The effect of methylmercuric chloride, cadmium chloride, and lead nitrate on six biochemical factors of the brook trout (Salvelinus fontinalis)

An experiment on the glucose metabolite, serum electrolytes, and somatic characteristics of the Levantine Barbel Luciobarbus pectoralis (Heckel, 1843) under the effect of heavy metals

Levantine Barbel (Luciobarbus pectoralis) is a benthopelagic, subtropical native fish living in the inland waters of the Mediterranean region in Türkiye and Syria. Even though it is widely consumed locally, experimental observations on how heavy metals [zinc (Zn), copper (Cu), cadmium (Cd), and lead (Pb)] and their mixtures affect the fish are lacking. Several bioindicators of the fish exposed to heavy metals are the focus of the current investigation. Initially, Fulton condition factor (K) and hepato-somatic index (HSI) were utilized in the somatic characteristics of L. pectoralis. Then, changes in the level of glucose metabolite and electrolytes [sodium (Na+), potassium (K+), and chloride (Cl-)] of blood were determined by Architect C-800 auto-analyzer after exposure durations. The results of the experiments demonstrated that heavy metals can rapidly have a negative impact on the regulation of blood and somatic characteristics of fish. It was observed that the K index decreased in all metal groups at 24 and 96 h, while considerably increased in the 24-h effect of cadmium only (P ≤ 0.05). Along with that, in the 96-h effect of metals, Cu indicated the highest decrease in the HSI value (19.33%, P ≤ 0.05). In general, all heavy metal exposures caused the fish's glucose metabolite level to rise compared to the control (P ≤ 0.05). Furthermore, sublethal effects of metals at both durations caused considerable changes in blood electrolytes of the fish compared to control (P ≤ 0.05). Additionally, putative biomarkers in both durations had the greatest difference in toxic similarity under the Cu impact compared to the control, according to Hierarchical clustering and Euclidean distance metrics. Although the applied concentrations of Zn, Cu, Cd, and Pb and their mixture studied were generally within the limits of the various organizations and the surface water regulations, changes in ecophysiological and somatic indices were nonetheless seen in fish.

Cypermethrin-induced toxic effect on glycogen metabolism in estuarine clam, marcia opima (gmelin, 1791) of ratnagiri coast, maharashtra

Cypermethrin is a synthetic pyrethroid class of insecticide. Toxic effects of cypermethrin were studied by selecting Marcia opima as an animal model. Cypermethrins effect on the total glycogen content of mantle, gill, foot, hepatopancreas, male gonad and a female gonad of an estuarine clam, Marcia opima was examined. The clams were exposed to 1.58 ppm cypermethrin for acute and 1/10th of that concentration for chronic treatment. It was found that there was a decrease in glycogen content in various tissues as compared to control. In LC(0) and LC(50) groups, glycogen was decreased in all tissues except in hepatopancreas compared to control. This decrease is greater in mantle, gill, and foot in LC(50) group than the decrease in those tissues of LC(0) group. In chronic exposure it was found that glycogen was decreased in mantle, foot, male gonad, and female gonad when compared to the control group except in gill and hepatopancreas. Decrease in glycogen content indicates greater utilization of glycogen for metabolic purposes and too combat with cypermethrin stress. The significant increase in glycogen content in gill and hepatopancreas may be a reaction to the increase in energy demand.

Assessment of tolerant sunfish populations (Lepomis sp.) inhabiting selenium-laden coal ash effluents. 3. Serum chemistry and fish health indicators

Sunfish were collected from fly ash discharge-receiving streams to assess the possible effects of exposure to elevated selenium. Concentrations of selenium, copper, and arsenic were statistically higher in fish tissue (liver) samples from effluent-exposed fish than in reference fish. Several biomarkers were indicative of metal exposure and effect. Plasma protein levels and cholesterol levels were significantly lower in exposed fish, indicating nutritional stress. Ion levels (i.e., K) increased with exposure to ash pond metals, indicating possible gill damage. Fish from the receiving streams also had increased serum glucose and osmolality indicating possible acute stress due to sampling. Fish health assessments revealed a lower incidence of fin erosion, kidney discoloration, urolithiasis or nephrocalcinosis, liver discoloration, and parasites in exposed fish and a higher incidence of skin, eye, and gill aberrations. Condition factors of exposed fish were correlated with biomarker response and were the same as or lower than those of reference fish, but not related to selenium levels. Although several serum biochemical indicators differed between the ash pond-receiving stream and reference sites, pollutant exposure was apparently not sufficient to cause functional damage to critical organ systems.

Changes in oxidative metabolism in selected tissues of the crab (Scylla serrata) in response to cadmium toxicity

Changes in oxidative metabolism were studied in hepatopancreas, muscle, and hemolymph of the edible crab Scylla serrata, exposed to a sublethal concentration (2.5 ppm) of cadmium chloride. A significant decrease in glycogen, total carbohydrates, and pyruvate and an increase in lactate levels in hepatopancreas and muscle were observed. Hemolymph sugar levels were increased in experimental crabs. An increase in phosphorylase suggested increased glycogenolysis during cadmium toxicity. The decrease in lactate dehydrogenase activity and the increase in lactate content indicated reduced mobilization of pyruvate into the citric acid cycle. Krebs cycle enzymes such as succinate dehydrogenase and malate dehydrogenase were found to be decreased, suggesting impairment of mitochondrial oxidative metabolism as a consequence of cadmium toxicity. Glucose-6-phosphate dehydrogenase activity was increased, suggesting enhanced oxidation of glucose by the HMP pathway. Cytochrome-c oxidase and Mg2+ ATPase activity levels decreased, indicating impaired energy synthesis during cadmium stress. Acid and alkaline phosphatase activities increased, suggesting enhanced breakdown of phosphates to release energy in view of impaired ATPase system during cadmium exposure. A significant decrease in protein and free amino acid and an increase in ammonia, urea, and glutamine levels were observed in the tissues during exposure. An increase in protease, alanine aminotransaminase, and aspartate aminotransaminase suggested increased proteolysis and transamination of amino acids. The increase in glutamate dehydrogenase, AMP deaminase, and adenosine deaminase indicated increased ammonia production. The increased arginase and glutamine synthetase suggested the detoxification or mobilization of ammonia toward the production of urea and glutamine. These results suggest that cadmium affects oxidative metabolism and induces hyperammonemia, and crabs switch over their metabolic profiles toward compensatory mechanisms for the survivability in cadmium-polluted habitats.

Toxicity of cadmium administration to the toad and the treatment of its poisoning with EDTA

The effect of cadmium administration on female Bufo regularis was studied. The median lethal doses were 22, 18, 15 and 6.2 mg Cd2+/kg after 24, 48, 72 and 96 hr respectively. After a single intramuscular injection of 6.2 mg Cd2+/kg (representing 96-hr LD50), the results indicated that Cd2+ causes severe physiological abnormalities to this experimental animal. The serums alanine aminotransferase (AlAt), aspartate aminotransferase (AAt), alkaline phosphatase (AlP) and lactic dehydrogenase (LDH) were elevated while the calcium serum was not influenced by Cd2+ throughout the experimental period. On the other hand, phosphorus, total protein and total bilirubin were increased. EDTA treatment (0.2 mmole/kg) protected female toads from mortality up to 20 mg Cd2+/kg. It overcame the physiological alterations that were caused by the Cd2+ injection. This may be due to the fact that Cd2+ is bound to EDTA in a strong complex which is readily excreted via the kidneys.

Effects of cadmium toxicity upon the in vivo and in vitro activity of proteins and five enzymes in blood serum and tissue homogenates of Mugil cephalus

This study reports changes in total protein and certain liver, heart, gill and serum enzymes after exposing fish or tissue homogenates and serum to Cd, i.e. in vivo and in vitro effects. Five enzymes were selected for assay; aspartate amino transferase (AAT), alanine amino transferase (A1AT), alkaline phosphatase (A1P), acid phosphatase (ACP) and lactic dehydrogenase (LDH). Total protein content in the exposed fish showed an increase in the liver, gill and serum while there was no change in heart protein. The sensitivity of the five assayed enzymes to Cd varied in different tissues. Gill AAT, A1AT were the most sensitive. Liver A1P and heart LDH showed the maximum inhibition at higher Cd concentrations.

Bioaccumulation of cadmium: toxicity in Mugil cephalus

A series of 12 lethal and sublethal concentrations of Cd were applied in seawater to determine LC50 for two sizes of fish. Fries were found to be more sensitive to Cd toxicity than juveniles. During 2, 4, 6 and 8 week exposure periods to graded Cd concentrations, mortality increased but no significant effect on growth occurred. From subacute experiments, the MATC for fries and juveniles were 0.05-0.02 ppm Cd2+/1 and 2-0.1 ppm Cd2+/1, respectively. Liver was found to accumulate the highest concentration of Cd followed by gill, muscle, alimentary canal and finally the heart.

Cadmium toxicity: inducement of changes in blood and tissue metabolites in fish

The effects of acute (24 h) and chronic (90 days) cadmium (Cd) poisoning on blood and tissue metabolite levels of a teleost, Puntius conchonius were studied. Significant hyperglycemia with an increment in liver, kidney and ovary cholesterol occurred during acute Cd poisoning. By contrast, an enduring hypoglycemia and diminished levels of tissue cholesterol manifested the chronically intoxicated fish. Both acute and chronic Cd poisoning, however, caused marked hypocholesterolemia, glycogenolysis in liver and brain, and a concomitant rise in myocardium glycogen concentration. Testes cholesterol was found to be depleted after both acute and chronic (60 days) Cd poisoning.