Comparison and phylogenetic analysis of the mitochondrial genomes of Synodontis eupterus and Synodontis polli.

We aimed to distinguish Synodontis eupterus and Synodontis polli. We performed sequencing and bioinformatic analysis of their mitochondrial genomes and constructed a phylogenetic tree of Mochokidae fish using maximum likelihood and Bayesian methods based on protein-coding gene (PCG) sequences of 14 Mochokidae species. The total length of the S. eupterus mitochondrial genome was 16,579 bp, including 13 (PCGs), 22 tRNA genes, two rRNA genes, and one D-loop, with an AT-biased nucleotide composition (56.0%). The total length of the S. polli mitochondrial genome was 16,544 bp, including 13 PCGs, 22 tRNA genes, two rRNA genes, and one D-loop, with an AT-biased nucleotide composition (55.0%). In both species, except for COI, PCGs use ATG as the starting codon, the vast majority use TAG or TAA as the ending codon, and a few use incomplete codons (T - or TA -) as the ending codon. Phylogenetic analysis showed that S. eupterus and Synodontis clarias converged into one branch, S. polli and Synodontis petricola converged into one branch, Mochokiella paynei, Mochokus brevis, and nine species of the genus Synodontis converged into one branch, and M. paynei clustered with the genus Synodontis. This study lays a foundation for rebuilding a clearer Mochokidae fish classification system.

Catfish spine injury to the hand with transient lymphangitis.

ABSTRACT: This case report describes a 45-year-old man whose left hand was skewered by a catfish spine while he was attempting to dehook the fish. Catfish spines can create punctures, lacerations, and foreign body injuries. The catfish spine generally is serrated, which can make removal difficult.

Temporal change in the parasite community of an invasive fish Trachelyopterus galeatus (Siluriformes: Auchenipteridae) in a neotropical floodplain.

The construction of dams and hydroelectric plants affects biodiversity in aquatic environments and can facilitate the invasion of species. Few studies assess the long-term response of parasite fauna under these events. The aim of this study was to investigate possible changes in the endoparasite composition of the invasive catfish Trachelyopterus galeatus (Linnaeus, 1766) in the floodplain of the upper Paraná River over a 27-year study period. A total of 79 fish were collected in period 1 (1993) and 31 in period 2 (2019/2020) at the same sampling points, and the endoparasites were located in the gastrointestinal system using a stereomicroscope. It was found that the development of the fish and the composition of their endoparasitic fauna changed over time. In the second period, the fish presented smaller values for mass (g) and standard length (cm) when compared to period 1. It was found that three species of endoparasites were found per period, but although the richness was the same, the composition differed, and only one digenean (Microrchis oligovitellum Lunaschi, 1987 (Trematoda: Paramphistomidae)) was shared. The Porto Primavera Dam was built upstream of the site between the sampling periods (1999) and caused a number of environmental changes, possibly being the main factor responsible for changes in components of the parasite community. Anthropic modification to an environment can cause loss of diversity and loss of ecological interactions. Through our results, we emphasize the importance of including parasite fauna in studies that assess environmental impacts.

Endohelminth diversity in the invasive Clarias gariepinus (Burchell, 1822) from two freshwater lakes: Naivasha and Ol'Bolossat, Kenya.

Fish parasitology contributes to our understanding of the potential risks posed by diverse groups of parasitic organisms on fish stocks in either wild and culture systems. This study was conducted in May 2023 and aimed at assessing the diversity of endohelminths in the invasive North African catfish Clarias gariepinus (Burchell, 1822) obtained from two freshwater lakes, Naivasha and Ol'Bolossat, in Kenya. Parasitological examination of 66 and 35 fish samples collected from the two lakes respectively was achieved using light and scanning electron microscopy methods. Results revealed endohelminth diversity broadly classified as four digeneans, two nematodes, and one cestode. Seven taxa of endohelminths were found in C. gariepinus samples, but only four of these taxa could be identified up to the species level. Six of the taxa (Diplostomum sp., Tylodelphys mashonense, Plagiorchioidea sp., Paracamallanus cyathopharynx, Contracaecum sp., and Tetracampos ciliotheca) were common in samples from the two lakes. Glossidium pedatum only occurred in samples from Lake Ol'Bolossat. Parasite prevalence ranged from 8.6 (T. mashonense) to 100% (Diplostomum sp., T. ciliotheca, and Contracaecum sp.) and mean intensity from 1.4 (T. mashonense) to 16.9 (Diplostomum sp.). The diversity and richness indices were comparatively higher in fish samples from Lake Ol'Bolossat and attributed to the occurrence of G. pedatum in the Ol'Bolossat. However, parasitic infestation of fish samples from the two lakes depicted close similarity, both in diversity and prevalence. These findings form an important baseline data for further follow-up studies, and they suggest the need for further molecular analyses to fully describe three of the taxa only identified up to the genus level.

Hyaluronic acid impacts hematological endpoints and spleen histological features in African catfish (Clarias gariepinus).

Since its identification in the vitreous humour of the eye and laboratory biosynthesis, hyaluronic acid (HA) has been a vital component in several pharmaceutical, nutritional, medicinal, and cosmetic uses. However, little is known about its potential toxicological impacts on aquatic inhabitants. Herein, we investigated the hematological response of Clarias gariepinus to nominal doses of HA. To achieve this objective, 72 adult fish were randomly and evenly distributed into four groups: control, low-dose (0.5 mg/l HA), medium-dose (10 mg/l HA), and high-dose (100 mg/l HA) groups for two weeks each during both the exposure and recovery periods. The findings confirmed presence of anemia, neutrophilia, leucopoenia, lymphopenia, and eosinophilia at the end of exposure to HA. In addition, poikilocytosis and a variety of cytomorphological disturbances were observed. Dose-dependent histological alterations in spleen morphology were observed in the exposed groups. After HA removal from the aquarium for 2 weeks, the groups exposed to the two highest doses still exhibited a notable decline in red blood cell count, hemoglobin concentration, mean corpuscular hemoglobin concentration, and an increase in mean corpuscular volume. Additionally, there was a significant rise in neutrophils, eosinophils, cell alterations, and nuclear abnormalities percentages, along with a decrease in monocytes, coupled with a dose-dependent decrease in lymphocytes. Furthermore, only the highest dose of HA in the recovered groups continued to cause a significant increase in white blood cells. White blood cells remained lower, and the proportion of apoptotic RBCs remained higher in the high-dose group. The persistence of most of the haematological and histological disorders even after recovery period indicates a failure of physiological compensatory mechanisms to overcome the HA-associated problems or insufficient duration of recovery. Thus, these findings encourage the inclusion of this new hazardous agent in the biomonitoring program and provide a specific pattern of hematological profile in HA-challenged fish. Further experiments are highly warranted to explore other toxicological hazards of HA using dose/time window protocols.

PACAP binds conserved receptors and modulates cytokine gene expression and protein secretion in trout cell lines.

Antimicrobial peptides (AMPs) are an alternative to antibiotics for treatment and prevention of infections with a lower risk of bacterial resistance. Pituitary adenylate cyclase activating polypeptide (PACAP) is an outstanding AMP with versatile effects including antimicrobial activity and modulation of immune responses. The objective of this research was to study PACAP immunomodulatory effect on rainbow trout cell lines infected with Aeromonas salmonicida. PACAP from Clarias gariepinus (PACAP1) and a modified PACAP (PACAP5) were tested. RT-qPCR results showed that il1b and il8 expression in RTgutGC was significantly downregulated while tgfb expression was upregulated after PACAP treatment. Importantly, the concentration of IL-1ß and IFN-γ increased in the conditioned media of RTS11 cells incubated with PACAP1 and exposed to A. salmonicida. There was a poor correlation between gene expression and protein concentration, suggesting a stimulation of the translation of IL-1ß protein from previously accumulated transcripts or the cleavage of accumulated IL-1ß precursor. In-silico studies of PACAP-receptor interactions showed a turn of the peptide characteristic of PACAP-PAC1 interaction, correlated with the higher number of interactions observed with this specific receptor, which is also in agreement with the higher PACAP specificity described for PAC1 compared to VPAC1 and VPACA2. Finally, the in silico analysis revealed nine amino acids related to the PACAP receptor-associated functionality.

Dietary Moringa oleifera mitigates Fluconazole-Induced immunological and spleen-histological alterations in Catfish (Clarias gariepinus).

Fluconazole (FCZ), an antifungal from the azole family, causes several detrimental effects in fish. In recent times, there has been a notable surge in interest regarding the utilization of Moringa oleifera (Mo) as a dietary antioxidant. This research aimed to evaluate the potential protective effects of dietary Moringa oleifera (MO) against the adverse impacts of fluconazole in the African catfish (Clarias gariepinus). The fish were allocated into four groups as follows: a control group fed a basal diet, an FCZ - exposed (200 ng/L) fed basal diet, 1% MO fed through basal diet, and an FCZ-exposed (200 ng/L) and 1% MO fed through basal diet fed group. The results showed that FCZ exposure decreased superoxide dismutase, total antioxidant capacity, and acetylcholine esterase levels. On the other hand, FCZ exposure increased malonaldehyde and cortisol levels as compared to control (P < 0.05). FCZ caused immunosuppressive effects in C. gariepinus as revealed by lower immunity indices (lysozyme and phagocytic activity and immunoglobulin level) and increased cytokine levels (IL-6 IL-1ß). Histological examination of the spleen from fish exposed to FCZ showed several splenic changes. We conclude that dietary MO supplementation has the potential to alleviate the oxidative stress, restore immune response balance, and mitigate histological damage induced by FCZ exposure, thus positioning MO as an immunostimulant in C. gariepinus when administered alongside FCZ.

Aquatic assessment of the chelating ability of Silica-stabilized magnetite nanocomposite to lead nitrate toxicity with emphasis to their impact on hepatorenal, oxidative stress, genotoxicity, histopathological, and bioaccumulation parameters in Oreochromis niloticus and Clarias gariepinus.

BACKGROUND: In recent years, anthropogenic activities have released heavy metals and polluted the aquatic environment. This study investigated the ability of the silica-stabilized magnetite (Si-M) nanocomposite materials to dispose of lead nitrate (Pb(NO3)2) toxicity in Nile tilapia and African catfish. RESULTS: Preliminary toxicity tests were conducted and determined the median lethal concentration (LC50) of lead nitrate (Pb(NO3)2) to Nile tilapia and African catfish to be 5 mg/l. The sublethal concentration, equivalent to 1/20 of the 96-hour LC50 Pb(NO3)2, was selected for our experiment. Fish of each species were divided into four duplicated groups. The first group served as the control negative group, while the second group (Pb group) was exposed to 0.25 mg/l Pb(NO3)2 (1/20 of the 96-hour LC50). The third group (Si-MNPs) was exposed to silica-stabilized magnetite nanoparticles at a concentration of 1 mg/l, and the fourth group (Pb + Si-MNPs) was exposed simultaneously to Pb(NO3)2 and Si-MNPs at the same concentrations as the second and third groups. Throughout the experimental period, no mortalities or abnormal clinical observations were recorded in any of the treated groups, except for melanosis and abnormal nervous behavior observed in some fish in the Pb group. After three weeks of sublethal exposure, we analyzed hepatorenal indices, oxidative stress parameters, and genotoxicity. Values of alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), urea, and creatinine were significantly higher in the Pb-intoxicated groups compared to the control and Pb + Si-MNPs groups in both fish species. Oxidative stress parameters showed a significant decrease in reduced glutathione (GSH) concentration, along with a significant increase in malondialdehyde (MDA) and protein carbonyl content (PCC) concentrations, as well as DNA fragmentation percentage in the Pb group. However, these values were nearly restored to control levels in the Pb + Si-MNPs groups. High lead accumulation was observed in the liver and gills of the Pb group, with the least accumulation in the muscles of tilapia and catfish in the Pb + Si-MNPs group. Histopathological analysis of tissue samples from Pb-exposed groups of tilapia and catfish revealed brain vacuolation, gill fusion, hyperplasia, and marked hepatocellular and renal necrosis, contrasting with Pb + Si-MNP group, which appeared to have an apparently normal tissue structure. CONCLUSIONS: Our results demonstrate that Si-MNPs are safe and effective aqueous additives in reducing the toxic effects of Pb (NO3)2 on fish tissue through the lead-chelating ability of Si-MNPs in water before being absorbed by fish.

Zinc modulates hypothalamo-pituitary-gonadal-liver axis to impair reproduction in female Mystus vittatus (Bloch, 1794).

The present study investigated the effects of zinc on the hypothalamo-pituitary-gonadal-liver (HPGL) axis of the bagrid catfish Mystus vittatus. Female fish (pre-ovulatory and ovulatory phases) were exposed to zinc sulphate at 1/10th of LC50 (5.62 mg/L) for 60 days and sacrificed at every 15-day interval to collect tissues. Zinc concentration in all tissues was significantly higher in the metal-exposed group at all exposure durations compared to control for both phases. Metallothionein (MT) levels increased in the brain, liver and ovary of fish from both phases with exposure duration. Reactive oxygen species (ROS) generation in the brain, liver and ovary tissues increased with exposure duration at both reproductive phases while serum cortisol levels in ovulatory fish increased significantly compared to pre-ovulatory. Condition factor, gonadosomatic index and hepatosomatic index decreased in Zn-exposed fish. Brain GnRH and kisspeptin levels decreased significantly in the Zn-exposed group for both phases. GnIH was significantly higher in Zn-exposed fish. Serum FSH levels in pre-ovulatory and LH levels in ovulatory fish decreased gradually with an increase in the duration of exposure. Zn exposure reduced vitellogenin (Vtg) and estradiol (E2) in the liver and ovary with an increase in duration from both phases. Ovary maturation-inducing hormone (MIH) levels showed a decrease with exposure duration in ovulatory fish. Moreover, Zn-exposed ovulatory fish showed a degenerated oocyte nucleus due to the disintegration of the nuclear membrane. It might be inferred that Zn altered the HPGL regulatory system of M. vittatus reproduction at both the pre-ovulatory and ovulatory phases.

Characteristics of the Vasa Gene in Silurus asotus and Its Expression Response to Letrozole Treatment.

The identification and expression of germ cells are important for studying sex-related mechanisms in fish. The vasa gene, encoding an ATP-dependent RNA helicase, is recognized as a molecular marker of germ cells and plays a crucial role in germ cell development. Silurus asotus, an important freshwater economic fish species in China, shows significant sex dimorphism with the female growing faster than the male. However, the molecular mechanisms underlying these sex differences especially involving in the vasa gene in this fish remain poorly understood. In this work, the vasa gene sequence of S. asotus (named as Savasa) was obtained through RT-PCR and rapid amplification of cDNA end (RACE), and its expression in embryos and tissues was analyzed using qRT-PCR and an in situ hybridization method. Letrozole (LT) treatment on the larvae fish was also conducted to investigate its influence on the gene. The results revealed that the open reading frame (ORF) of Savasa was 1989 bp, encoding 662 amino acids. The SaVasa protein contains 10 conserved domains unique to the DEAD-box protein family, showing the highest sequence identity of 95.92% with that of Silurus meridionalis. In embryos, Savasa is highly expressed from the two-cell stage to the blastula stage in early embryos, with a gradually decreasing trend from the gastrula stage to the heart-beating stage. Furthermore, Savasa was initially detected at the end of the cleavage furrow during the two-cell stage, later condensing into four symmetrical cell clusters with embryonic development. At the gastrula stage, Savasa-positive cells increased and began to migrate towards the dorsal side of the embryo. In tissues, Savasa is predominantly expressed in the ovaries, with almost no or lower expression in other detected tissues. Moreover, Savasa was expressed in phase I-V oocytes in the ovaries, as well as in spermatogonia and spermatocytes in the testis, implying a specific expression pattern of germ cells. In addition, LT significantly upregulated the expression of Savasa in a concentration-dependent manner during the key gonadal differentiation period of the fish. Notably, at 120 dph after LT treatment, Savasa expression was the lowest in the testis and ovary of the high concentration group. Collectively, findings from gene structure, protein sequence, phylogenetic analysis, RNA expression patterns, and response to LT suggest that Savasa is maternally inherited with conserved features, serving as a potential marker gene for germ cells in S.asotus, and might participate in LT-induced early embryonic development and gonadal development processes of the fish. This would provide a basis for further research on the application of germ cell markers and the molecular mechanisms of sex differences in S. asotus.

Optimizing nutrient utilization, hydraulic loading rate, and feed conversion ratios through freshwater IMTA-aquaponic and hydroponic systems as an environmentally sustainable aquaculture concept.

Water quality in land-based fish production can be controlled through either instantaneous water exchange or costly wastewater treatment followed by recirculation. Agricultural-aquaculture integration is an excellent alternative technique for reducing nutrient discharge levels, boosting profitability, and converting fish culture wastewater into valuable products. The current study employed a solar energy system to power two separate IMTA-aquaponics systems (Nutrient Film Technique, NFT, and Floating Raft Systems, FRS) for the cultivation of Nile tilapia, African catfish, thin-lipped grey mullet, freshwater crayfish, freshwater mussels, and a variety of vegetables. Tilapia and catfish were fed exclusively on diets under the IMTA system. All wastewater from tilapia and catfish ponds, both dissolved and solid, flows sequentially to ponds containing other cultivated species. The water then flows through the IMTA system's terminal point to the NFT and FRS systems before returning to the tilapia and catfish ponds, allowing complete control of the nutrient flow throughout this entire circular system. Two 147-day production cycles were concluded. The results from the second production cycle are reported. Total biomass gain for aquatic species in the IMTA system was 736.46 kg, compared to 145.49 kg in the tilapia and 271.01 kg in the catfish monoculture systems. The current IMTA system had a cumulative feed conversion ratio (FCR) of 0.90, while the FCRs for tilapia and catfish were 1.28 and 1.42, respectively. Nile tilapia and catfish consumed 571.90 kg of feed containing 25.70 kg of nitrogen (N) and 9.70 kg of phosphorus (P), reflecting, and gaining 11.41 and 3.93 kg of dietary N and P, representing 44.40 and 40.46% dietary N and P retention, respectively. In the IMTA system, the addition of mullet and prawn as detrivores aquatic animals improves dietary N and P utilization efficiency to 59.06 and 51.19%, respectively, while the addition of mussels as herbivore animals improves dietary N and P utilization efficiency to 65.61 and 54.67%, respectively. Finally, using FRS and NFT as hydroponic systems increased dietary N and P efficiency to 83.51% N and 96.82% P, respectively. This study shows that the IMTA-Aquaponic system, as a bio-integrated food production system, can convert the majority of fish-fed residues into valuable products suitable for desert, rural, and urban areas in impoverished and developing countries.

Cucullanus lithodorasi n. sp. (Nematoda: Cucullanidae), a parasite of Lithodoras dorsalis (Siluriformes: Doradidae) on the north coast of Brazil.

Cucullanus lithodorasi n. sp. (Nematoda: Cucullanidae), collected from the intestine of Lithodoras dorsalis (Siluriformes) and waters of the north coast of Brazil is described based on light and scanning electron microscopic observations. The new species differs from its congeners in the number and arrangement of cloacal papillae: five precloacal pairs and five postcloacal pairs and presence of unpaired ventral papillae located slightly anterior to the cloaca. This is the third nominal species of the genus infecting fishes from brackish water from Brazil.

Microbiological quality assessment of Clarias gariepinus, Bagrus bajad, and Pangasianodon hypophthalmus fillets.

In this study, 80 catfish fillets were randomly collected from Egyptian local markets and retailers. The samples included 20 African catfish (Clarias gariepinus), 20 bayad (Bagrus bajad), and 40 pangasius catfish (Pangasianodon hypophthalmus) fillets. Pangasianodon hypophthalmus fillet samples were divided into 20 white basa and 20 red basa fillets. We conducted a microbiological analysis of catfish fillet samples, evaluating mesophilic aerobic bacteria, psychrophilic aerobic bacteria, H2S-producing bacteria, Staphylococcus spp., Enterobacteriaceae, Coliforms, and fecal Coliform counts. Additionally, we identified the existence of Salmonella spp., Vibrio spp., Yersinia spp., Escherichia spp., Aeromonas spp., and Pseudomonas spp. in the catfish fillet samples. In our study, the psychrophilic bacterial counts in Bagrus bajad (5.21 log CFU/g) were found to be higher compared to the counts in Clarias gariepinus (4.31 log CFU/g) and Pangasianodon hypophthalmus (3.89-4.7 log CFU/g). The fecal Coliform in Clarias gariepinus fillets was significantly higher than in other catfish fillets. We isolated Escherichia coli, Escherichia fergusonii, Aeromonas hydrophila, and Pseudomonas luteola from the catfish fillets, while no Salmonella spp., Vibrio spp., or Yersinia spp. were detected. These isolates were identified using 16S rRNA sequencing and phylogenetic analysis. Furthermore, ten Escherichia spp. were serologically identified, revealing that O26 and O78 were the most commonly occurring serotypes. This study highlights the microbiological analysis conducted on catfish fillets and concludes that the fillet samples from these catfish were of superior quality and deemed acceptable for human consumption.

Antibiotic resistance profiles of sentinel bacteria isolated from aquaculture in Cambodia.

The misuse of antibiotics and the emergence of antimicrobial resistance (AMR) is a concern in the aquaculture industry because it contributes to global health risks and impacts the environment. This study analyzed the AMR of sentinel bacteria associated with striped catfish (Pangasisanodon hypophthalmus) and giant snakehead (Channa micropeltes), the two main fish species reared in the pond culture in Cambodia. Phenotypic and genotypic characterization of the recovered isolates from fish, water, and sediment samples revealed the presence of bacteria, such as 22 species belonging to families Aeromonadaceae, Enterobacteriaceae, and Pseudomonadaceae. Among 48 isolates, Aeromonas caviae (n = 2), Aeromonas hydrophila (n = 2), Aeromonas ichthiosmia (n = 1), Aeromonas salmonicida (n = 4) were detected. A. salmonicida and A. hydrophilla are known as fish pathogens that occur worldwide in both fresh and marine water aquaculture. Antibiotic susceptibility testing revealed antibiotic resistance patterns of 24 (50 %) isolates among 48 isolates with higher multiple antibiotic resistance index (> 0.2). All the isolates of Enterobacteriaceae were susceptible to ciprofloxacin. Ciprofloxacin is a frontline antibiotic that is not recommended to use in aquaculture. Therefore, its use has to be strictly controlled. This study expands our knowledge of the AMR status in aquaculture farms which is very limited in Cambodia.

Gap-free chromosome-level genomes of male and female spotted longbarbel catfish Hemibagrus guttatus.

Hemibagrus guttatus, also named as spotted longbarbel catfish, is an economical fish in China. However, their gender cannot be easily distinguished from their appearance, which largely impedes their artificial breeding. Therefore, we provided two gap-free chromosome-level genomes of male and female spotted longbarbel catfish by combining wtdbg2, LR_Gapcloser and TGS-GapCloser assembly approaches with Hi-C data and accurate Pacbio HiFi long-reads. We assembled 30 chromosomes without any gap. Their genome sizes are approximately 749.1 Mb and 747.8 Mb of male and female individuals. The completeness results of BUSCO evaluation show about 94.2% and 95.0%, representing a high-level of completeness of both genomes. We also obtained 35,277 and 34,571 protein-coding gene sets from male and female individuals. Both available gap-free chromosome-level genomes of H. guttatus will provide excellent references for resequencing of male and female individuals to identify accurate markers for distinguishing gender of this fish.

Advancing aquaculture: Production of xenogenic catfish by transplanting blue catfish (Ictalurus furcatus) and channel catfish (I. punctatus) stem cells into white catfish (Ameiurus catus) triploid fry.

Xenogenesis has been recognized as a prospective method for producing channel catfish, Ictalurus punctatus ♀ × blue catfish, I. furcatus ♂ hybrids. The xenogenesis procedure can be achieved by transplanting undifferentiated stem cells derived from a donor fish into a sterile recipient. Xenogenesis for hybrid catfish embryo production has been accomplished using triploid channel catfish as a surrogate. However, having a surrogate species with a shorter maturation period, like white catfish (Ameiurus catus), would result in reduced feed costs, labor costs, and smaller body size requirements, making it a more suitable species for commercial applications where space is limited, and as a model species. Hence, the present study was conducted to assess the effectiveness of triploid white catfish as a surrogate species to transplant blue catfish stem cells (BSCs) and channel catfish stem cells (CSCs). Triploid white catfish fry were injected with either BSCs or CSCs labeled with PKH 26 fluorescence dye from 0 to 12 days post hatch (DPH). No significant differences in weight and length of fry were detected among BSCs and CSCs injection times (0 to 12 DPH) when fry were sampled at 45 and 90 DPH (P > 0.05). The highest survival was reported when fry were injected between 4.0 to 5.5 DPH (≥ 81.2%). At 45 and 90 DPH, cell and cluster area increased for recipients injected from 0 to 5.2 DPH, and the highest cluster area values were reported between 4.0 to 5.2 DPH. Thereafter, fluorescent cell and cluster area in the host declined with no further decrease after 10 DPH. At 45 DPH, the highest percentage of xenogens were detected when fry were injected with BSCs between 4.0 to 5.0 and CSCs between 3.0 to 5.0 DPH. At 90 DPH, the highest number of xenogens were detected from 4.0 to 6.0 DPH when injected with either BSCs or CSCs. The current study demonstrated the suitability of white catfish as a surrogate species when BSCs and CSCs were transplanted into triploid white catfish between 4.0 to 6.0 DPH (27.4 ± 0.4°C). Overall, these findings allow enhanced efficiency of commercializing xenogenic catfish carrying gametes of either blue catfish or channel catfish.

Neurotoxic and cardiotoxic effects of pyrogallol on catfish (Clarias gariepinus).

Pyrogallol, a botanical hydrolysable tannin, has diverse medical and industrial applications. Its impact on aquatic ecosystems and fish health has been previously studied, revealing histopathological, immunological, biochemical, and haematological alterations in African catfish (Clarias gariepinus). In this study, the neurotoxic potential of pyrogallol was assessed through a 15-day exposure of catfish to concentrations of 1, 5, or 10 mg/L. Enzyme activities such as acetylcholinesterase (AchE), monoamine oxidase (MAO), aldehyde oxidase (AO), and nitric oxide (NO) were measured in serum and brain, along with histopathological examinations in the brain and heart. Pyrogallol exposure led to decreased AchE activity in the brain and serum, increased serum MAO activity, elevated AO in both brain and serum, and suppressed NO levels. Morphological abnormalities and dose-dependent pathological alterations were observed in the brain and heart, including neuropile deformities, shrunken Purkinje cells, cardiomyocyte degeneration, and increased collagen fibers. This suggests that pyrogallol induces adverse effects in fish.

Exploitation of multiple host-derived nutrients by the yellow catfish epidermal environment facilitates Vibrio mimicus to sustain infection potency and susceptibility.

Infection with Vibrio mimicus in the Siluriformes has demonstrated a rapid and high infectivity and mortality rate, distinct from other hosts. Our earlier investigations identified necrosis, an inflammatory storm, and tissue remodeling as crucial pathological responses in yellow catfish (Pelteobagrus fulvidraco) infected with V. mimicus. The objective of this study was to further elucidate the impact linking these pathological responses within the host during V. mimicus infection. Employing metabolomics and transcriptomics, we uncovered infection-induced dense vacuolization of perimysium; Several genes related to nucleosidase and peptidase activities were significantly upregulated in the skin and muscles of infected fish. Concurrently, the translation processes of host cells were impaired. Further investigation revealed that V. mimicus completes its infection process by enhancing its metabolism, including the utilization of oligopeptides and nucleotides. The high susceptibility of yellow catfish to V. mimicus infection was associated with the composition of its body surface, which provided a microenvironment rich in various nucleotides such as dIMP, dAMP, deoxyguanosine, and ADP, in addition to several amino acids and peptides. Some of these metabolites significantly boost V. mimicus growth and motility, thus influencing its biological functions. Furthermore, we uncovered an elevated expression of gangliosides on the surface of yellow catfish, aiding V. mimicus adhesion and increasing its infection risk. Notably, we observed that the skin and muscles of yellow catfish were deficient in over 25 polyunsaturated fatty acids, such as Eicosapentaenoic acid, 12-oxo-ETE, and 13-Oxo-ODE. These substances play a role in anti-inflammatory mechanisms, possibly contributing to the immune dysregulation observed in yellow catfish. In summary, our study reveals a host immune deviation phenomenon that promotes bacterial colonization by increasing nutrient supply. It underscores the crucial factors rendering yellow catfish highly susceptible to V. mimicus, indicating that host nutritional sources not only enable the establishment and maintenance of infection within the host but also aid bacterial survival under immune pressure, ultimately completing its lifecycle.

Hindering the biofilm of microbial pathogens and cancer cell lines development using silver nanoparticles synthesized by epidermal mucus proteins from Clarias gariepinus.

Scientists know very little about the mechanisms underlying fish skin mucus, despite the fact that it is a component of the immune system. Fish skin mucus is an important component of defence against invasive infections. Recently, Fish skin and its mucus are gaining interest among immunologists. Characterization was done on the obtained silver nanoparticles Ag combined with Clarias gariepinus catfish epidermal mucus proteins (EMP-Ag-NPs) through UV-vis, FTIR, XRD, TEM, and SEM. Ag-NPs ranged in size from 4 to 20 nm, spherical in form and the angles were 38.10°, 44.20°, 64.40°, and 77.20°, Where wavelength change after formation of EMP-Ag-NPs as indicate of dark brown, the broad band recorded at wavelength at 391 nm. Additionally, the antimicrobial, antibiofilm and anticancer activities of EMP-Ag-NPs was assessed. The present results demonstrate high activity against unicellular fungi C. albicans, followed by E. faecalis. Antibiofilm results showed strong activity against both S. aureus and P. aeruginosa pathogens in a dose-dependent manner, without affecting planktonic cell growth. Also, cytotoxicity effect was investigated against normal cells (Vero), breast cancer cells (Mcf7) and hepatic carcinoma (HepG2) cell lines at concentrations (200-6.25 µg/mL) and current results showed highly anticancer effect of Ag-NPs at concentrations 100, 5 and 25 µg/mL exhibited rounding, shrinkage, deformation and granulation of Mcf7 and HepG2 with IC50 19.34 and 31.16 µg/mL respectively while Vero cells appeared rounded at concentration 50 µg/mL and normal shape at concentration 25, 12.5 and 6.25 µg/ml with IC50 35.85 µg/mL. This study evidence the potential efficacy of biologically generated Ag-NPs as a substitute medicinal agent against harmful microorganisms. Furthermore, it highlights their inhibitory effect on cancer cell lines.

Characterization and expression profiles of toll-like receptor genes (TLR2 and TLR5) in immune tissues of hybrid yellow catfish under bacterial infection.

The yellow catfish (Pelteobagrus fulvidraco) is one of the most economically important freshwater species in Asia. However, pathogenic bacterial infections often cause high rates of mortality and economic losses in practical aquaculture. Previous studies in mammals have shown that Toll-like receptor 2 (TLR2) and Toll-like receptor 5 (TLR5) are involved in the recognition of cell wall components such as lipopolysaccharides and flagella of various bacteria, thereby acting as key regulators in the innate immunity response. However, TLR2 and TLR5 in yellow catfish have not been characterized. In the present study, TLR2 and TLR5 were examined through comparative genomic approaches. The gene structure, collinearity, protein spatial structure, and phylogenetic relationships were compared with those in multiple representative vertebrates. Meanwhile, quantitative real-time PCR was conducted to explore transcriptional changes in TLR2 and TLR5 in immune tissues after infection with exogenous A. hydrophila and E. tarda. The results demonstrated the presence of TLR2 and TLR5 in yellow catfish. However, a systematic analysis showed that TLR2 was not associated with the arrangement of diverse neighboring genes. The expression of hybrid yellow catfish TLR2 transcripts in multiple tissues (including liver, spleen, kidney, and intestine) was significantly up-regulated after infection with A. hydrophila and E. tarda, suggesting that hybrid yellow catfish TLR2 and TLR5 may participate in the immune process. Taken together, the results indicate that TLR2 and TLR5 are conserved in terms of evolution and possess significant antibacterial activity as well as regulatory properties in immune-related tissues and thus play key roles in host defense against pathogen invasion.