Jagdish C. Pant

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.

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.

Inducement of metabolic dysfunction by carbamate and organophosphorus compounds in a fish, Puntius conchonius

Abstract Exposure of a freshwater cyprinid ( Puntius conchonius ) to 2.142 and 4.784 ppm of carbaryl and dimethoate, respectively, for 24 hr, seriously affected carbohydrate and cholesterol metabolism. Significant hyperglycemia and glycogenolysis in liver, brain, and heart were manifested in the treated fish. Hypercholesterolemia and rise in liver cholesterol also occurred. Long-term exposure, 15–30 days, to chronically sublethal concentrations, 0.194 and 0.306 ppm carbaryl and 0.434 and 0.683 ppm dimethoate, elicited hypoglycemia and depletion of liver glycogen, together with enhanced glycogenesis in the heart. The glycogen level in brain fell in response to carbaryl exposure in contrast to a significant elevation caused by dimethoate. Reduction in blood and liver cholesterol at 15 days was followed by an increase at 30 days.

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.

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.