Hepatic toxicological responses of SiO2 nanoparticle on Oreochromis mossambicus.

The present study was carried out to investigate the impact of various concentrations of SiO2 nanoparticles (SiO2 NP) on the commonly available freshwater fish Oreochromis mossambicus. The 96 h median lethal concentration (LC50) of SiO2 NP was found to be between 270-280 ppm. This novel study has demonstrated histological alterations in the hepatic tissues and a dose-dependent depletion of tissue protein content and an elevated transaminases activity in the treated fish, which has facilitated understanding of the impact of SiO2 NP in O. mossambicus.

Effect of cobalt-60 gamma radiation on total hemocyte content and biochemical parameters in Macrobrachium rosenbergii (De Man, 1879).

Purpose: The effect of low level cobalt-60 (60Co) gamma radiation on the freshwater prawn Macrobrachium rosenbergii was evaluated by observing their hemocyte counts and biochemical parameters. Materials and methods: Prawns were exposed to 3, 30, 300 and 3000 milligray (mGy) dose levels and their tissues of gills, hepatopancreas and muscle were analyzed. Results: The results showed that the number of hemocytes in the hemolymph and concentrations of protein and carbohydrate were significantly reduced in irradiated groups than compared to the control prawn. Increased aspartate transaminase (AST), alanine transaminase (ALT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), Acetyl choline esterase (AChE) in the irradiated groups reflects tissue damage. Conclusions: Hence, this study concludes that even low level of ionizing radiation (60Co gamma) can cause acute damages in gills, hepatopancreas and muscles in irradiated groups. Highlights 60Co exposures effect the THC and biochemical of prawn M. rosenbergii. Different dose levels such as 3, 30, 300 and 3000 mGy. Biochemical parameters serve as reliable indicators of physical status of organism. Self-regulating mechanisms might be the reason for preventing from the lethality. Suggested that nuclear industries should manage below 3 mGy.

Haemato-immunological studies in ZnO and TiO2 nanoparticles exposed euryhaline fish, Oreochromis mossambicus.

The present study was aimed to analyze the effect of ZnO and TiO2 nanoparticles (NPs) on Haemato-immunological parameters in adult Tilapia, Oreochromis mossambicus. The nanoparticles size found as 47 nm and 30 nm for ZnO and TiO2 respectively. The acute toxicity (96 h) of ZnO (LC50: 100-110 ppm) and TiO2 (LC50: 80-90 ppm) NPs were identified by using probit analysis. RBC, Hb and HCT levels decreased in nanoparticles exposed groups resulted in decreased oxygen carrying capacity of RBC and other erythrocyte indices (MCH, MCV, MCHC). Increased WBC, neutrophils & monocytes and decreased lymphocyte levels were observed as increased concentration of the nanoparticles. The results were found as statistically significant (p < 0.05). In conclusion, the present study depicts that ZnO NPs exhibits more toxicity than TiO2 NPs. Nanoparticles presence even in low concentration (ppm) cause damage to the connective tissues of fish, so the existing permissible levels of these nanoparticles in water are need to be revised.

Toxicological effect of Al2O3 nanoparticles on histoarchitecture of the freshwater fish Oreochromis mossambicus.

In the present study, freshwater fish Oreochromis mossambicus were exposed to sub lethal concentrations (120, 150 and 180 ppm) of Aluminium oxide nanoparticles (Al2O3 NPs) for 96 h. Histological abnormalities were not observed in the organs of control fishes whereas severe damages and extensive architectural loss was found in the brain, gill, intestine, kidney and muscle tissues of treated fishes with more pronounced effects in 180 ppm. The results showed that the acute exposure to Al2O3NPs altered the histoarchitecture in various fish tissues.

Histological alterations in the hepatic tissues of Al2O3 nanoparticles exposed freshwater fish Oreochromis mossambicus.

Adverse effects of nanoparticles on aquatic environment and organisms have drawn much special attention to many researches. Aluminium oxide nanoparticles (Al2O3-NPs) have potential uses in varied fields and are seen entering into the ecosystem. Their potential toxicity to the freshwater fish is not much studied. Hence this study was framed to investigate the effect Al2O3 NPs on freshwater fish Oreochromis mossambicus in terms of sub lethal toxicity, histological changes and hepato somatic index (HSI) under laboratory conditions. Fishes were exposed to varying concentrations of Al2O3 NPs for 96hr. LC50 value was found to be in between 235 and 245ppm. The findings of the present work showed that the NPs were accumulated in the fish liver and caused major histological anomalies such as structural alterations in the portal vein, necrotic hepatocytes, vacuolation, aggregation of blood cells and melanomacrophages. Significant histological alterations were observed in the highest concentration. Our results evidenced that the Al2O3 NPs in the aquatic environment affects the health condition of the fishes.

Morphological and histological studies on freshwater prawn Macrobrachium rosenbergii (de man) irradiated with (60)Co gamma radiation.

This study was framed to investigate the (60)Co gamma radiation induced morphological and histological variations in freshwater prawn Macrobrachium rosenbergii. The LD50 value of (60)Co gamma irradiated M. rosenbergii observed (by probit analysis) at 30 Gy. Prawns were irradiated to four different dose levels (3 mGy, 30 mGy, 300 mGy and 3,000 mGy) using Theratron Phoenix TeleCobalt Unit [P-33] and one control group (without irradiation) maintained separately. Irradiated groups exhibited several morphological variations such as discoloration; damaged rostrum; opaque coloration in cephalothorax; black bands and dot formation in abdomen; deformed uropods and telson in tail regions when compared with control group. The Hepato Somatic Index reflected the severity of radiation on hepatopancreas. Histological variations in gills, hepatopancreas and muscles of irradiated groups were observed. In gills, structural changes such as swollen and fused lamellae, abnormal gill tips, hyperplasic, necrotic and clavate-globate lamellae were observed in gamma irradiated prawns. Accumulation of hemocytes in hemocoelic space, interstitial sinuses filled with abnormal infiltrated hemocytes, the tubular epithelium with ruptured basal laminae, abnormal and coagulated lumen, necrotic tubules, thickened basal laminae, tissue debris, necrotic hepatocytes were observed in irradiated prawn hepatopancreas. In muscle, shrinkage of muscular fiber and necrotic musculature were observed in irradiated prawns. These structural alterations of the organs it is felt could affect the vital physiological functions such as respiration, osmotic and ionic regulation in gills and muscles; absorption, storage and secretion of the hepatopancreas which in turn could adversely affect the growth and survival of freshwater prawn M. rosenbergii.

Effects of (60)Co gamma irradiation on behavior and gill histoarchitecture of giant fresh water prawn Macrobrachium rosenbergii (DE MAN).

Present study was designed to observe the effects of (60)Co gamma radiation in behavioral and histological changes in the gills of giant fresh water prawn Macrobrachium rosenbergii. The adult prawns were irradiated with four different dose levels (3mGy, 30mGy, 300mGy and 3000mGy) and the control group (without irradiation) was maintained separately. Behavioral changes like hyperactivity, loss of balance, reduced swimming rate, slower rate of food intake and convulsions were observed in higher dose levels of 300mGy and 3000mGy. The histological alterations such as accumulated haemocytes in haemocoelic spaces, abnormal gill tips, lifted lamellar epithelium, swollen and fused lamellae, hyperplasic, necrotic, clavate-globate and complete disorganization of lamellae were observed in (60)Co gamma irradiated prawns. Significantly more considerable histological alterations were observed in the highest dose level of 3000mGy, but no mortality was evidenced. This study serves as biomonitoring tool to assess the radiation pollution in the aquatic environment.

Histological variations in liver of freshwater fish Oreochromis mossambicus exposed to 60Co gamma irradiation.

The irradiation effect of (60)Co at the three dose level of 3 mGy, 30 mGy and 300 mGy on the histology of liver of the freshwater fish Oreochromis mossambicus was investigated. The liver of O. mossambicus was dissected out and processed for light microscopy studies. (60)Co exposed O. mossambicus were found to result in several alterations in the histoarchitecture of liver. The alterations included mild congestion of blood vessels, structural alteration, cellular swelling, vacuolation and necrotic liver cells, indicating a definite response to (60)Co irradiation. The results suggest that the liver of O. mossambicus exposed to (60)Co were structurally altered with increasing dose levels. It is to record that alteration in the liver does not affect the physiology, behaviour or lethality of the individuals. Self regulating mechanisms would have influenced the liver to remain sustained. To confirm the same further studies in the direction by increasing dose level is required.

Temperature effect on behaviour, oxygen consumption, ammonia excretion and tolerance limit of the fish fingerlings of Alepes djidaba.

The present study has been carried out to determine the effect of temperature on behaviour, oxygen consumption, ammonia excretion and tolerance limit of the fish fingerlings of Alepes djidaba, which were collected at Kalpakkam. The fish fingerlings were placed at different temperatures, based on the thermal tolerance limit of fish and thermal outfall of the Madras Atomic Power Station (MAPS). The thermal tolerance experiments were conducted in two ways: in direct exposure and in gradually increasing temperature for duration of 48 hr. The upper and lower lethal temperatures for the fish fingerlings of Alepes djidaba were 38.5 degrees C and 14 degrees C respectively. During tolerance experiment, no mortality was observed at 33 degrees C and 35 degrees C. But at 38 degrees C with gradual increase in temperature, 100% loss of equilibrium was observed at 37.7 degrees C in 36 min and mortality was observed at 38 degrees C in 55 min. On the contrary, when the fish fingerlings A. djidaba were directly exposed to 38 degrees C, almost 100% loss of equilibrium and mortality were recorded in 15 min and 31 min respectively. At 40 degrees C with gradual increase in temperature, 100% loss of equilibrium was recorded at 38.5 degrees C in 46 min and mortality was recorded at 39 degrees C in 50 min. On the other hand, when the fish fingerlings of Alepes djidaba were directly exposed to 40 degrees C, 100% mortality occurred immediately within one minute. These behavioral responses include an elevated temperature of deltaT 10 degrees C, surfacing, dashing against glass wall, jumping out of the water, etc. In general, the rate of oxygen consumption and ammonia excretion was found to enhance with increasing temperature. The oxygen consumption was found to increase from 0.97 mg O2/g/hr at 30 degrees C to 2.2 mg O2/g/hr at 35 degrees C. Similarly, the excretion of ammonia also increased from 3.18 microg/g/hr at 30 degrees C to 5.91 microg/g/hr at 35 degrees C. In the present study, it was found that gradual increase in temperature favours the fish population to escape from the thermal exposure as compared to direct exposure, and also the temperature impact due to thermal discharge from MAPS is only minimal (35 degrees C) and no mortality could be caused to the fish population.