Devicyprin induced gonadal impairment in a freshwater food fish, Channa punctatus (Bloch)

Synthetic pyrethroids are the recent major class of broad spectrum, photostable, organic insecticides used in agricultural, domestic and veterinary applications and now account for more than 30% of global insecticide use. Cypermethrin is metabolized and eliminated significantly more slowly by fish than by mammals or birds, which may explain this compound's high toxicity in fish compared to other organisms. The present communication deals with histoanatomical alterations in the gonads of a local fresh water food fish, Channa punctatus exposed to 0.033 ppm (96 hr LC50 X 1/10) concentration of a synthetic pyrethroid, devicyprin (cypermethrin 25%) in aquatic medium of aged tap water for 15, 30 and 45 days respectively. In testis, exposure dependent histological damage has been observed in terms of vacuolization, condensation of spermatogonic cells, distortion of tubular epithelium, shrinkage of interstitial cells and general inflammatory responses. Longest exposure of 45 days has resulted in peculiar starry-sky appearance of the testicular tissue. Gross histo-anatomy of ovarian tissue reveals epithelial lesions, inflammatory responses, stromal hemorrhage, increased interstitium and shrinkage of yolk vesicles towards periphery These findings are quite suggestive of reproductive impairments leading to delayed gonadal maturity and adversely affecting processes of sperm production and ovulation and thus, the fish production.     

Fecundity of the freshwater fish Channa punctatus (Bloch) from three aquatic bodies

The fecundity studies on Channa punctatus revealed that there is a relationship between length of the fish with fecundity, weight of the fish and ovary with fecundity. The length and fecundity exhibit curvilinear relationship and a straight line relationship is observed between fecundity and body weight. Fecundity and ovary weight also exhibited linear relationship. The comparative degree of fecundity of the fish is Jagat tank > Kadaganchi tank > Kagina river. Although fish collected from Jagat tank exhibits higher fecundity, all the other three aquatic bodies provide proper environmental conditions for the growth and reproductive activity of the fish.     

Changes in nutritive value of fish, Channa punctatus after chronic exposure to zinc

The present investigation was undertaken to assess the effects of sublethal concentrations of zinc (0.1 and 0.2 mgl(-1)) on the nutritional value of fish Channa punctatus after exposure for 135 days. The parameters studied were, levels of total proteins, glycogen, total lipids, cholesterol and vitamins (A and D) in the muscle. Total proteins, glycogen, total lipids and vitamin D show highly significant decline from day 90 to 135, while cholesterol and vitamin A, show no significant changes upto 105 days. This study signifies a drastic reduction in the nutritive value of fish, which is compounded by the fact that under natural conditions fish are exposed to these levels of zinc for prolonged periods.     

Toxicological effects on some biochemical parameters of fresh water fish Channa punctatus (Bloch.) under the stress of nickel

Toxicological effects of some biochemical parameters of freshwater fish Channa punctatus (Bloch), under the stress of Nickel (NiSO4. 6H2O), at various concentrations of 10, 20, 30 and 40 ppm for 30 days were observed. Gradual decrease in the levels of liver protein and liver ascorbic acid due to proteolysis and liver glucose breakdown respectively was observed. Contradictorily, high liver cholesterol level, may be due to hepatic disfunctioning and accumulation in brain. There was also gradual decrease in the brain protein level showing significant alterations but the brain ascorbic acid level showed no significant alterations. Decrease in the protein and ascorbic acid level and increase of cholesterol level thus indicates stressful condition of the fish.     

Observations on the histological alterations in various tissues of EUS affected fish, Channa striatus (Bloch)

Histopathological investigations have been made on the skin, liver, kidney and intestine of, (EUS) affected fish, Channa striatus and following anomalies have been observed. Varying degree of degeneration has been observed in the epidermis, dermis, hypodermis and underlying musculature. In all the cases, the skin lost the scales and epidermis completely at the site of infection. The dermis along with hypodermis showed the signs of necrosis. Necrosis also took place in subcutaneous layer underlying the hypodermis. Necrotization and formation of granulomas can clearly be seen in circular and longitudinal muscle layers. The liver exhibited the loosening of tissue and distension in cell bodies. While in case of kidney, shrinkage took place in all the components. Similarly, the intestinal villi got necrotised alongwith their constituent elements.     

Impact of copper on haematological profile of freshwater fish, Channa punctatus

The present study was to evaluate heavy metal toxicity stress symptoms in fish blood during long-term exposure of sublethal concentration of copper sulphate (CuSO4). The effects of copper on various heamatological parameters were evaluated exposing Indian fresh water fish, Channa punctatus to a sub-lethal concentration of copper sulphate (0.36 mg l(-1)) for different periods. Exposure of fish to copper showed a significant decrease in the haemoglobin (Hb) content from 10.73 to 6.60%, red blood cells (RBC) from 2.86 to 1.84 x 10(6)/mm3 and packed cell volume (PCV) from 31.00 to 23.33% at the end of 45th day as compared to control. Whereas the white blood cells (WBC) increased from 60.00 to 92.48 x10(3)/mm3, clotting time (CT) from 27.66 to 43.00 second, erythrocyte sedimentation rate from 5.0 to 13.66 mm/hr and mean corpuscular volume from 108.11 to 126.85 cmu, significantly, with increase in exposure periods. Although mean corpuscular haemoglobin concentration (MCHC) and mean corpuscular haemoglobin (MCH) values showed significant increase during 15 and 30 days exposures, both the values were found significantly increased at the end of the experimental period. The differential leucocytes count (DLC) showed a significant increase in the populations of lymphocytes and eosinophils, whereas neutrophils, monocytes and basophiles were found decreased after exposure to copper.     

Effect of cadmium individually and in combination with other metals on the nutritive value of fresh water fish,Channa punctatus

Impact of metal cadmium on the nutritive value of Channa punctatus on exposure to a sublethal concentration (1.12 mg/l) of cadmium (Cd2+) for 15 and 60 days has been studied. Among the various parameters selected, the level of moisture in liver and muscle was increased, while decrease was noted in the level of ash, total proteins and inorganic constituents like iron, calcium, inorganic phosphate, sodium and potassium in both liver and muscle in the two types of exposure. The total lipid level of liver increased, while muscle lipid level was decreased. On the other hand, calcium, iron, inorganic phosphate, sodium and potassium levels showed increase in blood. Zinc and selenium decreased the percentage alterations in all the parameters selected for study. In the two types of exposure, zinc was most effective to counteract the cadmium toxicity to fish as in almost all the parameters insignificant alterations were recorded. In combination studies, protection against cadmium toxicity by the two chemicals became more marked with increase in the tenure of exposure.     

Mercury induced architectural alterations in the gill surface of a fresh water fish,Channa punctatus

An air-breathing fresh waterfish Channa punctatus was exposed chronically to sublethal concentrations of mercuric chloride and the respiratory surface was found to exhibit lesions, lifting of lamellar epithelium and increased number of mucus gland openings. The damage increased with increase in the concentrations. The gill surface was studied using scanning electron microscope.     

Impact of endosulfan on the profiles of phospholipids at sublethal concentration in the male Heteropneustes fossilis (Bloch)

Male Heteropneustes fossilis were exposed for 30 days at sublethal concentration (0.002 ppm) during different phases of its annual reproductive cycle. Its impact on total phospholipids (TP), phosphatidylcholine (PC), phosphatidylserine (PS), phosphatdylinositol (PI) and phosphatidylethanolamine (PE) were measured in liver, plasma and testes. During preparatory phase, in general, the levels for TP, PC, PS, PI and PE decreased after endosulfan exposure in the above tissues. During prespawning and spawning phases, the phospholipids also showed decreasing trend. The postspawning phase, exhibited decline in hepatic levels of PS and PI only and remained unaffected in the other two tissues. During the resting phase too, the hepatic levels of TP, PS and PI declined and remained unaltered in others. The present results indicate that endosulfan have very selective effects on phospholipids classes during different phases of the annual reproductive cycle interfering with the production of lipid deprived energy i.e. vitellogenin. In general, endosulfan has inhibitory role during reproductive growth affecting phospholipid biosynthesis via hepatic enzyme systems as well as by hormonal imbalance.     

Carbofuran induced impairment in the hypothalamo-neurohypophyseal-gonadal complex in the teleost,Channa punctalus (Bloch)

The effect of chronic exposure to carbofuran (4.5 ppm in static water) for six months on the gonadal histophysiology and hypothalamo-neurohypophyseal complex was studied in Channa punctatus. Experimental observations revealed significant inhibition of gonadal development with associated degenerative abnormalities as evidenced by ovarian and testicular histology and reduced gonadosomatic index. Degenerative changes in ovary were exihibited by stage I (oogonium) and stage II (immature/non-vitellogenic) oocytes as marked by perinuclear ooplasmic lysis, clumping and dissolution resulting in disintigration of nuclear material altogether attributed to complete degeneration of such oocytes. Testicular deleterious changes included degeneration of spermatogenic elements and necrosis of interstitial cells of Leydig. Correlative histophysiological changes were also observed in the pituitary gonadotrophs and hypothalamic, nucleus pre-opticus, neurons that were smaller, inactive and less in number with associated necrosis. Corresponding to the changes in nucleus pre-opticus neurons, significant inhibition of brain monoamine oxidase enzyme activity was also recorded in treated group. These observations suggest that carbofuran even at low concentration level under long-term exposure is capable of inducing retardation of gonadal development which might have been mediated through the impairment of the hypothalamo-neurohypophyseal-gonadal axis in this species.     

Accumulation and elimination of cadmium and lead in juvenile milkfish during sublethal exposure

Pollution of aquatic environments by trace metals is a worldwide environmental problem. Metal pollutants are increasingly being released into the environment as a result of industrialization. In this study, the bioaccumulation of cadmium and lead in young juvenile milkfish liver (Chanos chanos) was investigated after exposure to three sublethal concentration of each pollutants (1/20, 1/10, and 1/5 LC₅₀ of 96-h LC₅₀) for acute time 12, 24, and 96 h and subchronically for 7, 14, and 21 days. Cadmium and lead accumulation in liver increased with the exposure period and concentrations of pollutant. Compared to controls, the uptake of cadmium is much higher than that of lead. Accumulation factors showed an increase with exposure time and for lead an inverse relationship between accumulation factor and exposure concentration. The elimination of the two pollutants during the 30 days depuration was investigated after 30 days depuration time. During this phase, cadmium and lead concentrations decreased.     

Changes of hematological parameters in Prochilodus lineatus (Pisces, Prochilodontidae) exposed to sublethal concentration of cypermethrin

Freshwater fish Prochilodus lineatus were exposed to sublethal concentrations of cypermethrin (0.3 and 0.6 microg/l) for 2, 5 and 8 days. It was observed that with the increase of exposure time total erythrocyte (RBC), hemoglobin (Hb), hematocrit (Ht) and mean corpuscular hemoglobin concentration (MCHC) values decreased but mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) values increased. These reports indicate that hematological parameters, may be useful as a diagnostic test for cypermethrin exposure in aquatic organisms.     

Histopathological changes in testis of the freshwater fish, Heteropneustes fossilis (Bloch) exposed to linear alkyl benzene sulphonate (LAS)

The objective of this study was to use the freshwater food fish, Heteropneustes fossilis, as a model to evaluate the concentration-dependent effects of LAS on the testicular structure through short-term static bioassays. Concentration mediated histopathological leisions were observed in testis of H. fossilis, treated with four different concentrations of LAS for 24, 48, 72 and 96 hr Inference drawn from the study is that the cytotoxic damage is more pronounced in fish exposed to higher concentrations of LAS for shorter durations than lower concentrations of LAS for longer durations. Gross damage of germinal epithelium, inflammatory response, intertubular vacuolations and contraction and condensation in the cells of tubules under all sets of intoxication and exposures are quite suggestive of reproductive impairment leading to delayed gonadal maturity.     

Ovarian changes in response to heavy metal exposure to the fish,Notopterus notopterus (Pallas)

The ovarian and hepatic protein, lipid and cholesterol content were estimated in the fish, N. notopterus after exposing it to heavy metals at sublethal concentrations. The protein, lipid and cholesterol content of ovary and liver got reduced and amongst the three exposures (mercuric chloride, cadmium chloride and their combination) it was significantly reduced in the order of (HgCl2>HgCl2>+CdCl2>CdCl2>control). The above results indicated that HgCl2 is highly toxic and its toxicity gets reduced in combination.     

Effects of sublethal concentrations of permethrin on bioaccumulation of cadmium in zebra cichlid (Cichlasoma nigrofasciatum)

The aim of this study was to evaluate the synergistic and antagonistic effects of permethrin on the bioaccumulation of cadmium in zebra cichlid (Cichlasoma nigrofasciatum). Zebra cichlid was exposed to various sublethal concentrations of permethrin combined with cadmium chloride for 15 days. Although at the lowest concentrations, permethrin (0.40 µg L^?1) decreased the bioconcentration potential of cadmium in fish, bioaccumulation of cadmium increased along with increasing concentrations of permethrin (0.80–1.20 µg L^?1). However, the magnitude of changes in the accumulation of cadmium in the fishes simultaneously exposed to 1.60 µg L^?1 permetrin and cadmium chloride was similar to the cadmium levels observed in fishes after exposure to the cadmium chloride alone. The results of this study suggest that the synergistic effects of permethrin on the bioaccumulation of cadmium highly depend on the concentrations of this pesticide in water.     

Impacts of sublethal lead exposure on the hemato-immunological parameters in tilapia (Oreochromis mossambicus)

The effects of exposure of tilapia (Oreochromis mossambicus) to sublethal concentrations of lead on hematological and immunological parameters were investigated. The fish were semistatically exposed to low (L) (0.5 mg L^?1), medium (M) (2.5 mg L^?1), and high (H) (5 mg L^?1) lead concentrations for 14 days. At the end of the trial, red blood cell (RBC) count, hematocrit (Hct) ratio and hemoglobin levels showed significant decreases in M and H groups, while RBC was significantly increased in L group compared to control group. Lysozyme activity showed a decrease in all groups on day 14 compared to control. A decrease in myeloperoxidase activity was seen in M and H groups on day 7, and in all treatment groups on day 14. In conclusion, it was found that exposure of O. mossambicus to lead concentrations affected hematological and immunogical parameters adversely.     

Impact of linear alkyl benzene sulphonate (LAS) on phosphatase activity in testis of the teleostean fish,Heteropneustes fossilis (Bloch)

Fishes are sensitive indicators of pollutants present in water.These pollutants cause various physical and physiological alterations in fishes. In the present work alteration in the activity of acid and alkaline phosphatase was evaluated in testicular tissue of fresh water fish Heteropneustes fossilis exposed to LC50 value of linear alkyl benzene sulphonate (LAS) for different exposure periods [24 h, 48 h, 72 h and 96 h] With increase in the concentration of chemical LAS, the activity of acid phosphatase (ACP) was reported elevated while a significant fall in the activity of alkaline phosphatase (ACP) was recorded for same exposure period. Elevated activity of ACP, one of the important hydrolases of lysosomes, is quite suggestive of bringing about gross necrosis and dysarchitecture. ALP is involved in various metabolic activities including gonadal maturation and as such decreased activity of this enzyme is definitely one of the important causative factors for reproductive impairment of the fish.     

Changes in oxygen consumption and heart rate of the blue swimming crab, Portunus pelagicus (Linnaeus, 1766) following exposure to sublethal concentrations of copper

Weight specific oxygen consumption and heart rates were investigated in blue swimming crab, Portunus pelagicus to indicate the stress in response to increasing salinities (50, 75, 100 and 125%SW) and increasing copper concentration (0, 0.75, 1.5, 3 and 6 ppm copper) at temperature 25 degrees C. Oxygen consumption (micromol.g(-1).h(-1) was measured using closed system respirometer (Strathkelvin Instruments oxygen meter model 781). Heart rates (beat.min(-1)) were recorded using impedance techniques. It has been found that oxygen consumption and heart rate increased with decreasing salinities and increasing copper concentration. The statistic showed weight specific oxygen consumption of P. pelagicus after 96 hr exposure to 6 ppm copper in all salinities were significantly different (P < 0.05) from 0 ppm copper. Mean heart rate of P. pelagicus in 50%SW after 96 hr exposure to 6 ppm copper were significantly different (P < 0.05) from 0 ppm copper.     

Alterations in serum electrolyte levels after dimethoate exposure and recovery in the freshwater air-breathing catfish,Heteropneustes fossilis (Bloch)

Dimethoate, a moderately toxic insecticide, has a wide range of agricultural and domestic applications. Like other organophosphates, dimethoate has anticholinesterase activity. Fish are non-target organisms, inadvertently exposed to pesticides and their metabolic products. The present study includes short-term (96 h) and long-term (36 d) effects of dimethoate exposure on some serum electrolytes Ca²⁺, Mg²⁺, and Pi in the freshwater air-breathing catfish Heteropneustes fossilis. The concentration of dimethoate for short-term exposure was 2.24 mg L^?1 (75% of 96 h LC₅₀) and for long-term exposure 0.75 mg L^?1 (25% of 96 h LC₅₀). The study includes the recovery pattern in serum electrolytes after placing the fish in pesticide-free water. Fish show hypocalcemia, hypermagnesemia, and hyperphosphatemia after short-term and long-term exposure to dimethoate. When placed in pesticide-free water, these electrolytes exhibit recovery towards normalization, indicating significant (p < 0.05) recovery.     

Metabolic responses of the squat lobster (Pleuroncodes monodon) larvae to low oxygen concentration

Squat lobster populations found in the Humboldt Current System over the continental shelf from ~28 to 37°S release pelagic larvae in sub-surface cold (~11 °C) hypoxic waters. Larvae subsequently spread throughout the water column encountering both normoxic and hypoxic conditions. We analyzed some short- and long-term responses of Pleuroncodes monodon larval metabolism to hypoxia at 11 °C. Routine and postprandial aerobic respiration rates were lower in hypoxia than in normoxia for all zoeal stages. Zoea V oxyconformed, while megalopae oxyregulated down to very low oxygen concentrations. Throughout zoea I development, the rate of nitrogen (protein) accumulation in zoea I was lower, and C:N ratios were higher under hypoxic conditions than in normoxia. Citrate synthase (CS) and malate dehydrogenase (MDH) apparent specific activities (as indicators of aerobic and metabolic potentials, respectively) decreased and remained at the same level, respectively, throughout zoea I reared under hypoxic conditions. Anaerobic to aerobic potential (lactate dehydrogenase (LDH)/CS) was higher in organisms reared under hypoxia, and MDH/LDH potential ratios were characteristic of organisms tolerant to hypoxia. In spite of P. monodon zoea endurance and metabolic adaptations to decreasing oxygen tensions, intense hypoxia as such of their release site would affect their overall condition especially toward the end of the molt cycle. Our results indicate the importance of considering the interaction between environmental oxygen variability and recruitment success.