signalling and cell‐mediated cytotoxicity, and performed a comprehensive protein expression analysis to highlight differences between the two groups in various organs. Significant differences in expression profiles of common carp with and without clinical signs were found to be strongly dependent on the organ from which the sample originated. Components of the complement cascade, including various C3 proteins, exhibited upregulation only in less affected organs, specifically the head kidney and spleen. Other complement proteins such as B/C2 and C9 showed upregulation in the kidney, spleen, and gills but not in the skin. Conversely, lysozymes C and G, were observed to be upregulated in the most affected organs of the skin and gills. This study submits the first description of the immune system related proteome using a mass spectrometry on the samples isolated from fish infected with CEV. It also offers a unique comparison of immune reaction of CEV infected and healthy fish under an infectious pressure. [ABSTRACT FROM AUTHOR]

This study investigated the in vitro antimicrobial and anthelmintic effect of copper nanoparticles (CuNPs) against the bacterium Aeromonas hydrophila, the monogeneans Dactylogyrus minutus, Dactylogyrus extensus, Gyrodactylus cyprini, and the cestode Schyzocotyle acheilognathi, as well as their toxicity to Cyprinus carpio Koi. In the antimicrobial in vitro test, the inhibition zone method and minimum inhibitory concentration (MIC) were performed. In order to determine the time and efficacy of monogenean parasite mortality, the parasites were exposed to CuNP concentrations of 20, 50, 100, 150, 200, and 300 mg L−1, and a control group with tank water and one with copper sulphate pentahydrate (CuSO4.5H2O) at a concentration of 0.3 mg L−1, performed in triplicate. The parasites were observed every 10 min for 300 min, and mortality was recorded. For the cestodes, parasites were immersed in CuNP concentrations of 50, 100, 150, and 300 mg L−1. At the end of the in vitro tests, the anthelmintic efficacy of each treatment was calculated. To assess the tolerance and toxicity in fish, they were exposed to CuNP concentrations of 0.6, 1.25, 2.5, 5, 10, 20, and 50 mg L−1 for 12 h. The MIC demonstrated that CuNPs effectively inhibited the growth of A. hydrophila up to a dilution of 12,500 mg L−1 and showed an inhibition zone of 14.0 ± 1.6 mm for CuNPs. The results of anthelmintic activity showed a dose‐dependent effect of concentration for both groups of parasites, with the most effective concentration being 300 mg L−1 in 120 min. In the toxicity test, the carps showed tolerance to lower concentrations. The study indicated that CuNPs were effective against the studied pathogens. However, it proved to be toxic to fish at high concentrations. The use of low concentrations is recommended still requires further investigation. [ABSTRACT FROM AUTHOR]

H2O2 is a significant reactive oxygen species (ROS) that hinders redox‐mediated processes and contributes to oxidative stress and neurodegenerative disorders. Oxidative stress causes impairment of cell macromolecules, which results in cell dysfunction and neurodegeneration. Alzheimer's disease and other neurodegenerative diseases are serious conditions linked to oxidative stress. Antioxidant treatment approaches are a novel and successful strategy for decreasing neurodegeneration and reducing oxidative stress. This study explored the antioxidant and neuroprotective characteristics of KK14 peptide synthesized from LEAP 2B (liver‐expressed antimicrobial peptide‐2B) derived from Cyprinus carpio L. Molecular docking studies were used to assess the antioxidant properties of KK14. The peptide at concentrations 5–45 μM was examined by using in vitro and in vivo assessment. Analysis was done on the developmental and neuroprotective potential of KK14 peptide treatment in H2O2‐exposed zebrafish larvae which showed Nonlethal deformities. KK14 improves antioxidant enzyme activity like catalase and superoxide dismutase. Furthermore, it reduces neuronal damage by lowering lipid peroxidation and nitric oxide generation while increasing acetylcholinesterase activity. It improved the changes in swimming behavior and the cognitive damage produced by exposure to H2O2. To further substantiate the neuroprotective potential of KK14, intracellular ROS levels in zebrafish larvae were assessed. This led to a reduction in ROS levels and diminished lipid peroxidation. The KK14 has upregulated the antioxidant genes against oxidative stress. Overall, this study proved the strong antioxidant activity of KK14, suggesting its potential as a strong therapeutic option for neurological disorders caused by oxidative stress. Highlights: KK14, a short‐chain sequence of amino acids derived from Cyprinus carpio, has a protective effect against free radicals.In H2O2‐exposed zebrafish larvae, KK14 reduced intracellular ROS and lipid peroxidation.Zebrafish model showed increased SOD, catalase, and glutathione activities.The KK14 revealed improved cognitive behavior and thus exhibited neuroprotective effects.The novel peptide KK14, a putative antioxidant peptide, has a significant and promising role in therapeutic drug discovery. Structural and Functional Insights into KK14 Peptide from Cyprinus carpio: Bioinformatics Analysis of its Toxicological, Neurobehavioral, and Antioxidant Properties [ABSTRACT FROM AUTHOR]

Long‐term consumption of high‐carbohydrate feed may adversely affect intestinal health of fish; however, the underlying roles remain ambiguous. This study examined the effects of varying carbohydrate levels on the intestinal flora of common carp and assessed how microbial metabolites influence intestinal health. Two hundred seventy common carps were chosen and distributed randomly into three groups that fed diets containing starch at levels of 15% (low‐carbohydrate diet [LCD]), 28% (medium‐carbohydrate diet [MCD]), and 45% (high‐carbohydrate diet [HCD]) for 60 days. A significant increase in final body weight, weight gain rate, and specific growth rate within the MCD group, while feed conversion ratio exhibited a decrease in comparison to the other groups (p < 0.05). Feeding with a HCD led to decreased activity of catalase and increased malondialdehyde content, which was consistent with reverse transcription‐quantitative real‐time polymerase chain reaction (RT‐qPCR) analysis results (p < 0.05). Specifically, the RT‐qPCR results revealed that HCD treatment significantly upregulated il1β, il6, and il8 transcript levels. Whereas, the il10 messenger RNA (mRNA) was markedly reduced in comparison to the LCD group. Furthermore, the HCD group exhibited an increased abundance of Proteobacteria, accompanied by a reduction in Fusobacteria abundance, and also revealed an upsurge in opportunistic pathogenic bacteria, such as Aeromonas and Shewanella. The correlation analysis demonstrated negative correlations of anti‐inflammatory active substances such as fucoxanthin, (S)‐reticuline, hecogenin, and uridine with Aeromonas, but positive correlations with Luteolibacter. In summary, dietary carbohydrates might mediate intestinal flora to regulate their metabolites and affect intestinal inflammatory response. [ABSTRACT FROM AUTHOR]

ABSTRACT Black Carp (Mylopharyngodon piceus) is one of the four invasive Asian Carp species (Bighead Carp, Hypophthalmichthys nobilis; Grass Carp, Ctenopharyngodon idella; and Silver Carp, Hypophthalmichthys molitrix) in North America. As benthic predators, Black Carp poses ecological risks to unionids within the Great Lakes and could bring other changes to local benthic communities. One means of assessing invasion risk and potential impact is to determine how critical life history characteristics depend on environmental conditions in new regions. Age at sexual maturity is negatively correlated to the maximum per capita population growth rate and thus can be used to estimate potential population growth for invasive species. Previous studies have found a significant negative relationship between age at maturity and temperature for all three other Asian Carp species, but not for Black Carp. With a more comprehensive dataset, we demonstrate that the same relationship exists for Black Carp. Winter duration is the best predictor of Black Carp age at maturity, followed by average winter air temperature. This significant relationship between age at maturity and temperature was not altered in artificial growing environments. Our results suggested that for Black Carp, temperatures in the winter months are more important for its energy accumulation and maturation and may determine invasion risk in northern locations, such as tributaries of the Great Lakes. [ABSTRACT FROM AUTHOR]

Parabens are the most prevalent ingredients in cosmetics and personal care products (PCPs). They are colorless and tasteless and exhibit good stability when combined with other components. Because of these unique physicochemical properties, they are extensively used as antimicrobial and antifungal agents. Their release into the aquatic ecosystem poses potential threats to aquatic organisms, including fish. We conducted an electronic search in PubMed (http://www.ncbi. nlm.nih.gov/pubmed) using the search term parabens and fish and sorted 93 articles consisting of methyl paraben (MTP), ethyl paraben (ETP), propyl paraben (PPP), butyl paraben (BTP), and benzyl paraben (BNP) in several fish species. Furthermore, we confined our search to six fish species (common carp, Cyprinus carpio; fathead minnows, Pimephales promelas; Japanese medaka, Oryzias latipes; rainbow trout, Oncorhynchus mykiss; Nile tilapia, Oreochromis niloticus; and zebrafish, Danio rerio) and four common parabens (MTP, ETP, PPP, and BTP) and sorted 48 articles for review. Our search indicates that among all six fish, zebrafish was the most studied fish and the MTP was the most tested paraben in fish. Moreover, depending on the alkyl chain length and linearity, long-chained parabens were more toxic than the parabens with short chains. Parabens can be considered endocrine disruptors (EDs), targeting estrogen-androgen-thyroid-steroidogenesis (EATS) pathways, blocking the development and growth of gametes, and causing intergenerational toxicity to impact the viability of offspring/larvae. Paraben exposure can also induce behavioral changes and nervous system disorders in fish. Although the USEPA and EU limit the use of parabens in cosmetics and pharmaceuticals, their prolonged persistence in the environment may pose an additional health risk to humans. [ABSTRACT FROM AUTHOR]

In this study, we developed an injectable DNA vaccine targeting the aopB gene of Aeromonas hydrophila, encapsulated within poly(lactic‐co‐glycolic acid) (PLGA) nanoparticles, for use in common carp. Juvenile common carp were divided into six groups with three replicates each. Groups A and B received intramuscular injections of the plasmid containing the target gene (pCDNA3.1‐aopB) with or without encapsulation, respectively. Groups C and D received the plasmid lacking the target gene via the same route. Group E received PLGA, while Group F (control) received phosphate‐buffered saline. Sampling occurred on days 0, 30, and 60, and hematological and immunological indices were compared among the groups. On day 60, all groups were challenged with Aeromonas hydrophila, and cumulative mortality rates were assessed. Our results indicated successful detection of the target gene in various tissues of vaccinated fish. Notably, vaccinated groups exhibited a significant decrease in cumulative mortality (p < 0.05). Immunological indices, such as serum antibody titer and nonspecific immune responses, significantly improved in vaccinated groups, particularly those receiving the DNA vaccine with PLGA encapsulation (p < 0.05). Overall, the DNA vaccine, especially when nanoencapsulated with PLGA, demonstrated efficacy and immunogenicity against A. Hydrophila in common carp, suggesting its potential as a vaccination strategy against this infection. Further research could optimize its effectiveness and applicability. [ABSTRACT FROM AUTHOR]

Background: Fish gut microbiota undergo dynamic changes under the influence of many factors and play an important role in the nutrition, immunity and development in fish. Although common carp (Cyprinus carpio L.) is an economically important freshwater fish, there are few reports on its gut microbiota changes at different early developmental stages. In the present study, the gut microbiota of common carp during the early developmental stages and its correlation with the feed and pond water flora were studied using the Illumina MiSeq sequencing platform. Results: The results showed that the gut microbiota of common carp underwent continuous and mild changes over the development process, and the pond water environment might provide bacterial resources and have a certain influence on the changes in the gut microbiota of common carp. However, host selection pressure played a more important role in shaping the gut microbiota. Although the gut microbiota was affected by many factors, the presence of core microbiota indicated that some bacterial species adapt to the gut microenvironment of common carp and played a role in its growth process. Conclusions: The dynamic changes of gut microbiota of carp in early development stage were related to the feed, water environment and host selection. The results of this study provide a theoretical basis for healthy farming and disease prevention of common carp. [ABSTRACT FROM AUTHOR]

Length-weight relationships (LWRs) were estimated for 30 fish species, i.e. Abbottina rivularis, Alburnus chalcoides, A. oblongus, A. taeniatus, Carassius gibelio, Channa argus, Cottus spinulosus, Cyprinus carpio, Gambusia holbrooki, Glyptosternon oschanini, Gobio lepidolaemus, Hemiculter leucisculus, Hypophthalmichthys nobilis, Iskandaria kuschakewitschi, Luciobarbus conocephalus, Micropercops cinctus, Opsariichthys bidens, Pelecus cultratus, Petroleuciscus squaliusculus, Pseudorasbora parva, Rhinogobius cf. lindbergi, Rhodeus ocellatus, Sabanejewia aralensis, Salmo oxianus, Schizothorax eurystomus, Triplophysa daryoae, T. elegans, T. ferganaensis, T. labiata, and T. strauchii from the Upper Syr Darya drainage, Uzbekistan. The LWR parameters were determined using a linear logarithmic regression model of the weight against the length, in which values for the slope of the regression, b, that were higher and lower than three indicated positive and negative allometric growth, respectively. The estimated values of parameter b ranged from 2.719 (Cyprinus carpio) to 3.442 (Pelecus cultratus). The correlation coefficient (r2) values varied from 0.945 to 0.998, indicating a strong positive relationship between the length and weight. This study established new maximum TLs for three species (Glyptosternon oschanini, Gobio lepidolaemus, and Petroleuciscus squaliusculus) and presented LWRs for the first time for 17 fish species in the inland waters of Uzbekistan, including seven previously unreported in FishBase. [ABSTRACT FROM AUTHOR]

Triphenyltin (TPT) is a commonly encountered organotin compound known for its endocrine-disrupting properties; it frequently interacts with antibiotics in aquatic environments. In this study, common carp (Cyprinus carpio) (17.43 ± 4.34 g, 11.84 ± 0.88 cm) were chosen as the experimental organisms. According to the environmental concentration in the heavily polluted area, the control group and the experimental groups were exposed for 21 days to the following treatments: 1 μg/L TPT, 1 mg/L NOR, and a combination of 1 μg/L TPT plus 1 mg/L NOR. The investigation examined the individual and combined toxicities of TPT and norfloxacin (NOR) on the gill, liver, and gut tissues of common carp in highly polluted areas. The findings revealed tissue-specific variations in 1L-1β enzyme activity; specifically, 1L-1β enzyme activity exhibited a significant reduction in liver tissue under both NOR exposure and combined exposure, indicating that high concentrations of NOR had the most pronounced impact on the immune system of liver tissue. Furthermore, the gene expression levels of IL-1β, Lysozyme-C, NKA, and CPT1 in the liver, intestinal, and gill tissues showed differences after exposure. In addition, TPT exerted the most significant effect on intestinal tissue, followed by the liver and gill tissues. Interestingly, when TPT and NOR were exposed together, the toxic effects on all tissues were reduced, suggesting the existence of antagonistic effects. [ABSTRACT FROM AUTHOR]

This study aimed to determine the expression and distribution of gangliosides in specific regions of the brains of rainbow trout (Oncorhynchus mykiss Walbaum) and common carp (Cyprinus carpio L.) with regard to seasonal temperature changes. Seasonal changes in ganglioside expression and distribution within the species were expected. The natural ecosystems of these fishes differ significantly due to their distinct habitat preferences, geographic distributions, and environmental requirements. Based on the fact that the common carp is eurythermic and adapts to a wide range of temperatures, while the rainbow trout is stenothermic and thrives in a narrower temperature range, it was expected that these species would exhibit distinct patterns of ganglioside modification as part of their adaptive response to temperature fluctuations. Immunohistochemistry using specific antibodies for the major brain gangliosides (GM1, GD1a, GD1b, GT1b), along with the Svennerholm method for quantifying sialic acid bound to gangliosides, revealed that cold acclimatization led to an increase in polysialylated gangliosides in the common carp brain and an increase in trisialogangliosides in the rainbow trout brain. Immunohistochemical analysis also identified region-specific changes in ganglioside expression, suggesting specific functional roles in neuronal adaptation. These results supported the hypothesis that the composition and distribution of brain gangliosides change in response to seasonal thermal shifts as part of the adaptive response. The results underscore the importance of gangliosides in neuronal function and adaptation to environmental stimuli, with implications for understanding fish resilience to temperature changes. This study offers valuable insights into species' temperature adaptation, with implications for physiological and ecological management and improved aquaculture practices. Future research could expand the species scale, study molecular mechanisms and regulatory pathways in ganglioside metabolism, and examine ganglioside interactions with membrane proteins and lipids for a deeper understanding of thermal adaptation. [ABSTRACT FROM AUTHOR]

Herbicides are widely applied in agriculture, which results in the pollution of ecosystems, including inland waters. Herbicides present in water may cause pathological changes in fish. The aim of this study was to evaluate the effects of a clomazone-based herbicide formulation, Command 480 EC, on the haematological and blood biochemical parameters of common carp as well as the microstructure of selected organs: gills, liver and trunk kidney. The fish were exposed to Command 480 EC at a concentration corresponding to 1 or 5 mg/l of clomazone (groups COM1 and COM2, respectively) for 10 days. The conducted analyses showed that the treatment caused numerous changes in red blood cell parameters, no significant changes in WBC count (in comparison to the control), and only a few transient changes in the leukogram. The only significant change in the biochemical parameters in comparison to the control was a decrease in the triglyceride concentration in fish observed after 3 days (group COM1) and 10 days (group COM2) of exposure to this herbicide. No considerable histopathological alterations were observed. The results of the present study suggest that exposure to the applied clomazone-based formulation can cause pathophysiological changes in common carp. It was also observed that blood parameters (especially haematological ones) are more sensitive markers of exposure to Command than the microstructure of the tested organs. [ABSTRACT FROM AUTHOR]

Chemical compounds used to prevent and control fish disease often cause environmental hazards; thus, alternative approaches as new and effective strategies are needed. The current investigation was performed with the aim of exploring the effects of dietary Moldavian balm (MB, Dracocephalum moldavica L.) on the growth, immune parameters, and antioxidant status of common carp (Cyprinus carpio). Fish (n=300, w=3.80±0.02 g) in four groups in triplicates were supplemented with 0%, 0.5%, 1%, and 2% MB. After 42 days, it was found that feed supplements increased final weight (FW), weight gain (WG), and specific growth rate (SGR) and decreased the food conversion ratio (FCR) (P<0.05). In addition, fish supplemented with 2% MB significantly showed higher serum total protein (TP), alternative complement pathway (ACH50), and glutathione peroxidase (GPx) (P<0.05). The 0.5% MB-supplemented fish represented higher levels of LYZ, alkaline phosphatase (ALP), total Ig, and ACH50 in their skin mucus in comparison with the unsupplemented fish (P<0.05). The results also indicated that 2% MB resulted in a significantly higher expression level of intestinal tumor necrosis factor (TNF- α) (P<0.05); however, the level of LYZ, interleukin-1β (IL-1β), and TLRs decreased in supplemented fish. CAT and SOD expressions were increased in 0.5% MB supplement. In conclusion, MB could be recommended as an efficient feed additive to boost common carp's growth, immunity, and health status. [ABSTRACT FROM AUTHOR]

ZnO nanoparticles (ZnONPs) and carbon nanotubes (CNTs) are frequently used nanoparticles with unique features. Aquatic organisms are exposed to a combination of contaminants in natural water systems, so the combination effect of two or more nanomaterials has caused much concern. In this study, the toxicity to the liver of common carp was explored under four weeks of exposure to single ZnONPs or in combination with multi-walled CNTs (MWCNTs). The results demonstrated that ZnONPs induced pathological changes and apoptosis in the liver. In combination, decreased pathological changes were observed in the LSC-ZnONPs group (50 mg L-1 ZnONPs and 0.25 mg L-1 MWCNTs) at the microscopic level and ultrastructural level, and increased pathological changes in the HSC-ZnONPs group (50 mg L-1 ZnONPs and 2.5 mg L-1 MWCNTs). A 52% reduction in the percentage of TUNEL-positive nuclei in the LSC-ZnONPs group and a 33% increase in the HSC-ZnONPs group were observed compared to the ZnONPs group. The mRNA expression of apoptosis-related genes, including caspase3, BAX, and XBP1, were significantly up-regulated in the exposure groups, confirming the occurrence of apoptosis. Significantly decreased caspase 3 and BAX mRNA levels in the co-exposure groups were detected compared to the ZnONPs group. Nevertheless, the XBP1 mRNA level was significantly upregulated in the LSC-ZnONPs group, but downregulated in the HSC-ZnONPs group, indicating multiple signal pathways involved in the apoptosis. In conclusion, a low concentration of MWCNTs (0.25 mg L-1) decreased the toxic effect of ZnONPs on common carp, but a high concentration of MWCNTs (2.5 mg L-1) enhanced it. This study will contribute to developing future risk assessment and management strategies for nanomaterials. [ABSTRACT FROM AUTHOR]

Aquatic invasive species (AIS) are a global threat to freshwater biodiversity and ecosystem services. Documenting AIS prevalence at broad spatial scales is critical to effective management and early detection. However, conventional monitoring for AIS is costly and is rarely applied at the resolution and scale required for effective management. Monitoring of AIS using environmental DNA (eDNA) has the potential to enable broadscale surveillance at a fraction of the cost of conventional methods, but key questions must first be addressed related to how eDNA detection probability varies among environments, seasons, and multiple species with different life histories.To quantify spatiotemporal variation in the detection probability of AIS using eDNA sampling, we surveyed 20 lakes with known populations of four aquatic invasive species: common carp (Cyprinus carpio), rusty crayfish (Faxonius rusticus), spiny waterflea (Bythotrephes longimanus), and zebra mussels (Dreissena polymorpha). We collected water samples at 10 locations per lake, five times throughout the open water season resulting in a total of 1,000 water samples. Quantitative polymerase chain reaction was used with species‐specific assays to determine the presence of each species' eDNA in water samples. With Bayesian occupancy models, we quantified the effects of lake and site characteristics and Julian date on eDNA detection probability.The probability of eDNA detection varied seasonally, and the seasonal variation was species‐specific and related to species life histories. Zebra mussel eDNA was generally the most detectable among the species we targeted, and detection probability peaked in midsummer when only six water samples were required to achieve a 95% probability of detection (80% Bayesian credible interval: 3–12 samples). Spiny waterflea eDNA detections also peaked in mid to late summer, but were overall the most difficult species to detect, requiring 160 samples for a 95% probability of detection (80% Bayesian credible interval: 67–1,616 samples). Common carp eDNA was most detectable in the spring and rusty crayfish eDNA was most detectable in the early autumn, corresponding to key life history events.Sampling for eDNA during the optimal time of the year for each species decreased the number of samples required to reach a 95% probability of detection by an order of magnitude or more.Our results are relevant for decision makers interested in using eDNA as a multi‐species monitoring tool and highlight the importance of life history in the efficacy of eDNA monitoring. [ABSTRACT FROM AUTHOR]

This study examined the concentrations of seven heavy metals (Pb, Cu, Zn, Cr, Cd, Ni, and Mn) in the muscle tissue of six commonly consumed fish species (Cyprinus carpio, Labeo rohita, Wallagu attu, Hypophthalmicthys molitrix, Channa punctuate, and Puntius sophore) from the River Indus in the Mianwali district Pakistan. Samples were collected during both pre-monsoon and post-monsoon seasons to assess the potential human health risks associated with these heavy metals. The levels of metals were measured using atomic absorption spectroscopic analysis. The results showed varying concentrations of heavy metals in the fish samples (mg/kg), ranging from 10.17-2.06 for Pb, 41.83-12.54 for Cu, 417.04-41.93 for Zn, 2.06-0.46 for Cr, 0.86-0.08 for Cd, 4.33-1.43 for Ni, and 50.16-8.74 for Mn. Notably, metal concentrations were generally higher during the pre-monsoon season, with Pb consistently exceeding standard limits in the muscle tissue of all fish species. ANOVA analysis revealed significant variations in heavy metal concentrations among different fish species. While the current consumption rate poses no significant health risks, ongoing monitoring of heavy metal concentrations in fish and their environmental sources is crucial to ensure consumer safety and sustainable aquatic ecosystems. [ABSTRACT FROM AUTHOR]

OBJECTIVE To establish an echocardiographic technique in koi carp (Cyprinus carpio), compare cardiopulmonary parameters under manual restraint versus anesthesia, and provide a gross anatomical and histologic cardiac description. METHODS A randomized, crossover echocardiography study was performed in 40 clinically healthy adult, unknown sex, privately owned koi carp on May 10 and 11 through June 26 and 27, 2021. Echocardiography was examined for each koi under manual restraint and isoeugenol at 50 ppm, with 3 measurements per examination performed by a radiologist and cardiologist. Two koi were euthanized for gross anatomic and histologic cardiac evaluation. RESULTS Mean ejection fraction (EF), stroke volume (SV), and cardiac output (CO) were significantly lower, mean heart rate (HR) was significantly higher, and opercular rate (OPR) was decreased significantly in anesthetized compared to manually restrained koi. Poor reproducibility for EF and SV was observed. CONCLUSIONS Echocardiography was feasible in both manually restrained and anesthetized koi; however, this technique may best be applied to monitoring trends over time in individual fish due to low reproducibility. Significant differences in multiple cardiopulmonary parameters, including HR, EF, SV, CO, and OPR, were present between manually restrained and anesthetized koi. A gross anatomic and histologic cardiac description is provided for this species to pair with the echocardiographic images. CLINICAL RELEVANCE This study provides the first description of echocardiography, cardiac gross anatomy, and histology in koi. The results support echocardiography as a safe and practical noninvasive diagnostic for cardiac assessment in koi under both manual restraint and anesthesia. [ABSTRACT FROM AUTHOR]

The present experiment was performed to reveal the mechanisms of toxic effects of ammonia nitrogen on Chinese hook snout carp (Opsariichthys bidens) based on the levels of antioxidant enzyme activities and the expression of 70‐kDa heat shock protein gene (HSP70) and tumor necrosis factor‐α (TNF‐α) after 96 h of acute toxic ammonia exposure to investigate its adaptability. The result showed that activities of antioxidant enzymes and lipid peroxidation in the intestine, liver, brain, and gills showed a general trend of increasing and then decreasing when exposed to ammonia nitrogen. The intestinal tissue structure was damaged to varying degrees, the expression of the HSP70 in the brain and gills increased at 0–12 h, and the expression of the TNF‐α in brain tissues decreased at 0–12 h. The expression of TNF‐α in the liver was continuously upregulated in the late stages of stress, and it did not decrease until the stress was released. The above results indicate that high concentrations of ammonia nitrogen caused varying degrees of damage to the neurological, respiratory, and metabolic‐related organs of the O. bidens. [ABSTRACT FROM AUTHOR]

Background: Thermal stress is a major environmental factor affecting fish development and survival. Common carp (Cyprinus carpio) are susceptible to heat stress in their embryonic and larval phases, but the thermal stress response of alternative splicing during common carp embryogenesis remains poorly understood. Results: Using RNA-seq data from eight developmental stages and four temperatures, we constructed a comprehensive profile of alternative splicing (AS) during the embryogenesis of common carp, and found that AS genes and events are widely distributed among all stages. A total of 5,835 developmental stage-specific AS (SAS) genes, 21,368 temperature-specific differentially expressed genes (TDEGs), and 2,652 temperature-specific differentially AS (TDAS) genes were identified. Hub TDAS genes in each developmental stage, such as taf2, hnrnpa1, and drg2, were identified through protein–protein interaction (PPI) network analysis. The early developmental stages may be more sensitive to temperature, with thermal stress leading to a massive increase in the number of expressed transcripts, TDEGs, and TDAS genes in the morula stage, followed by the gastrula stage. GO and KEGG analyses showed that from the morula stage to the neurula stage, TDAS genes were more involved in intracellular transport, protein modification, and localization processes, while from the optic vesicle stage to one day post-hatching, they participated more in biosynthetic processes. Further subgenomic analysis revealed that the number of AS genes and events in subgenome B was generally higher than that in subgenome A, and the homologous AS genes were significantly enriched in basic life activity pathways, such as mTOR signaling pathway, p53 signaling pathway, and MAPK signaling pathway. Additionally, lncRNAs can play a regulatory role in the response to thermal stress by targeting AS genes such as lmnl3, affecting biological processes such as apoptosis and axon guidance. Conclusions: In short, thermal stress can affect alternative splicing regulation during common carp embryogenesis at multiple levels. Our work complemented some gaps in the study of alternative splicing at both levels of embryogenesis and thermal stress in C. carpio and contributed to the comprehension of environmental adaptation formation in polyploid fishes during embryogenesis. [ABSTRACT FROM AUTHOR]

A 12-week feeding trial with common carp (Cyprinus carpio) was conducted to test the hypothesis that compound diets formulated on the basis of different soybean cultivars will have effects on growth parameters, feed utilization, and digestive system histology. Soybean grains were from the following cultivars: Alisa (SB-A), Balkan (SB-B), and Galeb (SB-G). The fourth tested diet contained grains from a mixture of different SB cultivars (SB-M). The results confirmed the tested hypothesis, as the fish from the group SB-A showed higher average weight gain, specific growth rates, and feed efficiency, as well as lower feed intake and feed conversion ratio, compared to the groups SB-B and SB-M. On the other hand, diets were expected to cause inflammation in the distal intestine of the fish, but this did not occur. Histological examination of the intestine and liver, performed at the end of weeks 1, 3, 6 and 12, showed no pathological changes. Most of the differences between the groups were found at the end of the trial. The group SB-A had a higher surface area of different intestinal layers compared to the groups SB-B and SB-G. The surface area of the goblet cells was greatest at most of the time points in SB-M. In the liver, the evaluation of the surface area of hepatocytes and their nuclei showed no significant differences between the groups. The differences in final body mass, which showed a maximum value of 18% between the groups, could be of significant importance for culture of this freshwater species. [ABSTRACT FROM AUTHOR]

Objective: The use of plant‐derived products in aquaculture has garnered considerable attention due to their potential benefits. This study investigated the impact of supplementing Withania coagulans root powder (WCRP) in the diet of Common Carp Cyprinus carpio on various parameters, including growth performance, digestive enzymes, hematology, antioxidant activity, and immunological aspects. Methods: Common Carp (mean weight ± standard deviation = 11.69 ± 0.48 g) were divided into four groups in triplicate, receiving different WCRP concentrations (0.0, 1.0, 1.5, and 2.0%; labeled as WCRP0, WCRP1.0, WCRP1.5, and WCRP2.0, respectively) over a 60‐day period, followed by an experimental challenge with Aeromonas hydrophila to assess the relative percentage survival (RPS) over 14 days. Result: Results showed that Common Carp receiving WCRP1.5 and WCRP2.0 demonstrated significantly improved growth performance, with reduced feed conversion ratios (FCRs) being particularly evident in WCRP1.5. Polynomial contrasts indicated significant linear and quadratic effects on weight gain and FCR. Additionally, WCRP1.5 and WCRP2.0 supplementation led to significantly higher activity of digestive enzymes (lipase and protease). Hematological parameters, including white blood cells, red blood cells, hemoglobin, and hematocrit, were significantly elevated in fish that were fed WCRP1.5 and WCRP2.0 compared to the control group. Moreover, serum parameters, such as total protein, albumin, globulin, lysozyme, catalase, superoxide dismutase, and total immunoglobulins, were significantly enhanced in WCRP1.5‐ and WCRP2.0‐treated fish. Notably, the WCRP1.5 group showed the lowest serum cortisol levels. The RPS was highest in WCRP1.5 (73.77%), followed by WCRP2.0 (70.43%), compared to the other groups. Conclusion: In conclusion, supplementation with WCRP1.5 and WCRP2.0 effectively improved both growth and health parameters in Common Carp. Impact StatementThe addition of Withania coagulans root powder (WCRP) to Common Carp diets significantly boosted growth, health, and disease resistance. Fish that were fed medium and high doses of WCRP showed better growth, improved blood health, and enhanced immune responses, leading to higher survival rates after a bacterial challenge. This natural supplement offers a cost‐effective way for farmers to improve fish productivity and resilience. [ABSTRACT FROM AUTHOR]

Taisho Sanshoku is a variant of Koi fish (Cyprinus carpio) that has high demand due to its high economic value and relatively expensive price. This study aimed to determine the sex of the Taisho Sanshoku Koi fish by molecular sexing using the PCR method to amplify the ArS.9-15 gene. This study was initiated by rearing a 4–6 month-old of 10 Taisho Sanshoku Koi fish in a fish tank with a filter and oxygen aeration. The fish were fed with fish pellets for 1–3 days. The Koi fishes were then anesthetized using Koi anesthesia containing β-hydroxyethyl phenyl ether. Each fish's peripheral blood was collected as much as 0.5 mL per fish and then stored in tubes containing Ca-EDTA anticoagulant. The genomic DNA was extracted from peripheral blood samples and used as a template DNA for PCR amplification targeting ArS.9-15 gene. Agarose with 1.5% concentration and CybrSafe staining was used in electrophoresis for visualization of the PCR results then visualized in a dark chamber using a UV transilluminator. The Taisho Sanshoku Koi fish's sex was determined using descriptive analysis based on the electrophoresis results. According to the PCR results, the female Taisho Sanshoku Koi fish only produced one 800 bp DNA band, whereas the male fish produced two 800 bp and 1,100 bp DNA bands. The outcome of molecular fish sexing of the 10 Taisho Sanshoku Koi fish reported that 60% were male and 40% were female. [ABSTRACT FROM AUTHOR]

We conceptualize and test a non-intrusive barrier, comprised of an oblique bubble screen (OBS) oriented at an angle to the mean flow, to prevent the downstream dispersal of invasive carp egg surrogates. Three surrogates of different densities and diameters were tested. Secondary flows created by the OBS were tuned to redirect surrogate eggs to facilitate their capture. Surface particle image velocimetry and acoustic Doppler velocimetry were used to characterize secondary flows. We assessed the influence of airflow rate, OBS angle, mean flow velocity, and surrogate density on particle redirection. In general, redirection efficiency improves by increasing the OBS angle with respect to the cross-section. At a mean flow velocity of 0.75 metres per second (m/s), the OBS system redirected up to 60% (%) of positively buoyant particles (specific gravity SG = 0.9, and diameter d = 7.09 millimetres [mm]) and 40% of semi-buoyant particles (SG = 1.001, d = 3.1 mm). Negatively buoyant particles (SG = 1.04, and d = 5.90 mm) were redirected by the physical structure of the diffuser rather than by OBS-induced flow. The study shows that an OBS system can be used to effectively redirect carp-egg surrogates over a wide range of particle sizes and densities, allowing for selective targeting of undesired particles in streams. [ABSTRACT FROM AUTHOR]

Seasonal feeding activity and ontogenetic dietary shifts of Cyprinus carpio (Linnaeus, 1758) were examined using 209 fish samples from Lake Arekit, Ethiopia. Among the 209 specimens, 174 (83.3%) displayed a range of dietary items in their stomachs. The species' feeding patterns were determined through numerical indexes (frequency of occurrence and volumetric contribution) and composite indexes (index of preponderance [IOP] and Geometric Index of Importance [GIIi]). Detritus emerged as the primary food source for C. carpio, followed by macrophytes, insects and zooplankton. A lesser amount of phytoplankton, nematodes and ostracods were also consumed. On the basis of the findings, C. carpio can be classified as a detri‐omnivore, as it consumes benthic species like nematodes, ostracods and insect larvae. Seasonal fluctuations in food item consumption were noted (p < 0.05), with higher intake during the rainy season and reduced consumption in the dry season. There was a distinct ontogenetic shift in the relative importance of food items and showed significant variations in food preferences among size groups (p < 0.05). The contributions of animal‐origin food categories (ostracods, zooplankton and insects) were important in the diet of the smaller size class, whereas food of plant origin (macrophytes) and detritus were more important in the diet of adults. Understanding the seasonal feeding patterns and ontogenetic dietary shifts of C. carpio in Lake Arekit provides crucial insights into their ecological role within the lake's ecosystem and highlights their adaptability to eutrophic conditions. Common carp in Lake Arekit are opportunistic feeders, consuming a variety of detritus, plants, insects, and small animals. Their diet adapts based on size and season, with smaller fish preferring animal prey and larger fish consuming more plants and detritus. This study provides valuable insight into carp diet in this specific lake, but further research is needed to understand lifelong feeding patterns and environmental influences. [ABSTRACT FROM AUTHOR]

Understanding the drivers and ecological effects of river water temperature (Tw) change remains a complex and challenging task in the field of ecohydrology. We developed the extreme‐point symmetric mode decomposition to quantitatively identify the trend, period and mutation of water temperature (Tw). The sparrow search algorithm‐long short‐term memory model was constructed to reconstruct the historical Tw to quantitatively identify the effects of human activities (HA) and climate change (CC) at different time scales. The random forest method was used to analyse the contribution rates of different meteorological factors and to clarify the main factors. Our results demonstrate that the Tw had a cooling trend in the 1980s, and the other decades have a warming trend, and the annual Tw distribution shows an obvious 'unimodal' distribution. The interannual Tw has a short period of 2–3a, 6–12a and a long period of 10–15a. At the interannual scale, as the distance from estuaries decreases, the influence of HA gradually diminishes, and only the great Tw is governed by CC. Contributions from HA and CC to Tw vary at the seasonal and monthly scales due to geographical differences. In Cuntan, the contribution of HA to Tw is greater than that of climatic factors. The contribution rates of climatic and HA in the three regions of Yichang, Hankou and Datong also exhibit their respective characteristics and fluctuation patterns. The maximum temperature is the most important factor affecting the change of Tw. Abnormal Tw changes result in delayed spawning and characteristic reproduction Tw attainment dates for the Four Major Chinese Carps and Acipenser sinensis. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of plasma-activated water (PAW) combined with a chitosan–oregano essential oil (CS-OEO) coating on the physicochemical, microbiological, and sensory attributes of carp fillets during chilled storage. Fresh carp fillets were immersed in sterile deionized water, PAW, CS-OEO, and PAW+CS-OEO, respectively, and stored at 4 °C for 10 d. The results showed that plasma-activated water combined with chitosan–oregano essential oil could effectively inhibit the microbial growth in carp fillets during chilled storage. At 10 d storage, the total viable count of carp fillets treated with PAW+CS-OEO decreased by 2.87 log10 CFU/g when compared to the control. The lowest pH values were found in the carp fillet samples after the PAW+CS-OEO treatment; as well, the carp fillet samples after the PAW+CS-OEO treatment showed the lowest total volatile basic nitrogen, thiobarbituric acid reactive substance values, and K values. In addition, the carp fillets in the PAW+CS-OEO treatment group showed the smallest color changes and the highest scores in sensory properties during chilled storage. This study provides a basis for the potential application of plasma-activated water combined with chitosan–oregano essential oil in the preservation of carp fillets and contributes to developing a new food packaging. [ABSTRACT FROM AUTHOR]

From 2011 to 2023, a total of 20 ecological operation experiments of artificial flood peak were conducted in the Lower Jinsha River-Three Gorges cascade reservoirs, focusing on the fish spawning, and a lot of experience was accumulated while achieving good experiments results. In order to systematically figure out the effectiveness and experience of the ecological operation experiments of artificial flood peak over the years, this paper takes the Lower Jinsha River-Three Gorges cascade reservoirs as an example. First, the principles, key points, monitoring and evaluation methods of the ecological operation experiments of artificial flood peak were introduced. Second, the development of operation experiments over the years was reviewed. Finally, the operation experience was summarized and the future optimal direction was proposed. The results showed that the ecological operation experiments of artificial flood peak in the Lower Jinsha River-Three Gorges cascade reservoirs effectively promoted the spawning of fishes spawning drifting eggs in the Yangtze River. The effect of promoting the natural spawning of the representative fishes spawning drifting eggs--the four major Chinese carps under the dam is the most significant in the Three Gorges Reservoir. By 2023, the total spawning scale of the four major Chinese carps in the middle reaches of the Yangtze River reached 38.25 billion. Under the joint promotion of multi-year ecological operation practice and 10-year fishing ban plan, the fish resources of the four major Chinese carps is close to the level of the 1980s. However, under the influence of climate change, fish spawning and developmental characteristics change, spawning ground change and other factors, the ecological operation experiments of artificial flood peak need to carry out targeted optimization and adjustment in the aspects of operation process optimization, operation effect evaluation, and operation effect improvement. The results can provide a reference for the ecological operation of artificial flood peak for fish spawning in similar basins under changing environment. [ABSTRACT FROM AUTHOR]

Cypermethrin, a Class II pyrethroid pesticide is well-documented for its toxicity to non-target organisms. Its environmental breakdown and the resulting harmful effects in various species have been widely researched because of its high toxicity. In this context, the present study aimed to evaluate the acute toxicity of cypermethrin (25% EC) on juvenile Cyprinus carpio, var. communis. Juvenile fish, each weighing 12±2 grams were used for the study. Initial range-finding tests were followed by definitive tests, and the acute toxicity data was analyzed using Finney's Probit Method. The 96-hour LC50 for Cyprinus carpio was determined to be 1.239 µg/L in a static bioassay setup. The mean values of the physicochemical parameters of the aquarium water measured during the bioassay showed slight variations, indicating that fish mortality was due to pesticide exposure rather than suffocation. The average laboratory temperature was recorded at 17°C, while the water temperature was measured at 12°C. The mean dissolved oxygen levels were 6 mg/L and the pH was 7.5. Total dissolved solids were 4.0 × 10³ mg/L and CO2 levels remained constant at 1.2 mg/L. [ABSTRACT FROM AUTHOR]

The unutilized and unproductive lands in alkaline and waterlogged areas can be used for income and employment generation through fisheries activities. Apart from the income generation, the reclamation of the land is also possible if the scientific practices are followed. Karnataka is bestowed with vast variety of water resources for fisheries activities, saline, alkaline and waterlogged areas are also present is large extent in the state where the land is unused in majority of the affected areas. In this study, Krishna command area was selected for demonstration of composite fish culture using alkaline and waterlogged lands. Four beneficiaries were identified and empowered on using of these affected areas for fish culture. They were provided with quality carp seed and 2 tons of supplementary feed to each and scientific fish culture practices were demonstrated. Meanwhile, the water quality, fish survival, health and growth were monitored throughout the demonstration period. The pH of the water gradually decreased from 8.9 to 7.5, majorly due to addition of organic load to the pond. Other water quality parameters were scientifically monitored and they exhibited a decreasing trend with optimal limits favoring to fish culture. Catla, sliver carp, grass carp, common carp and amur carp showed a better growth rate with others being in moderate condition. The total mean fish production was found to be 3.8 t/acre from the demonstration sites and with the mean gross revenue of 4.25 lakhs. [ABSTRACT FROM AUTHOR]

This experiment mainly explored the protective role of sulforaphane (SFN) against physiological toxicity of triphenyltin (TPT) in Cyprinus carpio haematopterus. In total, 320 Fish (56.90 ± 0.40 g) were randomly divided into four groups with four replicates each. The control group was fed the basal diet, the TPT group (TPT) was exposed to 10 ng L−1 TPT on the basis of the control group, the SFN + TPT group (TPT + SFN) was fed a diet supplemented with 10 mg kg−1 SFN on the TPT group, and the SFN group (SFN) was fed a diet supplemented with 10 mg kg−1 SFN. After 56 days of breeding trials, the results showed that TPT exposure resulted in a remarkable decrease (p < 0.05) in final weight, weight gain rate (WGR), specific growth rate (SGR), and condition factor (CF), but an increase (p < 0.05) in feed conversion ratio (FCR) and hepatosomatic index (HSI) of fish. TPT treatment decreased (p < 0.05) the amounts of hematocrit (Hct) and hemoglobin (Hb), plasma complement component 3 (C3) and C4 contents, alternative complement pathway (ACH50), acid phosphatase (ACP) and lysozyme (LZM) activities, liver glutathione (GSH) content, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX) activities, interleukin 10 (IL-10), and SOD mRNA expressions, but increased (p < 0.05) plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, liver malonaldehyde (MDA) content, tumor Cyclooxygenase 2 (COX2), and necrosis factor α (TNFα), IL-1β, and MDA mRNA expressions. A histological analysis of the liver showed that a higher occurrence rates of the hepatocyte hypertrophy, nuclear disappearance and hepatocyte vacuolization was observed in the hepatocytes of fish exposed to TPT, and it was accompanied by the dilation of hepatic sinusoids. In addition, the toxicity induced by TPT was significantly improved in the groups that were treated with SFN, and SFN was able to improve growth performance and immunity, alleviate TPT-induced changes in inflammatory factors, ameliorate oxidative stress, and increase the activity of antioxidant enzymes (p < 0.05). The addition of SFN also alleviated liver damage caused by TPT and protected the structural integrity of the liver. Overall, these findings suggest that TPT inhibited the growth, immunity, and antioxidant capacity of Cyprinus carpio haematopteru. Dietary SFN could be beneficial for growth promotion, immunity, antioxidant capacity, and protection of liver structural integrity. Therefore, SFN is a prospective feed supplement for ameliorating the damage caused to fish by TPT contamination. [ABSTRACT FROM AUTHOR]

Simple Summary: Common carp is in the top three among the farmed fish species worldwide. Spring viraemia of carp is caused by a virus that is economically significant, causing devastating losses in common carp aquaculture. Hence, the development of new-generation vaccines against this virus is pivotal. Previously, a salmonid alphavirus-based replicon vector system was developed and tested against viruses infecting Atlantic salmon. In our study, we demonstrate the first application of this vector system in a non-salmonid fish species. The replicon system provided significant protection against the spring viraemia virus as early as three weeks post-vaccination. Our study demonstrates the first application of the salmonid alphavirus-based replicon vector system (pSAV) as a DNA vaccine in a non-salmonid fish species, in common carp (Cyprinus carpio) against spring viraemia of carp virus (SVCV). SAV replicon encoding the glycoprotein of the SVCV was used as a DNA-layered plasmid, and its efficacy was compared with a previously described conventional DNA vaccine construct (pcDNA3.1 based vector) and with a control group (pcDNA3.1-empty-plasmid) in an SVCV challenge at a water temperature of 14 ± 1 °C. Vaccine prototypes were administered intramuscularly at a dose of 0.1 µg/g of fish (n = 25 per group). The DNA-layered SAV replicon resulted in 88% survival, compared to around 50% in all other groups. The DNA-layered pSAV vaccination induced the innate immune genes at the injection site, and increased IgM upregulation was also observed. Our preliminary results show that the SAV-based replicon construct may serve as a potential vaccine candidate for the protection of non-salmonid fish in the future provided that further clinical and field trials confirm its efficiency. [ABSTRACT FROM AUTHOR]

The synthetic pyrethroid pesticide fenpropathrin (FEN) is extensively used worldwide and has frequently been detected in biota and the environment, whilst the negative effects and toxicological mechanisms of FEN on non-target organisms are still unknown. In the present study, healthy immature common carp were treated with FEN (0.45 and 1.35 μg/L) for a duration of 14 days, and the negative impacts and possible mechanisms of FEN on fish were investigated. Biochemical analyses results showed that FEN exposure altered the levels of glucose (GLU), total cholesterol (T-CHO), triglyceride (TG), albumin (ALB), alkaline phosphatase (ALP), alanine transaminase (ALT), and aspartate transaminase (AST) in carp serum, and caused histological injury of the liver and kidney, indicating that FEN may cause hepatotoxicity and nephrotoxicity in carp. In addition, FEN also altered the activities of superoxide dismutase (SOD) and catalase (CAT) in carp serum, upregulated the levels of reactive oxygen species (ROS), and elevated the levels of malondialdehyde (MDA) in the liver and kidney. Meanwhile, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels were also upregulated, indicating that oxidative stress and inflammatory reaction may be involved in the hepatotoxicity and nephrotoxicity caused by FEN. Furthermore, RNA-seq analysis results revealed that FEN treatment induced a diverse array of transcriptional changes in the liver and kidney and downregulated differentially expressed genes (DEGs) were concentrated in multiple pathways, especially cell cycle and DNA replication, suggesting that FEN may induce cell cycle arrest of hepatocytes and renal cells, subsequently inducing hepatotoxicity and nephrotoxicity. Overall, the present study enhances our comprehension of the toxic effects of FEN and provides empirical evidence to support the risk assessment of FEN for non-target organisms. [ABSTRACT FROM AUTHOR]

Invasive carp populations have purported a negative influence on native biota at high densities. These invasive fishes (i.e., bighead carp Hypophthalmichthys nobilis, silver carp Hypophthalmichthys molitrix, grass carp Ctenopharyngodon idella, and black carp Mylopharyngodon piceus) each exhibit similar life history characteristics. In the Neosho River‐Grand Lake system (i.e., John Redmond Reservoir, Kansas, downstream to Grand Lake O' the Cherokees, Oklahoma), only bighead carp and grass carp have been documented to date. The distribution and status of bighead carp throughout this system were previously unknown due to limited historical data and low abundance. While few bighead carp are encountered within this system, grass carp exhibited relatively higher abundance a were used to provide insights into bighead carp. Captures of both species were used to inform management and suppression efforts. Sampling locations (n = 18) were established for environmental DNA analyses throughout the Neosho River‐Grand Lake system. We sampled 13 sites using a suite of gears for standardized targeted fish sampling. All invasive carp were measured, sexed, and otoliths removed for ageing and microchemical analysis. Grass carp were processed for ploidy testing following the U.S. Fish and Wildlife Service protocol. Environmental DNA analyses generated positive results for the eDNA presence of bighead carp and silver carp. Otolith age estimates suggest fish are long lived and supported by multiple year classes. Additionally, a sampled two‐year‐old grass carp demonstrates spawning and recruitment potential. Otolith microchemistry suggests largescale broad movement patterns. Ploidy testing confirmed the first documented evidence of diploid grass carp in the Neosho River‐Grand Lake system and revealed reproductive viability. Our results may provide future insights into locations for containment, removal, and/or eradication. [ABSTRACT FROM AUTHOR]

Common or European carp (Cyprinus carpio) were eliminated from Lake Winona during a 1973 lake reclamation project. Multiple efforts to prevent their return and eliminate spawning opportunities have failed. Carp have remained in the lake for the past 50 years, but more recent observations of spawning activity in the lake suggest that their numbers have increased. We used shoreline electrofishing data from Lake Winona (2005–2021), along with carp abundance and effects models, to estimate the abundance of carp in Lake Winona, and to evaluate the need for future carp management within the lake. Carp size (mean TL = 614 mm, mean weight = 3.42 kg) did not differ between eastern and western basins, but densities were three times higher in the western basin (105 compared to 34 fish/hectare), and carp had significantly higher relative weights in the western (117%) versus the eastern (107%) basin. Carp biomass estimates for the eastern (116 kg/hectare) and western (360 kg/hectare) basins suggest that the lake may soon experience significant declines in macrophyte cover and other ecological damage associated with that loss. With an estimated adult carp population of >6900 fish and a carp biomass (23,750 kg) 1.5 times greater than the biomass of all carp killed during the 1973 reclamation, carp management activities (e.g., fish removal and spawning migration barriers) should be initiated soon to protect the Lake Winona game fish community. [ABSTRACT FROM AUTHOR]

An 8-week feeding trial was conducted to investigate the effects of dietary fucoidan levels (0 mg/kg, 500 mg/kg, 1,000 mg/kg, 1,500 mg/kg, and 2,000 mg/kg) on the hepatic ultrastructure and the transcriptomic landscape within the liver tissue of common carp. The results revealed that the addition of 1,000 mg/kg fucoidan to the diet significantly altered the ultrastructure of hepatocytes. Notably, the quantities of lipid droplets, autolysosomes, enlarged mitochondria, and endoplasmic reticulum were increased in the hepatocytes. The liver transcriptome analysis revealed that DEGs were notably abundant in the 1,000-mg/kg fucoidan group in glucolipid metabolism signaling pathways, including eukaryotes and nicotinate and nicotinamide metabolism, steroid biosynthesis, and PPAR signaling pathways. The quantitative real-time PCR (qPCR) results showed an excellent agreement on those of RNA-seq for both up- and down-regulated genes (a total of 13 genes selected for validation). Furthermore, fucoidan significantly influenced hepatic glucolipid metabolism of common carp at the mRNA level. Notably, the inclusion of lower concentrations of fucoidan in the diet, specifically at 500 mg/kg and 1,000 mg/kg, was found to significantly enhance the expression of mRNA for genes involved in glycolysis, including hk, gk, and pk, as well as genes linked to lipogenesis, such as srebf1, fasn, elovl5, acsl3a, scd, fads2, and cyp24a1. Conversely, higher concentrations of dietary fucoidan, at 1,500 mg/kg and 2,000 mg/kg, were observed to markedly upregulate the mRNA expression of genes associated with gluconeogenesis, including pck1, pck2, gs, gsk3a, gsk3b, and g6pca.1, along with genes related to lipolysis, such as hadhb, acadl, ecil, acacba, cpt1, fabp1, and fabp3. In summary, varying levels of fucoidan intake appear to exert differential influences on the hepatic glucolipid metabolism of common carp, suggesting a complex dose-dependent regulatory mechanism. For the first time, this research has established that fucoidan possesses a pronounced regulatory influence on the hepatic glucolipid metabolism in fish. This discovery not only underscores its potential as an immunostimulant but also opens new avenues for its application as a feed additive, with implications for modulating the nutritional metabolism of aquatic species. [ABSTRACT FROM AUTHOR]

Duckweed grown in the water treatment unit of the Nineveh Pharmaceutical Factory contribute to reducing the level of pollution, and are used as a partial substitute for animal protein in common carp fingerling diets, in a growth experiment that lasted for 56 days, where the replacement rates reached 16.67, 33.33, and 50%, that is, a replacement rate, 0%, 2.6%, 5.2%, and 7.8% for treatments T1, T2, T3, and T4 of the total diet, respectively. The results of the statistical analysis showed that the fishes that fed the third diet were significantly superior (P≤0.05) to the other experimental diets in terms of criteria, final weight, total growth, daily gain, relative and specific growth rate, feed intake, feed conversion ratio, feed efficiency ratio, and protein efficiency ratio compared to the control treatment. The results showed that the highest percentage of pollutant removal from the water cleared from the treatment unit was in the spring season, which was represented by both total solids and phosphate compared to the winter and autumn seasons, while the highest percentage of nitrates was in the autumn season. It is clear from what was mentioned above that it is possible to partially replace duckweed with animal protein and that it is effective in reducing pollution of the water discharged from the process unit of the pharmaceutical factory. [ABSTRACT FROM AUTHOR]

Enterococcus faecium, a member of the Enterococcus genus, has emerged as a significant concern in aquaculture due to its potential pathogenicity and antibiotic resistance. This study aimed to investigate the molecular diagnosis and characterization of six different Enterococcus species isolated from the gastrointestinal tracts of the common carp (Cyprinus carpio) and tilapia (Oreochromis niloticus) and to evaluate their genetic diversity, antibiotic resistance profiles, and potential virulence factors. Among the isolates, 65.3% of the common carp and 60.8% of the tilapia were identified as E. faecium. All six species demonstrated the ability to metabolize various carbohydrates, indicating a broad metabolic capacity. Some species showed variability in their utilization of specific carbohydrates. For example, E. faecium and E. faecalis uniquely fermented adonitol, while E. avium and E. hirae were the only ones capable of fermenting D-arabitol. Additionally, Voges-Proskauer positivity was exclusively observed in E. faecalis. In terms of growth conditions, all species thrived at both 4°C and 45°C, except for E. faecalis, which failed to grow at 10°C. E. faecium and E. faecalis grew well at pH 9.6. Hemolysis tests revealed differences among the species: E. faecalis displayed beta-hemolysis, while E. gallinarum exhibited alpha-hemolysis. Motility was observed only in E. gallinarum, and esculin hydrolysis was exclusive to E. faecalis. Environmental adaptability varied among the species. E. avium showed limited growth in 6.5% NaCl, and some species exhibited little to no growth in 0.1% methylene blue milk. E. faecalis and E. faecium demonstrated survival at 60°C for 15 minutes, with E. faecium showing limited survival at 30 minutes, distinguishing them from the other species. The strains isolated from Cyprinus carpio and Oreochromis niloticus collected from local fish farms in Basrah City were confirmed as E. faecium through 16S rRNA gene sequencing. A PCR study using specific primers identified all isolates as E. faecalis. [ABSTRACT FROM AUTHOR]

This study evaluated how feeding the common carp (Cyprinus carpio) at multiple protein levels affected their growth and body composition during the winter season. Four experimental diets with varying protein levels were tested, with protein levels of 30% (T1), 28% (T2), 26% (T3), and 35% (T4), respectively. Fish were obtained and kept in a water culture pond with dimensions of 4x4x3 meters. Fish average weight was 148.7± 5.76g, while its length measurements were recorded at 24.33± 2.45cm, fork length at 21.15± 2.34cm, and standard length at 18.96± 1.66cm. The fish were purchased from a hatchery farm in Mosul City, northern Iraq. For 90 days, the fish were fed experimental feed once daily until they reached satiation. Compared to other treatments, fish fed T2 (28% protein) showed higher daily weight gain, total weight gain, weight growth rate, relative growth rate, metabolic growth rate, and specific growth rate. The feed diet T2 had the highest Fulton and modified condition factor, reaching 4.84± 0.14; 2.81± 0.03, whereas the highest condition factor was recorded (3.34± 0.16; 2.1± 0.03) for feed treatment T3. Feeding indicators in the feed treatment T2, such as total feed intake, daily feed consumption, and total protein productivity, were greater. The protein efficiency ratios of the fish groups fed formulations T2, T1, and T3 were recorded at 1.32± 0.004, 1.34b± 0.004, and 1.425c± 0.007%, respectively. In comparison, a significant difference was detected for the fish group consuming feed T4, with a value of 1.058d± 0.009%. For the length-weight relationships, an isometric growth (26, 35%) was recorded for T3, an allometric positive growth for T2, and a negative growth for T1. [ABSTRACT FROM AUTHOR]

Aims Beyond the pivotal roles of the gut microbiome in initiating physiological processes and modulating genetic factors, a query persists: Can a single gene mutation alter the abundance of the gut microbiome community? Not only this, but the intricate impact of gut microbiome composition on skin pigmentation has been largely unexplored. Methods and results Based on these premises, our study examines the abundance of lipase-producing gut microbes about differential gene expression associated with bile acid synthesis and lipid metabolism-related blood metabolites in red (whole wild) and white (whole white wild and SCARB1−/− mutant) Oujiang colour common carp. Following the disruption of the SCARB1 gene in the resulting mutant fish with white body colour (SCARB1−/−), there is a notable decrease in the abundance of gut microbiomes (Bacillus, Staphylococcus, Pseudomonas , and Serratia) associated with lipase production. This reduction parallels the downregulation seen in wild-type white body colour fish (WW), as contrasting to the wild-type red body colour fish (WR). Meanwhile, in SCARB1−/− fish, there was a downregulation noted not only at the genetic and metabolic levels but also a decrease in lipase-producing bacteria. This consistency with WW contrasts significantly with WR. Similarly, genes involved in the bile acid synthesis pathway, along with blood metabolites related to lipid metabolism, exhibited downregulation in SCARB1−/− fish. Conclusions The SCARB1 knockout gene blockage led to significant alterations in the gut microbiome, potentially influencing the observed reduction in carotenoid-associated skin pigmentation. Our study emphasizes that skin pigmentation is not only impacted by genetic factors but also by the gut microbiome. Meanwhile, the gut microbiome's adaptability can be rapidly shaped and may be driven by specific single-gene variations. [ABSTRACT FROM AUTHOR]

Heavy metals have serious negative effects on various aquatic organisms, and therefore rapid and accurate ecotoxicological assessments of heavy metals are necessary. Fish-derived cells sensitive to heavy metals have been used as valuable tools for ecotoxicological assessments. However, this method requires a minimum toxicity treatment time of 96 h, which limits its use when rapid ecotoxicological assessments are required or ecotoxicological assessments of a large number of toxicants are performed. In this study, these limitations were overcome by adjusting parameters including the concentration of fetal bovine serum (FBS) in the medium and the treatment time of the toxicant. Specifically, we found that the maximum time for fish cells to remain unstarved was 6 h when using a medium containing 1% FBS. We applied both parameters to the ecotoxicological assessment (using a medium containing 1% FBS for the toxicity assessment and treating the toxicant for only 6 h). Surprisingly, these adjusted parameters allowed us to obtain faster and more accurate data than the traditional assessment. This improvement was due to the new assessment conditions that minimized the possibility that the growth-inducing effects of nutrients present in excess in the medium could interfere with the cellular response to the toxicant. The accuracy of this assessment was not limited to measuring the toxicity of heavy metals. In conclusion, we have established an ecotoxicity assessment that can generate rapid and accurate data on heavy metals. This new platform will become the cornerstone of rapid and accurate ecotoxicity assessments of heavy metals. [ABSTRACT FROM AUTHOR]

Slimming grass carp is a commercial variety with good body form and meat quality, which is cultured by starving common grass carp in a clean flowing water environment. Compared to common grass carp, slimming grass carp has a far higher economic value. Until now, no molecular study has concentrated on the regulation mechanism of the muscle characteristics of slimming grass carp. This study first reported the gene expression profile of the muscle characteristics of slimming grass carp based on the level of extrachromosomal circular DNAs (eccDNAs). EccDNAs are double-stranded circular DNAs derived from genomic DNAs and play crucial roles in the functional regulation of a wide range of biological processes, none of which have been shown to occur in fish. Here, muscle eccDNAs from slimming grass carp and common grass carp were both generally sequenced, and the information, as well as the expression profile of eccDNAs, were compared and analysed. The findings reveal that 82,238 and 25,857 eccDNAs were detected from slimming grass carp and common grass carp, respectively. The length distribution of eccDNAs was in the range of 1~1000 bp, with two peaks at about 200 bp and 400 bp. When the expression profiles of eccDNAs between slimming grass carp and common grass carp were compared, 3523 up-regulated and 175 down-regulated eccDNAs were found. Enrichment analysis showed that these eccDNA genes were correlated with cellular structure and response, cell immunology, enzyme activity, etc. Certain differentially expressed eccDNAs involved in muscle characteristics were detected, which include myosin heavy chain, myosin light chain, muscle segment homeobox C, calsequestrin, calmodulin, etc., among which the majority of genes were linked to muscle structure and contraction. This indicates that during the process of cultivating from common grass carp to slimming grass carp, the treatment primarily affected muscle structure and contraction, making the meat quality of slimming grass carp different from that of common grass carp. This result provides molecular evidence and new insights by which to elucidate the regulating mechanism of muscle phenotypic characterisation in slimming grass carp and other fish. [ABSTRACT FROM AUTHOR]

Simple Summary: Dietary lipids are the main source of energy for the development of fish larvae, and an adequate supply of essential fatty acids is essential for rapidly growing larvae. Mirror carp (Cyprinus carpio) has been cultivated widely because of its advantages of a fast growth rate, strong disease resistance, and high feed conversion rate. In this study, mirror carp larvae were fed iso-nitrogen (approximately 33% dietary protein) diets with different lipid levels (3%, 5%, 7%, 9%, 11%, and 13%), and the weight gain rate, serum lipid-related indices, muscle amino acid and fatty acid contents, liver lipid deposition, antioxidant enzyme activity, and expression of genes related to growth and fat metabolism were determined in different experimental groups. The optimal dietary lipid requirement of the mirror carp cultivar (6.86 ± 0.95 g) was 9%. This study provides data for improving the breeding of new common carp varieties with unsaturated fatty acids. In fish, increasing the crude lipid level of feed can save protein and improve feed utilization. Mirror carp (Cyprinus carpio) is one of the most widely farmed fish species in the world. In this study, mirror carp larvae were fed isonitrogenous diets with different lipid levels (3%, 5%, 7%, 9%, 11%, and 13%). The rearing trial lasted for eight weeks. The results revealed that when the fat content was 9%, the AWGR, WGR, and FCR were highest, whereas FCR was lowest. The AWGR was correlated with the dietary lipid level, and the regression equation was y = −2.312x2 + 45.01x + 214.49. Compared with those in the control group, the T-CHO and TG contents were significantly greater in the 13% lipid content groups and significantly lower in the 9% lipid content groups (p < 0.05). In terms of muscle quality, the contents of MUFAs, PUFAs, and DHA + EPA were significantly greater than those in the other experimental groups (p < 0.05). Oil red O staining revealed a lipid content of 13% with severe fat deposition. In addition, the results of the analysis of antioxidant enzyme activity revealed that the activities of GSH, CAT and T-AOC were significantly greater at the 9% lipid content, and that the MDA content was significantly greater at the 13% lipid content (p < 0.05). Similarly, the mRNA levels of GH, IGF-I, FAS, and LPL were significantly highest at a lipid level of 9% (p < 0.05). The above results revealed that the optimal dietary lipid requirement for the fast growth of mirror carp (6.86 ± 0.95 g) was 9.74% on the basis of nonlinear regression analysis of the AWGR. The dietary lipid level (9%) improved the growth, stress resistance, and lipid utilization of mirror carp to a certain extent. [ABSTRACT FROM AUTHOR]

AbstractEfficient and safe extraction of microRNAs (miRNAs) from biological samples is pivotal for genetic regulation studies and biotechnological applications. This study focuses on optimizing the microRNA extraction process from the plasma of common carp, a significant species in aquaculture. Recognizing the limitations and hazards of commercial extraction kits, which often employ toxic chemicals like phenol and chloroform, we sought to develop a safer and more effective alternative. Our optimized protocol utilizes guanidinium isothiocyanate (GITC) and sarkosyl, omitting hazardous substances. We explored several parameters including GITC concentration, the addition of sarkosyl, and the role of sodium chloride in enhancing miRNA yield. Our findings demonstrate that optimal conditions involve a GITC concentration of 4.2 M, a 3% sarkosyl concentration, and the use of sodium chloride at 0.5 M. We also investigated the utility of glycogen as a nucleic acid carrier, finding 160 µg to be the optimal concentration. Comparative analysis with commercial kits indicated our method provides higher miRNA yields with reduced cycle threshold values, underscoring the effectiveness of our custom protocol. This optimized approach not only enhances miRNA recovery but also emphasizes safety and cost-effectiveness, making it a valuable method for both research and practical applications in aquaculture. [ABSTRACT FROM AUTHOR]

BACKGROUND: Sea buckthorn has the functions of antioxidation, antitumor, anti‐inflammation and regulating energy metabolism. In order to investigate the effects of sea buckthorn powder and sea buckthorn flavonoids on the antioxidant properties, immune function and muscle fatty acid composition of common carp, an oral feeding experiment was carried out. RESULTS: The administration of glucose significantly reduced the levels of glutathione and the activity of total antioxidant capacity enzyme in serum and hepatopancreas, while concurrently upregulating the level of malondialdehyde (MDA)(P < 0.05). Conversely, oral intake of sea buckthorn powder and flavonoids increased antioxidant enzyme activity and decreased MDA levels. In terms of antioxidant molecular indicators, sea buckthorn powder and sea buckthorn flavonoids significantly increased the mRNA levels of nuclear factor NF‐E2‐related factor (nrf2) in the hepatopancreas and muscle. Meanwhile, mRNA expression levels of downstream antioxidant‐related genes (gr, cat, gpx, and sod) regulated by Nrf2 were also upregulated. In the immune aspects, the mRNA expression levels of proinflammatory cytokines, such as interleukin‐6 (il‐6), interleukin‐1β (il‐1β) and nuclear factor‐κB (nf‐κb), were reduced but the expressions of anti‐inflammatory cytokines, such as growth factor‐β (tgf‐β) and interleukin‐10 (il‐10), were enhanced in the head kidney and spleen tissues after oral administration with sea buckthorn. In terms of muscle fatty acid composition, the ratio of n‐3 polyunsaturated fatty acid (PUFA)/n‐6 PUFA was notably higher after administering sea buckthorn flavonoids than that of the glucose group (P < 0.05). CONCLUSION: This study demonstrated that oral administration of sea buckthorn powder and sea buckthorn flavonoids significantly enhanced the antioxidant capacity and immune response and improved the muscle fatty acid compositions in common carp, and also mitigated the adverse effects of glucose treatment to a certain extent. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

There is a considerable interest in supplementing fish diets with bio-functional substances such as polyunsaturated fatty acids (PUFAs), and research is being conducted to evaluate their effects on fish physiology, particularly on breeding performances. The objective of this study was to find out how squid-derived lipids (PUFAs) influence the Rohu carp, Labeo rohita, in terms of reproduction, and embryonic and larval growth. The experimental fish were provided with formulated diet for a duration of 90 days, containing 1 % squid-extracted lipids as a primary source of polyunsaturated fatty acids (PUFAs). To determine the accuracy of the formulation, a proximate analysis of the feed ingredients and the formulated feeds were conducted. The results demonstrated remarkable reproductive outcomes during the spawning trial. Observations in fish treated with PUFAs revealed a significant improvement (p < 0.001) in sperm quality and viability, despite spawning occurring late in the breeding season. In addition, the fertilization rate (92.27 ± 1.74), hatching rate (89.33 ± 1.76), and survival rate (85.83 ± 1.74) of the offspring exhibited a statistically significant increase (p < 0.05) when subjected to PUFAs treatment in L. rohita. Consequently, the treated fish exhibited enhanced early embryonic and larval development in comparison to the control group. Hence, the current study demonstrates that the inclusion of PUFAs in the diet of Rohu carp leads to improved maturation, breeding, and developmental outcomes, specifically in terms of embryonic development and organogenesis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Warming impacted both individual and group behavior in juvenile C. carpio. • Long-term warming had a more pronounced impact on the decline of swimming activity. • Transcriptomics revealed that warming affected cytoskeletal organization, mitochondrial regulation, and energy metabolism in brain. • Synaptic transmission and signal transduction pathways were the key signature to explain behavior changes under warming. Global warming is increasing interest in how aquatic animals can adjust their physiological performance and cope with temperature changes. Therefore, understanding the behavioral changes and molecular underpinnings in fish under warming is crucial for both the individual and groups survival. This could provide experimental evidence and resource for evaluating the impact of global warming. Three genetic families of common carp (Cyprinus carpio) were generated. These juveniles were constructed short-term (4 days) and long-term (30 days) warming groups to investigate the effects of warming on behavioral responses and to elucidate the potential underlying mechanisms of warming-driven behavior. Behavioral tests were used to explore the effects of short- and long-term exposure to warming on the swimming behavior of C. carpio. Brain transcriptome combined with measurement of nervous system activity was used to further investigated the comprehensive neuromolecular mechanisms under warming. Long-term warming groups had a more significant impact on the decline of swimming behavior in juvenile C. carpio. Furthermore, brain comparative transcriptomic analysis combined with measurement of nervous system activity revealed that genes involved in cytoskeletal organization, mitochondrial regulation, and energy metabolism are major regulators of behavior in the juvenile under warming. Importantly, especially in the long-term warming groups, enrichment analysis of associated gene expression suggested functional alterations of synaptic transmission and signal transduction leading to swimming function impairment in the central nervous system, as revealed by behavioral tests. Our study provides evidence of the neurogenomic mechanism underlying the decreased swimming activity in juvenile C. carpio under warming. These findings have important implications for understanding the impacts of climate change on aquatic ecosystems and the organisms that inhabit them. [ABSTRACT FROM AUTHOR]