Lamellar Epithelium Research Articles

Morphological, Histological, and Phylogenetic Characterization of Myxobolus branchioepidermis n. sp. (Myxosporea: Myxobolidae) Infecting the Gills and Skin of the Oranda Goldfish (Carassius auratus).

Myxobolus Bütschli, 1882 is a highly important genus of fish myxozoans, consisting of many species that cause serious diseases in ornamental cyprinid fish species in different geographic areas by infecting a wide range of organs. This study describes a new Myxobolus species infecting the gill lamellae, gill rakers and skin epidermis of goldfish (Carassius auratus) from Mohammadshahr, Iran, based on detailed morphological, histological and molecular analysis. Mature spores were small and spherical in shape, consisting of two symmetrical shell valves in frontal view, measuring 10.3 (9.8-10.9) μm in length and 10.5 (10.3-11.2) μm in width. Two equal-sized relatively pyriform polar capsules were 5.4 (3.9-6.0) μm long and 4.5 (3.7-5.2) μm wide. The polar tubules were coiled with 4-6 turns. A comparative analysis of the morphological and molecular data confirmed that this species is distinct from other identified myxosporeans. Plasmodia in the cutaneous tissue were found in the epidermis, causing extensive hyperplasia of Malpighian cells and mild inflammatory infiltration. In the gill tissue, plasmodia affected only one side of the lamellae, leading to hyperplasia of the lamellar epithelium, edema, and lymphoplasmacytic branchitis. A novel myxozoan species, Myxobolus branchioepidermis n. sp., has been proposed. The study provides a comprehensive analysis of the morphological, histological, and molecular characteristics of this parasite, which infects the gill lamellae and epidermal layer of the skin in oranda goldfish (C. auratus). The identification of this new species adds to the growing body of research on myxozoan parasites and highlights its potential impact on ornamental fish aquaculture.

Effects of urban streams on muscle non-protein thiols, gill and liver histopathology in zebrafish (Danio rerio) assessed by active biomonitoring

Aquatic biota are exposed to toxic substances resulting from human activities, reducing environmental quality and can compromise the health of the organisms. This study aimed to employ Danio rerio as an environmental bioindicator, analyzing the effects of water from distinct urban aquatic environments. An active biomonitoring system was set up to compare the temporal dynamics of histological biomarkers for gill and liver and the patterns of non-protein thiols (NPSH) in muscle in specimens exposed for 3, 6, and 12 days. Three large urban basins in the city of Campo Grande (Midwest of Brazil) were selected. Two sites are in a very populous area (i.e Lagoa and Bandeira) and another on in an area with agricultural activities (i.e Anhanduí). All the streams displayed distinct qualitative characteristics. The presence of metals, including Mn, Zn, Fe, and Al, as well as pH, temperature, and dissolved oxygen, accounted for 38% of the variability (PC1), while total solids, conductivity, ammonia, nitrite, and explained 24 % (PC2). Degree tissue changes index (DTC) in gill and the concentration of NPSH increased in all streams during 3, 6 and 12 days of exposure. DTC in liver increases in all exposure times in most populous stream (i.e Lagoa and Bandeira). Histopathological evidence in the gill, including proliferation, desquamation, and necrosis of the primary lamellar epithelium; fusion and aneurysms in the secondary lamellar epithelium were observed after three days of exposure. Degenerative nuclear figures were noted in the liver after three days of exposure, followed by hepatocellular hypertrophy, lipidosis, and necrosis at twelve days. Our findings showing time-dependent effects of urban aquatic environments in histopathological (i.e DTC) and biochemical biomarkers in zebrafish. The biomonitoring model enabled a comparison of the temporal dynamics of various health markers, using zebrafish as bioindicator. Future studies might use this experimental model and biomarkers for environmental biomonitoring program.

Physiological and biochemical studies of young sterlet sturgeon (Acipenser ruthenus L.) in the lower reaches of the Volga river

In conditions of a decrease in the number of rolled sturgeon larvae in the lower reaches of the Volga River, an urgent issue is the study of the physiological and biochemical parameters of the fish organism. The purpose of this work is to conduct physiological and biochemical studies of juvenile sterlet (Acipenser ruthenus L, 1758). The study of fish was carried out using the methods of classical histology and biochemistry. The degree of damage to the gills and liver was assessed on a scale from 1 to 5 points. The content of total lipids and water-soluble protein in the muscle tissue of sterlet fingerlings was studied as biochemical parameters. The morphological picture of the gills of 80% of the fish corresponded to a weakly pronounced character of changes (2 points), while in others it was characterized by the presence of a borderline state between weakly pronounced changes and moderate injuries (2–3 points). Six types of disorders were found in the gills: hyperplasia of the respiratory epithelium of lamellae, dilation of the blood vessel of the filament, goblet-shaped swellings of the apical part of the filament, invasions, expansion of the apical part of the lamellae, proliferation of connective tissue of lamellae. In the liver of 80% of fish, a borderline state was recorded between mild changes and moderate damage (2–3 points), in 13.3% of individuals the liver had mild damage (2 points), in 6.7% there were medium damage (3 points). Four types of disorders were found in the liver of juvenile sterlet: fullness of the liver capillaries, pronounced venous fullness, cavities, capillary dilation. In the muscle tissue of fingerlings, the concentrations of total lipids were in the range of 1.39–5.28%, and water-soluble protein — 45.59–57.97 mg/g. The study of the physiological and biochemical parameters of juvenile sturgeon in the lower reaches of the Volga River is very important for the biology of the species and monitoring the natural reproduction of these valuable fish species.

Histopathology and micronuclei induction as pollution biomarkers in common carp, Cyprinus carpio from southern Iraq

This study aimed to assess the histopathological alterations and micronuclei induction in the gill, kidney and liver of common carp, Cyprinus carpio from Al-Huwaizah Marshes, Al-Hammar Marshes and Al-Sweap River. Thirty C. carpio were sampled at each locality using monofilament gillnets. Most prominent histopathological alterations recorded in the gill included formation venous sinus in primary lamellae, oedema, curling and distortion of primary lamellae fusion of secondary lamellae, hyperplasia of epithelial cells, necrosis, curling of secondary lamellae, severe dilation of lamellar capillaries, clavate lamellae formation at the tip of secondary lamellae, a proliferation of cartilage tissue in primary lamellae and lifting of the lamellar epithelium whereas congestion, fibrosis with proliferative inflammation, necrosis area, degenerated cells, vacuolar degeneration, vacuolation, nuclear pyknosis, hypertrophy of hepatocytes were reported in the liver. In the kidney, the most pronounced changes were necrosis of the hematopoietic tissue, hyaline droplet and activation of melanomacrophage centres. A higher prevalence of alterations was observed in the population from Al-Huwaizah Marshes, however, Al-Hammar population exhibited severe pathologies. Micronuclei frequency was significantly higher at Al-Huwaizah Marsh (p < 0.05) with low frequency being recorded at Al-Sweap River. This study attests to the effectiveness of histopathology and micronucleus induction as potential tools for discriminating the health of populations from different water bodies.

Assessment of patho-physiological responses, gill histopathology and SEM analysis in common carp (Cyprinus carpio) exposed to varied doses of chloramine-T: A potent chemotherapeutic agent

Chloramine-T (Cl-T) is a chemo-therapeutant used at aquafarms to control fish mortalities associated with bacterial and parasitic infections in freshwater aquaculture. It is also effective as a disinfectant against a wide range of viruses known to cause disease in fish. However, a very little information is available on the patho-physiological alterations in common carp (Cyprinus carpio) exposed to different doses of Cl-T. Herein, the present study aimed to assess the patho-physiological changes in common carp exposed to different doses of Cl-T (20 mg/L, 100 mg/L, and 200 mg/L) for 15 days followed by a post-exposure assessment for another 15 days. The results indicated a significant decrease in haematological indices viz., Total Erythrocyte Count (TEC), Total Leucocyte Count (TLC), Total Platelet Count (TPC), Haemoglobin (Hb), Haematocrit (Hct), and Mean Corpuscular Haemoglobin Concentration (MCHC) at higher Cl-T concentrations. Whereas, a decrease in some of the immune-biochemical parameters was also noted viz., lysozyme, NBT, Total Ig, phagocytic activity, protein, albumin and globulin in a dose-dependent manner. However, a significant increase in Mean Corpuscular Volume (MCV) and glucose levels was observed during exposure period. Histopathological analysis revealed gill hypertrophy, fusion of secondary lamellae, sloughing of lamellar epithelium and gill necrosis which were more pronounced with increasing concentration of Cl-T. The maximum damage to the gill was noted at a concentration of 200 mg/L. Whereas, scanning electron microscopic (SEM) analysis of gill revealed sloughing of lamellar epithelium, reduced interlamellar space and hypertrophy of secondary lamellae in Cl-T exposed fishes. Together, these results suggest that Cl-T exposure in common carp at 20 mg/L has a mild and acceptable effect on gill and physiology of fish, 100 mg/L has moderate effect, and 200 mg/L causes extensive damage to gills and physiology of fish.

Mechanisms of ammonotelism, epithelium damage, cellular apoptosis, and proliferation in gill of Litopenaeus vannamei under NH4Cl exposure.

Excessive ammonia-N in coastal environment and aquaculture threatens the health of marine organisms. To explore the mechanism of gill damage induced by ammonia-N, transcriptome of Litopenaeus vannamei 's gill was carried out under 20 mg/L NH4Cl for 0, 6, and 48 h. K-means clustering analysis suggested that ammonia excretion and metabolism-related genes were elevated. GO and KEGG enrichment analysis suggested that glycosyltransferase activity and amino acid metabolism were affected by ammonia. Moreover, histological observation via three staining methods gave clues on the changes of gill after ammonia-N exposure. Increased mucus, hemocyte infiltration, and lifting of the lamellar epithelium suggested that gill epithelium was suffering damage under ammonia-N stress. Meanwhile, the composition of extracellular matrix (ECM) in connective tissue changed. Based on the findings of transcriptomic and histological analysis, we further investigated the molecular mechanism of gill damage under multiple concentrations of NH4Cl (0, 2, 10, 20 mg/L) for multiple timepoints (0, 3, 6, 12, 24, 48, 72 h). First, ammonia excretion was elevated via ion channel, transporter, and exocytosis pathways, but hemolymph ammonia still kept ata high level under 20 mg/L NH4Cl exposure. Second, we focused on glycosaminoglycan metabolism which was related to the dynamics of ECM. It turned out that the degradation and biosynthesis of chondroitin sulfate (CS) were elevated, suggesting that the structure of CS might be destructed under ammonia-N stress and CS played an important role in maintaining gill structure. It was enlightening that the destructions occurred in extracellular regions were vital to gill damage. Third, ammonia-N stress induced a series of cellular responses including enhanced apoptosis, active inflammation, and inhibited proliferation which were closely linked and jointly led to the impairment of gill. Our results provided some insights into the physiological changes induced by ammonia-N and enriched the understandings of gill damage under environmental stress.

Feeding characteristics and assessment of histopathological changes in the organs of the Sandpiper goby (Neogobius fluviatilis)

The paper presents data from ichthyological, trophological and histological studies of the Sandpiper goby (Neogobius fluviatilis) endemic to the Caspian Sea, which has an important role in trophic chains, as food object for sturgeon, semi-migratory fish species, marine migratory Clupeidae family and Caspian seal. Place of sampling for the study were stations in the Northeastern part of the Caspian Sea, which is inferior in trophic content to its other parts, which had confirmed by data from trophic studies. The basis of the studied fish nutrition was Polychaeta, Bivalvia, Crustacea and in some cases juvenile fish, which indicates their nutritional plasticity, and the fact that they are not competitors to each other in nutrition. Depending on results of fish’s visceral organs histological studies, structural changes were determined, which were more adaptive in nature and were a response to the impact of aquatic environment factors. In gills was found protozoan invasion causing hyperplasia of secondary lamellae epithelium and sloughing of respiratory epithelium. There were growths of the epithelial layer of villi in the intestine. In the liver and pancreas were detected fatty degeneration and necrotic changes. In all organs were found microcirculatory disorders, including the presence of erythrocytes with hyperchromic cytoplasm.

Toxicity of crude extract of <i>Terminalia superba</i> sawdust to <i>Clarias gariepinus<i/> (Burchell 1822)

The study examined the toxicity of Afara tree (Terminalia superba) sawdust extract to African catfish, Clarias gariepinus. The fish were exposed to four concentrations 55 ml/L, 60 ml/L, 65 ml/L, 70 ml/L and the control for 96 hours. C. gariepinus juveniles exposed to sublethal concentrations of T. superba extract were examined in a static bioassay with reference to behavioural, haematological and histopathological changes. Early observations of fish exposed to T. superba extract showed erratic swimming, loss of equilibrium and respiratory distress. The behavioural response was dose-dependent and decreased with a decrease in concentration. At 24-96 hours of exposure, there were no significant differences in the temperature and pH (p>0.05) while there was a significant difference (p<0.05) in dissolved oxygen at 48-96 hours. The haematological results showed varying degrees of effects of the extracts on blood parameters. The histopathological changes of the gills of fish exposed to T. superba at 65-70 ml/L showed gills distortion, epithelial hyperplasia and disruption of primary lamellar epithelium and that of gills of fish in the control revealed a normal gill filament. Also, the liver of C. gariepinus of the control fish revealed normal structures. Histology of the liver of C. gariepinus in 65 ml/L and 70 ml/L showed varying degrees of space formation, vacuoles in the tissue and increased haemorrhage. The LC50 value of 53.35 ml/L was gotten. It was therefore concluded that sawmill wood waste did not only impact the water quality but also negatively affected the proper functioning of the gills and liver of C. gariepinus.

Biological responses to imazapic and methyl parathion pesticides in bioinspired lipid membranes and Tilapia fish

Pesticide misuse has well-documented detrimental effects on ecosystems, with Nile tilapia (Oreochromis niloticus) being particularly vulnerable. The current study focuses on the impact of widely used sugarcane crop pesticides, Imazapic (IMZ) and Methyl Parathion (MP), on tilapia gill tissues and their lipid membranes. This investigation was motivated by the specific role of the lipid membrane in transport regulation. Bioinspired cell membrane models, including Langmuir monolayers and liposomes (LUVs and GUVs), were utilized to explore the interaction of IMZ and MP. The results revealed electrostatic interactions between IMZ and MP and the polar head groups of lipids, inducing morphological alterations in the lipid bilayer. Tilapia gill tissue exposed to the pesticides exhibited hypertrophic increases in primary and secondary lamellae, total lamellar fusion, vasodilation, and lifting of the secondary lamellar epithelium. These alterations can lead to compromised oxygen absorption by fish and subsequent mortality. This study not only highlights the harmful effects of the pesticides IMZ and MP, but also emphasizes the crucial role of water quality in ecosystem well-being, even at minimal pesticide concentrations. Understanding these impacts can better inform management practices to safeguard aquatic organisms and preserve ecosystem health in pesticide-affected environments.

Global warming and nanoplastic toxicity; small temperature increases can make gill and liver toxicity more dramatic, which affects fillet quality caused by polystyrene nanoplastics in the adult zebrafish model

Increasing nanoplastics (NPs) pollution may lead to unknown environmental risks when considered together with climate change, which has the potential to become an increasingly important environmental issue in the coming decades. In this context, the present study aimed to evaluate the stressor modelling of polystyrene nanoplastic (PS-NPs) combined with temperature increase in zebrafish. For this purpose, changes in gill, liver and muscle tissues of zebrafish exposed to PS-NPs (25 ppm) and/or different temperatures (28, 29 and 30 °C) for 96 h under static conditions were evaluated. The results obtained emphasize that exposure to PS-NPs stressors under controlled conditions with temperature increase induces DNA damage through stress-induced responses accompanied by degeneration, necrosis and hyperaemia in zebrafish liver and adhesion of lamellae, desquamation and inflammation in lamellar epithelium in gills. Metabolomic analyses also supported changes indicating protein and lipid oxidation, especially PS-NPs-mediated. These findings will contribute to the literature as key data on the effects of PS-NPs presence on protein/lipid oxidation and fillet quality in muscle tissues.

Revealing the environmental pollution of two estuaries through histopathological biomarkers in five fishes from different trophic guilds of northeastern Brazil

Estuaries in Brazil are mostly anthropically affected due to the discharge of industrial and domestic effluents. In two of them, the Santa Cruz Channel Estuary (ITAP) and Sirinhaém River Estuary (SIR), historically affected by mercury pollution and sugarcane industry in Northeast Brazil, we assessed environmental pollution using liver and gill histopathological biomarkers in fish from different trophic levels. Liver samples exhibited serious damages such as hepatic steatosis, necrosis, and infiltration. The gills showed moderate to severe changes, such as lifting of epithelial cells, lamellar aneurysm, and rupture of lamellar epithelium. Most of the changes in the liver and gills were reported for species Centropomus undecimalis and the Gobionellus stomatus, which were considered as good sentinels of pollution. The combination of biomarker methodologies was efficient in diagnosing the serious damage to the species, reinforcing the need for monitoring the health of the ecosystems evaluated.

Toksisitas Letal (LC50) Zat Surfaktan Linear Alkylbenzene Sulfonate terhadap Ikan Cere (Gambusia affinis)

Mosquito fish (Gambusia affinis) is a species often used as a bioindicator because it has high adaptability to water quality changes. Linear alkylbenzene sulfonate (LAS) is a surfactant often found in waters and can cause death for the biota that lives in it. This study aimed to analyze the impact of LAS surfactant on the survival of mosquito fish and to determine the minimum concentration of LAS surfactant that can cause death and tissue damage. Research conducted during April 2022 using 500 mosquito fishes. We did several tests, including a lethal toxicity test to find out the concentration of LAS surfactant that can cause death and tissue damage. The results showed that the LC50 values of LAS surfactants at exposure times of 24, 48, 72, and 96 hours were 7.64, 7.43, 7.29, and 6.83 mg/L, respectively. Mosquito fish blood glucose levels at LAS concentrations of 0, 2.65, 4.30, 6.97, and 11.3 were 56, 75, 79.6, 95, and 95.6 mg/dl. Exposure to LAS surfactant in mosquito fish can cause gill damage in the form of edema, lamella fusion, hyperplasia, lamellae epithelium swelling, and gill filaments necrosis. Another damage occurs to the liver in the form of blockage of blood vessels and sinusoids, hyperplasia, widening of the hepatic sinusoid gap, fat accumulation, and necrosis of hepatocytes.

ANTIOXIDANT ACTIVITIES OF MORINGA OLEIFERA LEAF EXTRACT AGAINST ARSENIC INDUCED TOXICITY IN CIRRHINUS MRIGALA

This experimental study was conducted to evaluate the antioxidant activities of Moringa oleifera leaf extract against Arsenic (As) induced toxicity in Cirrhinus mrigala in Tawakkal Fish Hatchery at Muzaffargarh, Punjab, Pakistan. 288 fingerlings were collected from fish pond and kept in circular tank for acclimatization. 12 fish about 100-day old having similar size were selected randomly and kept in separate glass aquaria for each treatment groups T1, T2, T3 and control group T4. Fish in treatments groups T1, T2 and T3 were exposed with water born sublethal concentration of 1/10th LC50 of arsenic (As) for 7days (240 hours). On 8th and 16th days of the experiment three fish were collected from each aquarium, humanly dissected targeted organ was taken out and used for liver, muscle, and gills antioxidant enzyme activities and histopathological alteration. The findings indicate that in treatment group T2 which feed with 2% and 4% Moringa oleifera supplemented diet reduced significantly (P<0.05) arsenic induced oxidative stress in fish, enhance the superoxide dismutase and catalase activities but treatment group T2 is 2% Moringa oleifera supplemented diet is more effective near to control group T4 as compared to treatment group T3 with 4% Moringa oleifera supplemented. After 16 days exposure of 1/10th concentration of arsenic with 0% Moringa oleifera various degenerative alteration were seen in gills. In 2% and 4% Moringa oleifera with 1/10th arsenic, spiked secondary lamellae and lamellar epithelium lifting (EL) and rupture of epithelial layer (↑↑) and fusion of lamellae were observed at several points. Moringa oleifera is medicinal herb, which has various tremendous benefits.

Determination of acute toxicity of sodium pyrithione and its exposure effects on antioxidant enzymes activity, immune status, and histopathological changes in common carp

ABSTRACT This study determined the LC50-24 h value of sodium pyrithione (NaPT) on Cyprinus carpio at 102.7643 µg/L. Then, 60 healthy fish were randomly allocated into 6 exposure groups, each receiving varying levels of NaPT for different durations (control goup = 0% µg/L NaPT for 24 and 96 h; NaPT-10 = 10% of the LC50-24 h dose of NaPT for 24 and 96 h; NaPT-20 = 20% of the LC50-24 h dose of NaPT for 24 and 96 h). As a result, the increase in malondialdehyde (MDA) levels and the decrease in catalase (CAT), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) activities in the gill and liver tissue in both duration and dose groups were found to be statistically significant. In addition, NaPT increased serum tumour necrosis factor (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6) levels in both dose groups for both durations. The results revealed that NaPT exposure caused shortening of gill tissue lamellae and vacuolisation (separation) of the secondary lamellar epithelium. Likewise, NaPT exposure was responsible for vacuolisation and hepatocellular degeneration in liver tissue in hepatocytes. In conclusion, the toxicity study, antioxidant enzyme activities, cytokine immune response, and histopathological results indicate that NaPT has a toxic effect on the carp.

Morphological and genotoxic analysis of fish of the Okhchuchay River in Zangilan District

In July 2022, monitoring of the transboundary Okhchuchay River was carried out from the borders with Armenia deep into the Zangilan District of Azerbaijan. The Okhchuchay River is playing the role of an industrial waste collector, as it is constantly polluted with waste from the Kafan and Gajaran mining industries in Armenia. From the five monitoring points studied, only two specimens of Oxynoemacheilus brandtii were caught. For morphological and genotoxic studies, samples of peripheral blood, liver, and gills were taken. The analysis showed that in the gills of Oxynoemacheilus brandtii, hyperplasia of the interlamellar epithelium and respiratory epithelium of secondary lamellae, complete fusion of secondary lamellae, uneven distribution of hyperplasia of secondary lamellae, and detachment of the respiratory epithelium were detected. Expansion of sinusoids, melanomacrophage centers, and necrotic changes were revealed in the liver. When examining the blood, among the changes in the structure of the nucleus of erythrocytes, karyolysis, karyorrhexis, deformation of the nucleus, parietal nuclei, eccentric nuclei, and hemoglobin breakdown were observed. The obtained data confirm the catastrophic ecological state of the Okhchuchay basin.

Особенности изменений внутренних органов кефали-сингиля Liza aurata (Risso, 1910)

The purpose of the study is to analyze the changes in the internal organs of golden mullet specious caught in May 2022 in the scientific expeditions to the western part of the Caspian Sea. Mature mullets were examined. The caught species were weighed and measured. There were made 152 histological sections of 10 species (liver, spleen, gills, ovaries, muscles). The studied species were 3-4 years old. The collected samples were processed by classical histological techniques. According to the results of the conducted histological research, there have been found the numerous changes in the studied organs that indicate the adaptive capabilities of the fish: microcirculatory disorders (extensions of different sizes and durations in time), different abnormalities in the gills structure (proliferation of multilayer non-keratinizing epithelium of filaments and lamellae usually met in different species in the Volga river today), fatty hepatic degeneration to some degree, hemosiderosis of the spleen. Changes in the epithelium of the gills were estimated as 2.8 points, changes in the spleen – as 3.1 points. Hemosiderosis was also detected in the liver parenchyma; the changes made 2.5 points. Some skeletal muscle fibers were segmented; their change was estimated as 2.5 points. Cardiomyocytes had different thickness; their changes were estimated as 2.3 points. In general, the studied tissue and cell changes of the gill apparatus, liver, spleen, skeletal muscles and ovary indicated the morphological rearrangement caused by the adaptive response of the fish organisms to the environmental conditions.

Histopathological evaluation of Wallago attu (Bloch & Schneider, 1801) infested by ectoparasites

BackgroundHost-parasite interaction studies represent the dependency of the parasites on the host through various models. Gill infesting copepods, monogeneans and isopods served as excellent models to study the details of host-parasite interaction. In the present investigation, Wallago attu (Bloch & Schneider, 1801) was extensively studied for histopathological damage caused by ectoparasites like monogeneans (Thaparocleidus indicus, Thaparocleidus wallagonius and Mizelleus indicus), copepod (Ergasilus malnadensis) and an isopod (Alitropus typus) during August 2017 to February 2018. Both the control (least infested) and severely infested gills were examined through light microscope to approximate the intensity of damage caused by above ectoparasites.ResultsPathological effects of ectoparasites displayed a fusion of secondary lamella, hyperplasia of the gill filaments and the epithelial cells, propagation of bronchial tips, thinning of the central axis, deshaping, shortening and fusion of secondary gill lamellae epithelium, severe degenerative and necrotic changes in gill filaments and secondary lamellae, curling of secondary lamellae and mucous cells proliferation.ConclusionsEctoparasites cause severe damage to gills of W. attu, thereby diminishing the gill breathing capacity of the fish. Timely pathological studies can reveal the extent of damage caused by the parasites and thus various diagnostic programs and best management practices can be implemented in aquaculture for the better yield.

Histopathological changes and tissue residue concentrations of monosex Nile tilapia (Oreochromis niloticus, L) fries exposed to oxytetracycline.

The current study evaluated the biosafety of oxytetracycline (OTC) exposure for 30 days in monosex Oreochromis niloticus fries. The fries were exposed to OTC for 3 h/day for 30 days at 350 (0.5X), 700 (1X), 2100 (3X), 3500 (5X), and 7000 (10X) mg/L and compared with control (0X). The OTC exposure at 5X and 10X concentrations caused 100% mortality within 4 days and 5 min, respectively. The mortalities recorded in 0.5X, 1X, and 3X groups were 3.33 ± 1.15%, 14.67 ± 1.15%, and 47.33 ± 11.37% on day 30, respectively. The feed intake was decreased up to 23.33% in the 3X group during the exposure period. The OTC residue levels on 30-day exposure were 216.53 ± 14.71, 450.56 ± 44.31, and 1141.26 ± 63.64 μg/kg, which reduced to 40.40 ± 3.25, 76.68 ± 2.77, and 95.61 ± 5.13 μg/kg after 15 days of termination of exposure in the 0.5X, 1X, and 3X groups, respectively. The histopathological changes observed in the 1X group were epithelial detachment, desquamation of secondary lamellar epithelium, lamellar fusion, and inflamed cartilaginous core in the gills, alteration in the integrity of gut mucosa, degeneration of muscularis mucosae and necrosis in the intestine, the disintegration of the nephritic tubule, necrosis, and glomerulopathy in the kidney, and dilated vascular duct, necrotized hepatic tissue, diffused hepatic parenchyma, vacuolation, and fatty changes in the liver. The OTC exposure induced marked tissue changes histologically in a dose- and time-dependent manner, which undoubtedly reduced the growth of tilapia.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10499-022-00892-w.

Oxidative Stress and Histopathological Changes in Gills and Kidneys of Cyprinus carpio following Exposure to Benzethonium Chloride, a Cationic Surfactant.

One cationic surfactant with a wide spectrum of microbiocidal activity is benzethonium chloride (BEC). Despite being widely used, the toxicity data on vertebrate organisms are limited. Therefore, we aimed to evaluate within this study the acute toxicity of BEC on the gills and kidneys of Cyprinus carpio (European carp). An alteration of the antioxidant enzymes activities (glutathione reductase, glutathione peroxidase and glutathione S-transferase) was noticed after 96 h of exposure, along with an elevation of lipid peroxidation and decreased concentration of reduced glutathione, which confirmed that BEC was able to induce toxicity to these tissues. These metabolic effects were correlated with unspecific structural changes observed in gills and kidneys, having moderate degree of severity (such as an increase of melanomacrophages aggregation incidence and cytoplasm vacuolation of goblet cells in collecting tubules) and generally being compatible with life for the exposure time studied. The most severe structural effects were observed in gills after 96 h, noticing a lamellar aneurysm, hemorrhages and lamellar epithelium disruption due to the blood vessels and pillar cells damages and increased blood flow inside the lamellae. By our research we can confirm the utility of biochemical and histological analyses in the fish organs as tools for monitoring the water quality and ecotoxicological potential of chemicals.

Morphological and histochemical studies on the olfactory rosette of bagrid catfish, Rita kuturnee (Sykes, 1839)

In the present study, the functional anatomy, histological features and histochemical localization of two enzymes viz., alkaline phosphatase (ALPase) and adenosine triphosphatase (ATPase) of the olfactory epithelium in Rita kuturnee were described. The structural organization of the olfactory epithelium was studied by using the histological and histochemical techniques. The morpho-anatomical study revealed that the paired olfactory chambers were situated at the dorsal-lateral sides of the snout, which was communicated outside by an anterior and posterior nasal openings. The elongated olfactory rosette lied at the bottom of chamber and supported with 54-56 lamellae on either side of the central narrow raphe. The histological analysis characterized the olfactory epithelium of lamellae which was made up of receptor, flagellated supporting, non-flagellated supporting, labyrinth, mucous and basal cells. Intense alkaline phosphatase and adenosine triphosphatase activity were evidenced in the receptor cells, supporting cells, basal cells and also in blood cells of the central core. Various cells lining the olfactory epithelium were correlated with the functional significance of the fish was concerned.