Erhan Ünlü

Sublethal effects of commercial deltamethrin on the structure of the gill, liver and gut tissues of mosquitofish, Gambusia affinis: A microscopic study.

The histopathological effects of deltamethrin on the gill, liver and gut tissues of the mosquitofish, Gambusia affinis were determined by light microscopy. The fish were exposed to two sublethal concentrations of deltamethrin (0.25-0.50μg/l) for periods of 10, 20 and 30 days. The most common gill changes at all doses of deltamethrin were desquamation and necrosis. Besides, epithelial hypertrophy, lifting of the lamellar epithelium, oedema, dilatation of the capillaries primary lamellae, aneurism, epithelial hyperplasia and fusion of the secondary lamellae were other histopathological effects. Hepatic lesions in the liver tissues of fish exposed to deltamethrin were characterized by hypertrophy of hepatocytes, significant increase of kupffer cells, circulatory disturbances, focal necrosis, fatty degeneration, nuclear pycnosis and narrowing of sinusoids. Infiltration of mononuclear leucocyte and eosinophils towards lamina propria, necrosis were detected in gut tissues of fish after exposure to deltamethrin.

Histopathology of lambda-cyhalothrin on tissues (gill, kidney, liver and intestine) of Cirrhinus mrigala

The histopathology of lambda-cyhalothrin, a synthetic pyrethroid pesticide, on the gill, liver, intestine and kidney tissues in fish, mrigal (Cirrhinus mrigala), which is one of Indian major carp species were determined by light microscopy. The fish were experimentally exposed to sub-lethal concentrations (0.3ppb and 0.6ppb) of lambda-cyhalothrin for 10 days. Tissues were normal in the control group. Epithelial hyperplasia, aneurism, epithelial necrosis, desquamation, epithelial lifting, oedema, shortening of secondary lamellae and lamellar fusion were observed in gill tissues exposed to lambda-cyhalothrin. Necrosis of tubular epithelium, cloudy swelling of epithelial cells of renal tubules, narrowing of the tubular lumen, contraction of the glomerulus and expansion of space inside the Bowmans capsule were observed in the kidney tissues of fish after exposure. Hepatic lesions in fish exposed to lambda-cyhalothrin were characterized by hypertrophy of hepatocytes, cloudy degeneration, congestion, karyolysis, karyohexis, dilatation of sinusoids and focal necrosis. The intestinal lesions included infiltration of eosinophils into the lamina propria and atrophy of epithelial cells. The present study proves its toxic potential in terms of the damages induced by lambda-cyhalothrin in organ level. In natural condition lambda-cyhalothrin will be less than the present study, but continuous usage of the pesticide might lead to the concentration that was used in the experimental condition.

Cypermethrin-induced histopathological and biochemical changes in Nile tilapia (Oreochromis niloticus), and the protective and recuperative effect of ascorbic acid

The objective of this study was to investigate the effects of ascorbic acid on the toxicity of cypermethrins on histopathological lesions in tissues and protein, glycogen levels in Oreochromis niloticus. Nile tilapia was exposed to 0.22 and 0.44 μg/l cypermethrin+control diet, 0.22 and 0.44 μg/l cypermethrin+ascorbic acid supplemented diet for 20 days. The fish were allowed recuperation period of 15 days in pesticide-free water and fed with ascorbic acid suplementation diet. In light microscopic investigation, histopathological lesions were observed in the gill, liver and kidney. The severity of lesions accreted depending on increased pesticide concentration and control diet. Some of the lesions were reversible or at least were less pronounced after recuperation period. Protein levels decreased in some groups after treatment period according to control groups (p<0.05). The highest depletions in liver, muscle and gill protein levels were found in 0.44 μg/l cypermethrin+ascorbic acid supplemented diet group (62.23%), in 0.22 μg/l cypermethrin+control diet group (53.12%) and in 0.44 μg/l cypermethrin+control diet group (61.87%) after 10 days, respectively. These levels increased at the end of the recuperation period. The highest depletion in liver glycogen levels was found in 0.22 μg/l cypermethrin+control diet group (50.50%) after 10 days (p<0.05). At the end of recuperation period, there was no difference between the groups (except 0.22 μg/l cypermethrin+ascorbic acid supplemented diet group) and controls. The decrease of muscle glycogen, except 0.22 μg/l cypermethrin+ascorbic acid supplemented diet group, was recorded at the end of 10 and 20 days. In the recuperation period, an increase was observed at all groups. These results revealed that the histopathology, protein and glycogen can work as good indicators of stress of a toxicant on fish. Ascorbic acid serves fish as an antitoxic agent against pesticide toxicity.

THE HISTOPATHOLOGICAL EFFECTS OF THIODAN® ON THE LIVER AND GUT OF MOSQUITOFISH, GAMBUSIA AFFINIS

Thiodan® (33.7% endosulfan), a polychlorinated cyclodiene insecticide, was evaluated for its histopathological effects on mosquitofish, Gambusia affinis, by light microscopy. Fish were exposed to doses of 0.00 (control), 1.00, 2.50, and 5.00 μg/L on days 7, 14, 21, and 30. No histopathological effects were apparent at control group. The histopathological alterations were characterized as oedema, degeneration, accumulation of lymphocytes in the lamina propria, disintegration of villuses, pycnotic state of nuclei, and necrosis in gut; degeneration, hypertrophy, sinusoids enlargement, hemorrhage, pycnosis position of nuclei, vacuolization of cell cytoplasm, infiltration of mononuclear lymphocyte, and congestion in liver. These alterations were time- and dose-dependent.

The effects of fenvalerate on different tissues of freshwater fish Cirrhinus mrigala

The histopathological changes of fenvalerate on the gill, kidney, liver and intestine tissues of the Cirrhinus mrigala were determined by light microscopy. The fish were exposed to two sub-lethal concentrations of fenvalerate (1.5–3.0 ppb). The most common gill changes at all concentrations of fenvalerate were epithelial hyperplasia, epithelial necrosis, desquamation and lamellar fusion. Besides, epithelial lifting, oedema, swelling at the tips of secondary lamellae and curling of secondary lamellae were other histopathological changes. Necrosis of tubular epithelium, pycnotic nuclei in the hematopoietic tissue, hypertrophied epithelial cells of renal tubules, narrowing of the tubular lumen, expansion of space inside the Bowmans capsule and contraction of the glomerulus were observed in kidney tissues of fish. Hepatic lesions in the liver tissues of fish exposed to fenvalerate were characterized by congestion, cloudy swelling of hepatocytes and focal necrosis. Atrophy of epithelial cells, necrosis of epithelial cells, desquamation of mucosal epithelium and infiltration of lymphocytes into the lamina propria were detected in intestine tissues of fish after exposure to fenvalerate.

Histopathological changes in the gill and liver tissues of freshwater fish, Cirrhinus mrigala exposed to dichlorvos

The histopathological effects of dichlorvos, an organophosphate pesticide, on the gill and liver tissues in Cirrhinus mrigala were determined by light microscopy. The fishes were exposed to sublethal concentrations (0.91 and 1.82 ppm) of dichlorvos for 10 days with parallel untreated control. No histopathological effects were observed in control group. Hyperplasia, desquamation, and necrosis of epithelial, epithelial lifting, oedema, lamellar fusion, collapsed secondary lamellae, curling of secondary lamellae and aneurism in the secondary lamellae were observed in gill tissues exposed to dichlorvos. Hepatic lesions in the liver tissues of fishes exposed to dichlorvos were characterized by cloudy swelling of hepatocytes, congestion, vacuolar degeneration, karyolysis, karyohexis, dilation of sinusoids and nuclear hypertrophy.

Histopathology of gills in mosquitofish, Gambusia affinis after long-term exposure to sublethal concentrations of malathion.

The histopathological effects of malathion, an organophosphate pesticide, on the gill tissues in mosquitofish, Gambusia affinis, were determined by light microscope. The fish were exposed to sublethal concentrations (0.01 and 0.02 mg/L) of malathion for 10, 20 and 30 days. Histological examination of the gills treated with malathion showed a variety of histopathological effects. The gill lesions included necrosis and desquamation of secondary lamellar epithelium, lifting up of epithelium, intraepithelial oedema, fusion of adjacent secondary lamellae, haemorrhage at primary lamellae, disorganization and rupture in seconder lamellae, hypertrophy and hyperplasia of epithelial cells. These alterations were time‐ and dose‐dependent.

The toxicological effects of thiamethoxam on Gammarus kischineffensis (Schellenberg 1937) (Crustacea: Amphipoda).

Neonicotinoids are a new group of insecticides, and little is known about their toxicity to nontarget freshwater organisms an potential effects on freshwater ecosystems. The aim of this study is to establish the acute toxicity and histopathological effects of thiamethoxam-based pesticide on the gill tissue of Gammarus kischineffensis. In this study G. kischineffensis samples were exposed to 2.5, 5, 7.5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90 and 100mg/l of commercial grade thiamethoxam for 96 h. The 24, 48, 72 and 96 h LC50 values were determined as 75.619, 23.505, 8.048 and 3.751 mg/l respectively. In histopathological study the individuals were exposed to 0.004, 0.04 and 0.4 mg/l thiamethoxam concentrations for 14 days. The results showed that the most common changes at all doses of thiamethoxam were vacuolization and hemostatic infiltration in the gill tissue of G. kischineffensis.

Scale deformity descriptions for 23 species of fish, from various geographical areas and habitats

A renewed interest in fish scale anomalies prompted the present study, wherein we document a wide range of scale morphological abnormalities, including deformities in shape and structure, of a large number of species. In the present study, 63 cases of deformities were reported from 23 fish species collected from five countries. The abnormalities observed are discussed within the framework of contaminated aquatic environments, with a goal of recognising the cause of abnormality. Deformed scales exhibited different shapes, showing both slight (n=52 cases) and severe (n=9 cases) abnormalities. The scale deformations described in the present study should help direct future work on the relationships between environmental condition and fish health.