Search Results (209)

Common carp (Cyprinus carpio) fry were fed diets containing defatted Hermetia illucens (HI) larvae meal at three inclusion levels to investigate its effects on the nutriphysiological status, focusing on protein and fat digestibility (in vitro and in vivo), growth performance parameters, diet utilization, somatic indices, and GIT histomorphology. The HI meal was included at 0%, 2%, 4%, and 6%. A total of 240 carp fry were randomly divided into four groups, six replicates each (10 fish/tank), and the growth trials lasted 60 days. The dietary inclusion of HI meal up to 6% in carp feed did not significantly affect growth performance, feed utilization, or homeostasis. In vitro protein digestibility exceeded 97% across all treatments with pepsin, indicating efficient hydrolysis. However, the highest crude protein digestibility coefficients were recorded in all treatment groups, which differed significantly from the control group (90.5%). Also, villus width and crypt depth did not differ significantly; however, other parameters, such as villus height and area, showed some significant variations across the treatment groups. No adverse effects were observed on liver condition, structure, or function, reinforcing the safety of HI up to 6% in carp diets. In conclusion, this study demonstrates that HI can be incorporated as a functional, health-promoting ingredient in the diets of common carp fry. Full article

Freshwater ecosystems are increasingly exposed to metal contamination arising from natural and anthropogenic activities, potentially affecting fish physiology and ecosystem health. However, limited information is available regarding metal accumulation and associated biological responses in fish populations from Dukan Lake, northern Iraq. Therefore, this study investigated metal concentrations in water and tissues of common carp (Cyprinus carpio) and evaluated their relationships with selected fish health indicators. Water and fish samples were collected monthly from Dukan Lake, and a total of 60 fish were classified into three length groups (20–29 cm, 30–39 cm, and 40–49 cm). Metal concentrations in water, liver, and gonad tissues were analyzed using ICP-OES, while condition factor (CF), gonadosomatic index (GSI), and hepatosomatic index (HSI) were used to assess fish physiological condition. Sodium (Na), magnesium (Mg), potassium (K), iron (Fe), zinc (Zn), and barium (Ba) were detected in both water and fish tissues, with concentrations in water ranging from 50 to 7069 μg/L. In contrast, chromium (Cr), manganese (Mn), nickel (Ni), selenium (Se), silver (Ag), cadmium (Cd), antimony (Sb), lead (Pb), copper (Cu), and arsenic (As) were below detection limits. Biometric analysis revealed significant differences (p < 0.05) in the gonadosomatic index (GSI) among fish length groups, indicating size-dependent reproductive development. However, no significant relationship was observed between fish length and either the CF or HSI, suggesting relatively stable somatic condition or liver status across size classes. Correlation analysis showed no significant associations between water metal concentrations and CF or GSI. A significant positive correlation was identified between Zn concentration and HSI in the 30–39 cm length group, indicating a possible link between Zn exposure and hepatic physiological response. The findings indicate that essential elements dominate the metal profile in Dukan Lake, with limited evidence of toxic metal contamination. No major adverse effects on the general condition of the fish were observed. These results contribute to understanding metal bioaccumulation patterns and their implications for fish health in freshwater ecosystems. Full article

Introduction: Biological invasions constitute one of the main threats to freshwater ecosystems, causing significant ecological changes through the introduction of exotic species that compete with or prey upon native species. In Portugal, the introduction and spread of exotic species in lotic and lentic ecosystems, such as pike (Esox lucius), European catfish (Silurus glanis), and largemouth bass (Micropterus salmoides), all top predators, may have a big impact on autochthonous species. In contrast, bleak (Alburnus alburnus), European perch (Perca fluviatilis), and common carp (Cyprinus carpio) compete aggressively for food resources. In the Sousa River basin, gudgeon (Gobio lozanoi) is considered an exotic species with potential ecological impact, with the minnow (Phoxinus phoxinus) stand having been recently identified in Portugal and, so far, recorded only in this river basin, and not yet being classified as an invasive species in Portugal. Public knowledge regarding invasive aquatic biodiversity remains a significant bottleneck for conservation. Because recreational angling is a prominent dispersal vector, initiatives that directly target this community are relevant. Objective: The aim is to carry out a bibliographic review on the exotic ichthyofauna species present in the Sousa River, with special focus on the invasion potential of the minnow (P. phoxinus). Methodology: The literature review was conducted based on the ScienceDirect, Springer Nature Link, and Fauna Norvegica databases, selecting publications between 2006 and 2025 concerning relevant studies on the potentially invasive characteristics of the minnow (P. phoxinus). The methodology is based on the analysis of studies regarding the impacts caused on riparian ecosystems. Results: The species P. phoxinus presents a generalist diet and high adaptive capacity, allowing it to colonise new habitats and compete aggressively with native species for trophic resources. Its presence is associated with negative impacts on brown trout populations (Salmo trutta), reducing growth and productivity, especially in mountain ecosystems. Increased species density also causes a significant decrease in benthic macroinvertebrate biodiversity. Studies conducted in the Douro basin indicate that the arrival of minnow in Portugal resulted from human action, probably associated with its use as live bait in recreational fishing. Conservation programmes use diverse tactics to bridge the awareness gap. Recent initiatives feature electrofishing demonstrations to visually differentiate species, theatrical performances, and even culinary show-cooking events using invasive predators like the European catfish to promote harvesting. Conclusions: The potential transition of P. phoxinus into an exotic and invasive species may be associated with the ecological pressure exerted on native communities, particularly through competition for trophic resources, highlighting the need to assess its dispersion in the Sousa basin and its impacts on fish fauna and benthic macroinvertebrates. It is important to do more sampling to understand its real distribution in the Sousa Basin. Additionally is important to explain to recreational anglers and the general population the impacts of fish transfer and the adverse effects of invasive species on freshwater Portuguese ecosystems. Full article

Introduction: The invasive European catfish (Silurus glanis) is actively spreading across Iberian freshwaters, with no effective management measures in place to control its growing abundance or prevent its establishment in new localities. It poses a severe threat to endemic and already endangered species, and is simultaneously a preferred target by few anglers who continuously promote its spread. The LIFE-PREDATOR project aims to stop the spread of European catfish in lentic systems in Portugal and Italy, particularly in protected areas. Objectives: This talk will present the mid-term results of the LIFE-PREDATOR in Portugal, and discuss the difficulties and future challenges to reduce the size of local populations of European catfish. Methodology: The LIFE-PREDATOR team developed several tasks in Portugal: (1) established the reference situation of fish communities in six reservoirs in the Tagus Basin, using scientific fishing, fish telemetry and eDNA-based tools; (2) determined the optimal protocols for sampling catfish; (3) implemented an early detection programme based on warning teams, data-mining and eDNA tools; (4) developed population control actions in four reservoirs; and (5) organised dissemination events for the general public, anglers, and students from kindergarten to university levels. Results: Overall, there is a grim view about recipient communities in the studied lentic systems, which tend to be dominated by invasive fish species, including common carp (Cyprinus carpio), gibel carp (Carassius gibelio), European catfish, pikeperch (Sander lucioperca), European perch (Perca fluviatilis) and largemouth bass (Micropterus nigricans). At least three new localities harbouring catfish were identified from online data-mining and warning teams. A total of 8 tons of catfish were removed by mid-June of 2025, mostly from the Natural Park of International Tagus. Outreach activities were conducted in nearly 60 schools, reaching more than 5000 students. Moreover, 67 general public events have reached more than 4500 people since the project started (September 2023). Conclusions: Despite its positive outcomes, the LIFE-PREDATOR team has encountered challenges in engaging key stakeholders such as anglers, involving local municipalities, and implementing catfish removal actions in remote areas. Difficulties and challenges in catfish management must therefore be debated in order to assure the after-LIFE implementation across Portuguese protected areas. Full article

Introduction: The restoration of river connectivity through fishways is essential for the conservation of native freshwater fish, yet it may inadvertently facilitate the upstream spread of non-native invasive species. This trade-off is particularly relevant in Iberian river systems, where invasive cyprinids pose a growing ecological threat. Objective: In this study, we evaluated the potential for selective fish passage in a full-scale vertical slot fishway (VSF), aiming to promote native species movement while limiting invasive taxa. Methodology: Experimental trials were conducted with the common carp (Cyprinus carpio), a widespread invasive species, and the results were compared with those of the native Iberian barbel (Luciobarbus bocagei). Two fishway configurations were tested, both with high slope (15.2%) and high turbulence (volumetric power dissipation >150 W m⁻³), differing in water depth (0.55 m and 0.80 m). Fish passage performance was assessed through behavioural metrics, including motivation to attempt passage, ascent success, and transit time, using a time-to-event framework. Hydrodynamic conditions were characterised through computational fluid dynamics modelling. Results: The results revealed marked interspecific differences. Common carp exhibited significantly lower motivation to initiate passage and extremely limited success: no individuals ascended the shallower configuration, and only one ascended the deeper configuration. In contrast, Iberian barbel demonstrated high motivation and passage success under both configurations, particularly in more turbulent conditions. Conclusions: These findings suggest that manipulating key hydraulic parameters can create selective passage conditions that favour rheophilic native species while hindering limnophilic invasive taxa. This ecohydraulic approach offers a promising strategy to reconcile the restoration of longitudinal connectivity with the control of biological invasions. Nevertheless, further research under field conditions and across a broader range of species is required to validate and generalise these findings. Full article

Neolissochilus heterostomus, a cyprinid fish endemic to Yunnan Province, China, is highly valued for both ornamental and edible purposes, yet its wild populations are currently declining and classified as endangered. In this study, we present a chromosome-level genome assembly of N. heterostomus, utilizing the PacBio HiFi and Hi-C strategies. The assembled genome spans 1793.99 Mb and is anchored to 50 chromosomes, comprising a total of 50,203 genes. Genomic features and chromosomal karyotype data recorded in the present study are consistent with an allotetraploid origin for N. heterostomus. Comparative genomics shows that N. heterostomus shares a close phylogenetic relationship with another allotetraploid fish, the common carp Cyprinus carpio. In total, 4687 expanded and 1365 contracted gene families were identified in N. heterostomus. Further enrichment analyses indicated an overrepresentation of metabolism-related pathways among the expanded and positively selected gene families, whereas the contracted gene families were enriched in reproduction- and embryonic development-related pathways. Reproductive observations further indicate that N. heterostomus produces fewer eggs than other cyprinid species characterized by relatively long embryonic development periods (106.1 h; accumulated temperature: 2260.6 °C·h), including common carp, goldfish (Carassius auratus), grass carp (Ctenopharyngodon idella), pond loach (Misgurnus anguillicaudatus), and blunt snout bream (Megalobrama amblycephala). These findings suggest a potential association between metabolism-related genomic features and reproductive traits, although functional validation remains necessary. Overall, this study may offer insights into the polyploidization, metabolic, and reproductive traits of N. heterostomus, thereby providing genomic and biological resources that may support future studies relevant to the conservation and management of this endangered species. Full article

Water-quality monitoring is critical for maintaining the symbiotic balance and productivity of aquaponic systems. This study presents the design, implementation, and evaluation of a remote, real-time monitoring system based on the Internet of Things (IoT) paradigm. The system continuously monitors the key parameters of temperature, pH, electrical conductivity, total dissolved solids, salinity, dissolved oxygen, turbidity, and total suspended solids. Utilizing a modular architecture, the platform provides real-time visualization, cloud-based data management, and automated alerts via SMS and e-mail to notify operators of deviations from established tolerance ranges. The system was experimentally validated over a six-month period in a pilot-scale aquaponics system cultivating common carp (Cyprinus carpio). Statistical analysis demonstrated a 97% data acquisition reliability rate. Furthermore, no statistically significant differences (p > 0.05) were observed between the sensor-based measurements and reference laboratory analyses, confirming the system’s high accuracy. This versatile and cost-effective tool enables data-driven decision-making, facilitates timely interventions to reduce production losses, and ensures the long-term environmental stability of integrated aquaculture systems. Full article

An eight-week feeding trial was conducted to investigate methionine and lysine supplementation on the growth performance, body composition, antioxidant index and protein synthesis-related gene expression of the FFCR No. 2 strain common carp (Cyprinus carpio). The experiment included five groups: the CON group (basal diet), CM group (supplemented with 0.6% crystalline methionine), CML group (supplemented with 0.6% crystalline methionine and 0.3% crystalline lysine), HM group (supplemented with 0.6% coated methionine), and HML group (supplemented with 0.6% coated methionine and 0.3% coated lysine). The results showed that the WG (weight gain), SGR (specific growth rate) and CF (condition factor) of the HML group were significantly increased (p < 0.05), and the activities of amylase, lipase, and protease in the intestine of those belonging to the HML group were significantly higher than those in the CON group (p < 0.05). The whole-body crude lipid, SOD (superoxide dismutase), GOT (glutamic oxaloacetic transaminase) activity, and BUN (urea nitrogen) levels in serum were reduced significantly in the HM and HML groups than in the CON group (p < 0.05). Additionally, in the HML group the gene expression levels of IGF-1 (insulin-like growth factor-1), IGFBP (insulin-like growth factor binding protein), 4EBP1(recombinant eukaryotic translation initiation factor 4E binding protein 1), and S6K1 (ribosomal protein s6 kinase 1) in the muscle were significantly higher than those in the CON group. In summary, supplementing coated methionine and lysine improved amino acid utilization, enhanced growth performance, and upregulated the expression of genes associated with growth and protein synthesis. Full article

The assessment of sperm quality is essential for improving reproductive efficiency in aquaculture species such as common carp (Cyprinus carpio). While sperm motility is widely used as a key functional indicator, the predictive value of oxidative protein markers for sperm performance remains unclear. In this study, sperm motility and kinematic parameters were assessed using computer-assisted sperm analysis (CASA). Markers of oxidative status, advanced oxidation protein products (AOPPs), ceruloplasmin (CP), and total protein concentration were quantified in samples. The results showed relatively high total motility (70.51%) and progressive motility (69.00%), indicating good sperm quality. No statistically significant correlations (p > 0.05) were found between AOPP or CP and sperm motility. Protein concentration was positively associated with motility parameters, including curvilinear velocity (VCL) and amplitude of lateral head displacement (ALH). A significant negative correlation was found between Fulton’s condition factor (FCF) and AOPP (r = −0.686; p < 0.05), indicating that individuals with higher body condition had lower oxidative protein damage. These findings suggest that oxidative protein markers may not directly reflect sperm motility, highlighting the potential value of including additional oxidative stress-related parameters in sperm quality assessment. Full article

This study highlights the strong ability of a new bacterial strain, Hafnia paralvei UUNT_MP29, isolated from the gastrointestinal tract (GIT) of common carp (Cyprinus carpio), to break down polystyrene (PS). As an omnivorous bottom feeder, C. carpio is constantly exposed to microplastics, creating a unique environment that favors the evolution of specialized microbiota capable of degrading polymers. Genomic analysis of the isolate identified key homologs involved in xenobiotic breakdown, including alcohol dehydrogenase (Adh), 3-hydroxybutyrate dehydrogenase (HDH), and a small glutamine-rich tetratricopeptide repeat-containing protein (SGTA), showing a strong metabolic system for processing long-chain hydrocarbons. Growth experiments showed the strain quickly adapted, reaching maximum cell density and forming mature biofilms by Day 16. Gravimetric analysis confirmed that H. paralvei UUNT_MP29 uses PS as its primary carbon source, with a significant weight loss of 16.76% over 16 days. Kinetic modeling indicated the degradation follows first-order kinetics (R² = 0.9243) with a high degradation rate constant (k) of 0.2078 day⁻¹. Surface analyses using FTIR and SEM confirmed extensive oxidative changes, as evidenced by the rising Carbonyl Index and surface erosion. TGA also showed reduced thermal stability of the treated polymer, suggesting microbial chain scission. These findings demonstrate the strong degradative ability of H. paralvei UUNT_MP29 and highlight the GIT of plastic-exposed aquatic animals as a promising area for discovering powerful biocatalysts for microplastic cleanup. Full article

Glyphosate and its primary metabolite aminomethylphosphonic acid (AMPA) are widely detected in aquatic environments, yet their combined effects on fish remain insufficiently understood. This study used label-free blood plasma proteomic profiling to explore molecular patterns associated with 14-day exposure of juvenile common carp (Cyprinus carpio) to environmentally relevant concentrations of glyphosate (100 µg/L), AMPA (100 µg/L), and their mixture (50 + 50 µg/L). Across the three exposure groups, 41 proteins of interest showed pronounced abundance differences relative to the control based on fold-change selection criteria. These proteins were mainly associated with immune recognition, innate immune and complement-associated functions, coagulation and extracellular protease regulation, lipid/sterol transport, and extracellular matrix organization. In the mixture group, proteins of interest spanned several functional categories, suggesting that combined exposure deserves further attention in future studies of plasma-level responses to glyphosate and AMPA. Overall, these findings provide preliminary insights into blood plasma protein patterns associated with systemic responses of fish to glyphosate, AMPA, and their mixture at environmentally relevant concentrations and highlight the importance of considering parent compounds, metabolites, and their co-occurrence when assessing the potential biological effects of herbicide contamination in aquatic ecosystems. Full article

The accumulation of polyethylene (PE) in aquatic ecosystems represents a significant environmental challenge due to the polymer’s high molecular weight and chemical stability. This study investigates the biodegradation potential of Hafnia paralvei UUNT_MP29, a bacterial strain isolated from the gut of common carp (Cyprinus carpio), for low-density polyethylene (LDPE). Initial screening on LDPE-emulsified agar confirmed extracellular enzymatic activity through the formation of distinct clear zones. Quantitative analysis showed a cumulative mass loss of 24.10% by Day 16, with the most intensive degradation occurring between Days 4 and 8, which closely correlated with maximum bacterial count (CFU/mL). Kinetic modeling indicated that the degradation followed a first-order rate law (R² = 0.9269), with a rate constant (k) of 0.2991 days⁻¹ and a remarkably short half-life (t_1/2) of 2.32 days. Structural characterization via FTIR spectroscopy demonstrated oxidative transformation, evidenced by a reduction in sp³ C-H stretching and the emergence of C-O/C-O-C functional groups. SEM micrographs further confirmed extensive bio-deterioration, including surface pitting and macroscale erosion. Thermal analysis (TGA/DTG) supported these findings, showing a significant 10.95 °C decrease in the maximum degradation temperature (T_max), indicating a reduction in polymer chain length. These results suggest that H. paralvei UUNT_MP29 is a highly efficient agent for the rapid breakdown of polyethylene and highlight the potential of aquatic gut microbiota as reservoirs for plastic-degrading biotechnologies. Full article

Proximate composition, lipid classes, and fatty acid profile were comparatively analyzed in different body parts of carp (Cyprinus carpio) cultivated in Madagascar. Higher (p < 0.05) protein values (163.3–200.1 g·kg⁻¹ range) were detected in muscle tissue (epaxial, hypaxial, and tail) than in the liver tissue (118.4 g·kg⁻¹). The average lipid content showed the following decreasing tissue sequence: liver > hypaxial > tail > epaxial. The highest levels (p < 0.05) of phospholipids and sterols were obtained in the epaxial muscle part (94.0 and 24.0 g·kg⁻¹ of lipids, respectively). A high presence of free fatty acids (183.2 g·kg⁻¹ of lipids) was detected in the liver. In all tissues, α-tocopherol provided higher values (p < 0.05) than γ- and δ-tocopherol compounds; among body parts, the liver showed the highest levels (p < 0.05) for all tocopherols. Fatty acid (FA) groups revealed a higher range value (g·100 g⁻¹ of total FAs) for monounsaturated FAs (48.19–52.57) than for saturated FAs (SFAs; 28.50–29.41) and polyunsaturated FAs (PUFAs; 17.96–22.57). The following increasing sequence was observed for ω3-PUFA/ω6-PUFA ratios in body parts: liver < hypaxial < tail < epaxial. All parts of muscle tissue contained higher (p < 0.05) PUFA/SFA values (0.72–0.77) than liver (0.61). Comparison of body parts revealed an inhomogeneous distribution of bioactive compounds. The liver tissue was found a good source of valuable constituents. Full article

This study employed a 2 × 2 factorial design to investigate the transcriptomic responses of common carp intestine under the single and combined stress of high temperature and zinc. Results from Illumina RNA-seq, WGCNA, and qPCR showed high-quality sequencing data with good reproducibility. High temperature was the core driver of global transcriptomic reprogramming, inducing numerous DEGs via activating metabolic and stress signaling pathways. Zinc alleviated heat stress by reducing DEGs by 43.2% and activating DNA repair and cell cycle pathways. WGCNA identified core modules for heat response and zinc mitigation, revealing “emergency defense” and “repair adaptation” strategies. This study enriches the teleost stress adaptation theory and provides a scientific basis for healthy carp aquaculture. Full article

We evaluated the effect of our light-emitting diode (LED) light treatments (blue, peak at 468 nm; green, peak at 537 nm; red, peak at 630 nm; and white light) on the growth performance and serum lysozyme activity of the common carp Cyprinus carpio and bacterial communities in a closed recirculating system under an average power intensity of 1.29 ± 0.18 mW/cm² of LED light on the water surface of a circulating rearing system for 70 days. The specific growth rate, weight gain and K-factor were improved when carp were cultured under green or blue light. The specific lysozyme activity in the plasma of the common carp was significantly promoted under blue light compared to the green, white and red light conditions after 70 days. Compared to the other types of LED lights, the blue light treatment resulted in the lowest number of heterotrophic bacteria in the rearing water and the highest heterotrophic bacteria in the carp’s gut contents (both p < 0.05). The phyla Fusobacteria, Bacteroidetes, Tenericutes, Proteobacteria and Firmicutes were abundant in the carp’s gut contents after culturing with any of the four types of LED light. In short, the blue LED light can be considered a potential tool in sustainable aquaculture. Full article