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This study investigated the effects of dietary protein levels and feeding regimes on juvenile silver catfish (Rhamdia quelen) cultured in a biofloc technology (BFT) system. Over 60 days, fish were fed diets with either 32% or 36% crude protein (CP), with feeding frequencies of either 5 or 7 days per week. The results showed no significant differences in growth parameters across all diet groups. Fish fed a 36% CP diet exhibited higher protein content in both whole body and fillet, while those fed for 5 days weekly showed increased fat content. Biochemical analysis indicated higher ammonia levels in fish fed 32% CP diets, with increased glucose and cholesterol levels in those on 36% CP. Compared to those fed 7 days a week, fish fed for 5 days weekly exhibited decreased cholesterol levels and increased total plasmatic protein. Fish fed with a 36% protein diet exhibited higher levels of total protein and glucose in the liver, but lower AST values. In contrast, fish fed for 5 days a week had lower total liver protein but showed increased glycogen and ammonia levels in the liver tissue. Oxidative stress biomarkers displayed differences, particularly in the gills and liver, with higher lipid peroxidation in fish fed 32% CP. The study concludes that while reducing dietary protein levels and feeding frequency does not adversely affect growth, it influences body composition, biochemical parameters, and stress responses. [ABSTRACT FROM AUTHOR]

The current study tested the hypothesis that an increase in the ionic levels (Na+, Cl--, Ca2+, Mg2+, and K+) in the gastrointestinal tract (GIT), and hepatosomatic index (HSI), gonadosomatic index (GSI), and Fulton's condition factor (FCF) are associated with the reproduction period of silver catfish (Rhamdia quelen). So, we verified ionic levels of the fluid phase of the different portions of the GIT content, HSI, GSI, and FCF of silver catfish in different seasons in a dam in southern Brazil. The highest Na+ and Cl-- levels in GIT were found in spring. The stomach's Na+ and Cl-- values were lower than the other segments. The K+ and Ca2+ levels in GIT were higher in winter, except in the stomach, where the values increased in summer. The highest K+ levels were reported in the anterior intestine. The highest Ca2+ levels in winter and spring were reported in the anterior and mid-intestines. In summer, the Mg2+ levels in the intestine were lower. The values of GSI and FCF were higher in winter and spring, and those of HSI were higher in winter. In conclusion, ions in the GIT and HSI, GSI, and FCF were higher in the reproduction period (winter for spring). [ABSTRACT FROM AUTHOR]

In this study, twenty fresh African catfish (Clarias gariepinus) and silver catfish (Bagrus bayad) fillets as well as twenty frozen pangasius catfish (Pangasianodon hypophthalmus) fillets were collected from Egyptian local markets and retailers during 2021. Pangasius catfish fillets can be divided into two grades: white basa fillets (grade I, white colour) and red basa fillets (grade II, pale pink to red colour). This study aimed to assess the physical (colour and shear force), chemical (pH, TVB-N and TBARS) and sensory parameters of catfish fillet samples. The sensory attributes of raw catfish fillets were measured using a 9-point hedonic scale and these attributes include colour and appearance, odor, texture, and overall acceptability. The results of the proximate composition showed that the African catfish and silver catfish fillets had significantly lower moisture (76.12-76.94) and higher crude protein (17.19-17.24) and fat levels (3.35-4.12) compared to the frozen Pangasius catfish fillets. The total volatile basic nitrogen (TVB-N) ranged from 6.83 to 16.38 mg/100g, thiobarbituric acidreactive substances (TBARS) values ranged from 0.35 to 1.01 mg malonaldehyde/kg and pH ranged from 6.43 to 7.35. The TVB-N and TBARS values of examined catfish fillets were within acceptable limits. The African catfish fillets were darker and characterized by higher redness (a*) and lower yellowness (b*) values as well as higher shear force values (9.52 kgf/m3 ), while white basa fillet was the lowest darkness, less saturated with the red pigment (a*) and more saturated with the yellow component (b*) as well as lower shear values (2.17 kgf/m3 ) among the examined catfish fillets. African catfish and silver catfish fillets showed significantly higher sensory scores than the Pangasius catfish fillets. All the organoleptic properties of raw catfish fillets were above the rejection threshold score (≤4.0) In conclusion, catfish fillets were of superior quality and acceptable for human consumption. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Animal Science Biology & Bioeconomy is the property of University of Life Sciences in Lublin and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Microplastic ingestion was reported for common bottlenose dolphins (Tursiops truncatus) inhabiting Sarasota Bay, FL, USA, a community that also has prevalent exposure to plasticizers (i.e., phthalates) at concentrations higher than human reference populations. Exposure sources are currently unknown, but plastic-contaminated prey could be a vector. To explore the potential for trophic exposure, prey fish muscle and gastrointestinal tract (GIT) tissues and contents were screened for suspected microplastics, and particle properties (e.g., color, shape, surface texture) were compared with those observed in gastric samples from free-ranging dolphins. Twenty-nine fish across four species (hardhead catfish, Ariopsis felis; pigfish, Orthopristis chrysoptera; pinfish, Lagodon rhomboides; and Gulf toadfish, Opsanus beta) were collected from Sarasota Bay during September 2022. Overall, 97% of fish (n = 28) had suspected microplastics, and GIT abundance was higher than muscle. Fish and dolphin samples contained fibers and films; however, foams were common in dolphin samples and not observed in fish. Suspected tire wear particles (TWPs) were not in dolphin samples, but 23.1% and 32.0% of fish muscle and GIT samples, respectively, contained at least one suspected TWP. While some similarities in particles were shared between dolphins and fish, small sample sizes and incongruent findings for foams and TWPs suggest further investigation is warranted to understand trophic transfer potential. [ABSTRACT FROM AUTHOR]

A feeding trial was performed to evaluate the effects of dietary L-threonine supplementation on growth and body composition of fingerlings Rhamdia quelen (initial weight: 4.47 ± 0.39 g). Five diets (370 g/kg crude protein and 14.23 MJ / kg of digestible energy) containing levels of L-threonine (16.0, 22.0, 28.0, 34.0, 40.0 g threonine/kg protein) were fed to quadruplicate groups of fishes for 10 weeks. The analysed variables were influenced by the threonine levels. Fish fed with diet containing 16.0 g threonine/kg of CP showed lower growth and body deposition of nutrients. In addition to unsatisfactory performance, the fish subjected to lower levels of threonine presented higher hepatosomatic index scores and changes in the concentrations of some plasmatic metabolites. To determine the ideal level of threonine in the diet, the weight gain, specific growth rate and feed conversion ratio were subjected to broken-line and quadratic regression. The results showed indicate that a diet containing inadequate levels of threonine causes insufficient growth. Dietary threonine requirement of R. quelen was estimated between 24.5 and 32.5 g threonine/ kg of crude dietary protein, corresponding to 9.1 and 12.0 g/ kg threonine in the diet for the initial growth of silver catfish. [ABSTRACT FROM AUTHOR]

Simple Summary: This study aimed to identify the regions of the skin of a South American catfish with a higher number of mucous cells. Additionally, the effects of stressful conditions that may occur in fish cultures, such as different stocking densities and food deprivation, on the number of mucous cells in the skin and gills and their impact on cutaneous mucous lysozyme activity were investigated. The sampled catfish were exposed to the conditions of high stocking density (32 kg/m3) and fed, high stocking density and fasted, low stocking density (2.5 kg/m3) and fed, and low stocking density and fasted. After 14 days, samples of cutaneous mucous and skin fragments from seven different points and the second left branchial arch were collected. The ventral point in front of the ventral fin was the portion with the highest number of mucous cells. The number of mucous cells in both the skin and gills varied based on the collection point and treatment applied. The highest lysozyme activity in the epidermal mucous was observed in fish exposed to high stocking density and fed. Stocking density and food deprivation create stressful conditions for this type of catfish, which modulate its mucosal response in the skin to each situation. This study aimed to identify the regions of the body surface of silver catfish (Rhamdia quelen) with a higher population of mucous cells in the skin. Additionally, the effects of stressful conditions, such as different stocking densities and food deprivation, on the proliferative response of mucous cells in the skin and gill epithelium and their impact on cutaneous mucous lysozyme activity were investigated. Silver catfish were divided into four experimental groups: high stocking density (32 kg/m3) and fed (HSD-F), high stocking density and fasted (HSD-FS), low stocking density (2.5 kg/m3) and fed (LSD-F), and low stocking density and fasted (LSD-FS). Fish in the fed groups received commercial feed twice a day, amounting to 1% of the tank biomass. After a 14-day experimental period, the fish were anesthetized and euthanized. Samples of cutaneous mucous and skin fragments from seven different points and the second left branchial arch were collected. Histological slides of the skin and gills were stained with PAS + Alcian Blue at pH 2.5, and the epidermal mucous lysozyme activity was assessed using the turbidimetric method. The ventral point in front of the ventral fin was found to be the optimal location for collecting cutaneous epithelia due to its higher density of mucous cells. The population of mucous cells in both the skin and gills varied based on the collection point and treatment applied. The highest lysozyme activity in the epidermal mucous was observed in fish from the HSD-F group. Overall, these findings suggest that stocking density and food deprivation create stressful conditions for silver catfish, which modulate their mucosal response to each situation. [ABSTRACT FROM AUTHOR]

A better understanding of trophic interactions between hardhead catfish (Ariopsis felis) and gafftopsail catfish (Bagre marinus) is crucial for developing multi-species management strategies for the northern Gulf of Mexico (GOM). These two species are often aggregated in food web models; however, limited data are available to substantiate this approach. Therefore, the present study aimed to describe the dietary habits of hardhead catfish and gafftopsail catfish using analysis of stomach contents aided by DNA barcoding. Hardhead (n = 693) and gafftopsail (n = 655) catfish were sampled in the northern GOM from 2015–2019 using both fisheries-dependent and -independent techniques. The average percent number (%N), average percent mass (%M), prey specific number (%PN), prey specific mass (%PM), and prey-specific index of relative importance (%PSIRI) were computed to quantify prey species. The stomach content analysis identified distinct differences in diet between hardhead and gafftopsail catfish. Crustaceans were the most important prey for hardhead catfish, while gafftopsail catfish showed a significantly broader dietary breadth and were primarily piscivorous. Multivariate analyses indicated that the location of capture explained the greatest amount of diet variability for both species. These findings address fundamental knowledge gaps regarding the dietary habits of hardhead and gafftopsail catfish in northern GOM ecosystems. [ABSTRACT FROM AUTHOR]

Simple Summary: Increased intensification of the fish farming system requires care in production due to induced stress conditions, which contribute to the occurrence of infectious diseases. In this research, we evaluated how dietary supplementation with R-(+)-limonene, a compound found abundantly in essential oils from plants such as lemon and orange, affects growth, plasma and liver metabolic parameters, and antioxidant and stress responses in silver catfish, Rhamdia quelen, challenged or not with Aeromonas hydrophila. Dietary R-(+)-limonene (L0.5, L1.0, and L2.0 mL/kg of diet) improved the productive performance of fish and increased the expression of insulin growth factor 1 gene, which is related to growth. The metabolic responses indicated that the additive in the feed was not harmful to the health of the animals and increased resistance to A. hydrophila. R-(+)-limonene did not cause damage to the liver and exhibited a hepatoprotective effect against A. hydrophila. The expression of stress-related genes decreased with R-(+)-limonene dietary supplementation. R-(+)-limonene is a monoterpene from plants of the genus Citrus with diverse biological properties. This research evaluated the effects of dietary supplementation with R-(+)-limonene on growth, metabolic parameters in plasma and liver, and the antioxidant and stress responses in silver catfish, Rhamdia quelen, challenged or not with Aeromonas hydrophila. Fish were fed for 67 days with different doses of R-(+)-limonene in the diet (control 0.0, L0.5, L1.0, and L2.0 mL/kg of diet). On the 60th day, a challenge with A. hydrophila was performed. R-(+)-limonene in the diet potentiated the productive performance of the fish. The metabolic and antioxidant responses indicate that R-(+)-limonene did not harm the health of the animals and made them more resistant to the bacterial challenge. Histological findings showed the hepatoprotective effect of dietary R-(+)-limonene against A. hydrophila. Igf1 mRNA levels were upregulated in the liver of fish fed with an L2.0 diet but downregulated with bacterial challenge. The expression levels of crh mRNA were higher in the brains of fish fed with the L2.0 diet. However, the L2.0 diet downregulated crh and hspa12a mRNA expression in the brains of infected fish. In conclusion, the results indicated that R-(+)-limonene can be considered a good dietary supplement for silver catfish. [ABSTRACT FROM AUTHOR]

The Silver catfish, Chrysichthys nigrodigitatus is of major economic importance in Nigeria. This species has been harvested for decades; however, the inability to spawn in captivity and the availability of fry is still a limiting factor in aquaculture of the species. Thus, it has been subjected to over-harvesting and posing a threat to the population in many water bodies. The aim of this research was to study the knowledge and practice of Chrysichthys nigrodigitatus fishery of the New Calabar River and discuss the implications for conservation. We carried out a survey of fishermen and the fishery characteristics of C. nigrodigitatus of the New Calabar River using questionnaires containing closed-ended items, direct observations, and interviews. The results indicate that the fishing of the species was dominated by males, as it was an all-male affair. Additionally, the average household size was 5.57±persons. The fishermen identified two species of Chrysichthys in the river. The drum trapping was the most practiced method of fishing, and the fishery was unregulated. The fishermen demonstrated good knowledge of the breeding characteristics of the species which was the reason the fish could be easily trapped in drums. The adoption of drum trapping is going to be essential in developing captive breeding of the species because it is noninvasive. [ABSTRACT FROM AUTHOR]

Oil extracted from fish waste could be a source of valuable fatty acids such as saturated (SFAs), monounsaturated (MUFAs), and polyunsaturated fatty acids (PUFAs). In this study, the solid fat from silver catfish (Pangasianodon hypophthalmus) waste was used to extract oil by centrifugation using different extraction solvent (distilled water, 70% ethanol, 70% acetone and 70% cyclohexane), rotation time (15, 25, 35 & 45 min), rotational speed (2000, 4000, 6000, 8000 & 10000 r.p.m) and rotational temperature (5, 10, 15, 20 & 25 °C). The compositions of fatty acids in the extracted oil were determined by gas chromatography-mass spectrometry (GC-MS) analysis. The highest oil yield of 156.7 ± 16.7 mg/g was achieved by centrifugation at 10000 r.p.m, 25 °C for 15 min using 70% acetone. The extracted oil contains 0.0223 mg/g palmitic acid, 0.0216 mg/g steric acid, and 0.0262 mg/g oleic acid. However, the essential PUFAs such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) could not be detected by GC-MS analysis. This study found that the fish oil extracted from the solid fat of the silver catfish waste can be used as a potential source of palmitic acid, stearic acid, and oleic acid. [ABSTRACT FROM AUTHOR]

In brief: The containers used in cell cryopreservation are essential to maintain cell integrity and viability after thawing. This paper reveals the methodology of using biodegradable containers for fish sperm cryopreservation. Cryopreserved sperm in biodegradable containers showed high fertility capability. Biodegradable capsules could be alternative containers to plastic straws for sperm cryopreservation. Containers used to cryopreserve sperm are made with non-biodegradable plastic compounds, having a high monetary and environmental cost. Therefore, the development of biodegradable alternative containers for cell cryopreservation is necessary. Thus, this study aimed to evaluate the efficiency of hard-gelatin and hard-hydroxypropyl methylcellulose (HPMC) capsules as low-cost and biodegradable alternative containers for sperm cryopreservation. Sperm from 12South American silver catfish Rhamdia quelen were individually cryopreserved in plastic straws 0.25 mL (as control), hard-gelatin, and hard-HPMC capsules. The quality of post-thaw sperm cryopreserved in the different containers was checked by measuring spermatozoa membrane integrity, kinetic parameters, mitochondrial activity, fertilization, hatching, and normal larvae rates. The samples cryopreserved in straws showed a higher percentage of membrane integrity (68%) than those frozen in hard-gelatin (40%) and hard-HPMC capsules (40%). However, we did not observe differences between the samples stored in straws and hard capsules for the rest of the tested sperm parameters. Thus, based on the high sperm fertility capability, both capsules were efficient as cryopreservation containers for maintaining sperm functionality. [ABSTRACT FROM AUTHOR]

Copyright of Avances is the property of Instituto de Informacion Cientifica y Tecnologica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study was to determine the biological effects of dietary supplementation with 0.05% and 0.1% cinnamon essential oil extracted from Cinnamomum cassia on silver catfish (Rhamdia quelen). The final body weight, weight gain, and specific growth rate were significantly higher in fish supplemented with 0.05% cinnamon essential oil than in the control(untreated) group. Muscle reactive oxygen species and lipid peroxidation levels were significantly lower in fish supplemented with 0.05% cinnamon essential oil but higher at the 0.1% concentration. Muscle antioxidant capacity against peroxyl radicals (ACAP) and superoxide dismutase activity were significantly higher in fish supplemented with 0.05% cinnamon essential oil, while ACAP levels were lower in fish supplemented with 0.1%. The total saturated fatty acid content was significantly higher in the muscle of supplemented fish than in controls, while the total monounsaturated fatty acid content was significantly higher only in fish fed 0.1% cinnamon essential oil. Finally, the total content of polyunsaturated fatty acids was significantly lower in fish fed 0.1% essential oil. Thus, data demonstrated that 0.05% C. cassia essential oil improves fish health by improving performance and muscle oxidant/antioxidant status. Higher doses of cinnamon essential oil produced oxidative stress in muscle, suggesting toxicity at the 0.1% level. Although this cinnamon essential oil diet exerted positive health effects, this diet impaired the muscle fatty acid profile, suggesting adverse impacts on human health. [ABSTRACT FROM AUTHOR]

The current study aimed to determine the effects of extraction time on the extractability and physicochemical properties of collagen from the skin of silver catfish (Pangasius sp.). Pepsin soluble collagen (PSC) was extracted for 24 and 48 h and analysed in terms of chemical composition, solubility, functional group, microstructure, and rheological properties. The yields of PSC at 24 h and 48 h extraction time were 23.64% and 26.43%, respectively. The chemical composition exhibited significant differences, with PSC extracted at 24 h showing better moisture, protein, fat, and ash content. Both collagen extractions indicated the highest solubility at pH 5. In addition, both collagen extractions exhibited Amide A, I, II, and III as fingerprint regions for collagen structure. The morphology of the extracted collagen appeared porous with a fibril structure. The dynamic viscoelastic measurements of complex viscosity (η*) and loss tangent (tan δ) decreased as temperature increased, and the viscosity increased exponentially as the frequency increased, whereas the loss tangent decreased. In conclusion, PSC extracted at 24 h showed similar extractability to that extracted at 48 h but with a better chemical composition and shorter extraction time. Therefore, 24 h is the best extraction time for PSC from silver catfish skin. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are mistakenly consumed by people through their diet, including food and water. The occurrence, source, and health hazards of 16 PAHs in 36 tilapia (Sarotherodon melanotheron) and silver catfish (Chrysichthys nigrodigitatus) samples from Okulu River, Nigeria were investigated in this study. The total PAH concentration ranged from 11.70–24.20 to 13.40–19.60 µg/kg, being statistically different between the two species. The values were higher than the European Commission limits of 12 µg/kg and within the World Health Organization limit of 20 µg/kg. The 16 PAHs were detected in both fish species. The diagnostic ratio revealed that petroleum, fossil fuel, and incomplete combustion of biomass wastes were the sources of PAHs in the fishes. Pearson's correlation showed that the PAHs can come from diverse sources. The non-carcinogenic risk quotients (HQs) and hazard index (HI) in both fish species were 1, an indication of no adverse health effects. Among the 9 PAHs that were used to calculate the HI, BaP and BgP accounted for 31% and 62%, respectively, for Chrysichthys nigrodigitatus, and 25% and 69%, respectively, for Sarotherodon melanotheron. The carcinogenic hazard of the 7 PAHs assessed was within the acceptable range of 10−6–10−4. But the sum of the carcinogenic hazard was on the order of 10−3 in both species of fish, an indication of carcinogenic health effects. 79% and 75% of the total carcinogenic risk for Chrysichthys nigrodigitatus and Sarotherodon melanotheron, respectively, are from DaA and InP. The consumption of PAHs by residents of the study area and other population groups through fish foods from the studied river underlines the importance of checking PAHs in aquatic foods for health concerns on a frequent basis. [ABSTRACT FROM AUTHOR]

A better understanding of trophic interactions between hardhead catfish (Ariopsis felis) and gafftopsail catfish (Bagre marinus) is crucial for developing multi-species management strategies for the northern Gulf of Mexico (GOM). These two species are often aggregated in food web models; however, limited data are available to substantiate this approach. Therefore, the present study aimed to describe the dietary habits of hardhead catfish and gafftopsail catfish using analysis of stomach contents aided by DNA barcoding. Hardhead (n = 693) and gafftopsail (n = 655) catfish were sampled in the northern GOM from 2015–2019 using both fisheries-dependent and -independent techniques. The average percent number (%N), average percent mass (%M), prey specific number (%PN), prey specific mass (%PM), and prey-specific index of relative importance (%PSIRI) were computed to quantify prey species. The stomach content analysis identified distinct differences in diet between hardhead and gafftopsail catfish. Crustaceans were the most important prey for hardhead catfish, while gafftopsail catfish showed a significantly broader dietary breadth and were primarily piscivorous. Multivariate analyses indicated that the location of capture explained the greatest amount of diet variability for both species. These findings address fundamental knowledge gaps regarding the dietary habits of hardhead and gafftopsail catfish in northern GOM ecosystems.

Exposure to acidic and alkaline pHs results in an ionic imbalance. Cellular responses involved in osmoregulation in silver catfish exposed to different pHs (5.5, 7.5, and 9.0) for 24 h were evaluated. The gills and kidney were collected to measure Na+/K+-ATPase (NKA) and H+-ATPase (V-ATPase) activities and to evaluate the expression of ion transporter-related genes: NKA (atp1a1), H+-ATPases (atp6v0a1b, atp6v0a2a, atp6v0a2b), Na+/H+ antiporter (slc9a3), K+/Cl− symporters (slc12a4, slc12a6, slc12a7a, slc12a7b), Na+/K+/2Cl− symporter (slc12a2), and ammonium transporter Rh type b (rhbg). The gills presented greater responses to pH changes than the kidney. The pH alterations changed the atp1a1 gene expression and NKA activity, whereas the H+-ATPase activity increased in the gills in alkaline water, probably to maintain ionic balance. The slc9a3 and slc12a2 genes play more prominent roles in the ion uptake at acidic pH than H+-ATPase. The slc12a7a was the only isoform of this transporter affected by pH. The rhbg is apparently related to ammonia excretion through the gills and kidney (minor scale). Exposure to alkaline pH seems to be battled by impairment of NKA and H+-ATPase activities in the gills, whereas the expression of some ion transporters in silver catfish changes during both acidic and alkaline pHs. [ABSTRACT FROM AUTHOR]

Bycatch remains a challenging issue for many fisheries across the globe. Due to the cost and effort of (bycatch) observer programs, many fisheries—particularly those not in U.S. federal waters—operate with little information about bycatch. The Black Drum Pogonias cromis and Sheepshead Archosargus probatocephalus fishery in Louisiana comprises one of the largest fisheries by volume and in recent years has exceeded US$5 million in annual value. The vast majority of Black Drum and Sheepshead are harvested by the baited trotline fishery that operates in state waters. Very little is known about the bycatch from this fishery; however, because of the magnitude of the fishery quantifying bycatch is needed for the management of this resource. We observed 59 baited trotline sets on 13 different dates spanning 2 years of sampling (2020–2021). The total bycatch (n = 1,392) was similar in number to the harvest of the target species (n = 1,265). However, most bycatch species were nongame fishes and were released alive. Of all the bycatch caught, only 4% was dead and the majority of that 4% (47 out of 57 fish) consisted of Gafftopsail Catfish Bagre marinus and Hardhead Catfish Ariopsis felis, both species for which there is little fishery and no known issues with the populations. We also found that catch rates for bycatch did not vary by season or between the two areas fished. The catch rate of bycatch did not increase as the catch rate of target species increased; although, as expected, bycatch mortality did significantly increase as water temperature increased. Overall, the baited trotline fishery for Black Drum and Sheepshead catches about one individual of bycatch for one target individual; however, the overall extremely low bycatch mortality (of common species) suggests that this fishery operates with few adverse effects on nontarget species. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate seminal and sperm production, growth, health, and lipid metabolism of male silver catfish (Rhamdia quelen) fed diets containing l -carnitine and varying lipid sources. Herein, males and females (167.33 ± 9.24 g) were both fed across 223 d with eight (08) isoproteic (282 g of digestible protein kg of ration −1) and isoenergetic (13.34 MJ of digestible energy kg of ration −1) diets, containing 0.00, 0.15, 0.45, and 0.75 g l -carnitine kg −1 of feed, soybean, and marine fish oils. Feeding males with diets containing l -carnitine and different oils resulted in an interactive effect (p < 0.05) that improved sperm production. Furthermore, males fed soybean oil and 0.45 g l -carnitine kg −1 had the highest seminal pH and sperm velocities. Fish fed fish oil and 0.75 g l -carnitine kg−1 had the highest gonadosomatic indexes, sperm production, and superoxide dismutase activities recorded in the testes. The testes of these fish also showed increases in docosahexaenoic acid (DHA), polyunsaturated fatty acids (PUFAs), n-3 fatty acids, and higher n-3: n-6 ratios. The individual effect of oils produced viscera with more (p < 0.05) fat, in addition to having higher (p < 0.05) blood levels of albumin, total cholesterol, triglycerides, alongside the lowest level of aspartate aminotransferase in fish fed marine fish oil. The individual effect of l -carnitine also produced muscles with less (p < 0.05) fat, in addition to the highest (p < 0.05) amount of total cholesterol with the lowest amount of high-density lipoprotein (HDL) cholesterol in the blood of fish fed with 0.75 g l -carnitine kg−1. l -carnitine and oils in the diets promoted hepatic and testicular protection whilst regulating lipid metabolism and fatty acid profile in the liver and testes of silver catfish (Rhamdia quelen) males. These benefits led to greater sperm production when fish oil and 0.75 g kg −1 were used, and faster spermatozoa with soybean oil and 0.45 g kg −1. • Diets with 0.75 g kg−1 l -carnitine and fish oil improved the Rhamdia sperm production. • Rations with l -carnitine and fish oil increased PUFAs deposition in Rhamdia testes. • Dietary l -carnitine and fish oil improved the antioxidant status of Rhamdia testes. • Lipid metabolism of Rhamdia male were regulated by dietary l -carnitine and oil source. [ABSTRACT FROM AUTHOR]

Background: Metal pollution is a problem in many parts of the world. These metals can be harmful when they exceed the recommended limits. By analyzing metal concentrations in living organisms, it is possible to deduce the bioavailability and the level of environmental contamination for specific metals in an ecosystem. The aim of this study was to determine the heavy metals copper, cadmium, lead, nickel and mercury in edible tissues of fish, to establish the risk analysis for human health. There are currently no studies in this area indicating these factors. Methods: The edible tissue samples were treated under the techniques of the official mexican standards (NOM-117-SSA1) and analyzed using atomic absorption spectroscopy (flame and graphite). The heavy metal concentrations were used to calculate the estimated daily intakes, target hazard quotients, hazard indices, and target cancer risks for children and adults. Results: The highest concentrations of copper (138.82 µg/g), cadmium (1.28 µg/g) and lead (3.20 µg/g) in the edible tissue samples exceeded the permissible limits considered in this study while nickel and mercury levels did not. The target hazard quotient indices for copper, cadmium and nickel in specific sites were higher than the United States Environmental Protection Agency (US-EPA) criteria (>1), while the values for mercury and lead were below one. The hazard indices were higher than the US-EPA criteria (>1) in more than 50% of the sites analyzed. Conclusion: This study is an alert, indicating that inhabitants who consume the fish, particularly children, are at risk of cadmium, lead and nickel toxicity. [ABSTRACT FROM AUTHOR]

Cinnamon essential oils (EOs) are widely known for their pharmaceutical properties; however, studies investigating the use of these EOs in aquaculture are scarce. The aims of this study were to evaluate the anesthetic effect of bathing silver catfish (Rhamdia quelen) with Cinnamomum cassia EO (CCEO) and its nanoemulsion (NCCEO); the growth-promoting and antioxidant effects of dietary supplementation with CCEO in silver catfish; and the in vitro antibacterial effect of CCEO, NCCEO, and Cinnamomum zeylanicum EO (CZEO) against bacteria isolated from diseased silver catfish. The two cinnamon EOs showed promising antibacterial activity, which was potentiated by the nanoemulsion. CCEO showed satisfactory anesthetic activity in silver catfish, and its nanoemulsion intensified the sedative activity. Supplementation of 1.0 mL CCEO per kg of diet for 60 days increased weight, length, and weight gain when compared to the control group, evidencing the growth-promoting activity of this EO. Dietary supplementation of CCEO for 30 and 60 days also showed an antioxidant effect, as it decreased levels of thiobarbituric acid reactive species and increased the superoxide dismutase activity in the liver of silver catfish. Therefore, cinnamon EOs have a promising use in aquaculture. [ABSTRACT FROM AUTHOR]

The aim of the present study was to assess the effects of crude biodiesel‐derived glycerol on the zootechnical performance, carcass and fillet chemical composition, and blood parameters of silver catfish (Rhamdia quelen) during the fattening phase. A total of 150 adult silver catfish specimens (mean weight 188.89 ± 0.60 g) were distributed in thirty 1000 L‐tanks containing a water recirculation system with mechanical filter and biofilter, in a completely randomized design comprising six treatments, 0%, 20%, 40%, 60%, 80% and 100% maize replacement by glycerol, with five repetitions each. The experiment was conducted for 206 days. Silver catfish morphometric parameters were not influenced (p > 0.05) by the glycerol maize replacement, although silver catfish standard length and width exhibited linear improvements (p < 0.05) with the dietary glycerol replacement. Fillet yield was affected (p < 0.05) by glycerol maize replacement, where the 80% replacement treatment led to better fillet yields (46.04%), differing only from the 20% replacement treatment (42.40% fillet yields). The blood plasma levels of glucose, pyruvic glutamic transaminase and triglycerides were influenced by the treatments (p < 0.05). The crude protein of fillet was influenced by the treatments (p < 0.05), where the highest value was observed in 100% glycerol maize replacement. Therefore, crude glycerol derived from biodiesel production is a suitable alternative energy source ingredient for silver catfish during their fattening phase, as it can replace maize in up to 100%. [ABSTRACT FROM AUTHOR]

Two species of marine catfishes (family: Ariidae) are abundant within the Apalachicola Bay System for much of the year. They function as 2nd and 3rd order consumers and as prey for top predators. Males perform oral incubation, a trait of most ariid catfish species, and thus, unique considerations may be factored into conservation efforts. The purpose of this study was to reveal trends in catfish abundance and spatial distributions and identify the abiotic factors associated with these patterns. Data from fifteen years of monthly fishery-independent monitoring surveys performed by the Florida Fish and Wildlife Conservation Commission were used to examine catch per unit effort and an optimized hot spot analysis was used to observe spatial distributions. Boosted regression tree models were used to examine the relationship between abiotic factors and catfish abundance and movement. Both species co-occurred with overlapping distributions throughout most of the year and were most abundant prior to and during the spawning season in May through August. Hardhead catfish (Ariopsis felis Linnaeus) were much more abundant than gafftopsail catfish (Bagre marinus Mitchill) throughout the study. A migration event was observed for both gafftopsail catfish and hardhead catfish, likely in response to temperature changes. Boosted regression tree models revealed that salinity and water clarity were mainly influencing hardhead catfish distributions with temperature also being relevant throughout much of the year. Salinity was less influential for gafftopsail catfish which were mostly affected by water clarity and temperature. These results differ from observations of ariid catfish in tropical ecosystems in which ariid distributions are segregated and migration events occur twice a year and are salinity driven. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the toxicity of tucumã oil nanocapsules from the Amazon region in silver catfish, Rhamdia quelen. Fish were exposed to water treated with different concentrations of tucumã nanocapsules, white, solubilized oil and surfactant vehicles. After three days of exposure, fish were euthanized and liver, gills and brain removed for analysis of the dichlorofluorescein, nitric oxide and PicoGreen® assays. Plasma was collected for assay of hepatic transaminases. The nanocapsules had a diameter of 221 ± 1.27 nm, confirmed by atomic force microscopy. The oil nanocapsules were not toxic to this species of fish, but white nanocapsules and surfactant increased the levels of reactive oxygen species. Thus, nanocapsules are promising for the transport of tucumã oil. In view of the anti-inflammatory properties of this oil, it is possible to envisage its application in skin diseases for example, since they present essentially inflammatory conditions. The most abundant carotenoid in tucumã oil was all-trans-beta-carotene. Nanocapsules are good carriers for tucumã oil. Tucumã oil nanocapsules does nothas toxicity effect in catfish. [ABSTRACT FROM AUTHOR]

The objective of the study was to evaluate the partial replacement of the protein of fish meal by the protein from the intermediate residue of rice ethanol distilleries in the proportions of 0%, 25%, and 50% in Rhamdia quelen. Three hundred and seventy-five fish (3.56 ± 0.6 g/7.07 ± 0.46 cm) were distributed in 15 tanks and fed three times a day for 60 days. At the end of the period, biometrics were performed to collect data and tissues, evaluating growth parameters, sonatic indices, digestive enzyme activity, plasma and hepatic metabolism, body nutrient composition, protein, and fat deposition. Fish fed the control diet showed higher feed intake (765.86 ± 53.86 g). The 50% replacement diet reduced final growth (14.27 ± 3.88 g), deposition of body protein (1.63 ± 0.05 g) and increased free liver amino acids (8.72 ± 0.41). The use of intermediate residue from rice ethanol distilleries in silver catfish diets was inefficient, requiring further studies to evaluate the protein quality of this ingredient. [ABSTRACT FROM AUTHOR]

To verify the efficacy of citral in inducing sedation and anesthesia in silver catfish (Rhamdia quelen) and grass carp (Ctenopharyngodon idella) and to assess the safety of essential oil (EO) of Aloysia citriodora and citral in inducing and maintaining anesthesia in silver catfish. Clinical study, randomized, parallel, multi-arm with control group in target species. A total of 96 juvenile and 72 adult silver catfish and 80 juvenile grass carp were used. Silver catfish and grass carp were exposed to different concentrations of citral, 15–675 and 15–600 μL L–1, respectively, during the maximum period of 30 minutes to verify sedation and anesthesia induction and recovery times. In addition, for anesthetic induction, silver catfish were exposed to the EO of A. citriodora and citral at 225 μL L–1 for 3.5 minutes. Then, fish were transferred to an anesthesia maintenance solution at 50 μL L–1 for 10 minutes to assess hematologic and biochemical variables at 60 minutes, 2 and 6 days after treatment. Citral only induced sedation from 15, 25 and 40 μLL–1 in both species. Anesthesia without mortality was induced in silver catfish at 50–600 μL L–1 and grass carp at 75–450 μL L–1. At 675 and 600 μL L–1, mortality was recorded in silver catfish and grass carp, respectively. The EO of A. citriodora and citral were safe in inducing and maintaining anesthesia in silver catfish, with mean corpuscular hemoglobin concentration being the only variable that varied in relation to time and treatments. Citral was effective in inducing sedation and anesthesia in both species. In addition, A. citriodora EO and citral were safe in inducing and maintaining anesthesia in silver catfish. Both agents are promising substances for the development of new drugs for fish. [ABSTRACT FROM AUTHOR]

Muscular growth in fish is influenced by diet quality, mainly the protein sources and amino acids balance. A feeding trial was conducted for a period of 28 days. Muscle growth and histology of Silver catfish post-larvae was evaluated. The diets tested were partial and total replacement of broiler liver by fish meal and soybean protein concentrate (basal, 15FM, 30FM, 15SPC and 30SPC). The basal diet consisted mainly of fresh poultry liver plus sugarcane yeast. After the feeding test, the fish fed with 15FM diet presented higher growth (P < 0.05) than the post-larvae fed with the other diets. The muscle development was performed in post-larvae-fed diets 15FM and 30SPC. Higher diameter and total number of fibres were found in fish fed diet 15FM diet (P < 0.05). The replacement of 50% of the broiler liver by fishmeal provided a good diet for Rhamdia quelen post-larvae. [ABSTRACT FROM AUTHOR]

Aquaculture handling requires fast anaesthesia, assuming an action‐time within 3 min and a recovery time of <5 min. This study aimed to determine the lowest effective concentration (LEC) of eucalyptus (Eucalyptus globulus) essential oil (EEO) administered to Rhamdia quelen and its anaesthetic effects. Analysis of EEO chemical profile showed 1,8‐cineole as the main component. Two assays were then carried out. In the first, four concentrations were tested (600, 650, 700 and 750 µl L−1). EEO was found to be an effective anaesthetic in R. quelen with LEC of 700 µl L−1. During this assay, no fish mortality occurred. The second assay evaluated stress. Fish were divided into three groups: control (baseline values, without anaesthetic); eugenol (50 mg L−1) and EEO (700 µl L−1). In this assay, EEO also inhibited the primary stress response. While cortisol did not increase in the EEO regime, plasma glucose and lactate levels did increase in blood. Meanwhile, eugenol kept all stress indicators equal to those of the control group. Therefore, although EEO has suitable anaesthetic characteristics, it should be used with caution, as it does not prevent changes in plasma glucose and lactate for R. quelen. [ABSTRACT FROM AUTHOR]

The aim of the current study is to investigate whether silver catfish (Rhamdia quelen) individuals exposed to commercial formulation of the chlorantraniliprole insecticide used in rice crops present changes in biochemical parameters. Fifty-four (54) silver catfish individuals were distributed in six units per tank (n = 6/repetition; triplicate/treatment) and subjected to the following treatments: T1—control, without insecticide; T2 (0.02 µg/L of insecticide) and T3 (0.20 µg/L of insecticide). Exposure time lasted 24 or 96 h, and it was followed by 96 h recovery in pesticide-free water. Results have indicated biochemical changes in cortisol, glucose, lactate and plasma protein levels, as well as few ionic changes in animals' gills during the exposure and recovery periods. Chlorantraniliprole incidence in water resulted in some biochemical changes in silver catfish specimens' plasma and gills throughout the acute exposure protocol (sub-lethal dose). Thus, chlorantraniliprole insecticide has caused osmoregulatory and/or biochemical imbalance in the investigated species under the herein adopted laboratory conditions; these changes did not get back to normal levels even after specimens were left to recover for 96 h in clean water. [ABSTRACT FROM AUTHOR]

There is growing interest for using essential oils (EOs) in fish feed as they can improve fish health, growth, and productive yield. But, there is little information concerning their effects on fish flesh quality and whether EO residues can be found in flesh. The EO of lemongrass was recently demonstrated to increase the productive yield of silver catfish. Thus, the aim of this study was to evaluate the impact of lemongrass EO supplementation on physico-chemical properties, sensory acceptance, and stability during frozen storage of fish fillets. Silver catfish (Rhamdia quelen) were fed diets containing 0, 1, or 3 mL/kg of EO for 20 days. Fish were slaughtered, and fillets were stored at −20°C for 12 months and evaluated every 90 days. Dietary supplementation with EO did not affect proximate composition, fatty acid composition, or sensory acceptance of fish fillets. EO constituents (especially citral) were not detected in fish fillets. EO supplementation at 1 mL/kg appears to be more suitable to maintain physico-chemical changes similar to control during frozen storage. These data support the safety of lemongrass EO for use in aquaculture for human consumption purposes. [ABSTRACT FROM AUTHOR]

Maclura tinctoria is a tree species native from Brazil and rich in phenolic compounds. Since plant antibacterial activity is highly associated with phenolic compound concentration, we aim to evaluate the in vitro antimicrobial activity of different extracts against fish pathogenic bacteria. In addition, some phenolic compounds have central depressant effects and can be useful in aquaculture due to possible sedative and/or anesthetic effects. Four M. tinctoria extracts were extracted separately with ethanol; leaves (LE), bark (BE), heartwood (HE), and the sapwood (SE). In vitro antimicrobial activity was tested against Aeromonas strains at concentrations of 6400 to 3.125 μg/mL. The sedative effect was evaluated for 24 h with 30 and 100 mg/L concentrations. Chemical composition was analyzed by HPLC-DAD-MS. The HE extract had the best MIC (400 μg/mL) and MBC (800 μg/mL) compared to the LE, BE, and SE extracts. LE extract induced deep sedation and the BE, SE, and HE extracts induced light sedation. Additionally, BE, SE, and HE induced a normal behavior without side effects. Polyphenolic compounds with antimicrobial activity and sedative effects were identified mainly in HE. Thus, HE extract is safe and can be used as a sedative for silver catfish. [ABSTRACT FROM AUTHOR]

The silver catfish Schilbe intermedius (Rüppell, 1832) is single-spawning species spread in Africa and may reach 50 cm in length. Since there are no studies on the artificial reproduction of S. intermedius, the aim of the present study was to induce for the first time spawning by hormonal injection and to determine the reproductive parameters for this species. Artificial induction was carried out by the injection of Ovaprim (0.5 ml kg− 1) to males and females. Different eggs measurements were carried out by micrometer. Egg stripping was carried out ten hours after hormone injection at 27.17 ± 0.22 °C (mean ± standard deviation) with mean spawning rate 58.15 ± 2.88 %. Relative fecundity was 613.25 ± 71.83 oocytes/g with mean diameters 0.94 ± 0.10 mm and 1.11 ± 0.06 mm, respectively, before and after eggs fertilization. Fecundity and hatching rates ranged, respectively, from 60.30 to 68.02 % and 56.11–60.96 %. Egg hatching occurred about 22 or 28 h after fertilization at 26.02 °C, and the larvae average length was 1.24 ± 0.14 mm. Yolk sac resorption occurred 48 h after hatching and larvae acquired their morphological structures in about 72 h after hatching. This information will be important in improving the artificial reproduction protocols of S. intermedius in controlled breeding programs. [ABSTRACT FROM AUTHOR]

Tilapia and catfish are the most popular fish species in aquaponics. However, they are not well-accepted in all markets, and finding alternative species is important in order to increase the variety of food products and meet market demands. South America has several potential fish species for aquaponics systems. Encouraging the implementation of integrated aquaculture systems by providing information about the production of South American species can help to increase the supply of high-quality food and aquaculture diversification. Thus, data for five South American fish species with potential for aquaponics were compared with existing data for the main traditional warm water species in this system, tilapia and catfish. Moreover, the degree of suitability of the novel species for these systems in terms of zootechnical performance, tolerance to water quality and nutritional composition of fish flesh were discussed. The South American species considered were jundia or silver catfish (Rhamdia quelen), yellowtail lambari (Astyanax lacustris), pacu (Piaractus mesopotamicus), tambaqui (Colossoma macropomum) and snook (Centropomus spp.). Their description and the tabular comparison with the most traditional aquaponic-cultured species show they are suited for this production system. How suitable they are will depend on the system design, as well as the regional characteristics of the market where they will be produced. [ABSTRACT FROM AUTHOR]

Hardhead catfish Ariopsis felis are a common marine catfish in the coastal waters of the Gulf of Mexico (GOM). The low economic value of this species has depressed interest and research, and although the species is known for its extremely low fecundity and large oocytes, little else is known about this catfish species. A total of 1230 samples across all months of the year from 2016 to 2018 resulted in 681 females, and analysis of gonado‐somatic index (IG) revealed 1% to be a clear cut‐off indicating maturity. Females are considered capable of spawning from April to June when IG averaged 4–8%. Both atresia and post‐ovulatory follicles were present in July, suggesting that spawning ends in July in the northern GOM. The 1% IG cut‐off was used to designate maturity, and from that an L50 of 253 mm was estimated. Batch fecundity from 41 females estimated a mean batch size of 36 oocytes. Perhaps the most interesting finding was the presence of secondary growth stage oocytes (e.g., cortical alveoli) from July through November, well outside the spawning capable period. Furthermore, 78% of females had some early vitellogenic oocytes present during the non‐spawning season, and the distribution of these relatively large (2–5 mm) oocytes did not change over time. The results here are not only important as reproductive biology information for a common and abundant species, but also present interesting and unusual patterns of non‐spawning season oocyte development that is not commonly seen in Western Hemisphere subtropical fish species. [ABSTRACT FROM AUTHOR]

(%), sperm motility; Norm. (%), per cent of normal spermatozoa; I p i , I p i value; Sp. Conc. (SPZ/ml), sperm concentration; SPZ, spermatozoa; SV (µm/s), sperm velocity. Therefore, the present study was carried out to evaluate the effects of hygienic procedures used during handling and sperm collection of male silver catfish ( I R i . I quelen i ) on the presence of bacteria in fresh sperm, fresh sperm characteristics and male survival. Keywords: antibiotic sensitivity; bacteria; CASA; embryo; hygiene; sperm EN antibiotic sensitivity bacteria CASA embryo hygiene sperm 4003 4007 5 07/21/21 20210801 NES 210801 Aquaculture is rapidly growing worldwide. [Extracted from the article]

This study aimed to evaluate the apparent digestibility coefficients (ADCs) of dry matter, crude protein, gross energy, and minerals of marine fish meal (MFM), salmon meal (SM), tilapia by-product meal (TBM), meat and bone meal (MBM), poultry by-product meal (PBM), blood meal (BM), and feather meal (FM) by silver catfish Rhamdia voulezi. Groups of 12 fish were fed the experimental diet three times a day until apparent satiation, and the fecal samples were collected from an accumulation device. SM and PBM exhibited the highest digestibility values for dry matter, crude protein, and gross energy, while MBM and FM presented significantly lower ADCs for dry matter. BM and FM exhibited higher ADCs for phosphorus, 65.05 and 63.87%, respectively. The ADCs for calcium were 58.8% for MFM, 56.69% for TBM, and 60.08% for PBM. PBM and FM had the highest iron ADCs, 44.01 and 46.29%, respectively. Magnesium ADCs ranged from 44.87% for MBM to 75.50% for TBM. BM had the highest digestibility for zinc (62.77%), whereas MBM (36.68%) and FM (39.39%) had the lowest. In general, SM and PBM showed higher values as feedstuffs for silver catfish feeds. At the same time, the digestibility was lower for TBM and MBM for macronutrients and minerals such as phosphorus, iron, and zinc. [ABSTRACT FROM AUTHOR]

This study investigated the ingestion of microplastics by silver catfish (Chrysichthys nigrodigitatus) from New Calabar River in Niger Delta, Nigeria. Microplastics from the guts of 45 fish were examined with microscope after dissolution with potassium hydroxide. Microplastics, mostly fragments were found in about 56% of the samples at an average of 3.87±5.97 particles per fish. This study highlights the consequences of plastic pollution in freshwater environment and the potential risk to aquatic and human life. This also shows a potential threat to public health and therefore needs attention from health and environmental policy makers. [ABSTRACT FROM AUTHOR]

Growth, biochemical and haematological parameters, and oxidative biomarkers were evaluated in juveniles of silver catfish (Rhamdia quelen). Fish were fed with tocopherol (0, 200, 300 and 400 mg kg−1) during an experimental period of 60 days. Growth parameters of the silver catfish showed no changes with the addition of tocopherol in diets. Tocopherol favoured the deposition of polyunsaturated fatty acids in muscle tissue, changed the erythrocyte count and increased resistance of the erythrocytes. The inclusion of tocopherol at 300 mg kg−1 in diets reduced oxidative stress in the brain, gills, liver and kidney. The addition of this compound improved the stability of biological membranes. The antioxidant protection exerted by tocopherol decreased ROS activity, and increased deposition of unsaturated fatty acids and oxidative stability, indicating favourable fish health. Silver catfish that ingested tocopherol in the diet obtained a higher body deposition of polyunsaturated fatty acids. Results of the present study recommend inclusion of tocopherol at 300 mg kg−1 and higher in silver catfish diets. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of different concentrations of glutamine (experiment 1) and glutamine + cysteine (experiment 2) on post‐thaw sperm quality of South American silver catfish (Rhamdia quelen). The sperm was cryopreserved in cryoprotectant solution (fructose 50 g/L, powdered milk 50 g/L and methanol 100 ml/L) containing different glutamine concentrations (0, 2.5 and 5 mM; experiment 1) and a combination of glutamine (2.5 and 5 mM) and cysteine (2.5 and 5 mM; experiment 2). In experiment 1: glutamine supplementation groups increased DNA fragmentation; the concentration of carbonyl groups was lower and the concentration of sulfhydryl groups was higher in control; a higher activity of superoxide dismutase (SOD), catalase (CAT), glutathione‐S‐transferase (GST) and glutathione peroxidase (GPx) enzymes was observed in the 2.5 and 5 mM groups. In experiment 2: the group with 5 mM of cysteine +5 mM of glutamine presented the higher DNA damage; treatments with 5 mM of glutamine presented the higher concentration of carbonyl groups and a higher activity of CAT and GST. The findings of this study show that glutamine and cysteine, at the concentrations evaluated in this study, does not present satisfactory results but rather damaging effects on sperm quality of R. quelen. [ABSTRACT FROM AUTHOR]

Heavy metal pollution in aquatic ecosystems in the area is one of the most severe problems that compromise food security at the local, regional and global levels. In this study, the specific problem of the bioconcentration of mercury (Hg), lead (Pb), and Zinc (Zn) in 2 of the higher nutritional importance fish species (Ariopsis felis and Diplodus annularis) for the riverside inhabitants of the Ranchería river, in northern Colombia, is addressed. The organic tissue samples were subjected to acid digestion (HNO3 and HClO4 in a 3:1 ratio), and the quantification of metals was carried out by atomic absorption spectrophotometry. Additionally, the levels of metals in the sediment were measured, in order to determine environmental quality indices. This allow to determine that heavy metals do not present a risk to the aquatic organisms that inhabit this area. Different heavy metal concentration values were found: in decreasing order, Zn> Hg> Pb in sediment, and Hg> Zn> Pb in biological tissue. The results reveal that the concentrations of heavy metals present in fish tissue and sediment show a positive correlation, and a statistically significant linear regression (p = 0,001, p < 0,05). The presence of heavy metals in river sediment and bioconcentrates in fish could derive from point and diffuse sources related to agricultural, livestock, mining and wastewater activities. [ABSTRACT FROM AUTHOR]

Ariopsis felis (Hardhead Catfish) is an abundant yet understudied estuarine fish species in the US Atlantic and Gulf of Mexico. Very little is known about the species' trophic role and place in coastal food webs. This study was designed to provide baseline information on A. felis stable isotope values and to examine for any ontogenetic changes. n = 126 A. felis were sampled in the summer of 2018 in Terrebonne Bay, LA, USA, and muscle tissue was analyzed for stable carbon (δ13C) and nitrogen (δ15N) values. Overall, we found little evidence for any ontogenetic trophic niche shifts, expansions, or contractions; mature males and females have similar isotopic values and little to no differences were detected between immature and mature fish. Ultimately, A. felis occupy a trophic niche similar to that of other common estuarine fishes; however, the lack of any ontogenetic change in trophic position suggests that A. felis may be occupying a more stable and long-term place in coastal food webs. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of a probiotic additive on reproductive variables of the silver catfish (Rhamdia quelen). Three hundred juveniles (initial mean weight 17.35 ± 0.97 g) were fed for 90 days with diets containing increasing levels of a probiotic additive (0.15, 0.30, 0.45 and 0.60 g/kg of feed), which consisted of a blend between Bacillus subtilis and B. cereus, both at a concentration of 4 × 1011 CFU/g, and a control diet without the additive. In males, the presence of the probiotic had an effect on relative seminal volume, sperm cells' survival, gonadosomatic, hepatosomatic and viscerosomatic indexes, as well as transpose beat frequency, displacement velocity, motility rate and straightness of sperm cells. In females, the probiotic inclusion resulted in presented better in spawning and fertilization rates, viscerosomatic fat accumulation and development of germ cells. Additionally, the hepatic integrity and hepatocyte developmental characteristics were preserved by the presence of the probiotic additive. Thus, the inclusion of 0.60 g/kg of the probiotic could be recommended for the improvement of the reproductive performance of R. quelen. [ABSTRACT FROM AUTHOR]

This study aimed at evaluating the effects of a probiotic additive in productive performance and physiological parameters for Rhamdia quelen. The fish were fed diets containing increasing levels of the additive (0.15; 0.30; 0.45; and 0.60 g/kg of feed), which consisted of a blend of Bacillus cereus and B. subtilis, both at the concentration of 4 × 1011 CFU). Productive performance parameters were higher in fish fed diets containing 0.60 g/kg of the probiotics. Both the proximate composition and carcass yield were affected when 0.30 and 0.60 g/kg of the additive was included, whilst serum biochemical parameters were higher in fish fed diets containing 0.60 g/kg of the additive. An increase in the hepatic oxidative stress activity was found when 0.30 g/kg was supplied. The development of intestinal villi was influenced by the inclusion of the additives, as well as the activity of mucous‐secreting cells in the tissue. Hepatocyte's growth was differential in fish fed diets containing 0.30 g/kg and other tissue alterations were found using 0.60 g/kg of the additive. The inclusion of 0.60 g/kg of the probiotic in diets for R. quelen enhances its growth performance and physiological status. [ABSTRACT FROM AUTHOR]

A 60‐day feeding trial was conducted to evaluate the efficiency of the substitution of fishmeal (FM) with linseed protein concentrate (LPC) in the diet of silver catfish, Rhamdia quelen (6.13 g). Five isonitrogenous and isoenergetic experimental diets were formulated to replace 0, 10, 20, 30, or 40% of FM with LPC, and silver catfish were fed these diets to apparent satiation. LPC had a lower protein content compared to FM, but in vitro results showed higher protein digestibility of LPC as compared to fishmeal. There were no significant differences (p >.05) in growth, digestive somatic index, and intestinal quotient in the groups receiving LPC diets. The activity of the digestive enzymes did not differ among treatments, except for chymotrypsin, which was higher (p <.05) in the 30 and 40% LPC treatment groups. These results show that LPC protein can replace up to 40% of FM in silver catfish diets without adverse effects on growth performance. [ABSTRACT FROM AUTHOR]

A 17-year-old male presented to our ED complaining of pain and swelling at the base of the first metacarpal after attempting to remove a catfish from his fishing line 12 hours prior to arrival. Radiographic images demonstrated a foreign body (FB), which was detectable by ultrasound. Hand surgery was consulted and took the patient to the operating room for exploration and removal of two serrated radiopaque catfish spines that were deeply embedded in the left thumb. Conclusion. Penetrating injury from hardhead catfish (Ariopsis felis) spines can cause hidden FB, envenomation, infection, and secondary damage to nearby structures. Imaging should be done for these patients to ensure they obtain timely and complete extraction of the venomous structures. Surgery should be consulted for operative management to avoid damage on removal of the catfish spine remnants. [ABSTRACT FROM AUTHOR]

Background: The irruption of Next-generation sequencing (NGS) and restriction site-associated DNA sequencing (RAD-seq) in the last decade has led to the identification of thousands of molecular markers and their genotyping for refined genomic screening. This approach has been especially useful for non-model organisms with limited genomic resources. Many building-loci pipelines have been developed to obtain robust single nucleotide polymorphism (SNPs) genotyping datasets using a de novo RAD-seq approach, i.e. without reference genomes. Here, the performances of two building-loci pipelines, STACKS 2 and Meyer's 2b-RAD v2.1 pipeline, were compared using a diverse set of aquatic species representing different genomic and/or population structure scenarios. Two bivalve species (Manila clam and common edible cockle) and three fish species (brown trout, silver catfish and small-spotted catshark) were studied. Four SNP panels were evaluated in each species to test both different building-loci pipelines and criteria for SNP selection. Furthermore, for Manila clam and brown trout, a reference genome approach was used as control. Results: Despite different outcomes were observed between pipelines and species with the diverse SNP calling and filtering steps tested, no remarkable differences were found on genetic diversity and differentiation within species with the SNP panels obtained with a de novo approach. The main differences were found in brown trout between the de novo and reference genome approaches. Genotyped vs missing data mismatches were the main genotyping difference detected between the two building-loci pipelines or between the de novo and reference genome comparisons. Conclusions: Tested building-loci pipelines for selection of SNP panels seem to have low influence on population genetics inference across the diverse case-study scenarios here studied. However, preliminary trials with different bioinformatic pipelines are suggested to evaluate their influence on population parameters according with the specific goals of each study. [ABSTRACT FROM AUTHOR]

Schilbe mystus is a valued endemic fish species in the Nigerian freshwater, with great potential for culture. Nevertheless, controlled rearing is currently rare due to the lack of knowledge on its food and feeding habits besides other factors. Therefore, growth, food and feeding habits of S. mystus in Asejire Lake were investigated for six months (July to December, 2018). A total of 105 specimens (86.00±14.30 g) were collected from fishers. Samples were sexed and grouped according to sizes. Length-weight relationships (LWR) and condition factor were assessed using standard procedures. Gut contents and niche breadth (Bi) were analyzed and quantified using a standard approach. In addition, qualitative and quantitative variations in diet were determined according to sex, size and seasons. Data were analyzed using descriptive statistics, chi-square and multiple linear regressions. The LWR indicated negative allometry growth with 'b' value of 2.87 and coefficient of determination (R²) of 0.85. The condition factor of S. mystus was 1.32±0.26, sex ratio of 1:1.23 (♂: ♀) with size distribution ranged from 9.40 cm to 29.70 cm. Dietary analysis showed that S. mystus is a europhagous feeder and a benthic omnivore. Insects, crustaceans and planktons constituted the major food items. Furthermore, significant differences in feeding habits of S. mystus occurred according to sex, size and seasons. The Bi value was high (2.15), indicating a trophic generalist. Hence, this research was conducted to provide key information necessary for formulation of artificial diet for S. mystus under captivity. [ABSTRACT FROM AUTHOR]

Objective: To determine the incidence of non-target fishing species, in riparian fishing, as a dietary alternative for the agricultural sector in the state of Campeche, Mexico. Design/methodology/approach The ports surveyed in the state of Campeche Champotón, Seybaplaya and Campeche. A total of 89 questionnaires were applied at random and at the free will to participate to coastal fishermen. The obtained data were analyzed with the R vr 3.4.4 statistical software. Results The results showed that the coastal fishing catch is 760.1 kg on average/week, and fishing discards of 30.42 kg/week. Of the bycatch, 68.8% is discarded and the rest sold at a low price (US $ 0.2). Among the waste products, 34 species stand out, but seven represent the 58.7% of maximum incidence, mainly Bosh Ariopsis felis, Chac-chi Haemulon plumierii, Cojinuda Caranx crysos, Ixpil Upeneus sp., Macabi Elops saurus, Postà Bairdiella chrysoura and Sardina Herengula jaguana. Delimitations/implications There is a wide variety of species of which their potential as a protein source is unknown, which can be used as input in feed. Findings/conclusions Registered fishing discards are made up of more than 30 non-target species and according to their incidence can be considered as inputs in feed manufacturing for the agricultural sector. [ABSTRACT FROM AUTHOR]