Gill Histology Research Articles

The role of rice husk in Oreochromis niloticus safety enhancement by bio-adsorbing copper oxide nanoparticles following its green synthesis: an endeavor to advance environmental sustainability

Lowering nanoparticles (NPs) toxicity before discharge into aquatic environments and employing agricultural waste materials for environmental sustainability are necessary nowadays. Since this has never been done, this work examines how green CuO NPs treated with rice husk (RH) as a bio-adsorbent may be safer for Nile tilapia (Oreochromis niloticus) than chemically manufactured ones. So, five groups of fish were randomly placed in glass aquaria. One group was a control, and four groups received 50 mg/L green and chemically produced CuO NPs (GS and CS) with and without RH for 24, 48, and 96 h. RH was collected from all groups, and the results showed GS-CuO NPs had a greater adsorptive capacity than CS-CuO NPs after all time intervals. After analyzing fish indicators in all groups compared to the control, higher Cu bioaccumulation was exhibited in the liver and gills. The liver and gills showed elevated levels of glutathione peroxidase (GPx), catalase (CAT), and thiobarbituric acid reactive substances (TBARS), while the levels of glutathione reduced (GSH) were significantly lower. In addition, Cu exposure impaired liver and gill histology. Finally, our results indicated that using RH as an adsorbent for CuO NPs after their green synthesis instead of chemical synthesis before they enter the aquatic environment can enhance the overall health of fish and environmental sustainability.

Histology of skin, gill, liver, and kidney of tilapia Oreochromis niloticus exposed by azo dyes acid red 88.

Abstract Coloring is one of the main process in textile production. Using azo dyes type are the first pick of textile industries. Therefore, the disposal of dye waste containing high levels of azo can increase the toxicity level also impact the fish. Acid Red 88 is an azo type dye which provides a red color as the basic color for coloring textile products. Acid Red 88 are left behind as much as 60% of textile waste. the textile factories wastewater in Indonesia contains an average of 750 mg/L suspended solids. The aim of this study was to determine the effect of azo dye Acid Red 88 exposure to tilapia by the histology of its skin, gills, liver and kidneys. The method used was experimental method with 4 different exposure concentrations of Acid Red 88 P0 (0 mg/L), P1 (75 mg/L), P2 (150 mg/L), P3 (225 mg/L), and P4 (300 mg/L). The damage is identified on the histology of the organs and then measured using a scoring method. The results showed that several damages were found such as epithelial erosion, edema, hyperplasia, telangectasis, hemorage, fatty degeneration, congestion and necrosis.

Evaluation of Catalase Activity, Gill Histology and Genotoxic Effects of Cadmium in Tilapia (Oreochromis Niloticus) Fingerlings

This research was designed to assess the toxicity of cadmium (Cd), and its effects on catalase (CAT) activity, histology of gills and geno-toxicity of Oreochromis niloticus. The acute toxicity of Cd (96-h) for fish was computed as 56.021 mg/L (LC50) and 80.7336 mg/L (LC100) using Probit method. The inferences showed that catalase level was significantly (P<0.05) lower in Cd treated O. niloticus as compared to control that was metal-stress free. It followed the order as: intestine<gills<muscles<brain. Results of gills histology showed that Cd-exposure caused prominent damage to both primary and secondary lamella. The histological alterations included fusion and curling of secondary lamella, hyperplasia in secondary lamella, epithelial lifting, and aneurysm observed in gills. Geno-toxic results showed that a significant (p<0.05) increase in micronuclei, de-shape and notched nuclei in erythrocytes of Cd-exposed O. niloticus was found as compared to control. The inferences of this study confirmed the genotoxic properties of Cd. This study will be helpful in understanding the histological and geno-toxic changes in fish body kept under Cd stress. This study will also help in the development of a specific approach to minimize the negative and genotoxic impacts of cadmium. Furthermore, tilapia can be used as a good bio-indicator for detecting toxic impacts associated with water pollution.

Assessing the Role of Detergents in Pond Ecosystem.

Detergents are used as a part of our daily life routine. Though they are widely used but their active ingredients which are highly toxic and persist in the environment for long are an important cause of environmental pollution. In our current work, we have studied the harmful effects of a combination of some commonly used detergents which find their way into the water bodies especially the pond ecosystem through everyday activities like washing clothes, utensils, and bathing in water. This water is the home to many flora and fauna especially the fishes like Cirrhinus mrigala. In our work, we have analysed the levels of the hepatic enzymes Alanine Transaminase and Aspartate Aminotransferase as well as the histology of gill and liver tissues. We have also analysed the presence of micronucleus in the fish blood. It was observed that the presence of detergents has increased the enzyme level as well as resulted in destruction of gill and liver tissue morphology. Detergents also increased the presence of micronucleus in fish blood. These results are indicators of deterioration of fish health due to detergent pollution.

Effects of prolonged application of peracetic acid-based disinfectant on recirculating aquaculture systems stocked with Atlantic salmon parr

The use of recirculating aquaculture systems (RAS) for Atlantic salmon (Salmo salar) production has become increasingly common. RAS water disinfection plays a crucial role on its biosecurity. Peracetic acid (PAA) is a promising disinfectant due to its powerful oxidative properties, broad antimicrobial spectrum, and rapid degradation into no harmful compounds. This study focused on assessing the consequences of prolonged application of a PAA-based disinfectant in a RAS stocked with salmon parr. The experiment included three treatment groups in triplicate: 0 mg/L PAA (control), 0.1 mg/L PAA, and 1 mg/L PAA, using nine-replicated RAS with a total of 360 fish (14.8 ± 2.3 g; N = 40/RAS). The study spanned 28 days, with samples collected on days 0, 14, and 28. The analyzed parameters were water quality, and fish parameters, including external welfare indicators, gill histology, total antioxidant capacity (TAC), reactive oxygen species/reactive nitrogen species (ROC/RNC), oxidative stress biomarkers related to DNA and protein, cellular DNA damage, and global gene expression. While water quality remained relatively stable, there was an increase in bacterial populations in the groups exposed to PAA, particularly 1 mg/L PAA. Fish weight did not differ between the control and PAA-exposed groups. TAC, ROC/RNC, and oxidative stress biomarkers exhibited similar trends. The study identified >400 differentially expressed genes (DEGs) in the skin, gill, and olfactory organ, with many of these DEGs associated with immune responses. Comparing the transcriptomic profiles of the three tissue organs revealed that the olfactory organ was the most reactive to PAA treatment. This study shows that calculated PAA concentrations of 0.1 mg/L and 1 mg/L in the pump-sump, contributed to an increase of bacteria whereas no detectable differences in health and welfare of salmon parr were found. These findings are promising for the implementation of PAA-based disinfectants in RAS stoked with Atlantic salmon parr.

Assessment of dietary polyvinylchloride, polypropylene and polyethylene terephthalate exposure in Nile tilapia, Oreochromis niloticus: Bioaccumulation, and effects on behaviour, growth, hematology and histology

Microplastics (MPs) have been recognized as emerging aquatic pollutants receiving major concern due to their detrimental effects on aquatic life. Nile Tilapia, Oreochromis niloticus is a model species considered in toxicological studies to address the effects of pollutants in freshwater animals. However, comprehensive knowledge comparing the impacts on fish across various MPs polymers is scarce. Therefore, the overarching aim of the current study was to examine the bioconcentration of MPs polymers: polyvinylchloride (PVC), polypropylene (PP), and polyethylene terephthalate (PET), and their toxic effects on growth, and behavioral responses, hematology, and histology of gills, liver, and intestine in O. niloticus. Fishes were subjected to a 21-day dietary exposure to MPs by assigning them into six treatment groups: T1 (4% of PVC), T2 (4% of PP), T3 (4% of PET), T4 (8% of PVC), T5 (8% of PP), T6 (8% of PET), and control (0% of MPs), to assess the effects on fish across the polymers and dosage. Results showed several abnormalities in anatomical and behavioral parameters, lower growth, and high mortality in MPs-exposed fish, indicating a dose-dependent relationship. The elevated dosage of polymers raised the bioavailability of PVC, PP, and PET in gills and gut tissues. Noteworthy erythrocyte degeneration referred to cytotoxicity and stress imposed by MPs, whereas the alterations in hematological parameters were possibly due to blood cell damage, also indicating mechanisms of defense against MPs toxicity. Histopathological changes in the gills, liver, and intestine confirmed the degree of toxicity and associated dysfunctions in fish. A higher sensitivity of O. niloticus to PET-MPs compared to other polymers is likely due to its chemical properties and species-specific morphological and physiological characteristics. Overall, the present study reveals valuable insights into the emerging threat of MPs toxicity in freshwater species, which could be supportive of future toxicological research.

Salinity tolerance in Clarias gariepinus (Burchell, 1822): insight on blood parameter variations and gill histological changes.

This study was designed to evaluate the tolerance of Clarias gariepinus juveniles to a gradual and abrupt increase in salinity over time. To this effect, C. gariepinus juveniles were exposed to three salinity incremental protocols namely 1g L-1day-1, 5g L-1day-1, and 10g L-1day-1. Changes in the hematological parameters and the gill histology of fish were analyzed to determine the impact of osmotic stress on the health status of the fish and its osmoregulatory ability. The result obtained showed that juveniles of C. gariepinus can tolerate salinity stress up to 14g L-1. At 15g L-1 and beyond, all samples died regardless of gradual (i.e., 1g L-1day-1 administered for 15days) or abrupt salinity exposure (i.e., 5g L-1day-1 administered for three days and 10g L-1day-1 administered for two days). Interestingly, more than 90% of the fish survived a direct 10g L-1 exposure for 24h without prior acclimation. The hematological parameters accessed in the fish exposed to 10g L-1 (either gradually or abruptly) showed a significant increase in the white blood cells and a decrease in the red blood cells, packed cell volume, hemoglobin concentration, and all derived blood parameters. The results of the serum biochemistry show a lower total protein and albumin in the salinity-treated fish compared to the control group. However, the serum glucose and the plasma electrolytes (i.e., K+, Na+, and Cl-) were higher in the former group than in the latter. Aside from the stress response expressed in the blood parameters, severe gill degenerations were seen in the histological micrograph obtained for the salinity-treated fish, while the control had a near-normal gill architecture. It was concluded that C. gariepinus could tolerate salinity exposure of 10g L-1day-1 (administered gradually or abruptly) and below without killing the fish within 24h.

Effect of burnt tire-ash (water-soluble fraction) on blood and histopathological markers in Clarias gariepinus

Aquatic habitats serve as pollutant reservoirs and experience massive pollution disasters due to anthropogenic pressure. The effect of the Water-Soluble Fraction (WSF) of burnt tire ash (BTA) was investigated on Clarias gariepinus juvenile using blood biomarkers as well as liver and gill histology. The model fish were exposed to 5 % (0.56 g/L), 10 % (1.12 g/L) and 20 % (2.24 g/L) of 96-hr LC50 (11.2 g/L) value of BTA sub-chronic doses during the experiment. Hematological indices, the liver, and gill histology were studied throughout the 28-day exposure study, which was followed by a 14-day post-exposure trial. The studies revealed that BTA-exposed fish had reduced red blood cells, packed cell volume, and hemoglobin levels with time, whereas white blood cells and leukocyte numbers increased. Concentration-dependent histopathologic abnormalities such as hyperplasia, telangiectasis, hemorrhage, desquamation, lamellar edema, and vacuolation were observed in the gill of the affected fish, in contrast to the control. Likewise, the presence of histopathologic abnormalities in the liver of BTA-exposed fish, such as vacuolar degeneration, hyperplasia, dilated portal vein, pyknotic nucleus formations, hypertrophy hepatocytes, and aggregated macrophages, was concentration-dependent. Following apparent histologic deformities that persisted in the tissues after recovery, healing from BTA exposure was only partial. C. gariepinus is an essential bioindicator of burnt tire ash’s ecotoxicological impact. Point and non-point traces of burnt-tire ash to the aquatic systems may harm aquatic animal species, thus necessitating preventative actions.

Essential oil of Piper hispidum (Piperaceae) has efficacy against monogeneans, and effects on hematology and gill histology of Colossoma macropomum.

This study investigated for the first time the effectiveness of therapeutic baths with essential oil (EO) of Piper hispidum against monogeneans Anacanthorus spathulatus, Notozothecium janauachensis, Mymarothecium boegeri and Linguadactyloides brinkmanni from the gills of Colossoma macropomum, as well as the hematological and histological effects on this fish. In therapeutic baths, 100 mg/L of P. hispidum essential oil and two control groups (water from the culture tank and water from the culture tank with 70% alcohol) were exposed for 1 h/day, with intervals of 48 hours for 3 days, and three replicates each were used. Therapeutic baths with 100 mg/L of P. hispidum essential oil had an efficacy of 78.6% against monogeneans. The toxicity of this essential oil was low, since there were a few physiological and histopathological changes that did not compromise the functioning of the gills of the fish. Therefore, 100 mg/L of P. hispidum essential oil was effective for controlling monogeneans in C. macropomum, when short therapeutic baths were used without compromising the health of the exposed fish.

Non specific immune response of batik lobster (Panulirus longipes) at different salinity

Salinity has gave significant impact to stress levels that trigger of adjustment hemocyst with surroundings.The research aims to identify the Ideal maintenance of salinity on batik lobster (Panulirus longipes). It was conducted during at ninety days for maintanance period from September 2019 to Januari 2020 in Mata Shrimp Seeds Center, Kendari City. The Animals studied were batik lobsters (P. longipes) caught by nature with the male lobsters weighed 235±60 g and females were 237±50 g and total lobster under testing of 36 lobsters. The research had several test paremeters used to determine the effect of salinity such Osmotic Pressure (TKO), Total Hemocyte Count (THC) and histology of female gills. The statistical test Univariate Analysis of Variance and Duncan Test if (P<0.05) just used TKO parameters. The study discovered that TKO value of 833-1318 mOsmo/L with salinity exerting a strong influences (P<0.05). THC parameters of males showed a low stress response with a range of 3x106 - 14x106 cells/mL, it contrasts with the females had a high stress response with a range of 3x106 - 25x106cells/mL. The Conclusion was the male lobsters gave a low stress response with the ideal salinity of the cultivation, especially at 31⁰/ₒₒ and 34⁰/ₒₒ ware based on good response of maintenance TKO values and low stress levels on THC values

Effects of hyperoxia during oxygen nanobubble treatment on innate immunity, growth performance, gill histology, and gut microbiome in Nile tilapia, Oreochromis niloticus

Oxygen nanobubble (NB–O2) technology has been introduced to the aquaculture industry in recent years. This treatment usually results in a tremendously high level of dissolved oxygen (DO) in the water. However, little is known about the possible negative effects of hyperoxia due to NB-O2 treatment (hyper-NB-O2) on farmed fish. Here, we investigated i) the effect of short-term hyper-NB-O2 exposure (single treatment) on the innate immunity in Nile tilapia, Oreochromis niloticus, and ii) the effect of long-term hyper-NB-O2 exposure (26-day treatments) on survival, growth performance, gill histology, and gut microbiome in Nile tilapia. A single treatment with NB-O2 for 10 min in 50 L of water resulted in 24.2 ± 0.04 mg/L DO (approximately 2-3 × 107 nanoscale oxygen bubbles/mL). This treatment did not result in differences in expression of several immune-related genes (e.g., TNF-α, LYZ and HPS70) in various tissues (e.g., gill, head kidney, and spleen) compared to the non-treated control. Over a 26-day period of exposure, no significant differences were observed in survival and growth performance of the fish, but minor histological changes were occasionally noted on the gills. Analysis of the gut microbiome revealed a significant increase in the genera Bosea, Exiguobacterium, Hyphomicrobium, and Singulisphaera in the group receiving NB-O2. Moreover, no signs of “gas bubble disease” were observed in the fish throughout the duration of the experiment. Overall, these results suggest that both short- and long-term hyper-NB-O2 exposure appears to be benign and has no obvious adverse effects on fish.

Effect of Chlorpyrifos on Histology of Liver, Gills, and Brain of Oreochromis Mossambicus (Peters)

Most of the river waters in Kerala are found to have several pollutants such as heavy metals, plasticizers, and pesticides. Chlorpyrifos, commonly known as Dursban is a broad-spectrum organophosphate insecticide widely used in Kerala to control insects in crops, termites and to control mosquito larvae. This pesticide is known to reach the aquatic ecosystem causing several damages to aquatic organisms. Fish being on top of the food chain bioaccumulation of these pesticide residues are of concern. This study was to find the histological changes in the liver, brain, and gills of Orechromis mossambicus, commonly called Tilapia, a common freshwater edible fish, on exposure to chlorpyrifos for 7, 14, and 21 days to evaluate the extent of toxicity. For this fish, Orechromis mossambicus of age one to three were procured from a local fish farm of Pathanamthitta district, Kerala, and were acclimatized in tanks in the laboratory and exposed to chlorpyrifos for 7, 14, and 21 days and histology of brain, liver, and gills were carried. The microphotographs of the sections show severe damage to these tissues as early as 14 days of exposure.

Thymol-enriched diet alleviates the toxic impacts of zinc oxide nanoparticles on growth performance, blood biochemistry, oxidant/antioxidant status and stress-related genes and histology of liver and gills in Oreochromis niloticus

Dietary natural components emerged as key supplements for protecting fish against aquatic pollutants. In this study, we explored the efficacy of thymol supplementation (1 or 2 g/kg diet) in alleviating the toxic effects induced by exposing Oreochromis niloticus to zinc oxide nanoparticles (ZON) at 1.14 mg/L (equivalent to 1/5th LC50) for 28 days. Relative to control, the fish treated with ZON showed a reduction in the survival rate and growth performance, with the highest zinc residues detected in the liver, followed by muscle and, finally, gills. Alterations were recorded in serum biochemistry reflecting ZON's hepatotoxicity and nephrotoxicity, along with reductions in growth hormone, T3 (triiodothyronine) and T4 (thyroxine). The intestinal amylase, lipase, and protease activities were suppressed with increases in the intestinal Aeromonas and total bacterial counts in the ZON-exposed group. Elevated tissue levels of MDA (malondialdehyde) and PC (protein carbonyl) content, with depletion of the SOD (superoxide dismutase) and CAT (catalase) activities, and GSH (reduced glutathione) levels were also noted in ZON-exposed group, in addition to upregulation of the hepatic HSP-70 (heat shock protein-70), Caspase-3, and P53 (Tumor suppressor protein). Moreover, histomorphological changes were recorded in the ZON-treated fish's liver and gills. Conversely, concomitant administration of thymol with ZON blunted these toxic impacts in a dose-specific manner. Based on these data, thymol could be an effective dietary supplement for stressed fish.

Effects of salinity on gill histology in sailfin velifera (Poecilia velifera)

Effects of salinity on gill histology in sailfin velifera (Poecilia velifera)

Life-cycle exposure to tris (2-chloroethyl) phosphate (TCEP) causes alterations in antioxidative status, ion regulation and histology of zebrafish gills

Tris (2-chloroethyl) phosphate (TCEP) has been receiving great concerns owing to its ubiquitous occurrence in various environmental compartments and potential risks to wildlife and humans. Gill is structural basis for ion regulation and homeostasis in fish and susceptible to xenobiotics. However, current knowledge on the impacts of long-term exposure to TCEP on the structure and physiological function of fish gills are insufficient. In this work, zebrafish were exposed to environmental realistic concentrations (0.8, 4, 20 and 100 μg/L) of TCEP from 3 h post ferterlization (hpf) till 120 days post ferterlization (dpf). Our results demonstrated that life-cycle exposure to TCEP significantly decreased the activity of glutathione S-transferase (GST), but elevated the activities of antioxidative enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and increased malondialdehyde (MDA) content in zebrafish gills. Gene transcription analysis implied that the mRNA expressions of antioxidant-related genes (nrf2, cat and nqo1) were induced, while the transcription of gstα1, hmox1, keap1 were down-regulated, indicating that Nrf2-Keap1 pathway might be activated to defend the oxidative stress induced by TCEP. Additionally, the ion homeostasis was disrupted by TCEP exposure, evidenced by reduced activities of Na+/K+-ATPase (NKA), Ca2+-ATPase and Mg2+-ATPase and downregulated transcription levels of ncc, nkcc, cftr and clc-3. Besides, whole-life exposure to TCEP resulted in a series of structural damages to gills, including epithelial lifting, epithelial rupture, telangiectasis, vacuolation, edema and shortened gill lamellae. Overall, our results demonstrated that long-term TCEP exposure could induce oxidative stress, affect ion regulation and cause histological changes in zebrafish gills.

The protective effect of vitamin C on growth, digestive enzymes, immune response, and gill histology in Caspian roach (Rutilus rutilus caspicus) under diazinon stress

In recent years, the increase in the use of agricultural pesticides has endangered the production of marine creatures. However, exposing farmed creatures to water contaminated with pesticides is one of the current challenges. This study aims to investigate the defensive impact of diets containing varying amounts of vitamin C on the growth, digestive enzyme activity, immune response, and resistance of Caspian roach (Rutilus rutilus caspicus) exposed to diazinon. Fish (average weight: 1.12 ± 0.17 g) were fed diets containing 0 (control; C0), 500 (C1), 1000 (C2), and 1500 (C3) mg/kg of vitamin C for 56 days. Then they were exposed to diazinon stress for 14 days (0.32 mg/liter). The highest final weight and lowest feed conversion ratio were obtained in fish fed a diet containing vitamin C. The highest protease activity and lowest amounts of lipase and amylase were observed in the C3 group. At the end of the feeding period, lysozyme activity, total immunoglobulin amount, and complement (ACH50) in the C3 treatment were significantly higher than in the control treatment. After the stress period, lysozyme and complement activity were higher in all groups fed vitamin C supplements than in the control treatment. The highest levels of stress indicators (cortisol and alkaline phosphatase) were detected in the control group before and after stress. Based on the preparation of gill tissue sections, most lesions included edema, hyperplasia, adhesion of secondary lamellae, and necrosis of gill-covering cells. Overall, the results indicate that adding vitamin C to the diet can be used as a sustainable bioremediation tactic and reduce the adverse effects of diazinon exposure in Caspian roach.

Dibutyl phthalate disrupts energy metabolism and morphology in the gills and induces hepatotoxicity in zebrafish.

This study investigated the acute effects of dibutyl phthalate (DBP) exposure on energy metabolism and gill histology in zebrafish (Danio rerio). The in vitro incubation of gill tissue with 10 μM DBP for 60 min altered tissue energy supply, as shown by decreased lactate content and lactate dehydrogenase (LDH) activity. Higher concentrations of DBP (100 μM and 1 mM) increased lactate content and LDH activity; however, they blocked glucose uptake, depleted the glycogen content in cellular stores, and induced injury to the gills, as measured by LDH release to the extracellular medium. In addition, in vivo exposure of fish to 1 pM DBP for 12 h induced liver damage by increasing alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) activities. Gill histology indicated hyperemia, lamellar fusion, lamellar telangiectasis, and necrosis. Data indicate that acute exposure of zebrafish gills to the higher DBP concentrations studied induces anaerobic cellular activity and high lactate production, causing gill damage, diminishing cell viability, and incurring liver dysfunction.

Histological and hematological changes to Clarias gariepinus juveniles exposed to acute doses of Emamectin benzoate in a static bioassay.

Emamectin benzoate (EMB) is a potent neurotoxic pesticide, extensively used in agriculture and aquaculture in Nigeria. The knowledge of its toxicological impact to C. gariepinus in Nigeria is scarce. Thus, the investigation was designed to uncover its 96 h LC50, safe level to aquatic media, histological impact on fish liver, gill and hematological changes in the blood parameters. 96 h LC50 was 0.34 mg L-1. Safe level of EMB was 0.034 mg L-1. Dose dependent liver degenerations were characterized by; Congestion of the central vein by inflammatory cells, pyknotic nuclei of hepatocytes, coagulation necrosis, focal necrosis, dilations of sinusoidal spaces and infiltration of periportal regions by inflammatory cells. Dose dependent changes in gill were characterized by; mucus secretion, shrinkage of secondary lamellae, hyperplasia, occlusion of secondary lamellae, degeneration of gill cartilage, necrosis of respiratory epithelia and erosion of secondary lamellae. Red blood cell indices decreased minimally at the end of the 96 h exposure. White blood cell count (WBCC), mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) were significantly (p ≤ 0.05) elevated in three treatments. Neutrophils decreased significantly (p ≤ 0.05), basophils, eosinophils and monocytes showed mixed tendencies. The findings of this investigation imply that C. garipinus exposed to EMB may cause dose and time-dependent changes in the liver and gill histology as well as alterations in the fish's hematological profile, all of which were harmful to the fish's health. To avoid negative effects on fish in nearby aquatic settings, it is advised that the use of EMB be monitored and limited.

A Study of Cr (VI) Induced Toxicity on the Histology of Gill, Liver, Kidney of Freshwater Fish Channa punctatus (Bloch. 1793)

A Study of Cr (VI) Induced Toxicity on the Histology of Gill, Liver, Kidney of Freshwater Fish Channa punctatus (Bloch. 1793)

Sampling artefacts in gill histology of freshwater Atlantic salmon (Salmo salar)

Fish gills are delicate structures, which are vulnerable to damage from pathological as well as non-pathological aetiologies. They are frequently sampled for histology as they are involved in many recognised disease processes. Artefacts, arising from sampling techniques, can potentially interfere with interpretation of gill histology. A range of possible processes that can result in sampling artefact were assessed in a group of freshwater Atlantic salmon (Salmo salar) pre-smolts. A range of histopathologies resulted, illustrating how critical both sampling efficiency and careful tissue handling are for optimal tissue sections to enable accurate histopathological interpretation.