Juvenile Common Carp Research Articles

The impact of plant cryoextract on productivity and factors of innate immunity of pond fish against the background of stress in the experiment

The search for effective and environmentally friendly means to increase the productivity and natural resistance of animals, especially in aquaculture, remains an urgent socio-economic task. This article presents the results of the study of the effect of the cryobiological supplement ‘Immunolife-Fish’, based on medicinal plants, on the weight gain of juvenile common carp (Cyprinus carpio) and indicators of innate immunity of two-year-old common carp (Cyprinus carpio) and silver carp (Hypophthalmichthys molitrix) under the influence of thermal stress factor in aquarium conditions. It was found that the weight gain of juvenile carp treated with the cryobiological supplement ‘Immunolife-Fish’ was higher than that of the control group at all stages of the study. The increase was most pronounced during the first 42 days of feeding. A significant increase in the number of leukocytes was found in the blood of fish (common carp and silver carp) exposed to a heat stressor compared to control values. In fish that received a supplement of the herbal preparation during stress, this indicator only tended to increase. The effect of the stressor in fish of both species is manifested by a significant increase in the leukocyte content, a decrease in the indicators characterizing the functional state of cellular immunity — phagocytic activity and number of phagocytes, as well as a tendency to decrease the phagocytic index of neutrophils in the blood. The use of the cryobiological supplement ‘Immunolife-Fish’ in fish exposed to stress not only prevented the decrease in the phagocytic activity of neutrophils but also contributed to a slight increase in their activity in comparison with the control. A significant decrease in the activity of lysozyme and the level of circulating immune complexes, as well as an increase in the content of seromucoids, was found in the blood serum of common and silver carp under the influence of the stress factor. The use of the drug against the background of stress leveled the negative changes in the above indicators characterizing the state of the humoral link of innate immunity. In addition, a mild immune stimulating effect of the cryobiological supplement on fish of both species, which were kept in optimal conditions, was noted. The research is aimed at the development and testing of organic, environmentally friendly anti-stress and immunostimulant agents in commercial fish farming

Inhibition of fish rhabdovirus demonstrates application prospect of two methylimidazole phenylpropanoid-based small molecules in aquaculture

Aquaculture faces significant challenges, notably spring viremia of carp (SVC) caused by spring viremia of carp virus (SVCV), which is particularly devastating due to its high mortality rates and rapid transmission among fish populations. This study introduces two novel methylimidazole phenylpropanoid-based small molecules, LML1013 and LML1014, synthesized for combating SVCV in aquaculture environments. Comprehensive in vitro and in vivo evaluations demonstrated that these compounds have potent antiviral activities against SVCV. They effectively inhibited SVCV replication in epithelioma papulosum cyprinid (EPC) cells and significantly reduced mortality rates in infected juvenile common carp. Further analyses revealed that daily administration of these compounds not only blocked SVCV replication but also stimulated the innate immune responses of the fish, thereby enhancing their overall resistance to viral infection. Notably, the antiviral efficacy was observed in a dose- and time-dependent manner without inducing cytotoxic effects, emphasizing their therapeutic potential. The stability of LML1013 and LML1014 in aquacultural water and their ability to prevent horizontal viral transmission were also confirmed, further supporting their feasibility as treatment options in aquaculture. Overall, the development of LML1013 and LML1014 provides a promising strategy for controlling SVCV outbreaks and enhancing the sustainability of fish farming operations. This approach offers significant implications for improving aquaculture biosecurity and effectively managing viral disease threats.

Synergistic effects of dietary selenium nanoparticles and vitamin C improve growth performance, immune response, and antioxidant status of juvenile common carp (Cyprinus carpio)

IntroductionThis study aimed to investigate the synergistic effects of dietary selenium nanoparticles (Se-NPs) and vitamin C (VC) on growth, body composition, antioxidant defense, immunity, and serum biochemical indexes of common carp (Cyprinus carp) juveniles. MethodologyThe test diets were supplemented with three levels of Se-NPs (0, 0.5, and 1 mg/Kg) and three levels of VC (0, 500, and 1000 mg/Kg): the basal diet without supplemental Se-NPs and VC (VC0SeNPs0; control), 0.5 mg Se-NPs /Kg (VC0SeNPs0.5), 1 mg Se-NPs /Kg (VC0SeNPs1), 500 mg VC/Kg (VC500SeNPs0), 1000 mg VC/Kg (VC1000SeNPs0), 500 mg VC/Kg and 0.5 mg Se-NPs (VC500SeNPs0.5), 1000 mg VC/Kg and 0.5 mg Se-NPs (VC1000SeNPs0.5), 500 mg VC/Kg and 1 mg Se-NPs (VC500SeNPs1), 1000 mg VC/Kg and 1 mg Se-NPs (VC1000SeNPs1). The fish were randomly divided into nine experimental groups in triplicate tanks per treatment and fed on their respective diets for 60 days. ResultsThe findings displayed that fish fed with VC500SeNPs1 and VC500SeNPs0.5 diets had significantly (P < 0.05) higher specific growth rates when compared to other groups. The lowest feed conversion ratio was detected in the VC1000SeNPs1 group and the highest in the control group (P < 0.05). VC, Se-NPs, and their interaction had no significant effect on serum malondialdehyde, ACH50, and IgM (P > 0.05). However, the best parameters associated with antioxidant capacity (higher serum levels of superoxide dismutase and total reduced glutathione) and physiological status (higher concentration of serum globulin and lower amounts of aspartate aminotransferase and lactate dehydrogenase) belonged to the VC1000SeNPs1 and VC500SeNPs1 groups. The results suggest that the Se-NPs and VC combination more efficiently influence the common carp’s growth performance, antioxidant status, immunity, and physiological parameters. ConclusionOverall, the diet enriched with 500 mg VC and 1 mg Se-NPs /Kg (VC500SeNPs1) is suitable for boosting the growth and immunity of common carp.

Effect of aflatoxin B1 and sterigmatocystin on DNA repair genes in common carp

The present study aimed to investigate the short-time (24 h) effect of aflatoxin B1 (AFB1) and sterigmatocystin (STC) on the expression of hsp70, p53, gadd45, and ogg1 genes in common carp hepatopancreas. Our results showed that aflatoxin B1 and sterigmatocystin can stimulate the expression of DNA repair genes, mainly by hour 24. This significant finding contributes to our understanding of the short-term effects of these mycotoxins on ogg1 genes in common carp hepatopancreas. One-year-old common carp juveniles were randomly distributed into five groups (Control, AFB1 0.4 mg kg−1 feed, STC1 1 mg kg−1 feed, STC2 2 mg kg−1 feed, and STC3 3 mg kg−1 feed). Hepatopancreas samples were collected three times (8, 16, and 24 h) in each group. No significant ogg1 and p53 expression changes were observed at 8 and 16 h after exposure. All measured genes were upregulated by the 24th hour in aflatoxin and STC3 groups. An increase in hsp70 gene expression was detected in all groups and all sampling. A significant decrease in gadd45aa gene expression was observed in the aflatoxin B1 group at hour 8. At hour 16, there was no significant change, while at hour 24, all treated groups were significantly different from the control. In summary, our results suggest that aflatoxin B1 and sterigmatocystin can stimulate the expression of DNA repair genes, mainly by hour 24. Further investigations are needed to get information about DNA damage parallel to the DNA repair mechanisms.

Polystyrene nanoparticles with different particle sizes cause autophagy by ROS/ERS/FOXO1 axis in the Cyprinus carpio kidney affecting immunological function

Microplastic pollution poses challenges for ecosystems worldwide, and nanoplastics (NPs, 1–1000 nm) have been identified as persistent pollutants. However, although some studies have described the hazards of NPs to aquatic organisms, the toxicological processes of NPs in the common carp kidney and the biotoxicity of differently sized NPs remain unclear. In this study, we used juvenile common carp as an in vivo model that were constantly exposed to freshwater at 1000 μg/L polystyrene nanoparticle (PSNP) concentrations (50, 100, and 400 nm) for 28 days. Simultaneously, we constructed an in vitro model utilizing grass fish kidney cells (CIK) to study the toxicological effects of PSNPs of various sizes. We performed RT-PCR and Western blot assays on the genes involved in FOXO1, HMGB1, HIF-1α, endoplasmic reticulum stress, autophagy, and immunoreaction. According to these results, exposure to PSNPs increased reactive oxygen species (ROS) levels, and the carp kidneys experienced endoplasmic reticulum stress. Additionally, PSNPs promoted renal autophagy by activating the ROS/ERS/FOXO1 (ERS: endoplasmic reticulum stress) pathway, and it affected immunological function by stimulating the ROS/HMGB1/HIF-1α signaling pathway. This study provides new insights into the contamination hazards of NPs in freshwater environments, as well as the harm they pose to the human living environments. The relationship between particle size and the degree of damage caused by PSNPs to organisms is a potential future research direction.

Evaluation of corn steep liquor on the digestibility and growth performance of juvenile common carp strain Sinyonya

This study aimed to observe the digestibility performance, digestive enzyme activity, and growth performance of the common carp using corn-steep liquor (CSL). The reference diet used commercial feed with 30% protein, and the test diet used CSL at 0% (CSL0), 10% (CSL10), 20% (CSL20), and 30% (CSL30). Common carp (9.38 ± 0.73 g) were stocked at 10 fish per aquarium. Feeding was performed until apparent satiation thrice daily for the 45-day maintenance period. The study used a completely randomized design with four treatments and four replications. The results showed that CSL contained 44.04% protein and an essential amino acid index of 0.80. The additional dose of CSL reduced feed pH and stomach pH compared to the control due to the lactic acid content. In addition, CSL elevated the activity of protease, amylase, and lipase enzymes in the digestive tract of common carp. By applying 20% dose in formulated diet, CSL could increase the total digestibility, ingredient digestibility, protein digestibility, lipid digestibility, and energy digestibility. The high feed digestibility value in the CSL20 treatment was due to the fish ability to utilize carbohydrates and fats as non-protein energy sources, thus producing higher final weight, daily growth rate, and feed conversion ratio. The results of this study indicate that CSL can be used as a source of plant protein for the common carp diet, whereas an administration of CSL at 20% in diet improves the digestibility performance, digestive enzyme activity, and growth performance of common carp. Keywords: common carp, corn steep liquor, digestibility, enzyme, growth ABSTRAK Tujuan penelitian ini untuk melihat kinerja kecernaan, aktivitas enzim pencernaan dan pertumbuhan ikan mas Sinyonya (Cyprinus carpio) menggunakan bahan baku corn steep liquor (CSL) sebagai sumber protein nabati. Pakan acuan menggunakan pakan komersial dengan protein 30% dan pakan uji menggunakan CSL sebanyak 0% (CSL0), 10% (CSL10), 20% (CSL20) dan 30% (CSL30). Pengukuran kecernaan menggunakan indikator Cr2O3 0,5 %. Ikan mas Sinyonya dengan bobot tubuh rata-rata 9,38 ± 0,73 g dipelihara dalam akuarium 60×50×40 cm3 dengan kepadatan 10 ekor per akuarium. Pakan diberikan secara at satiation sebanyak 3 kali sehari selama 45 hari masa pemeliharaan. Penelitian menggunakan desain rancangan acak lengkap dengan empat perlakuan dan masing-masing empat ulangan. Hasil penelitian menunjukkan bahwa CSL mengandung protein sebesar 44,04%, dan indeks asam amino essensial 0,80. Penambahan dosis CSL secara signifikan menurunkan pH pakan dan pH lambung dibandingkan dengan kontrol karena kandungan asam laktat. Sampai dengan dosis CSL 20%, dapat meningkatkan aktivitas enzim protease, amilase dan lipase pada saluran pencernaan ikan mas Sinyonya. Di samping itu, penambahan CSL 20% meningkatkan nilai kecernaan total, kecernaan bahan, kecernaan lemak dan kecernaan energi. Nilai kecernaan pakan yang tinggi pada perlakuan CSL20 disebabkan karena kemampuan ikan dalam memanfaatkan karbohidrat dan lemak sebagai sumber energi non-protein. Disamping itu penambahan CSL sampai dengan dosis 20% meningkatkan bobot akhir, laju pertumbuhan harian dan rasio konversi pakan. Hasil penelitian ini menunjukkan bahwa CSL dapat digunakan sebagai sumber protein nabati untuk pakan ikan mas Sinyonya dan pemberian CSL pada level 20% dapat meningkatkan kinerja kecernaan, aktivitas enzim pencernaan dan pertumbuhan ikan. Kata kunci: corn steep liquor, enzim, ikan mas Sinyonya, kecernaan, pertumbuhan

Dual effects of dietary Lactobacillus helveticus and chlorogenic acid on growth performance, digestibility, immune-antioxidant capacity and resistance against heat stress of juvenile common carp

Dual effects of dietary Lactobacillus helveticus and chlorogenic acid on growth performance, digestibility, immune-antioxidant capacity and resistance against heat stress of juvenile common carp

Infectivity of an emerging fish parasite Gyrodactylus sprostonae in juvenile carp (Cyprinus carpio)

AbstractThe gill monogenean ectoparasite Gyrodactylus sprostonae is an emerging pathogen within recreational UK carp fisheries, and a major cause of mortality in adult carp. This gill infection has only been noted in adult carp and not in juveniles, and no reports of its fundamental infection dynamics exist. The current study compared the infective potential of G. sprostonae between adult and juvenile common carp (Cyprinus carpio) and quantified parasite numbers on the body surface and gills of infected juveniles at two temperatures (14 and 24°C). G. sprostonae was able to infect the body surface and the gills of juvenile carp, and temperature significantly impacted the duration of infection and number of parasites. Interestingly, however, all juveniles under both temperature treatments lost their infections after a maximum of 40 days, with no observed clinical signs of parasitaemia or mortalities. This study therefore indicates that G. sprostonae does not appear to be harmful to juvenile common carp, and we discuss why this infection only seems to impact prised adult carp in the UK.

Ultrastructural investigation of iron oxide nanoparticles accumulation in the liver of common carp (Cyprinus carpio Linnaeus, 1758)

In recent years, the intensive production of nanoparticles with a wide application has led to their transfer to the environment, including the water ecosystem. The accumulation of nanoparticles in fish, causing various pathological changes in the host, raises certain concerns. In the current study, we investigated the penetration and bioaccumulation of Fe3O4 nanoparticles, in the liver of common carp (Cyprinus carpio Linnaeus, 1758). Common carp juveniles were exposed to Fe3O4 nanoparticles at concentrations of 10 and 100 mg. After 7 days, their livers were examined by light and transmission electron microscopes. Compared to normal fish's liver, after using a small concentration (10 mg) of nanoparticles, changes were observed in erythrocytes, hepatocytes, intracellular canaliculi, and bile ducts of the liver. At a high concentration (100 mg), the intensity of changes increased significantly. The liver's capsule was damaged, and a considerable number of hepatocytes were completely destroyed. Additionally, the walls of blood vessels and biliary ductule walls was notably disturbed. It was found that the intensity of pathologies occurring in the liver, increases proportionally with higher concentrations of nanoparticles. Confirmation via electron microscopic methods revealed that Fe3O4 nanoparticles, when administered with food to common carp, enter the fish's liver through erythrocytes localized in the lumen of blood vessels. From there, they traverse through the endothelium of vessels, proceed to hepatocytes, including cytoplasmic organelles, intracellular canaliculi, biliary ductules, and eventually reach the bile ducts. Fe3O4 nanoparticles in all structural elements of fish liver was up to 20 nm. Therefore, high concentrations of nanoparticles in the environment harms the bodies of aquatic organisms, including fish. The changes identified in the liver of common carp in the present study are valuable information in assessing possible risks to other components of the aquatic ecosystem and organisms.

(-)-Epigallocatechin-3-O-Gallate Regulates Muscle Growth, Antioxidant Status, and Nutritional Composition of Juvenile Common Carp (Cyprinus carpio L.)

Among the polyphenolic compounds commonly found in green tea, (-)-epigallocatechin-3-gallate (EGCG) is known to have various functions, including the promotion of antioxidant and myofiber growth in mammals. However, the effect of EGCG on common carp (Cyprinus carpio L.) remains poorly understood. To evaluate the role of EGCG on juvenile common carp, 255 fish (initial weight 17.33 ± 0.34 g) were fed with five experimental diets containing 0, 0.05, 0.25, 0.5, and 1 g/kg EGCG. The results showed that diet supplementation with 0.05–0.5 g/kg EGCG supplementation significantly enhanced the specific growth rate (SGR) and reduced the feed conversion ratio (FCR). Weight gain rate (WGR) was significantly enhanced in the 0.25 and 0.5 g/kg EGCG groups. As for antioxidants, 0.25–1 g/kg EGCG significantly reduced protein carbonyl (PC) content and upregulated superoxide dismutase (sod) gene expression in the muscle. As for muscle nutritional composition, 0.05–0.5 g/kg EGCG increased total amino acid (TAA) and flavor amino acid (FAA) contents, likely via the rapamycin (mTOR) signaling pathway. Muscle n-3 polyunsaturated fatty acids (n-3 PUFA) content was increased with 0.5 g/kg EGCG, presumably owing to the upregulation of fatty acyl elongase 5 (elovl5), long-chain fatty acyl-CoA synthetase 6 (acsl6), and peroxisome proliferator-actiated receptor α (pparα). Dietary EGCG (0.05–1 g/kg) significantly increased muscle hardness and chewiness, accompanied by an increase in myofiber density. EGCG supplementation (0.25–1 g/kg) increased the pH value and reduced lactate contents in the muscle. However, muscle crude lipid and hydroxyproline contents significantly decreased with 1 g/kg EGCG. Overall, quadratic regression analysis of WGR, SGR, TAA, and FAA showed that optimal EGCG (0.46–0.52 g/kg) dietary supplementation improved the growth and nutritional composition of juvenile common carp.

Effects of rosemary enriched diet on physiological parameters in common carp Cyprinus carpio L reared in cages culture

The current study investigated at how rosemary leaf powder supplementation influenced the growth performance, carcass composition, hematological and biochemical parameters, stress hormones, and heat shock proteins of cage-reared common carp. Nine cylindrical cages of 0.2 m³ (radius = 25 cm, height = 100 cm) were randomly allocated to hold 54 juvenile common carp C. carpio (mean weight=18.18±0.08 g). Three groups of fish were fed a control diet (C) as well as diets containing 1.5% and 3% rosemary powder, respectively. The addition of 3% rosemary resulted in a substantial enhancement in growth parameters and feed consumption. The levels of WBC, Hb, MCHC, RBC, and Hct were significantly elevated by the addition of rosemary to experimental fish. A rosemary-supplemented diet resulted in higher levels of TG, urea, total protein, albumin, lipase, amylase, ferrum, and globulin. However, the addition of substantially reduced the levels of ALT cholesterol, creatinine, and glucose. The value of cortisol, T3, and T4 were considerably reduced with the addition of rosemary to diets of experimental fish. HSP70 and HSP90 levels in fish feed diets administered rosemary increased significantly as supplementation amount increased. According to the findings of this investigation, adding rosemary leaf powder, particularly at a concentration of 3%, in the diet improved growth parameters, hematological and biochemical parameters, and be able to reduce stress responses, thyroid hormone levels, and other stressors that fish exposed in cage culture system.&#x0D;

Effects of Stocking Density on the Growth Performance, Physiological Parameters and Antioxidant Status of Juvenile Common Carp (Cyprinus carpio L.) Reared in the Cage system

Stocking density is one of the most important factors influencing growth performance, health status and welfare of fish in aquaculture. This research was carried out to investigate the effect of different stocking densities on growth performance, feed utilization, survival rate, haematology, serum biochemistry and serum antioxidants enzyme responses in common carp juveniles (Cyprinus carpio L.) reared in outdoor cage culture. The fish were randomly stocked in four density groups; 7F fish/0.2m3 (Control group), 14F fish/0.2m3, 21F fish/0.2m3 and 28F fish/0.2m3 in 12 cylindrical cages (0.2m3) in concrete pond, with three cages in each density for 84 days. The results of the 14f density group significantly improved the FW, WG, SGR, FCR, FCE, PER, FI, PI, WBC, RBC, Hct, GSH and SOD activities. The 21F and 28F had significant impacts on FW, WG, SGR, FCR, FCE, PER, FI, PI, glucose, cortisol, ALT, AST, ALP, TG, MDA and GSH increased significantly with increasing stocking density. In contrast, the survival rate, TP, TG, HDL, GPx and SOD activities were significantly decreased. In general, the results demonstrated that the best stocking density is 14F fish/0.2m3 which provided a better growth performance and health status of C. carpio cultured in the cage in the concrete pond.

Assessing organophosphate insecticide retention in muscle tissues of juvenile common carp fish under acute toxicity tests

Organophosphate insecticide spray poses potential threat of contamination of environmental components their accumulation in aquatic organisms. Although various physiological deficits associated with their exposure in fishes are documented, yet their retention in their edible muscle tissues has been poorly studied. In this context, the study was undertaken to ascertain the bioaccumulation of two organophosphate insecticide compounds (dimethoate and chlorpyrifos) in the muscles of juvenile Cyprinus carpio. The study could provide insight into the risks to human health associated with consuming contaminated fish flesh. The fishes exposed to various concentrations of dimethoate and chlorpyrifos in-vivo for 96 to ascertain the uptake and retention of these insecticides in the muscle. Results indicated that fish muscles accumulated the residues at all the concentrations with the recovery of 2.99% (0.032 ppm) of dimethoate exposed to LC50 concentrations. In contrast, the chlorpyrifos residues were found Below the Detection Level (BDL) in the fishes exposed to LC50 concentrations. The percentage bioaccumulation of dimethoate in fish muscle was 88.10%, and that of chlorpyrifos was BDL. The bio-concentration factor was dose-dependent and increased with increasing doses of both insecticides. The study invites attention to human health risk assessment in the regions where contaminated fish are consumed without scientific supervision.

Long-term dietary exposure to the non-steroidal anti-inflammatory drugs diclofenac and ibuprofen can affect the physiology of common carp (Cyprinus carpio) on multiple levels, even at “environmentally relevant” concentrations

The aim of the study was to evaluate the effects of emerging environmental contaminants, the non-steroidal anti-inflammatory drugs (NSAIDs) diclofenac (DCF) and ibuprofen (IBP), on physiological functions in juvenile common carp (Cyprinus carpio). Fish were exposed for 6 weeks, and for the first time, NSAIDs were administered through diet. Either substance was tested at two concentrations, 20 or 2000 μg/kg, resulting in four different treatments (DCF 20, DCF 2000, IBP 20, IBP 2000). The effects on haematological and biochemical profiles, the biomarkers of oxidative stress, and endocrine disruption were studied, and changes in RNA transcription were also monitored to obtain a comprehensive picture of toxicity. Fish exposure to high concentrations of NSAIDs (DCF 2000, IBP 2000) elicited numerous statistically significant changes (p < 0.05) in the endpoints investigated, with DCF being almost always more efficient than IBP. Compared to control fish, a decrease in total leukocyte count attributed to relative lymphopenia was observed. Plasma concentrations of total proteins, ammonia, and thyroxine, and enzyme activities of alanine aminotransferase (ALT), aspartate aminotransferase, and alkaline phosphatase (ALP) were significantly elevated in either group, as were the activities of certain hepatic antioxidant enzymes (superoxide dismutase, glutathione-S-transferase) in the DCF 2000 group. The transcriptomic profile of selected genes in the tissues of exposed fish was affected as well. Significant changes in plasma total proteins, ammonia, ALT, and ALP, as well as in the transcription of genes related to thyroid function and the antioxidant defense of the organism, were found even in fish exposed to the lower DCF concentration (DCF 20). As it was chosen to match DCF concentrations commonly detected in aquatic invertebrates (i.e., the potential feed source of fish), it can be considered “environmentally relevant”. Future research is necessary to shed more light on the dietary NSAID toxicity to fish.

Development of an Injectable DNA Vaccine Against Aeromonas hydrophila Infection Nanoencapsulated With Poly(Lactic‐Co‐Glycolic) Acid (PLGA) in Common Carp

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 &lt; 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 &lt; 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.

Unlocking the potential of N-acetylcysteine: Improving hepatopancreas inflammation, antioxidant capacity and health in common carp (Cyprinus carpio) via the MAPK/NF-κB/Nrf2 signalling pathway

N-acetylcysteine (NAC) positively contributes to enhancing animal health, regulating inflammation and reducing stress by participating in the synthesis of cysteine, glutathione, and taurine in the body. The present study aims to investigate the effects of dietary different levels of NAC on the morphology, function and physiological state of hepatopancreas in juvenile common carp (Cyprinus carpio). 450 common carps were randomly divided into 5 groups: N1 (basal diet), N2 (1.5 g/kg NAC diet), N3 (3.0 g/kg NAC diet), N4 (4.5 g/kg NAC diet) and N5 (6.0 g/kg NAC diet), and fed for 8 weeks. The results indicated that dietary 3.0–6.0 g/kg NAC reduced hepatopancreas lipid vacuoles and nuclear translocation, and inhibited apoptosis in common carp. Simultaneously, the activities of hepatopancreas alanine aminotransferase and aspartate aminotransferase progressively increased with rising dietary NAC levels. Dietary NAC enhanced the non-specific immune function of common carp, and exerted anti-inflammatory effects by inhibiting the MAPK/NF-κB signaling pathway. Additionally, dietary 3.0–6.0 g/kg NAC significantly improved the antioxidant capacity of common carp, which was associated with enhanced glutathione metabolism, clearance of ROS and the activation of Nrf2 signaling pathway. In summary, NAC has the potential to alleviate inflammation, mitigate oxidative stress and inhibit apoptosis via the MAPK/NF-κB/Nrf2 signaling pathway, thereby improving hepatopancreas function and health of common carp. The current findings provide a theoretical basis for promoting the application of NAC in aquaculture and ecological cultivation of aquatic animals.

Synergistic effects of Sargassum vulgare extract and lipid levels on growth performance, blood biochemical indices, immunological competence, and antioxidant capacity in juvenile common carp (Cyprinus carpio)

The aim of this study was to investigate the potential synergistic effects of Sargassum vulgare extract (SVe) and lipid (L) on growth, feed conversion, blood biochemistry, antioxidant protection, and immunity of juvenile carp (Cyprinus carp). Test diets were formulated with three levels of SVe (0, 7.5, and 15 g/kg) and two levels of lipids (50 and 100 g/kg): the control diets without additional SVe (SVe0L50; SVe0L100), 7.5 g SVe/kg (SVe7.5L50; SVe7.5L100), and 15 g SVe/kg (SVe15L50; SVe15L100). Three replicate fish tanks were randomly assigned to six experimental groups, each receiving one of the diets for a duration of eight weeks. The results showed that 7.5–15 g SVe/kg significantly improved growth performance and feed utilization. The SVe15L100 group showed improved health indicators, including higher concentrations of hematocrit, hemoglobin, high-density lipoprotein, total protein, globulin, lysozyme, and complement. Additionally, the SVe15L100 group displayed the most robust antioxidant capacity, as evidenced by higher serum levels of superoxide dismutase, glutathione peroxidase, catalase, and lower levels of malondialdehyde. Based on results, it is recommended to enrich the diet with 15 g SVe and 100 g lipid/kg for simultaneous enhancement of antioxidant capacity and immune of juvenile common carp.

Molecular underpinnings underlying behaviors changes in the brain of juvenile common carp (Cyrinus carpio) in response to warming

IntroductionGlobal 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. ObjectiveThree 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. MethodsBehavioral 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. ResultsLong-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. ConclusionsOur 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.

Dietary propolis complementation relieves the physiological and growth deterioration induced by Flavobacterium columnare infection in juveniles of common carp (Cyprinus carpio).

The current study was proposed to explore the role of dietary propolis (PR) supplementation in alleviating the negative effects of columnaris disease (CD) challenge on the growth performance, plasma biochemicals, antioxidant activity, stress indicators, and immunological reactions of common carp (Cyprinus carpio) fish. Five hundred forty common carp juveniles were evenly placed in thirty-six 100-L tanks and stocked for acclimatization to the lab conditions with a control diet within a started period of 14 days. Fish (average initial weight of 7.11±0.06 g) were randomly distributed into one of six treatment groups (6 replicate tanks × 15 fish per tank in each treatment group). Fish in the first group was assigned as a negative control without CD challenge or PR supplementation. Fish in the other five groups were challenged with CD by immersion of fish for 60 min into a 10-L water bath supplemented with 6×106 CFU/mL (median lethal dose, LD50) of pathogenic F. columnare bacteria. After infection, the fish were restored to their tanks and fed on a basal diet supplemented with PR at 0, 3, 6, 9, or 12 g/kg diet. The experimental period continued for 6 consecutive weeks in which the feed was introduced twice a day (8:00 and 15:00 h) at a rate of 2% of the fish biomass. Ten percent of water was siphoned and renewed after each meal every day, in addition to 50% of water refreshment after cleaning the tank every three days. The tanks were continuously aerated and provided with standard rearing conditions for carp fish (24.0±1.12°C, 7.7±0.22 pH, 6.3±0.16 mg/L O2, and 14L/10D photoperiod). The growth performance traits such as feed intake (FI), weight gain (WG), final weight (FW), specific growth rate (SGR), feed efficiency (FE), and cumulative mortality rates (CM) were recorded during the experimental period. At the end of the trial, blood samples were obtained from the fish to evaluate some plasma biochemicals, including aspartate aminotransaminase (AST), alanine aminotransferase (ALT), creatinine (CRE), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH), antioxidant biomarkers, including total antioxidant capacity (TAOC), total superoxide dismutase (TSOD), reduced glutathione (rGSH), and catalase (CAT), stress indicators, including heterophil to lymphocyte (H/L) ratio, cortisol (COR), malondialdehyde (MDA), and myeloperoxidase (MPO), and immunological reactions, including peripheral blood leukocyte proliferation (PBLP), phagocytosis activity (PHG), lysozyme activity (LYS), alternative complement hemolytic action (ACH50), and total immunoglobulin concentration (TIG). In addition, samples of infected fish gills were taken to quantify the number of F. columnare in the PR-supplemented groups using the quantitative real-time polymerase chain reaction (qPCR) technique. The results showed that incorporating PR into the dietary ingredients of common carp has a protective effect against the challenge with F. columnare infection. There were linear and quadratic positive trends (P < 0.05) in most parameters of growth performance, plasma biochemicals, antioxidant activity, stress indicators, and immunological reactions with the increased PR-supplemented levels in the diet of infected fish. The best results were obtained when using PR at 9 g/kg in the diet, while higher levels (12 g/kg PR) showed an adverse trend in the evaluated parameters. The FI, WG, FW, SGR, and FE were improved by approximately 37, 104, 34, 73, and 49% in the fish treated with 9 g/kg PR compared to none-PR-infected fish. In addition, adding PR at the 9 g/kg diet level was the best dose that reduced the H/L ratio, COR, MDA, and MPO by about 14, 52, 48, and 29%, respectively, in the infected fish. Furthermore, the mortality rate was reduced by 94%, and the number of pathogenic bacteria cells adherent to the fish gills was lowered by 96% in the infected fish treated with 9 g/kg PR compared to none-PR infected fish. Our results concluded that dietary supplementation with 9 g/kg PR could be a promising nutritional approach for improving the growth performance, physiological profile, and health status of common carp fish, particularly when challenged with F. columnare or similar bacterial infections.

The influence of methylene blue and malachite green on common carp (Cyprinus carpio) blood parameters

Methylene blue (MB) and malachite green (MG) are pharmaceuticals which were used in aquaculture to treat fish diseases for many years. Nowadays, they are prohibited in many countries but illegal use is still reported. The aim of the current study was to evaluate the effects of these agents on blood parameters of common carp (Cyprinus carpio L.) juveniles. The fish were exposed for 7 or 14 days to therapeutic concentrations of the tested drugs (2 mg/l in the case of MB and 0.2 mg/l in the case of MG). The results indicate that fish treated with MB or MG showed inflammatory state and anaemic response (slight in the case of MG). Moreover, increased erythropoiesis was observed in MB-treated fish. The results of the present study indicate that the tested pharmaceuticals at therapeutic concentrations are toxic to common carp juveniles. MB turned out to be more toxic than MG. Therefore, we advise against their use in the above-mentioned concentrations (even if the legislation of a given country allows it). In our opinion, the prohibition of use of the mentioned substances in the case of fish intended for human consumption seems to be justified.