Silver Catfish Research Articles

Gaultheria procumbens essential oil longevity and oxidant/antioxidant status of silver catfish Rhamdia quelen experimentally infected by Aeromonas caviae

The increase in bacterial resistance in animals and the buildup of antimicrobials in animal meat pose significant nutritional and economic challenges. Given this context, this study explored the potential of Gaultheria procumbens essential oil (GPEO) as a sustainable alternative for aquaculture, focusing on its effects against Rhamdia quelen infected with Aeromonas caviae. Longevity tests revealed that R. quelen, when treated with 5 and 10 µL/L of GPEO, displayed significantly improved survival rates compared to both the untreated infected control group and those treated with ethanol. To understand the mechanisms behind the increased survival, a subsequent experiment with a 10 µL/L GPEO treatment aimed to investigate the oxidative stress pathway. This involved measuring levels of thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS), alongside enzyme activities for superoxide dismutase, glutathione peroxidase, and glutathione S-transferase. Our findings showed elevated TBARS and ROS levels in the non-infected control group treated with GPEO, suggesting an increase in these enzymes as a response to ROS balance. Therefore, our data indicate that the mechanism leading to enhanced longevity in R. quelen infected and treated with GPEO does not involve the oxidative stress pathway.

Evaluation of heavy metals and their potential risk to human health from seafood in Escravos Estuary, Southern Nigeria

In this study, we investigated the levels of heavy metals in sediment, shrimps, silver catfish and their potential bioaccumulation, trophic transfer and the associated risk to human health from the Escravos estuary in southern Nigeria. The values of heavy metals in shrimps and silver catfish were disproportionately higher than the allowable limits for seafood, with values in the gills and the rest of the fish higher than those of the muscle, liver and gonads. Furthermore, the increased BSAF for Cd, Cr and Cu in the study, underscore the uptake of metals from sediments into shellfish. High EDI and HR values from silver catfish for adults and children indicate immediate health risks, with the values for children considerably high, emphasizing the urgent need for regulatory measures and continuous monitoring of seafood from the estuary to protect the health of coastal population within the subregion.

Protium heptaphyllum essential oil from the fruit as a sedative and anesthetic in Rhamdia quelen: influence in cardiac frequency, biochemical, and oxidative parameters.

This study aimed to evaluate the effects of Protium heptaphyllum fruit essential oil (PHEO) on the physiology of silver catfish (Rhamdia quelen) during anesthesia and recovery, through studying echocardiograms, oxidative status, and metabolic parameters. Three experiments were performed: (1) 50 silver catfish juveniles were submitted to anesthesia and recovery tests with 300, 400, 500, 600, and 700mg L-1 of PHEO. (2) Echocardiogram analysis was performed in anesthetized and non-anesthetized fish. (3) Biochemical parameters were evaluated at 0, 30, 60, and 120min of recovery after being anesthetized for 3min with 600mg L-1 PHEO. Times to sedation and deep anesthesia were reduced with PHEO increasing concentrations. The echocardiogram showed a higher cardiac rate in anesthetized fish. Plasma glucose levels increased in control fish through recovery time, but anesthetized fish showed lower levels than controls at 120min of recovery. Metabolic parameters such as plasma and hepatic glucose did not show changes considering the recovery time of up to 120min. Hepatic glycogen, lactate, and triglycerides reduced their levels over recovery times. Fish anesthetized enhanced superoxide dismutase activity and thiobarbituric acid reactive substances levels but decreased reduced glutathione (GSH) levels at 30min compared to controls. After 60min, GSH values were significantly higher in anesthetized fish than in controls. These results suggest that PHEO at 600mg L-1 is an effective anesthetic for the rapid handling of silver catfish, providing stable metabolic parameters and enhanced antioxidant responses during recovery. Echocardiogram analysis confirms the anesthetic effect, supporting PHEO as a viable and efficient option for fish anesthesia in aquaculture. The use of PHEO in aquaculture can enhance fish welfare by reducing stress during handling and transportation, potentially leading to improved growth, health, and survival rates.

Implementation system monitoring and control temperature and pH in urban silver catfish hatchery to enhance efficiency and responsiveness based on IoT

Implementation system monitoring and control temperature and pH in urban silver catfish hatchery to enhance efficiency and responsiveness based on IoT

Intestinal histomorphology of silver catfish fed diets supplemented with Citrus x Aurantium essential oil

The aim of this study was to investigate the effects of dietary Citrus x aurantium essential oil (EOCA) on the growth and intestinal histomorphology of silver catfish (Rhamdia quelen) fingerlings. Five diets with different doses of EOCA (0.0, 0.25, 0.5, 1.0, and 2.0 mL/kg diet) were evaluated. At the end of 60 days, the growth performance was positively correlated with dietary EOCA supplementation. The results showed an increase in fold height in the middle intestine (MI) of fish fed the EOCA diet compared to the control group. In the anterior intestine (AI), the enterocyte height increased, while the goblet cell number decreased in all EOCA-supplemented diets. The goblet cell number in the MI and posterior intestine (PI) was higher with EOCA and lowest in the control group. Diets with EOCA did not affect the fold height in the PI. Similarly, to the AI, the fold width in PI increased in the 0.5 mL/kg treatment compared to the control group. These results revealed that dietary supplementation with EOCA, primarily at a dose of 0.5 mL EOCA/kg diet, promoted positive effects on the intestinal morphology of R. quelen, indicating that the use of EOCA extracted from sweet orange peel, a fruit residue, could be considered in fish diets.

Diets including l-carnitine and varying oil sources regulate liver and testes fatty acids profile and interfere with sperm production in silver catfish (Rhamdia quelen)

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.

The Prevalence of Trypanosoma Species in Silver Catfish (Bagrus bajad) from Zobe Reservoir, Dutsin-Ma, Katsina State

This research investigates the prevalence of Trypanosoma species in the silver catfish (Bagrus bajad) population in Zobe Reservoir, Dutsin-Ma, Katsina State. The study aims to provide insights into the parasitic infection rates, identify prevalent Trypanosoma species, and assess its potential impacts on the health and population dynamics of silver catfish in the reservoir. A total of 108 silver catfish samples were collected from Zobe Reservoir in Dutsin-Ma, Katsina, Nigeria at bi-weekly intervals, from July-September; 2023 for the discovery of blood parasites and subjected to thorough parasitological examination. Microscopic analysis, including blood smears and tissue samples, was employed to identify and classify Trypanosoma species. Preliminary findings revealed the presence of Trypanosome infections in the silver catfish population, with a variation in prevalence rates among the sampled specimens. The study identifies specific Trypanosoma species affecting the silver catfish in Zobe Reservoir, shedding light on the diversity and distribution of these parasites in the aquatic ecosystem. The Bagrus bajad obtained according to sex indicates 29 males and 79 females were examined. Females had the highest percentage of infection, 10.12%, while males had the lowest percentage of infection, 3.45%. The results of this research contribute valuable data to the understanding of Trypanosome infections in silver catfish populations, with implications for fisheries management, conservation efforts, and the potential transmission of these parasites to other aquatic organisms. Furthermore, the study underscores the importance of continued monitoring and surveillance to assess the dynamic interactions between Trypanosomes and their fish hosts in freshwater ecosystems.

Prevalence of Ecto-Parasitic Fauna in Silver Catfish (Bagrusbajad) from Zobe Reservoir, Katsina State

Fish parasitic infections inflict a most importanteconomic concern on fish farming industries. Helminthic infestations can cause a variety of fitness difficulties as well as economic sufferings for fishing populations. Prevalence of ecto-parasites fauna in silver catfish Bagrusbayad from Zobe reservoir, Katsina Nigeriawas inspected to comprehend the healthiness conditionof the fish, possibledanger to their existence as well asprotection of consumption of fish from the water body.The current study was undertaken between August and October, 2023 to determine the prevalence of fish ecto-parasites of Bagrusbajad and the associated risk factors in Zobereservoir Dutsin-Ma, Katsina State, Nigeria. A total number of108 fish samples were collected and examined from Zobe reservoir. The fish was identified as well as separated based on their sex before being transferred live to the Fish Biology laboratory, Federal University Dutsin-Ma, Katsina State for additional evaluation. Out of 108 fish samples from Zobe, 88 were male and 20 were female. Fish parasites recovered and their prevalence among Bagrusbajad obtained from Zobe reservoir includes; Tricodinaspp 17 (68%), and Gyrodactylusspp 8 (32%). The prevalence of parasites recovered from the fish species in this study was low. In conclusion, Bagrusbajad from Zobe reservoir were infected by parasites that are of economic importance. The findings suggest that the observed parasitic infections may adversely affect Bagrusbajad and if not well managed, could also infect human beings who consume the fish. It is therefore recommended that communities along the reservoir should desist from activities likely to increase parasite load, also, the part organs of harvested fishes from the study area should be discarded rather than consume to prevent zoonotic diseases.

BASELINE SURVEY ON ENDOPARASITIC FAUNNA OF THE SILVER CATFISH (Chrysichthys nigrodigitatus) FROM ESCRAVOS ESTUARY, DELTA STATE NIGERIA, AND ITS ZOONOTIC IMPLICATION FOR FISH CONSUMER’S HEALTH

The Silver Catfish (Chrysichthys nigrodigitatus) is one of the important food fishes for the inhabitants of the Escravos Estuary. Due to lack of information on the parasites of fish species in the Escarvos Estuary, including C. nigrodigitatus, fish eaters from the Escravos Estuary are at grave danger of contracting zoonotic diseases. The purpose of this study was to determine the prevalence of endoparasites in the Silver Catfish (Chrysichthys nigrodigitatus) from the Escravos Estuary, Nigeria. A total of 180 samples of C. nigrodigitatus were collected from September 2023 to February 2024 from fish landing sites in Okerenkoko community. The fish samples were transported to Fisheries and Aquaculture Laboratory, Nigeria Maritime University, Okerenkoko for examination and endoparasites identification. Two genera of endoparasites were found that infect C. nigrodigitatus from the Escravos Estuary, namely Procamallanus laevionchus and Pomphorhynchus laevis belonging to nematode and acanthocephalan. Only 6 samples were infected with 12 endoparasites with a total prevalence of 3.33 %. More hosts were infested with more parasites in the rainy season than dry season with a rainy season prevalence of 4.17 % and 1.17 % for dry season. Prevalence (6.25 %) of endoparasites was higher in 40.0 – 49.9 cm size class than other length classes with 20.0 – 29.9 cm size class recording the least prevalence (1.67%). More female hosts (66.67%) were infested than male hosts (33.33 %). Parasites were only found in the intestine and stomach of C. nigrodigitatus with no parasite in the fillet, liver, heart, and kidney. In conclusion,...

Some Biological Characteristics of Chrysichthys nigrodigitatus from Luubara Creek, Niger Delta, Nigeria

The study of biological characteristic of C. nigrodigitatus caught using multiple and single long-line was carried out for twelve months. The Von –Bertallanffy growth function was used to estimate the growth characteristics. The growth coefficient (K) and growth performance index (Ø) were 0.740 and 2.37, respectively, indicating it grows fast. The instantaneous rates of total, natural, and fishing mortality were 3.23, 1.18 and 2.05 per year, respectively. The resultant exploitation ratio was 0.635, indicating that the fishery was overexploited. More so, the ratio of length at first capture (Lc) to asymptotic length (L∞). (Lc/ L∞) depicted that this species was caught at a small size which may lead to growth over-fishing. The extreme mounting fishing pressure and harvesting silver catfish when the size small require application fishing regulations that will watch over the species in creek. Management regulation, particularly seasonal closures coinciding with the period of spawning, should be implemented to avoid the eventual collapse of this fishery.

ESTIMATION OF GENETIC DIVERSITY IN SILVER CATFISH (Chrysicthys nigrodigitatus) USING RANDOM AMPLIFIED POLYMORPHIC DNA

The Silver catfish (Chrysicthys nigrodigitatus) is widely distributed along River Niger.This study was carried out to characterize Silver Catfish found along River Niger, with the help of morphometric and random amplified polymorphic DNA for genetic analysis to determine variation in strain that can be used for identification of the strains and possible allocation. Samples were collected from three stations, namely; Illushi, Illah and Onitsha and total of 1 50 samples (50 each) of silver catfish was collected from landing station. Where 12% of the total sampled fish was used for genetic analysis and 100% of the sample was used for morphometric analysis. Result obtain from the morphometric analysis along River Niger show that dorsal fin length and head length with a value of 0.749 and 0.230 respectively are significantly different (p&lt;0.05) in the sample fish can be used for identification. Result obtained for genetic analysis indicate that samples from the three locations are positively correlated. Value between Illah and Illushi is 0.8991 with a percentage variation of 80%; Onitsha and Illah with a correlated value of 0.79045, a variation of 63% and Onitsha and Illushi with a correlated value of 0.76354 a percentage variation of 50%. Dendogram, Darwin’s hierarchy and Darwin’s radii graph from the study also show that species are from one ancestry. Identification of species for domestication purpose can use morphometric features. Inline breeding between strains in these locations may be necessary to improve strains because of correlation of samples.

Anesthetic potential of essential oils from Brazilian native plants in Rhamdia quelen juveniles (silver catfish)

Abstract The sedative and anesthetic actions of several essential oils (EO) on fish have been demonstrated, stimulating the search for new options for natural anesthetics. This work evaluated the safety and sedative and anesthetic efficacy of EOs from three native Brazilian plants, Acmella oleracea (jambu), Aloysia hatschbachii and Cordia verbenacea (whale herb) in juvenile Rhamdia quelen (silver catfish). Anesthetic induction and recovery protocols (20 to 400 mg L-1) and long exposure (48 h) from 10 to 100 mg L-1 were tested. The EOs performed sedative and/or anesthetic activities: AOOi at a concentration of 20 mg L-1, AOOl at 50 and 100 mg L-1, AHOl, and CVOL (only sedation) 50 mg L⁻¹, as there were no important adverse effects and/or mortality. The results obtained indicate that Cordia verbenacea EO is the most promising as a sedative for juvenile silver catfish at a concentration of 50 mg L⁻¹.

Physico-Chemical and Sensory Assessment of Local and Imported Catfish Fillets

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 acid-reactive 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.

Níveis de íons no conteúdo do trato gastrointestinal de jundiá Rhamdia quelen (Siluriformes: Heptapteridae) são relacionados ao período reprodutivo

ABSTRACT: 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).

Parasitos de peixes de um rio costeiro neotropical dentro de um hotspot de biodiversidade

Abstract: Aim We investigated the ichthyofauna parasite component community across a gradient of anthropogenic pressures of the Guaraguaçu River, south Brazil, a Neotropical river of central importance for biodiversity conservation. Methods After fish sampling, all fish were identified, measured, weighed and eviscerated. The viscera and gills were inspected for parasite screening and subsequent identification. Parasite diversity estimators were calculated for the most abundant host species. Results A total of 159 host specimens from 12 species were examined, being 140 (88.05%) found to be infected with at least one parasite, including 14 new parasite occurrences. The most widely distributed parasite was the nematode Contracaecum sp., found in 8 host species. The highest mean infection intensity and mean abundance was observed for the monogenean Aphanoblastella mastigatus, infecting the Silver catfish Rhamdia quelen. The Shannon-Wiener, Jost and Simpson indexes were higher for the more abundant fishes, except for the Trahira Hoplias malabaricus. Most host species harbored parasites in poorly aggregated distribution, according to the discrepancy index. The Berger-Parker index showed monogenean dominance in all hosts except for H. malabaricus. We found little evidence for parasite infracommunity changes across the gradient of the river. Conclusions We described the infection patterns in an important Neotropical river. The new parasite occurrences highlight the contribution of our study. Fish-parasite interactions changed throughout the river stretches, and we argue that it does not necessarily means changes in diversity and abundance of parasite within species, but the rearrange of interactions. Moreover, it seems that parasites are more abundant in most impacted sites, another reason to continue the monitoring.

Redox profile of silver catfish challenged with Aeromonas hydrophila and treated with hexane extract of Hesperozygis ringens (Benth.) Epling through immersion bath.

The growing increase in the fish farming sector has favored the establishment of bacterial outbreaks caused by Aeromonas hydrophila in several species. The hexane extract of Hesperozygis ringens (HEHR) (Lamiaceae) leaves increased the survival rate of silver catfish (Rhamdia quelen) experimentally infected by A. hydrophila. However, it is noteworthy that no reports have been found on the possible mechanisms of action of this extract in infected fish. This study aimed to evaluate the effect of the HEHR, administered through single immersion bath, on lipid peroxidation and antioxidant defenses in muscle and liver tissue of silver catfish challenged with A. hydrophila. The results showed that the oxidative status of silver catfish was altered, although oxidative stress was not triggered during the experiment. HEHR at 30 mg/L (HEHR30) was not characterized as a pro-oxidant agent in the presence of infection, unlike florfenicol and HEHR at 15 mg/L treatments in some cases. In short, HEHR30 provided an important increase in hepatic catalase activity, characterizing one of the possible mechanisms involved in the greater survival of fish experimentally infected by A. hydrophila. Additionally, HEHR30 did not induce lipid peroxidation, nor reduced antioxidant defenses of silver catfish infected or not by A. hydrophila.

Assessment of Gastrointestinal Parasite in Silver Catfish (Bagrus bayad; Forskal, 1775) from Ajiwa Reservoir Katsina State, Nigeria

Gastrointestinal parasite in Silver catfish was studied for six months between June 2022 and November 2022 to determine the prevalence of parasites infesting Bagrus bayad and the associated risk factors in Ajiwa reservoir Batagarawa, Katsina State, Nigeria. A total of 90 fish samples were collected and examined from Ajiwa reservoir, comprising 41 and 49 males and females, respectively. Observed parasites and their prevalence (%) in Bagrus bayad include: Cestode genera; Corallobothrium solidum 21 (23.86%), Pleurocercoid or Coradium sp. 8 (9.09%), Nematode genera; Capllaria philipinesis 31 (35.23%), Cammallanus sp 16 (18.18%), Procamallanus laevichonches 12 (13.64%). The prevalence of parasites recovered from the fish species in this study was high. In conclusion, Bagrus bayad in Ajiwa reservoir was susceptible to parasite infestation. It is recommended that this species of fish from the Ajiwa reservoir should be gutted before consumption to prevent zoonotic diseases.

Metabolical and hematological responses of silver catfish (Rhamdia quelen) to diet composition

This study investigated the metabolic and hematological responses of silver catfish fed diets composed of different protein sources for 90 days. Six different diets were formulated: MBY (meat and bone meal + yeast); SY (soybean meal + yeast); S (soybean meal); MBS (meat and bone meal + soybean meal); FY (fish meal + yeast); FS (fish meal + soybean meal). In the liver, the concentration of glucose, lactate and protein was lower in fish fed SY and S diets. Liver glycogen did not differ between diets. At the muscular level, the glycogen, glucose, lactate content was lower in the FS diet, while the protein decreased in the fish that received the soybean meal-based diet (S). On the other hand, higher values of protein, glucose and lactate were observed in the diet containing meat and bone meal + soybean meal (MBS). The silver catfish fed diets based on fish meal (FY and FS) had a higher protein content in the kidney. Hematological parameters were influenced by diets. The absence of animal protein sources in the diets resulted in lower values of hematocrit and hemoglobin in silver catfish blood. It is concluded that diets containing vegetable and animal protein sources improve the nutritional and health status of silver catfish.

The Effects of Stocking Density and Food Deprivation on Mucous Cells and Lysozyme Activity in the Skin and Gills of Silver Catfish.

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.

Evidence of genotoxicity, neurotoxicity, and antioxidant imbalance in silver catfish Rhamdia quelen after subchronic exposure to diisopentyl phthalate

Evidence of genotoxicity, neurotoxicity, and antioxidant imbalance in silver catfish Rhamdia quelen after subchronic exposure to diisopentyl phthalate