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The U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) conducts surveillance of metallic elements in U.S. meat, poultry, and Siluriformes fish samples collected immediately postmortem as part of its National Residue Program (NRP). From 2017 to 2022, 13,966 samples were analyzed under the NRP. The Federal Emergency Response Network (FERN) Cooperative Agreement Program (CAP) tests meat, poultry, and Siluriformes fish products collected at retail in the United States for metals. From 2018 to 2022, 2,902 samples were analyzed by FERN CAP laboratories. Meat and poultry samples collected by FSIS show that most metals were not detected at all or were detected infrequently. Meat is a rich source of iron and zinc, and iron was detected in 22% (1,255/5,623) and zinc was detected in 48% (2,742/5,676) of meat and poultry samples, respectively. The percentage of samples testing positive for manganese, molybdenum, lead, and cadmium were higher in the FERN CAP retail samples than in FSIS samples. Expected human exposure from average levels of lead and cadmium found in meat and poultry was compared to toxicological reference values and was not found to exceed these values. Detections of arsenic and mercury were found more often in Siluriformes fish samples (2017–2022) than in terrestrial animals. Trace amounts of arsenic and mercury were detected in 8% and 4% of Siluriformes samples, respectively, but were not detected at levels that raise concern. On the whole, both the FSIS and FERN CAP datasets provide reassuring evidence of the safety of the FSIS-regulated food supply with regard to the studied elements.

Cultivated Aurantiochytrium sp. FIKU018 contained 64.0% crude lipid, 22.6% crude protein, and 4.47% crude ash, on a dry matter basis. This ingredient has been supplemented in artificial diets across a number of aquatic animal species. However, no studies have evaluated this dietary supplement for African sharptooth catfish (Clarias gariepinus) aquaculture. In this study, isonitrogenous, isolipidic, and isoenergetic diets were formulated containing different grade levels of dried Aurantiochytrium sp. (0, 2, 4, 6, 8, and 10%). These diets were given to triplicate groups of juvenile African sharptooth catfish (1.68–1.70 g body weight) for six weeks. At the end of the feeding trial, fish in all treatments had similar survival rates, ranging from 88.9% to 97.2% (P > 0.05). The growth performance (weight gain = 68.5 g) and feed utilization (feed conversion ratio = 1.47 g feed g gain−1, protein efficiency ratio = 1.94 g gain g protein−1) indicated a suitable level of 6% dried Aurantiochytrium sp. in diet. Based on broken-line analysis indicated an optimal supplementation level of 6.41% would produce the highest weight gain. This preferred treatment significantly improved skin lightness, muscle protein synthesis capacity, and whole-body crude protein (P < 0.05) without causing effects on fillet color parameters, digestive enzyme activities, and myosin and actin in white muscle (P > 0.05). Our observations suggest that 6.41% is the optimal dietary supplementation level of Aurantiochytrium sp. for juvenile African catfish. The supplemented diet that produced the best results can be used in the cultivation of African sharptooth catfish, and could support the use of dried Aurantiochytrium meal as an alternative feed supplement for other aquatic animals.

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Flavobacterium covae and virulent Aeromonas hydrophila are prevalent bacterial pathogens within the US catfish industry that can cause high mortality in production ponds. An assessment of in vivo bacterial coinfection with virulent A. hydrophila (ML09‐119) and F. covae (ALG‐00‐530) was conducted in juvenile channel catfish (Ictalurus punctatus). Catfish were divided into seven treatments: (1) mock control; (2) and (3) high and low doses of virulent A. hydrophila; (4) and (5) high and low doses of F. covae; (6) and (7) simultaneous challenge with high and low doses of virulent A. hydrophila and F. covae. In addition to the mortality assessment, anterior kidney and spleen were collected to evaluate immune gene expression, as well as quantify bacterial load by qPCR. At 96 h post‐challenge (hpc), the high dose of virulent A. hydrophila infection (immersed in 2.3 × 107 CFU mL−1) resulted in cumulative percent mortality (CPM) of 28.3 ± 9.5%, while the high dose of F. covae (immersed in 5.2 × 106 CFU mL−1) yielded CPM of 23.3 ± 12.9%. When these pathogens were delivered in combination, CPM significantly increased for both the high‐ (98.3 ± 1.36%) and low‐dose combinations (76.7 ± 17.05%) (p < .001). Lysozyme activity was found to be different at 24 and 48 hpc, with the high‐dose vAh group demonstrating greater levels than unexposed control fish at each time point. Three proinflammatory cytokines (tnfα, il8, il1b) demonstrated increased expression levels at 48 hpc. These results demonstrate the additive effects on mortality when these two pathogens are combined. The synthesis of these mortality and health metrics advances our understanding of coinfections of these two important catfish pathogens and will aid fish health diagnosticians and channel catfish producers in developing therapeutants and prevention methods to control bacterial coinfections. [ABSTRACT FROM AUTHOR]

This study attempted to discriminate the population of Heterobranchus longifilis in Nigeria using their morphological characteristics. Therefore, 60 sexually mature wild samples of H. longifilis (1:1 for the male and female ratio) of relatively similar size (40 cm) were collected from three eco-regions namely, Guinea Savanna (Benue River, Makurdi), Rainforest Savanna (Niger River, Onitsha) and Sahel Savanna (Rima River, Sokoto). They were transported to the hatchery unit of the Fisheries and Aquaculture Department, Joseph Sarwan Tarka University Makurdi where the morphometric data was collected. The data for 39 traditional morphometric measurements and 5 meristic counts obtained from each fish were subjected to univariate and multivariate analysis. While significant differences were observed in some parameters following univariate analysis; it was revealed that the morphometric parameters and meristic counts could not separate the fish from the different ecoregions into distinct multivariate spaces or clusters following Principal Component Analysis. Hence, this suggests that morphological parameters cannot be used to discriminate H. longifilis from the different ecoregions. Studies using molecular markers are needed to further characterise the distinctiveness of the different populations. [ABSTRACT FROM AUTHOR]

Research on water quality in test ponds based on the influence of the application of sago-based catfish food has been carried out in Udapi Hilir Village, Manokwari Regency. The effect of sago pulp composition was carried out on variations of rice bran: fish meal: sago pulp was 1:1:0.5, 1:1:1, 1:1:1,5, and rice bran: the fish meal was 1:1. This research explains the water quality of test ponds using physical and chemical parameter monitoring methods. The results of this study contain several chemical and physical parameters that exceed the quality standard threshold. The results of the proximate analysis showed that adding sago pulp provided a chemical value of the feed that was still following the recommended standards. The results of water quality tests carried out for 4 weeks showed an increase in TDS levels, without draining the test pool during the research. The average Nitrate (NO3 -) has increased but is still below the quality standard of 10 mg/L. Nitrate (NO3 -) concentrations are rising in all ponds for all treatments. Nitrate levels impact fish growth because they can lower water oxygen levels. Overall, the application of sago pulp as a raw material for catfish feed results in pond water quality that is still within the pond water quality standards so it has the potential as an alternative feed raw material. [ABSTRACT FROM AUTHOR]

Fish motifs in Aboriginal rock art of the Laura area (Cape York Peninsula, Queensland, Australia) include a heterogenous group that has been imprecisely classified by rock art researchers. By analysing motif attributes, style and contexts (including natural populations), we characterised three categories: fork-tailed catfish (Neoarius paucus), eel-tailed catfish (Neosilurus spp.) and eel (Anguilla reinhardti). We label the categories with the local names 'catfish', 'jewfish' and 'eel'. The catfish cohort has a relatively naturalistic style, while the eel exhibits anatomical trends of eels, distinctive arrangements, and stylistic overlaps with jewfish that may denote shared meanings. Ambiguity is confirmed as a cultural value and communication mode of the rock art system. [ABSTRACT FROM AUTHOR]

Objective: Bacterial community profiling in aquaculture can be useful for monitoring environmental conditions that may lead to disease outbreaks, understanding the impact of dietary treatments on fish health, and identifying microbes that have potential as probiotics. Microbiota characterization is commonly performed with high‐throughput sequencing using short‐read platforms (i.e., Illumina) targeting variable regions of the bacterial 16S ribosomal RNA (rRNA) gene. Long‐read platforms (i.e., Oxford Nanopore Technologies [ONT]) enable sequencing of full‐length 16S rRNA genes. While short‐read platforms are highly accurate, long‐read platforms sacrifice sequence quality in exchange for longer read lengths. Methods: Herein, a typical short‐read approach (Illumina MiSeq; V4 region of 16S rRNA gene) was compared with two near‐full‐length 16S rRNA gene ONT protocols (ONT Custom and ONT 16S). Sequencing was performed on a mock community composed of fish‐relevant bacteria, in addition to samples (digesta, gill, skin) obtained from 10 hybrid catfish (female Channel Catfish Ictalurus punctatus × male Blue Catfish I. furcatus) and their environment (pond and holding tank). Fish were euthanized with either an overdose of MS‐222 or cranial concussion and subsequent pithing to enable comparisons of these sequencing protocols in the context of a realistic experimental design. Result: The ONT Custom protocol best recapitulated the theoretical composition of the mock community, followed by the ONT 16S and Illumina MiSeq protocols. Phylum‐level composition was consistent within sample type across sequencing methods. However, at lower levels there were biases for several taxa, particularly in pond samples. Euthanasia method also appeared to introduce differences, primarily on the cutaneous communities. The three sequencing methods consistently identified significant differences between euthanasia methods, with Illumina MiSeq revealing the greatest differences. While all strategies performed comparably for digesta, skin, and water samples, the ONT strategies underperformed for gill samples. Conclusion: Depending on application, results indicate that near‐full‐length 16S rRNA gene nanopore sequencing is a viable option for aquaculture microbiota studies. Impact statementIn this study, we found nanopore sequencing of catfish‐related samples was a viable approach for characterizing bacterial populations. Utilizing a mock community composed of known amounts of bacterial DNA, we were able to evaluate how accurate each protocol was. These results provide valuable information to aquaculture researchers conducting bacterial community profiling studies. The methods described can be used in future studies to evaluate the effects of various treatments and environmental factors on fish and pond bacterial communities, allowing for an improved understanding of aquaculture management practices on the fish microbiota. [ABSTRACT FROM AUTHOR]

Coastal river systems provide essential habitats for a diversity of fish species that transition marine, estuarine, and freshwater environments to complete their lifecycles. Movement among and within these environments is important to access resources that optimise growth, survival, and reproduction. Knowledge on the movements, including the drivers, underpins management strategies, although this information is often lacking for many species. We used acoustic telemetry to quantify the relative importance of a range of abiotic stimuli in relation to seasonal movement patterns in blue salmon catfish Neoarius graeffei throughout an unregulated coastal river catchment, the Clarence River in northern New South Wales, Australia. Neoarius graeffei continuously occupied the Clarence River system for the duration of the 1-year study and were mostly confined to estuarine reaches, with occasional movement into freshwater habitats. Seasonal differences in habitat occupation were observed, with N. graeffei using habitats close to the river mouth in winter and upstream estuary habitats in spring. Broad-scale movement patterns were influenced by both water temperature and river flow, and high-flow events (> 1.5 m) resulted in short-term changes (~ 10 days) in habitat use. Sex-specific differences in seasonal habitat use were also observed which we hypothesise is linked to contrasting energetic investment in reproduction. The response of N. graeffei to changes in river flow highlights the need for assessment on these impacts for estuarine-dependent species more broadly, in the face of climate change and increased river regulation. [ABSTRACT FROM AUTHOR]

Even though several studies have reported how stress induces detrimental pathophysiological responses that are linked to increase in disease susceptibility, no study has evaluated the impact of overcrowding on the serum chemistry of Heterobranchus longifilis. This study aimed at evaluating the impact of overcrowding on serum chemistry in Heterobranchus longifilis. Briefly, 30 apparently healthy Heterobranchus longifilis weighing between 1 kg and 1.5 kg were randomly divided into 2 groups of 15 catfish, each designated as groups 1 and 2. Group 1 (control group) was not subjected to stress, while group 2 was subjected to 3 hours of overcrowding in a 120 L plastic water tank at 201 g/L of water. Blood samples were collected from the caudal vein into non-heparinized tubes before stress, immediately after stress and 24 hours after stress. Sera were collected, and serum chemistry and electrolytes were analyzed. At 24 hours after stress, alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, creatinine, uric acid, total bilirubin, conjugated bilirubin, total protein, albumin, total cholesterol, triglyceride, chloride, potassium, and sodium were significantly higher in group 2 compared to the control group. Based on the findings of this study, it was concluded that overcrowding of Heterobranchus longifilis for 3 hours has a significant impact on its health status. [ABSTRACT FROM AUTHOR]

The objective of this research is to assess the length-weight relationship (LWR) as well as Fulton's condition factor of freshwater catfish species i.e., Rita rita from Gomti River, Lucknow, Uttar Pradesh. A total of 319 fish specimens were randomly sampled from January 2022 to December 2022. The results revealed the values of 'b' for male, female, and pooled populations are 2.68, 2.73, and 2.70 respectively which represents negative allometric growth. The coefficient of correlation, 'r²' between total length and body weight for males, females, and pooled population were estimated as 0.931, 0.934, and 0.933 which is significant at a 1% level. The fish were found to be in good health condition, as the calculated value of Fulton's condition factor varied from 1.33 to 1.39. The present research is beneficial as it offers pertinent data for studying fish biology, assessing the condition of fish in their habitat, and evaluating parameters about population dynamics.² [ABSTRACT FROM AUTHOR]

Aeromonas hydrophila, a gram-negative bacterium belonging to the Aeromonadaceae family, has significantly impacted global catfish production within the Siluriformes family, resulting in economic losses. Despite being recognized as part of the normal flora found in water systems and fish organs, the pathogenicity of A. hydrophila is often activated by the expression of virulence genes encoding toxins. To systematically gather reliable scientific studies on the virulence of A. hydrophila in catfish Siluriformes, the PRISMA method was employed, utilizing the Scopus database. Following the application of inclusion and exclusion criteria, a total of 66 documents were scrutinized, and a bibliometric analysis was conducted using VOSviewer. Based on the keyword analysis, aerolysin toxin emerged as the most prevalent virulence factor, appearing in 64% (n = 42) of the papers, followed by hemolysin, enterotoxin, and biofilm. The analysis also revealed that the primary organs associated with infection were the kidney and liver, recognized as immune secretion organs, followed by the gills, intestine, skin, and mucus, identified as entry points. The major clinical signs of A. hydrophila infection included hemorrhage, lesion, ulceration, and septicemia. This study elucidates the scientific consensus on the infection mechanisms of A. hydrophila, covering entry points, adherence, and invasion. The ranked entry points and virulence factors identified herein offer valuable insights for designing novel treatments or preventive measures in catfish farming. [ABSTRACT FROM AUTHOR]

Background: Water pollutants cause adverse effects in aquatic ecosystems. The immunomodulatory and mitigating effects of dietary 1,3-glucan on fipronil and lead-induced intoxication in African catfish (Clarias gariepinus) were investigated. Two hundred forty catfish were randomly divided into four equal groups: those in the first group were fed basic diet and served as controls; those in the second group were supplemented with β-1,3-glucan (0.1%); those in the third group were exposed to combination of lead nitrate at 0.041 mg/L (1/10 96 h LC50) and fipronil at 2.8 mg/l (1/10 96 h LC50); and those in the fourth group were exposed to combination of fipronil, lead, and β-1,3-glucan. The health status, haematological, immunological, and histological changes were all evaluated. Result: Swelling on the dorsolateral side, spinal column deviation, sluggish movement, skin bleaching, excessive mucus secretion, significant variations in blood indices-related measures, and a 45% death rate were observed in the third group. There was a significant reduction in interleukin-1 (IL-1) and interleukin-6 (IL-6) and immunoglobulin M (IgM) concentrations, as well as decrease in their corresponding gene expression, indicating that fipronil and lead had immunosuppressive activity. Severe catarrhal enteritis and mucinous degeneration of the lining epithelium, and notable depletion of white pulp, congested red pulp and hemosiderosis were common pathological findings in the spleen. β-1,3-glucan alone or in combination with fipronil and lead provoked physical activity, blood indices, with elevations in IL-1β, IL-2, IL-6, and IgM concentrations, as well as up-regulation in their genes' expression in splenic tissues, when compared to the third group. The spleen and intestine had normal histological architecture with 5% mortalities. There were no fish deaths in the β-1,3-glucan-alone or control groups. Conclusion: The use of β-1,3-glucan (0.1%) as dietary supplement could be implemented to protect against the toxic effects of fipronil and lead toxicity by improving the health and immunological parameters of intoxicated catfish. [ABSTRACT FROM AUTHOR]

Commercial aquaculture production of channel catfish (Ictalurus punctatus) occurs in shallow ponds with daily cycling of dissolved oxygen concentration ranging from supersaturation to severe hypoxia. Once daily minimum dissolved oxygen concentration falls below 3.0 mg O2/L, channel catfish have a reduced appetite, leading to reduced growth rates. In other fishes, upregulation of the neuropeptides corticotropin-releasing factor (CRF) and urotensin I (UI) have been implicated as initiating the mechanism responsible for decreasing appetite once an environmental stressor is detected. Channel catfish maintained at 27 °C in aquaria were subjected to varying durations and patterns of hypoxia (1.75 ± 0.07 mg O2/L) to evaluate underlying physiological responses to hypoxia and determine if hypothalamic CRF and UI are responsible for hypoxia-induced anorexia in channel catfish. During a short exposure to hypoxia (12 h), venous Po2 was significantly lower within 6 h and was coupled with an increase of hematocrit and decrease of blood osmolality, yet all responses reversed within 12 h after returning to normoxia. When this pattern of hypoxia and normoxia was repeated cyclically for 5 days, these physiological responses repeated daily. Extended periods of hypoxia (5 days) resulted in similar hematological responses, which did not recover to baseline values during the hypoxia exposure. This study did not find a significant change in hypothalamic transcription of CRF and UI during hypoxia challenges but did identify multiple physiological adaptive responses that work together to reduce the severity of experimentally induced hypoxia in channel catfish. [ABSTRACT FROM AUTHOR]

Artificial light in various spectral is a relatively new development for modifying the environment of fish. According to research, light has a spectral and species-specific effect on fish.. As a result, the goal of this study was to see how different visible light colors affected Clarias gariepinus growth and digestive enzymes. 105 Juvenile fish (body length 10.00 ± 0.55 cm, initial weight 8.67 ± 0.62 g) were randomly exposed in triplicate to the following LEDs: Red (RL), Blue (BL), Green (GL), and Yellow (Y). Total Darkness (TD) and Ambient Light (AL) were used as controls. The fish were exposed for 12 hours overnight for 50 days. At five-day intervals, the fish's body weights were measured with an electric weighing scale (0.01g sensitivity); head length (cm), tail length (cm), and total body length (cm) were measured with a graduated measuring plastic box. The variables listed below were computed: Weight Gain (WG), Daily Weight Gain (DWG), Daily Growth Rate (DGR), Specific Growth Rate (SGR), Percentage Weight Gain (PWG), Food Conversion Ratio (FCR), Length Gain (LG), Daily Length Gain (DLG), Survival Rate (SR) and Condition Factor are some of the metrics used to calculate weight gain. Standard methods were used to measure the activities of digestive enzymes (proteinase and amylase). ANOVA was used to compare the acquired means, and Duncan's multiple range tests were used to further separate the means. Fish reared in YL had significantly higher WG, DWG, DGR, PWG, DLG, LG, and CF levels. SR of fish reared under TD conditions was the lowest, but it was significantly (P < 0.05) higher in fish reared under YL and RL conditions. Fish exposed to YL had significantly higher FCR and CF than those exposed to the other light treatments and the Control. The digestive enzyme activities were significantly (P < 0.05) reduced during the light treatment. Finally, nighttime artificial light exposure had a significant impact on juvenile catfish growth performance and digestive enzymes, with yellow light eliciting better growth performance. [ABSTRACT FROM AUTHOR]

Objective: Proliferative gill disease (PGD) in Channel Catfish Ictalurus punctatus and hybrid catfish (Channel Catfish × Blue Catfish I. furcatus) is attributed to the myxozoan Henneguya ictaluri. Despite evidence of decreased H. ictaluri transmission and impaired parasite development in hybrid catfish, PGD still occurs in hybrid production systems. Previous metagenomic assessments of clinical PGD cases revealed numerous myxozoans within affected gill tissues in addition to H. ictaluri. The objective of this study was to investigate the development and pathologic contributions of H. ictaluri and other myxozoans in naturally and experimentally induced PGD. Methods: Henneguya species‐specific in situ hybridization (ISH) assays were developed using RNAscope technology. Natural infections were sourced from diagnostic case submissions in 2019. Experimental challenges involved Channel Catfish and hybrid catfish exposed to pond water from an active PGD outbreak, and the fish were sampled at 1, 7, 10, 12, 14, 16, 18, and 20 weeks postchallenge. Result: Nine unique ISH probes were designed, targeting a diagnostic variable region of the 18S ribosomal RNA gene of select myxozoan taxa identified in clinical PGD cases. Partial validation from pure H. ictaluri, H. adiposa, H. postexilis, and H. exilis infections illustrated species‐specific labeling and no cross‐reactivity between different myxozoan species or the catfish hosts. After experimental challenge, mature plasmodia of H. ictaluri and H. postexilis formed in Channel Catfish but were not observed in hybrids, suggesting impaired or delayed sporogenesis in the hybridized host. These investigations also confirmed the presence of mixed infections in clinical PGD cases. Conclusion: Although H. ictaluri appears to be the primary cause of PGD, presporogonic stages of other myxozoans were also present, which may contribute to disease pathology and exacerbate respiratory compromise by further altering normal gill morphology. This work provides molecular confirmation and more resolute developmental timelines of H. ictaluri and H. postexilis in Channel Catfish and supports previous research indicating impaired or precluded H. ictaluri sporogony in hybrid catfish. Impact statementThis work implicates Henneguya ictaluri as the primary cause of proliferative gill disease, a devastating parasitic disease of U.S. catfish aquaculture, but demonstrates other myxozoan parasites can contribute to disease severity. The study better defines the developmental timeline of H. ictaluri and H. postexilis in Channel Catfish and supports research indicating impaired maturation of H. ictaluri in hybrid catfish. [ABSTRACT FROM AUTHOR]

A two-month study was conducted to investigate the effect of turmeric root on the haematology, growth performance and feed utilization of the African catfish (Clarias gariepinus). A total of one hundred and fifty (150) four week old C. gariepinus fingerlings were randomly allotted into five treatments with three replicates each. Five dietary treatments containing varying levels of 0.00, 0.25, 0.5, 0.75 and 1.0 g of turmeric as supplement were pelleted with other ingredients for the experimental diet. Fish fed with 0.25 and 1.00 g of turmeric supplemented feed had the best growth performance although 0.25 g supplementation group performed significantly better on week 8. The acceptability of the diet was less than four seconds in all treatments, 0.25 g of turmeric supplemented diet was most readily accepted by the fish followed closely by the 0.75 and 1.00 g/100 g of feed. The haematological profile of the fish showed that the turmeric supplemented diet was good for the fish and were within range irrespective of their different values across the concentration. This was true for all the parameters apart from the neutrophil which was the lowest at 0.25 g concentration of turmeric supplement with 15.33 ± 1.16 compared to the control with 19.67 ± 1.53 (p<0.05) which is an indication that the fish may be suffering from acute neutrophilia. It was concluded that turmeric supplemented feed improved the growth performance and the immunity of the fish at 1.00 g inclusion of turmeric as supplement per 100 g of feed. [ABSTRACT FROM AUTHOR]

The present study was executed to evaluate the effect of photoperiod on serum biochemical parameters (glucose, cortisol, ALT, AST and LDH), electrolytic balance (Sodium and potassium), acute phase response (CRP) and histopathology (liver, kidney and skin) of an endangered high valued catfish, Ompok bimaculatus. Catfish (21.00 ± 1.53 cm and 30.00 ± 2.31 g) from the acclimatized stock were randomly distributed to six 120 × 45 × 60 cm3 FRP tanks (n = 20 fish per tank) and exposed to 1500 lx light intensity under different photoperiods [24:0 light: dark (L: D), 15L: 9D, 12L: 12D, 9L: 15D, 0L: 24D and a natural photoperiod (control)], and fed at a daily rate of 2% of bodyweight, twice a day for 60 days. Serum glucose, cortisol and enzymes including aspartate transaminase (AST), lactate dehydrogenase (LDH), alanine transaminase (ALT), and acute phase reactant, such as C-reactive protein (CRP) increased significantly (P < 0.05) in continuous light (24L: 0D), continuous dark (0L: 24D) and short day (9L: 15D) photoperiods, whereas in 15L: 9D and 12L:12D photoperiods, those were in decreasing trend. Serum electrolytes, i.e. potassium level was elevated and sodium level was declined in 24L: 0D, 0L: 24D and 9L: 15D photoperiod groups. Moreover, significant histological alterations in the liver, kidney and skin tissue were also evidenced in the experimented catfish. Typical polygonal hepatocytes with normal blood vessels in liver and normal organization of kidney were seen in catfish of 15L: 9D group. Histological analysis of other groups displayed nuclear degeneration, karyorrhexis, karyolysis, melanomacrophages, nuclear hypertrophy, sinusoid dilation and vacuolar degeneration in liver and hyaline droplets accumulation, granular degeneration, fragmentation of glomerulus and focal necrosis of epithelial cells in kidney. Additionally, general structure of the skin was observed in control group as well as in 15L: 9D group. Contrarily, in 24L: 0D group increased number of mucous cells and vacuoles was observed in the skin of butter catfish. In 9L: 15D and 0L: 24D photoperiods, O. bimaculatus exhibited ruptured epithelial cells, enlarged alarm cells, fat cells, necrotic cells and vacuoles in the skin tissue. The present study depicted that 15L: 9D photoperiod can induce better health of catfish, O. bimaculatus, which, in turn, can help farmers to increase the production of this high valued catfish in future. [ABSTRACT FROM AUTHOR]

Our study helps to evaluate the immune response, antioxidative status, and resistance against heat stress (HS) in Clarias gariepinus treated with propolis extraction; the results will contribute to theories of fish physiology and immunity under high-temperature conditions. Forty-five fish were divided into three equal groups: the control, the HS group at 36 °C, and the HS treated with alcoholic extraction of propolis that dissolved in water for 3 weeks. The results of our study suggested that the stress response differs among tissues thymus, spleen, and liver. All the tissues showed alteration in morphological and cytological structure at the light microscope (LM) and transmission electron microscope (TEM); thymus showed edema and thymocyte destruction; the spleen detected collagen deposition, and the liver displayed endoplasmic reticulum amplification (ER). In addition, we examined oxidative stress and antioxidant defenses (lipid peroxidation, catalase, and glutathione) of the spleen and measured blood biochemical parameters (alanine transaminase and aspartic transaminase levels) after heat stress. However, this toxic effect of HS was neutralized by the propolis extraction. To conclude, propolis is recommended to cope with the impacts of heat stress on catfish (Clarias gariepinus) by improving immunity and antioxidative resistance. [ABSTRACT FROM AUTHOR]

Frass–the by-product of the larva meal industry–was recently shown to be a sustainable ingredient for use in diets of several fish species. Additionally, because of its possible immunomodulatory activity and anti-microbial properties, frass may have great potential as an organic method of pathogen control in aquaculture. Five diets containing 0, 5, 10, 20 and 30% frass from black soldier fly larvae, Hermetia illucens, were fed to channel catfish (5.24 ± 0.04 g) in quadruplicate aquaria to apparent satiation twice daily. At the end of the 10-week feeding trial, blood samples were collected from all groups to measure hematological and immune parameters, and to determine the effects of dietary frass on resistance to Flavobacterium covae infection. Hematological parameters (red blood cell count, hemoglobin, and hematocrit)—but not white blood cell count—were improved with the inclusion of frass. Serum glucose levels were significantly lower in fish on the diet with frass than fish on the diet without frass. Fish fed the highest dietary levels of frass (30%) had a significantly higher serum cholesterol level than fish on the control diet. Serum complement activity was significantly higher in fish on diets containing frass at levels of 10% and 20%. No significant differences were observed in other measure serum components including albumin, alkaline phosphatase, alanine aminotransferase, amylase, calcium, phosphorus, potassium, total protein, globulin, thyroxine and lysozyme activity. Even though overall mortality was low (0–17%), fish on the diets containing frass at levels 20% or more showed significantly higher survival than that of control fish or fish on lower levels of dietary frass. The use of frass in the catfish diet may prove beneficial by improving hematological parameters, and select serum immune effectors, and the overall resistance of juvenile channel catfish against F. covae infection. [ABSTRACT FROM AUTHOR]

Integrating fish farming with wastewater recycling can improve fish farming programs, ensuring environmental sustainability while improving cost of fish farming. This study examines the influence of wastewaters from slaughterhouses and palm oil mils on the growth performance of catfish. Artificial ponds created with transparent buckets, where the fingerlings were grown for six weeks, contained each wastewater type comprising 30%, 40% and 50% wastewater, the rest being tap water. Tap water was used as the control. Live body weight, weight gain, live length and gain in length of fish were used to monitor fish growth performance on a weekly basis. Pond temperature and pH were also monitored weekly. The physicochemical parameters of the water in the ponds were above the standards required for fishponds. There was no significant difference between the growth performance parameters in the control and other treatments during the entire period of study. There was also a strong correlation (r = 1) between the growth performance and the duration of study for all the treatments, indicating the fish could survive in the ponds for as long as necessary. Highest live weight of 14 g in T3R1, 13.33 g for control, 12 g for T2R1 and T4R1 were obtained. Highest live length values of 13.70, 13.50, 13.30, 13.20, 13.10 cm were obtained for T3R2, T3R3, T2R2, control and T2R3 respectively. Temperature in the adapted ponds ranged from 24-28 °C, and pH raged from 6-8. A low mortality rate of 4.16% (4 deaths) was obtained in the case of T3R3 only for the first week, but there no other mortality in other treatments throughout the period of the study. Results obtained show that wastewaters from slaughterhouses and palm oil mills can effectively be used to grow fish, reducing cost of fish farming and ensuring environmental sustainability from dumping of the wastewaters. [ABSTRACT FROM AUTHOR]

Fat deposition and off-flavor in the muscle are the main problems affecting flesh quality in aquaculture fish, especially in catfish, leading to low acceptability and reduced market price. Yellow catfish is an important aquaculture fish in China. In this study, 40 days of depuration and starvation treatment were explored to improve the muscle quality of aquaculture yellow catfish. After depuration and starvation, the body weight, condition factor (CF) and mesenteric fat index (MFI) were all significantly decreased 20 days after treatment. The metabolomic profiles in muscle were characterized to analyze the muscle quality in yellow catfish. The results showed that the content of ADP, AMP, IMP, glutamic acid and taurine were significantly increased between 20 and 40 days post-treatment in the muscle of yellow catfish during the treatment, which was positively associated with the flesh tenderness and quality. In contrast, aldehydes and ketones associated with off-flavors and corticosterone associated with bitter taste were all decreased at 20 days post-treatment. Considering the balance of body weight loss and flesh quality improvement, depuration and starvation for around 20 days is suitable for aquaculture yellow catfish. Our study not only provides an effective method to improve the flesh quality of aquaculture yellow catfish but also reveals the potential mechanism in this process. [ABSTRACT FROM AUTHOR]

ABSTRACT: Objectives: Edwardsiella ictaluri is an important pathogen in farmed raised catfish. Recently, we showed that resistance to tetracycline and florfenicol in the E. ictaluri MS-17–156 strain isolated from channel catfish was facilitated by acquisition of a 135 kb plasmid (named pEIMS-171561). Methods: We described the genetic structure of pEIMS-171561. Plasmid copy number and stability within E. ictaluri strain MS-17–156 was determined. We also investigated the in vitro and in vivo transferability of pEIMS-171561 using catfish as a model for in vivo transfer. Results: pEIMS-171561 belonged to the IncA/C group and contained florfenicol efflux major facilitator superfamily (MFS) (floR), sulfonamides (sul2), and tetracycline efflux MFS (tetD) genes. The plasmid contained two conjugative transfer-associated regions and encoded six transposases and insertion sequences. In vitro conjugation experiments demonstrated that the IncA/C plasmid can transfer from E. ictaluri to Escherichia coli. The plasmid was stable in E. ictaluri without selection pressure for 33 days. We showed that pEIMS-171561 did not transfer from E. ictaluri MS-17–156 to endogenous microbiota in catfish. Moreover, we could not detect in vivo conjugal transfer of pEIMS-171561 from E. ictaluri to E. coli. Results from real-time PCR revealed upregulation of the floR gene in the intestines of catfish receiving florfenicol-medicated feed, compared with that in catfish receiving unmedicated feed. Conclusion: This study demonstrated that pEIMS-171561 did not disseminate from E. ictaluri to gut microbiota under selective pressure. This result suggests a limited role of the fish microbiota as a reservoir for this plasmid and for the spread of resistance.

Abstract Interest in retail seafood sales increased dramatically with the onset of the COVID‐19 pandemic. The diversity of species, types of products, product forms, and packaging of the seafood sold at retail, combined with diverse consumer preferences across the United States, requires detailed data and analysis to provide guidance and understanding of emerging trends. Weekly, store‐based, Nielsen Scantrack data for the period of September 2016 through August 2021 were used to compare trends in US retail (supermarket) seafood sales across the 5‐year study period, in continental regions, cities, and species categories sold. Results showed continuous increases in retail seafood sales over the study period at an average annual growth rate of 8.1%, much of which was fueled by the 21% increase in total sales (19.5% increase in quantity sold) the first year after the onset of the pandemic. The South Atlantic region was found to have the greatest total sales and sales per capita among regions. New York City had the greatest total seafood sales, followed by Los Angeles and Philadelphia. The top five most important species categories in terms of sales were, in declining order, shrimp, salmon, tuna, crab, and tilapia, although regional variability became apparent from the fourth‐ranked species. The most important package sizes were 454‐ and 907‐g packs. Frozen and refrigerated categories dominated sales (70% in 2021), with little growth in entrées and a decline in market share of shelf‐stable seafood products in 2021. Retail supermarket seafood sales increased dramatically following the onset of the pandemic, with especially notable percentage increases in lobster (77%) and crab sales (70%) and the lowest percentage increases in tuna (1%) and tilapia (13%). Given that US per capita seafood consumption did not show a corresponding increase over the study period, study results likely indicate a shift to greater relative consumption at home and not an overall increase in US seafood sales.

Pangasiids are an economically significant group of catfish, and many pangasiids are threatened in the wild from anthropogenic pressures, including increases in fishing pressure, habitat degradation, and improperly managed aquaculture practices. This study demonstrates the usage of DNA barcoding of the Cytochrome Oxidase subunit I (COI) gene as an identification tool in detecting potentially threatening invasive pangasiid species by establishing the diversity and phylogenetic relationship of Pangasiidae catfishes in Peninsular Malaysia. A neighbour-joining (NJ) dendrogram (Kimura-2-parameter model) generated five clades to represent distinct genera. Pangasius was further subdivided into two clades (Clade A: Pangasius bocourti-P. djambal and Clade B: P. nasutus-P. conchophilus). Given the marginal genetic divergence, indigenous and non-native species should be treated cautiously in allopatrically distributed species. The analysis used Automatic Barcode Gap Discovery (ABGD) and revealed barcode gaps between the intraspecific and interspecific distances. The sequences were partitioned into five groupings, corresponding with the species delineation based on the distribution of pairwise differences, which could not be differentiated using the NJ dendrogram. ABGD allows the recognition of one or two additional species using the recursive approach, but other taxonomic methods should be considered for a solid conclusion. DNA barcoding demonstrates the identification of closely related species, thus justifying its application towards the conservation of these fish.

Fish farmers in Buket village already have basic catfish farming skills using soil ponds and biofloc. Obstacles occur when harvesting catfish simultaneously causes oversupply so that catfish prices fall and if they are not harvested immediately, farmers will experience losses due to feed needs that continue to increase along with the growth of catfish. Therefore, the purpose of this service activity is to manage financial management and help market the results of catfish rearing with biofloc technology that is converted into smoked catfish, and increase the value of the results of processing smoked catfish products. This service activity uses educational, participatory, survey, and persuasive methods. This community service activity consists of several stages, namely: (1) Socialization and coordination of activities (2) catfish smoking techniques (3) smoked catfish marketing techniques. Evaluation of service participants' success and satisfaction rate was carried out using a questionnaire. Based on the analysis of the level of satisfaction and success 80-90% of partners are satisfied with this service activity. This service activity provides positive knowledge and motivation to partners.

Fish growth is a fundamental biological process driven by a multitude of intrinsic (within-individual) and extrinsic (environmental) factors that underpin individual fitness and population dynamics. Interannual variability in river hydrology regarding the intensity and duration of floods and droughts can induce interannual variations in the biotic and abiotic variables that regulate fish growth. However, the understanding of how interannual variability in river hydrology affects fish growth remains limited for most species and ecosystems. We evaluated how inter-annual hydrological variations within the Amazon River basin influence the growth of the catfish Pseudoplaystoma fasciatum. Our research questions were as follows: Do floods lead to the faster growth of P. fasciatum and droughts lead to the slower growth? And do floods and droughts affect all age classes in the same manner? We sampled 364 specimens of P. fasciatum from five sites in the Amazon basin, estimated their growth rates, and related the growth rates to indices of the intensity of floods and droughts. We fitted linear mixed-effects models to test the relationship between growth increments and hydrological indices (with F and D quantifying the intensities of floods and droughts, respectively), age as fixed effects, and basins and Fish ID as random effects. We found an inverse relationship between the increment width in the fish hard parts and hydrological indices. That is, intense floods and droughts negatively affected the growth rates. We also found that the growth of P. fasciatum was no different in years with intense and mild floods across age classes 1–5, although was different for age class 6. However, the growth of P. fasciatum was faster in years of mild droughts for all age classes. Our results showing that the growth of P. fasciatum was slower in years of intense droughts are supported by those of previous studies in the Amazon basin and elsewhere. However, our results showing for the first time that the growth of P. fasciatum is slower in years of intense flooding is the opposite of patterns found in other studies. These results thus suggest that the growth of P. fasciatum is maximized within an optimum range of hydrological conditions, where neither floods nor droughts are intense.

In this study, we present in vitro actions of pure commercial preparations of oxidized and/or dehydrated metabolites of cholesterol (OS) identified in the lipid fraction of Fraction B (FB) prepared from a catfish skin preparation on calcium transients and on the formation of human neutrophil extracellular traps (NETs). These investigations are part of an ongoing effort to understand the important roles these compounds play as components of FB when FB is applied to accelerate the healing of wounds and the healing of highly infected non-healing diabetic foot ulcers, without the use of antibiotics. Our aim was to determine potential therapeutic interventions for various disease states. Our results reveal interesting findings, demonstrating specific actions of the individual compounds. Compounds 7α-hydroxy-cholesterol (S3), Cholestane-3,5,6-triol (S5), 5-cholesten-3β-ol-7-one (S8) and Cholesta-3,5 dien-7-one (S10) are inhibitory, while Cholesterol 5β,6β-epoxide (S4) and 5α-cholestane-3,6-dione (S11) activate the response for calcium influx in human neutrophils. A somewhat similar response is observed in dHL60 cell lines, where S3, S5, S7, S8, and cholesta-2,4-diene (S14) inhibit the calcium influx, although S4, S10, and S11 activate the response in this cell line. Furthermore, we observed a relationship between actions against NETosis and calcium transients. Interestingly, relative to the vehicle control, S3, Cholesta-3,5 diene (S9), and S14 appeared to significantly stimulate DNA release (NETosis), while S2, 7α-hydroxy-cholesterol (S6) and cholesta-3,5 dien-7-one (S10) caused lesser stimulation. We provide the IC50 activities for each compound tested in each assay. Calcium influx and NETs formation (NETosis) correlate with diseases exacerbation. These findings offer valuable insights into the potential therapeutic applications of individual OS for various diseases, highlighting their importance in future interventions.

The global surge in multi-drug resistant bacteria, including extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has led to a growing need for new antibacterial compounds. Despite being promising, the potential of fish-derived antimicrobial peptides (AMPs) in combating ESBL-producing E. coli is largely unexplored. In this study, native African catfish antimicrobial peptides (NACAPs) were extracted from the skin mucus of farmed African catfish, Clarias gariepinus, using a combination of 10% acetic acid solvent hydrolysis, 5 kDa ultrafiltration, and C18 hydrophobic interaction chromatography. Peptides were then sequenced using Orbitrap Fusion Lumos Tribrid Mass Spectrometry. The identified peptides were screened for potential antibacterial activity using Random Forest and AdaBoost machine learning algorithms. The most promising peptide was chemically synthesized and evaluated in vitro for safety on rabbit red blood cells and activity against ESBL-producing E. coli (ATCC 35218) utilizing spot-on-lawn and broth dilution methods. Eight peptides ranging from 13 to 22 amino acids with molecular weights between 968.42 and 2434.11 Da were identified. Peptide NACAP-II was non-hemolytic to rabbit erythrocytes (p > 0.05) with a zone of inhibition (ZOI) of 22.7 ± 0.9 mm and a minimum inhibitory concentration (MIC) of 91.3 ± 1.2 μg/mL. The peptide is thus a candidate antibacterial compound with enormous potential applications in the pharmaceutical industry. However, further studies are still required to establish an upscale production strategy and optimize its activity and safety in vivo.

This study aimed to evaluate cinnamaldehyde (CN) and clove oil (CO) effectiveness in inhibiting growth and killing spoilage and total aerobic bacteria when overlaid with catfish fillet stored at 4 °C. A 1.00 mL concentration of CO inhibited growth by 2.90, 1.96, and 1.96 cm, respectively, for S. baltica, A. hydrophilia, and total bacteria. Similarly, treatment with 1.00 mL of CN resulted in ZIB of 2.17, 2.10, and 1.10 cm, respectively, for S. baltica, A. hydrophilia, and total bacteria from catfish exudates. Total bacteria from catfish exudates treated with 0.50 mL CN for 40 min, resulted in a 6.84 log decrease, and treatment with 1.00 mL resulted in a 5.66 log decrease at 40 min. Total bacteria exudates treated with 0.50 mL CO resulted in a 9.69 log reduction at 40 min. Total bacteria treated with 1.00 mL CO resulted in a 7.69 log decrease at 7 days, while untreated pads overlaid with catfish resulted in ≥9.00 CFU/mL. However, treated absorbent pads with catfish at 7 days, using 0.50 mL and 1.00 mL CN, had a bacterial recovery of 5.53 and 1.88 log CFU/mL, respectively. Furthermore, CO at 0.50 mL and 1.00 mL reduced the bacteria count to 5.21 and 1.53 log CFU/mL, respectively, at day 7.

AbstractA total of 525 catfish samples were collected with various fishing equipment, including hooks, longlines, and different mesh sizes of gillnets (4–12 cm). Out of these specimens, 379 (72.2%) stomachs contained prey items, whereas 146 (27.8%) were empty stomachs. Overall, fish prey, zooplankton, detritus and phytoplankton were the four most important food items, accounting for 48.1%, 21.8%, 17.1% and 5.9% of C. gariepinus diets by volume respectively. Diet composition varied across different size classes of the fish. The smallest fish (37 cm SL) primarily fed on fish prey (14.0–74.1%) followed by zooplankton (11.2–21.3%) by volume. The relative importance of detritus, mud, zooplankton, phytoplankton, and insects decreased with increasing fish size from the Ribb Reservoir. The food and feeding habits of C. gariepinus significantly differed between dry and wet seasons. Fish prey and detritus were mainly consumed in the dry season and contributed to 63.6% and 21.9% of the total volume respectively. Zooplankton and phytoplankton were the most preferred food items during the wet season, contributing 71.8% and 22.2% of the total volume. Generally, C. gariepinus appears to be an omnivore, the species exhibits ontogenetic dietary shifts with larger specimens being more carnivorous, and the species exhibits dietary plasticity across wet and dry seasons, which may be linked to food availability from the Ribb Reservoir.

AbstractThe outdoor gamma dose rates and the activity concentrations of potassium-40, uranium-238, and thorium-232 within the study area were carried out using calibrated hand-held gamma detector (RS-125 gamma spectrometer) and NaI(Tl) gamma spectroscopy. The in-situ measurement results of the gamma dose rate indicate that the hotspot is at location 4 with a value of 100 nGyh-1. The results from the NaI(Tl) gamma detector revealed the highest activity concentrations of potassium-40, uranium-238, and thorium-232 to be 288.09, 96.49, and 136.12 Bqkg−1 for sediments and 257.31, 66.93, and 96.57 Bqkg for water, respectively. The highest mean activity concentration of potassium-40 and uranium-238 was observed in Catfish with values of 151.87 and 38.00 Bqkg−1, whereas the highest value for the activity of thorium-232 was observed in Tilo Fish with a value of 89.02 Bqkg-1. In comparison, all the observed values are higher than the population-weighted average of 420.00, 32.00, and 45.00 Bqkg−1 for potassium-40, uranium-238, and thorium-232 according to UNSCEAR. Geologically, this may be attributed to the marine incursion of regional tectonic subsidence during transgression. Statistically, the correlation results confirmed that the enhanced outdoor dose rates at the coastline environment were caused mainly by uranium-238, followed by thorium-232 and then potassium-40 in magnitude. The mean hazard indices calculated for the samples were also observed to be within the global average values recommended by ICRP.

The lectotype and paralectotype of Synodontis victoriae Boulenger, 1906, designated by Poll (1971), were examined. Inconsistencies between data presented for the designated lectotype and the illustrated individual raise the question of whether lectotypification by Poll is valid. This case is not formally regulated by the International Code of Zoological Nomenclature, but based on Article 74.5, the lectotypification for S. victoriae should be considered invalid because it cannot unambiguously indicate a single name-bearing specimen. Thus, we designate a new lectotype for S. victoriae (BMNH 1906.5.30.191, Entebbe, standard length 188.2 mm) out of two syntypes and provide illustrations and new morphometric and meristic data for both specimens. [ABSTRACT FROM AUTHOR]

Bolbophorus damnificus is a digenetic trematode causing significant economic losses within the United States commercial catfish industry. The indirect life cycle is complex, requiring piscivorous birds, aquatic snails, and fish to complete. With federal protections on many piscivorous birds and no FDA‐approved therapeutic treatment for trematode infections in fish, management within the catfish industry is primarily limited to controlling the snail host. Planorbella trivolvis and Biomphalaria havanensis are snails commonly found in commercial catfish ponds and known to transmit B. damnificus. This study evaluated a low‐cost snail trap prototype for monitoring populations of these snails in efforts to better inform treatment regimes. Snail traps were deployed into ponds on a commercial catfish farm and checked weekly throughout the production season. All snails were identified and counted to evaluate trap efficacy. Traps captured significantly more snails in foodfish ponds than in fingerling ponds; however, this trend was not present in monthly box samples. B. havanensis was rarely collected and was only found consistently within one pond, while P. trivolvis was routinely collected from all ponds, although abundance varied widely among ponds. Snail traps could be a useful, low‐cost method to monitor snail populations within ponds and better inform control treatments. [ABSTRACT FROM AUTHOR]

The U.S. catfish industry has adopted several production practices which embody varying degrees of economic risk. Employing commercial farm data, this study quantified the economic risks associated with six catfish food fish production strategies. Stochastic Monte Carlo simulations employing established enterprise budgets found fish yield, feed price, and feed conversion ratio contributing highly to variations in the cost of production. While multiple-batch (MB) farming of channel catfish was the least risky strategy, both MB and intensively aerated production were stochastically dominant (second-order) to low-intensity single-batch production. Split-pond and intensively aerated hybrid catfish production demonstrated consistently lower production costs and were stochastically dominant (second-order) to medium-intensity single-batch production. Multiple-batch and intensively aerated production of channel catfish were more susceptible to price (market) risk while hybrid catfish production was more susceptible to yield (production) risks. First order stochastic dominance of split-pond technology on larger farms as compared to low-intensity culture on smaller farms suggested that yield increasing intensive production practices supersede low-intensity technologies and help achieve economies of scale. Study results provide critical information on the relative risk associated with different catfish production strategies under varying economic and market conditions. [ABSTRACT FROM AUTHOR]

The two gonadotropins, FSH and LH, stimulate growth and development of the gonads through gonadal biosynthesis of steroid hormones and growth factors. To date, cDNA sequences encoding gonadotropin subunits have been isolated and characterized from a large number of fish species. Recently, we successfully cloned and characterized gonadotropins (LHβ, FSHβ, and GPα) from the pituitary glands of the catfish, Heteropneustes fossilis. In the present study, we describe herein the production of recombinant stinging catfish, H. fossilis (hf) FSH (rhfFSH) and LH (rhfLH) using the methylotrophic yeast P. pastoris expression system. We further explored the hypothesis that the recombinant gonadotropins can modulate the hypothalamus-pituitary-ovarian (HPO) axis genes (avt, it, gnrh2, kiss2, and cyp19a1a) and regulate their transcriptional profile and steroid levels in relation to their annual developmental stage during preparatory and pre-spawning phases under in-vitro conditions. We found that the different concentrations of recombinant rhfFSH and rhfLH significantly stimulated E2 levels in the preparatory and prespawning season, and also upregulated gonadal aromatase gene expression in a dose dependent manner. Our results demonstrate that the yeast expression system produced biologically active recombinant catfish gonadotropins, enabling the study of their function in the catfish. [ABSTRACT FROM AUTHOR]

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Background: Soil salinity, soil infertility, and freshwater scarcity are among the major constraints affecting agricultural ecosystems in arid and semi-arid regions of the world. Hence, there is a need to look for salt-tolerant crops and fish that can be successfully cultivated and reared respectively in such harsh environments. The implementation of biosaline integrated aquaculture-agriculture systems (IAAS) utilizing both salt-tolerant crops and fish could improve food and feed production in arid and semi-arid regions. This study, therefore, investigated the influence of salinity on the biometric traits of striped catfish (Pangasianodon hypophthalmus) and barley (Hordeum vulgare) under an IAAS. Method: The experiment followed a randomized completely block design of three salinity treatments with three replicates namely, T0: Control (freshwater mixed with chemical fertilizers), T1: 5,000 ppm, T2: 10,000 ppm, and T3: 15,000 ppm. Results: Irrigating barley with saline aquaculture wastewater at different salinities (5,000 ppm, 10,000 ppm, and 15,000 ppm) did not significantly affect the agro-morphological parameters (internode number per plant, stalk diameter, leaf number per plant, leaf area index, and leaf chlorophyll content (SPAD)) of the plants at 90 days after sowing. Moreover, the forage yield and forage quality in terms of fiber fraction, nutrient composition, and in vitro digestibility of the forage biomass were not severely affected by high salinity compared to the control (freshwater and inorganic fertilizers). Our results also showed that rearing striped catfish in saline water not exceeding 10,000 ppm did not negatively impact the growth performance (final weight, body weight gain, feed conversion ratio, specific growth rate, condition factor, and survival) and the health status of the fish. Conclusions: The integration of striped catfish and barley production in water salinities below 15,000 ppm could be a feasible alternative in safeguarding food and feed security in regions affected by soil salinity, soil infertility, and freshwater scarcity. Moreover, the salinity regime of 5,000 ppm could bring higher economic gains to farmers regarding higher crop yields (fish and forage yield). [ABSTRACT FROM AUTHOR]

This study investigated histopathological changes in the liver and gills of C. gariepinus juveniles treated intermittently with different concentrations of prophylactics. Potassium permanganate (T2), Hydrogen peroxide (T3), and Formalin (T4) were used as prophylactics and administered to 15 fish each at concentrations of 2 ppm, 150 ppm, and 100 ppm respectively. The treatments which were in three replicates each with a control setup (T1) were repeated biweekly for 10 weeks. The histomacrographs of the liver and the gills show that there were no visible alterations in the structures of the tissues of fish in the control experiment (T1). However, major histopathological observations for the fish in T2, T3, and T4 were severe degeneration in the gill structure, fusion of the gill rakers, slight changes in the hepatocytes, and diffuse vacuolation of hepatocytes. Among the used chemicals, potassium permanganate appeared to have the least negative effects on the tissues and it is therefore recommended at 2 ppm for prophylactic treatment of fish against diseases. [ABSTRACT FROM AUTHOR]

Cost of fish production can be reduced by replacement of high-priced fishmeal (FM) with insects sourced ingredients. Four months feed experiment was conducted at a fish farm in Baringo County, Kenya to investigate effects of substituting fishmeal (FM) with black soldier fly larvae meal (BSFLM) on survival and growth performance of C. gariepinus under aquaponic system. Three test diets 35% crude protein content (CP) in which FM was substituted by BSFLM at 25%, 50% and 75% were formulated and experimented with commercial diet of 35% CP. Four weeks old C. gariepinus were stocked in 12 tanks at a density of 50 fish/tank and subjected to the diets. Fish were sampled every three weeks; water parameters were sampled weekly and mortality recorded on occurrence. Diet with 50% BSFLM obtained better FCR for formulated diets with no significance (P<0.05) for FCR and survival. Weight gain of control diet (97.07 g) was significant (P<0.05) compared to formulated diets 64.09g, 69.78g and 67.77g for 75%, 50% and 25% of BSFL replacement respectively. Growth performance and survival demonstrated that BSFLM has potential to substitute FM up to 75%. The fish productivity can be improved and feed cost reduced by incorporating fully defatted BSFLM with CP higher than 25.3% used for the diets. [ABSTRACT FROM AUTHOR]

Fish meat has great flavor, nutritional values, competitive lesser price. Fish meat comprises of minerals, vitamin, healthy fats, protein, and small amount carbohydrates, these constituents make the fish a good healthy diet and fish meat can be easily digested also. The demand for fish for human consumption is increasing. Fisheries and aquaculture play an important role in the improving human nutrition and food security. Fishes have more nutrition than plant-based food. Fishes are also more efficient from other animal food sources in converting food into nutritious food. Fish contributes important and healthy part of the human diet which contains good amount of protein, fats, vitamins and minerals, etc. Fish has a lot of food potential; therefore, fish can be used to overcome malnutrition in developing countries especially. Proximate composition is being utilized as an indicator for the quality of fish. Clarias batrachus (Linnaeus, 1758) the Asian catfish commonly known as walking catfish is a highly valued endemic to India which is now in severe decline in the majority of its natural habitat. Clarias batrachus is one of the important local food fish, this fish has been used in traditional medicine also. It possesses therapeutic significance and its demand is high, especially in North East India. Clarias batrachus contains high protein, vitamins and minerals and it is a rich source of poly unsaturated fatty acids (PUFA). [ABSTRACT FROM AUTHOR]

Freshwater rivers are considered the major route for microplastics (MPs), yet limited studies have been reported on MPs in freshwater river fish, especially in Bangladesh. This research reveals the intake of MPs by the giant river catfish Sperata seenghala, collected from the Meghna River, which is the only outlet of the Ganges-Brahmaputra River. Three locations, namely, Chandpur Sadar, Bhola Sadar, and Char Fasson, along the Meghna River, were selected in order to investigate the gastrointestinal tracts (GIT) of the fish. Ninety percent (n=27) of fish (n=30) were contaminated, with fragment-shaped MPs (65%) as the most abundant among the four types. A total of 179 MP particles were detected using micro-Fourier transformed infrared spectroscopy (μ-FTIR), with an average of 5.96 ± 1.32 MP particles per fish. Among the four size groups, the highest proportion of MPs (54%) occurred in the 45–100 μm group; the dominant color among the seven color groups was white (30%). The highest quantity of MPs was found in the relatively densely populated Chandpur Sadar region. Polypropylene-polyethylene copolymer (PP-PE, 23%) was proportionally dominant among the 15 types. No significant relationship was found between the total number of observed MPs and the GIT weight. This study will help us to understand MP pollution in S. seenghala that may transmit to the human body through the food chain. [ABSTRACT FROM AUTHOR]

(1) Background: Trichomycterinae represent 60% of the species in the family and, while seven genera comprise 1–3 species each, Trichomycterus and Cambeva have over 180 known species between them. Although integrative studies aimed to clarify the relationships within the subfamily, the diversity of species of Trichomycterus remains an open question. Herein, we explored an unprecedented sample to investigate the divergence in the lineages of Trichomycterus. (2) Methods: we recovered the phylogenetic relationships of the subfamily using 566 sequences (999 bp) of the mitochondrial gene cytochrome b, calculated intra- and intergroup distance percentages, and estimated divergence times. (3) Results: we recovered 13 highly supported and geographically structured lineages; intergenus divergence was 11–20%, while interspecies divergence was 3–11%; Trichomycterus, Cambeva, Scleronema, Hatcheria, Eremophilus, and Ituglanis were recovered as monophyletic, with three other highly divergent clades: Guiana Shield, Magdalena basin, and Tapajós basin. (4) Conclusions: We propose that the trans-Andean austral clades be allocated into Hatcheria, and the Guiana clade supports a new genus. We also observed that the headwaters nearest the Magdalena and Orinoco basins showed a high diversity and endemism of Trichomycterinae lineages. We discussed the role of geomorphological events and the climatic features which may explain cladogenesis events in Trichomycterinae. [ABSTRACT FROM AUTHOR]

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Imidacloprid, a systemic neonicotinoid insecticide widely used across the world, has been discovered in numerous freshwater bodies. There are vast information available on the effects of imidacloprid on freshwater fish. This study further assessed the effects of acute doses (0, 10, 30, 50 and 70 mg/L) of imidacloprid on behaviour, swimming, hepatic and thyroid parameters of African catfish (Clarias gariepinus) after 96 hours exposure. Imidacloprid caused significant behavioural alterations (gulping, abnormal surface distribution, under-reactivity, hypoactivity, reduced opercula activity and loss of buoyancy) in the fish. Reduction in swimming speed and distance travelled was observed in fish exposed to imidacloprid. The levels of amylase significantly increased, while alterations were also recorded in the levels of hepatic (ALT, AST, total and conjugate bilirubin and lipase) and thyroid (T3, T4 and TSH) biomarkers. The findings showed that imidacloprid has the potential to harm aquatic species, justifying restrictions on the use of imidacloprid-based pesticides especially near aquatic habitats. [ABSTRACT FROM AUTHOR]

The increasing demand for protein in Nigeria has resulted in the culture of many fishes in confinements. This practice has exposed many fish species to some tedious processes, thus the need to sedate fishes to reduce stress during breeding. In this study, the efficacy of two anesthetic agents (clove oil and sodium bicarbonate) was compared on the two most cultured species; Clarias gariepinus and Oreochromis niloticus. Clarias gariepinus (798.9 ± 0.07 g) and Oreochromis niloticus (581.8 ± 0.2 g) were subjected to different concentration of clove oil (mg/L) and sodium bicarbonate (g/L) of 20, 40, 60, 80, 100 and 10, 20, 30, 40, 50 respectively. There were significantly decreased induction times as concentrations and size of the species increases in all the anesthetic agents. Similarly, recovery times increases as concentrations and weight of the species increases (P<0.05). A significant correlation (P<0.05) was observed between body weight, anaesthetic concentrations, times to reach complete anesthesia and time to recover. Duration for induction and recovery depended significantly (p < 0.05) on the concentration of the anaesthetic agents. The lowest effective concentrations that induced complete anesthesia in this study were 20 mg/L (15.1 ± 0.8 mins and recovery time 4.2 ± 0.2 mins) for clove oil, 20 g/L (7.0 ± 0.12 mins and recovery time 7.0 ± 0.12 mins) for sodium bicarbonate. No mortality was recorded for all sizes of species exposed to the anaesthetic agents. Clove oil and Sodium bicarbonate have been found to be effective and safe at different concentrations for both species. [ABSTRACT FROM AUTHOR]

According to their toxicity, toxic heavy metals such as arsenic, mercury, cadmium, copper, zinc, and lead are believed to be the most harmful to humans, fish, and the environment. Because their levels are rising due to human activities endangering aquatic species and people, the current study sought to ascertain the level of toxic heavy metals in five catfish parts (skin, liver, muscles, gills, and ovaries). In the northern part of the Shatt Al-Arab, catfish samples were collected in March 2022. ICP-MS was used to detect target metal levels. According to the results, arsenic accumulated in the skin and muscles at a rate of 0.22 and 0.21ppm, respectively. In contrast, the levels of arsenic in the various body parts are not statistically different. Additionally, cadmium showed no noticeable variances in the studied body parts. Furthermore, the liver had the most significant copper accumulation 18.72ppm. Furthermore, mercury accumulation in various body parts was shown to vary statistically, with the highest levels in muscles 0.66ppm. In addition, zinc was accumulated in the body parts in the following sequence: gills, ovaries, liver, skin, and muscles, respectively, while in the following sequence: muscles, skin, gills, liver, and ovaries respectively in the lead. Moreover, there were no statistically significant differences in the quantity of zirconium that accumulated. According to the current study, the catfish’s body parts did not accumulate toxic heavy metals at high rates. This may be due to study area the environment and the mechanisms of treating these types of metals by catfish.

Background: Dry noodles are products made from wheat flour which are dried to a maximum moisture content of 10%. This study investigated on analysis preference between dried catfish noodles and yellow flour and determined the protein and water content.Methods: In an experimental completely randomized design using 3 treatments with different pumpkin flour substitutions, namely 5%, 7.5% and 10%, analysis preference between dried catfish noodles andyellow flour and a protein and water content analysis were undertaken according to the terms of the dry noodle quality requirements (SNI 8217-2015). The appearance, color, aroma, texture, flavor, overall appearance were also compared between dried catfish noodles and yellow flour.Results: The 10% pumpkin flour substitution showed the highest value for appearance, color, aroma, texture and overall acceptance; whereas the flavor was dominated by 5% pumpkin flour substitution. The test for the highest protein content and the lowest water content was in 7.5% pumpkin flour substitution. The higher the water content, the lower was the protein content. Based on the proximate test, protein content of dried catfish noodles ranged 12.95-15.47%; and the water content of dried catfish noodles ranged 9.49-12.60%.Conclusion: The 5% pumpkin flour substitution was preferably organoleptic, but the best water content was in 7.5% pumpkin flour substitution in accordance with the quality requirements for dry noodles (SNI 8217-2015). It is necessary to test acceptability of the product with variations in noodle processing techniques and differences in cooking recipes. Therefore, these finding can help the health authorities in nutritional plans.