Tejendra S. Gill

Sublethal effects of an organophosphorus insecticide on certain metabolite levels in a freshwater fish, Puntius conchonius Hamilton

Abstract Alterations in the metabolite levels were monitored in a common freshwater bony fish, Puntius conchonius, chronically exposed to a sublethal concentration (109.5 ppm) of an organophosphorus insecticide, phosphamidon. Significant hyperglycemia, hyperlactemia, hypercholesterolemia, hyperlipemia, hyperproteinemia, and increased blood-free fatty acids were manifested in the exposed fish for up to 4 weeks. The phosphorus levels in the blood, however, fell. In other tissues, there was an increase in the hepatosomatic index, moderate hepatic and skeletal muscle glycogenesis, a severe depletion of glycogen reserves in the brain, and a significant increase in heart glycogen. Cholesterol (liver, ovary, and testes), total lipids (liver and ovary), free fatty acids (liver and skeletal muscles), and total proteins (liver) were elevated in the exposed fish, and there were signs of lipolysis and protein breakdown in the skeletal muscles. Except for the liver-free fatty acids and heart glycogen, organophosphorus effects on other variables were not abolished during recovery in clean water.

Hematological and pathological effects of chromium toxicosis in the freshwater fish, Barbus conchonius Ham

Experimental exposure to Cr(VI) induced anomalies in the peripheral blood and tissues of a freshwater fish, Barbus conchonius. Clinical findings in the blood corpuscles included swelling of erythrocytes, numerous circulating polychromatophils, and vacuolation of large lymphocytes during acute exposure. Poikilocytosis, severe cytoplasmic vacuolation and deterioration of cytoplasmic membrane in erythrocytes occurred following chronic exposure. Significant polycythemia with collateral rise in Hb and Hct were manifest in the acutely intoxicated fish. By contrast, chronic exposure caused marked erythropenia and an accompanying reduction in Hb and Hct values. Leucocyte subpopulations showed an initial rise and then a fall in the thrombocytes together with a significant lymphocytosis, neutropenia, and basophilia. Pathological changes were observed in the gills, kidneys, and liver of Cr-exposed fish.

Impact of chronic lead poisoning on the hematological and biochemical profiles of a fish,Barbus conchonius (Ham)

The contamination of natural waters by lead is mostly caused by a variety of anthropogenic activities related to increased mining operations and industrial uses of this metal. Adverse effects of lead poisoning in the fishes have been reported with references to both hematological and biochemical variables. The aim of present investigation was to study the effects of chronically administered sublethal levels of inorganic lead on the hematological and biochemical profiles of widely distributed freshwater fish, Barbus conchonius. The variables such as erythrocyte numbers, hemoglobin, hematocrit, mean corpuscular volume, blood glucose, glycogen in liver, skeletal muscles, and myocardium, and cholesterol in blood, liver, ovary, and testes were evaluated.

Erythrocytic and leukocytic responses to cadmium poisoning in a freshwater fish, Puntius conchonius ham

Chronically sublethal concentrations of cadmium caused conspicuous hematological anomalies in the cyprinid fish, Puntius conchonius. Exposure to 0.63 and 0.84 mg/liter cadmium chloride (1/20 and 1/15 of 96-hr LC50) induced morphological aberrations in mature erythrocytes including cytoplasmic vacuolation, hypochromia, deterioration of cellular membrane, basophilic stippling of cytoplasm, clumping of chromatin material and extrusion of nuclei, and schistocytosis. Anomalous basophils and monocytes were also encountered though less frequently. Decreased erythrocyte counts, hemoglobin and hematocrit values were also associated with chronic cadmium poisoning. The mean corpuscular hemoglobin and mean corpuscular volume increased (30 days) but mean corpuscular hemoglobin concentration showed no obvious change. A significant thrombocytopenia (90 days), elevated small lymphocyte and basophil populations, and a mild neutropenia were manifested in the cadmium-exposed fish. Large lymphocytes were not significantly affected.

Cadmium nephropathy in a freshwater fish, Puntius conchonius hamilton

Renal pathology was examined in a freshwater fish, Puntius conchonius, during a 12-week exposure to 500, 630, and 840 micrograms CdCl2/liter (1/25, 1/20, and 1/15 fractions of the 96-hr TLm, respectively). Multifocal tubular epithelial degeneration including severe vacuolation and nuclear pyknosis and karyorrhexis composed the most obvious lesions. The degenerative changes were found mainly in the proximal segments, while the distal segments and the collecting tubules and ducts remained unaffected. Collapsed and shrunken glomeruli and swollen Bowmans spaces were also frequently observed. The cadmium-exposed fish appeared heavily stressed and moribund. A comparison of the renal pathology with that of other fishes and mammals and possible mechanisms of cadmium nephropathy are discussed.

Mercury-induced blood anomalies in the freshwater teleost

Experimental Hg poisoning in the fish, Barbus conchonius led to marked hematological anomalies. Acute exposure to 181 μg L−1 mercuric chloride (96 h LC50) led to erythrocytic anomalies including vacuolation, nuclear deterioration, microcytosis and collapsed cytoplasmic membranes. In addition, there was significant thrombocytosis and neutropenia together with a slight reduction in lymphocyte count. Chronic exposure to 36 and 60 μg L−1 mercuric chloride led to poikilocytosis, hypochromia, fragmentation and nuclear displacement in erythrocytes. The large lymphocytes revealed vacuolation, cellular and nuclear hypertrophy and cytoplasmic outgrowths. Thrombocytosis, lymphocytosis, neutropenia and mild basophilia were manifested in fish subjected to chronic poisoning.

Branchial pathogenesis in a freshwater fish, Puntius conchonius ham., chronically exposed to sublethal concentrations of cadmium

Effects of sublethal concentrations, 630 and 840 micrograms/liter (0.05 and 0.066 fractions of the 96-hr LC50), of cadmium chloride on the gills of a freshwater fish, Puntius conchonius, were examined light microscopically during a 12-week exposure. The secondary gill lamellae showed disrupted epithelium, necrosis, accumulation of cellular debris, capillary congestion, and wilting of the pillar cell system. Hypertrophy and hyperplasia of chloride cells as well as partial or complete fusion of secondary lamellae also occurred in the Cd-exposed fish. Branchial lesions together with coagulation film anoxia are likely to result in serious respiratory distress and related tissue hypoxia.

Chromatin condensation in the erythrocytes of fish following exposure to cadmium.

Experimental cadmium poisoning in the fishes has been investigated and a variety of hematological changes have been observed. Studies on mammals have also revealed that Cd interferes with basic cellular processes and the metal has been shown to cause chromatin condensation and emptying of interchromatin spaces in cultured hepatocytes. The present work illustrates the effect of chronic Cd poisoning on the erythrocytes of a freshwater fish, Puntius conchonius with reference to chromatin condensation.

Branchial and renal pathology in the fish exposed chronically to methoxy ethyl mercuric chloride

Pathological manifestations causally related to pesticide poisoning have been described in both surficial and internal tissues of the fishes. Among the various organomercurials are phenyl mercuric acetate, methyl mercuric dicyanidiamide, methoxy ethyl mercuric chloride, methoxy ethyl mercuric silicate etc. Of these, the methoxy ethyl mercuric chloride (MEMC) is used in agriculture as an antifungal seed dressing, and its toxicity is primarily manifest in the Hg/sup 2 +/ ion. This report describes pathogenesis of branchial and renal lesions in the common freshwater fish, Puntius conchonius exposed chronically to sublethal levels of MEMC. Prior to this, alterations in the peripheral blood and metabolite levels in response to experimental MEMC poisoning have been demonstrated in this species.

Effect of organomercurial poisoning on the peripheral blood and metabolite levels of a freshwater fish

This work evaluated the hematological and biochemical changes in the fish, Puntius conchonius, under experimental organomercurial poisoning. Long-term (8 weeks) exposure to 3.63 and 6.03 mg/liter methoxyethyl mercuric chloride (MEMC) (0.2 and 0.33 fractions of 96-hr LC50) led to morphological aberrations in mature erythrocytes including nuclear and cytoplasmic deterioration, vacuolation, chromatin condensation, and hypochromia. Immature erythrocytes showing membrane leakage were also encountered. Erythrocyte count and hemoglobin (Hb) were significantly lowered after 1 and 3 weeks followed by a marginal rise persisting upto 8 weeks. Differential leucocyte counts revealed significant thrombocytopenia, lymphocytosis, and neutropenia. Collateral evaluation of blood glucose and tissue glycogen levels revealed significant hyperglycemia as well as glycogen depletion in liver and brain. Heart glycogen content evinced a substantial increase after 5 and 8 weeks exposure.