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In the present study, an attempt has been made to analyze the toxicity of fluoride and arsenic on morphology and behaviour of fish Clarias batrachus. Based on 96 hour LC50 values at the 95% confidence limits of sodium fluoride (NaF) and arsenic trioxide (As2O3) obtained from the preliminary tests, various sub-lethal concentrations of NaF and As2O3 were selected for combined toxicity testing. During the experiment, fish were regularly observed for any changes in their external morphology and behaviour. Behavioural changes were observed in terms of air gulping, opercular movement, swimming activity, body position, general activity and food sensitivity. Control fish remained normal throughout the experiment period (96 hour) but erratic, exodus and speedy movements were found in all treated groups. The number of air gulps (per 15 min, 24-96 hour) significantly increased (P<0.001) in the exposed Group I (20 mg.L-1 As2O3) as compared to control. A significant increase (P<0.01) in the number of opercular movements (per min for 24-96 hour) was recorded in treatment groups as compared to control. Apparent changes such as excessive mucous secretion, increased body discolouration, loosening of skin and complete loss of skin (head region and fins) were also observed. Skin loss was more intense in fish subjected to Group I.

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.

A comparative study on the relationship between condition factors and parasite density of Heterobranchus isopterus and Clarias gariepinus was conducted during the wet and dry seasons. Specimens were collected from the Bagoué River from August 2020 to July 2021. Two hundred eighty-four specimens of H. isopterus and 272 specimens of C. gariepinus were collected from all stations during both seasons. The standard length and weight of the fish were recorded and the condition factor was calculated for each individual. The gills were examined under a binocular loupe and the monogeneans were collected. Parasite counts showed that for both host species, the total number of parasites was higher in the dry season than in the wet season ( p < 0.05). The correlation coefficient was determined to investigate the relationship between the condition factor and the total number of parasites. A significant positive correlation was observed between the condition factor and the number of parasites in both host species during the wet season. A negative correlation was observed in both hosts during the dry season. The information from this study could be taken into consideration in the sanitary management of the fish farming industry. The dry season could be considered as the season with favorable conditions for the development of most parasite species.

The study investigated the effect of polyphenols present in Cassia auriculata (CA) leaves in enhancing the stability of the collagen protein and the wound healing potential of collagen films. The crude ethanol extract of CA was analyzed for the presence of phytochemicals and purified by column chromatography using solvents with increasing polarity. The ethanol eluted active fractions (EEAF) that precipitated gelatin was characterized using HP-TLC, FTIR spectroscopy, ESI-FT-MS/MS, and 1H NMR spectroscopy. The active compound was identified to be procyanidin B belonging to the proanthocyanidins group. The wound healing property of EEAF and collagen type I extracted from Clarias batrachus fish skin and the bovine tendon was assessed by in vitro scratch assay on L929 mice fibroblast cell lines. The EEAF-treated collagen coating enhanced in vitro wound closure in comparison with the uncoated dish. It was observed that EEAF treatment improved the physical strength of collagen films. The in vivo wound healing of the EEAF-treated collagen film was examined in male Wister rats and the wound site tissues were assessed. In vivo wound examination showed enhanced healing with EEAF incorporated collagen films. Comparatively, the EEAF-treated bovine tendon collagen films showed improved physical properties and better wound healing property than fish collagen films.

Aim Ecological niche models (ENMs) are widely used to address urgent real‐world problems such as climate change effects or invasive species; however, the generality of models when projected through space and/or time, that is transferability, remains a key challenge. Here, we explored the effects of complex predictors and feature selection on ENM transferability in a widely employed algorithm, Maxent, using five globally invasive freshwater species as case studies. Location Global. Methods We modelled the global distributions of five notorious freshwater invasive species (African sharptooth catfish Clarias gariepinus, Mozambique tilapia Oreochromis mossambicus, American bullfrog Lithobates catesbeianus, red swamp crayfish Procambarus clarkii, and Australian redclaw crayfish Cherax quadricarinatus), using three predictor datasets of varying complexities derived from two commonly used climatic data sources (WorldClim and IPCC) and three methods of model tuning that differentially incorporated feature selection. Spatially explicit transferability assessments were then conducted using a suite of evaluation metrics previously used to quantify Maxent model performance. Results We show that in the absence of detailed biological knowledge of focal species, simpler predictor datasets produce models that are more accurate than those calibrated using comprehensive “bioclimatic” datasets. Additionally, we find that tuning models for both optimal regularization parameters as well as feature‐class combinations led to the greatest increases in transferability and geographic niche conservatism. Results indicate a tenuous link between model transferability and Akaike's information criterion corrected for small sample sizes (AICc), suggesting that the indiscriminate use of AICc as an estimate of model parsimony may lead to erratic model performance. Main conclusions Our findings demonstrate that methodological considerations can drastically affect the reliability of spatial and possibly temporal projections, which has severe implications when ENMs are used to infer species’ niches, and quantify ecological or evolutionary change across impacted landscapes.

Background/Objectives: North African catfish (Clarias gariepinus) and bighead catfish (Clarias macrocephalus) play crucial roles in Thai aquaculture. Although significant growth disparities exist among these species, the genetic factors underlying these differences are still unknown. This study aimed to identify GH1 gene polymorphisms, in North African and bighead catfish populations across Thailand and Laos. Methods: Sequencing, phylogenetic, and clustering analyses were performed to assess genetic diversity, selection patterns, and lineage differentiation of catfish partial GH1 fragment. Results: Six alleles of the studied fragment of GH1 gene were identified; they differed at 33 variable sites within intron 2, located between the conserved regions at the 3′ end of exon 2 and the 5′ end of exon 3. At the population-level, GH1 exhibited low heterozygosity (mean Ho = 0.043 ± 0.023; He = 0.059 ± 0.028). Bayesian clustering analyses identified two distinct genetic clusters, corresponding to North African and bighead catfish, apart from the bighead population in Laos, indicating their distinct genetic origins. Evidence of purifying selection was observed in both species. Phylogenetic analysis indicated the presence of lineage-specific alleles in the GH1 gene. Conclusions: These findings provide valuable insights into GH1 polymorphisms in commercially important catfish species and may help to develop future breeding programs aimed at enhancing aquaculture productivity.

Catfish is a commonly-cultivated freshwater fish in Thailand and many Southeast Asian countries. The molecular data obtained for the IgM heavy chain (IgMH) of catfish have been useful for distinguishing monoclonal antibodies (mAbs). A mAb specific to Cμ1 of the IgMH of catfish (IgMHCμ1 mAb) was developed in a rabbit model using sequence information from bighead catfish (Clarias macrocephalus). The IgMHCμ1 mAb strongly recognized the IgM heavy chain of the tested catfish, namely, bighead catfish, African catfish (Clarias gariepinus) and their hybrid (C. macrocephalus × C. gariepinus), in immunological Western blot analysis and competitive ELISAs. Additionally, the IgMHCμ1 mAb successfully recognized IgM+ cells by detecting IgM molecules in both secreted and membrane-bound forms in peripheral blood leukocytes (PBLs). The IgMHCμ1 mAb was further used to quantify the percentage of IgM+ cells among PBLs through flow cytophotometry. The IgM+ cell percentages of healthy bighead catfish, African catfish and their hybrid were 38.0–39.9%, 45.6–53.2%, and 58.7–60.0%, respectively. Furthermore, the IgMHCμ1 mAb showed no cross-reactivity with the IgM of zebrafish. These findings suggest that this mAb can be used as an immunological tool for monitoring the health, immune status, and immune development of cultivated Clarias catfish.

Climate change has driven global temperature increases, resulting in severe heat waves, altered precipitation patterns, and extreme weather events. In April 2024, a massive die‐off of hybrid catfish larvae and fry occurred in Thai aquaculture farms, coinciding with elevated temperatures of air (37–41°C) and freshwater (30–32°C). This study aimed to investigate the correlation between elevated temperatures and abnormal embryonic development in hybrid catfish. Controlled mating of male North African catfish (Clarias gariepinus) and female bighead catfish (Clarias macrocephalus) was conducted in May and June 2024. We examined the effects of water temperature changes in hybrid catfish, focusing on fertilization, hatching, yolk sac absorption, and mouth morphology, while keeping the conditions of water quality, feeding, and disease management constant. The fertilization rate was 67.7% at 29°C, whereas it significantly decreased to 59.0% at 32°C. The hatching rate decreased from 43.4% at 29°C to 26.6% at 32°C. Survival rates plummeted, with no larvae surviving beyond 72 h post‐hatching (hph) at 32°C. Yolk sac absorption was notably accelerated at 32°C, being completely absorbed by 48 hph. Mouth morphometry revealed that a gap in the mouth started to develop 12 hph, and the opening size of the mouth increased out to 72 h. These findings indicate that higher temperatures (32°C) lead to faster yolk absorption, causing embryos to deplete yolk reserves rapidly, potentially before full development and independent feeding. This results in a smaller body size and lower survival rates. Present study provides crucial insights for enhancing breeding practices and creating management protocols for hybrid catfish hatcheries during the period season of high temperature in the context of climate change.

Two novel immunoglobulin heavy chain ( Ighμ ) transcripts encoding membrane-bound forms of IgM (mIgM) were discovered in bighead catfish , Clarias macrocephalus . The first transcript contains four constant and two transmembrane domains [Cμ1-Cμ2-Cμ3-Cμ4-TM1-TM2] that have never been reported in teleosts, and the second transcript is an unusual mIgM that has never been identified in any vertebrate [Cμ1-(Cδ2-Cδ3-Cδ4-Cδ5)-Cμ2-Cμ3-TM1-TM2]. Fluorescence in situ hybridization (FISH) in bighead catfish, North African catfish ( C. gariepinus ) and hybrid catfish revealed a single copy of Ighμ in individual parent catfish, while two gene copies were found in diploid hybrid catfish. Intensive sequence analysis demonstrated multiple distinct structural variabilities in the VH domain in Clarias , and hybrid catfish were defined and used to generate diversity with various mechanisms. Expression analysis of Ighμ in Aeromonas hydrophila infection of the head kidney, peripheral blood leukocytes and spleen revealed significantly higher levels in North African catfish and hybrid catfish than in bighead catfish.

This research was conducted to determine the effects of Andrographis paniculate extract on hybrid catfish. The fish were fed 0, 0.2, 0.4 and 0.6 g/kg extract to supplement their diets for 90 days. The highest weigh gain, average daily growth, specific growth rate, feed efficiency and protein efficiency ratio, as well as the lowest feed conversion rate, were found in the group fed 0.6 g/kg. RBC were at their highest in all treatment groups, while the highest levels of total WBC and haematocrit percentage were observed in the group fed 0.6 g/kg. ALT and triglyceride were at their lowest levels in all treatment groups, while the highest amounts of glucose were found in all treatment groups. The highest levels of high-density lipoprotein and the lowest cholesterol were observed in fish fed 0.6 g/kg. Lysozyme activity was initially observed at a significant difference on days 60-90, the highest activity was found in the group fed 0.6 g/kg. After bacterial challenge test, lysozyme activity and WBC were significantly increased in all treatment groups, the lowest cumulative mortality was found in the group fed 0.6 g/kg. These results suggest that 0.6 g/kg of the extract has positive effects on hybrid catfish.