Anilava Kaviraj

Ascorbic acid supplementation of diet for reduction of deltamethrin induced stress in freshwater catfish Clarias gariepinus.

Static bioassays were made to evaluate efficiency of supplementation of ascorbic acid to remove stress of pyrethroid pesticide deltamethrin from freshwater catfish Clarias gariepinus. Clarias gariepinus exhibited several symptoms of stress when treated with deltamethrin (0.005 mg/l) for 24 h. Hepatosomatic index, liver glycogen, ascorbic acid of blood, liver, and kidney decreased while plasma glucose levels increased. Fish previously fed for 60 days with a diet supplemented by a high level of ascorbic acid (100 mg/100 g) could remove most of the stresses. Low levels of ascorbic acid supplement did not remove the stress. Dietary supplement of ascorbic acid at also appropriate level appeared to be a good way to counter toxicity of deltamethrin to the catfish.

Effects of cypermethrin on some biochemical parameters and its amelioration through dietary supplementation of ascorbic acid in freshwater catfish Heteropneustes fossilis

Static bioassays were made to evaluate efficiency of dietary supplementation of ascorbic acid to counter stress exerted by the pyrethroid pesticide, cypermethrin on freshwater catfish Heteropneustes fossilis. Three levels, a control and two sub-lethal concentrations (0.3 and 0.5 microg L(-1)) of cypermethrin were tested. Stress on H. fossilis was evident from the rise of plasma glucose level and reduction in the level of liver glycogen after 4 h of cypermethrin treatment. Acid and alkaline phosphatase activities of liver and ascorbic acid level of blood, liver and kidney also decreased significantly in H. fossilis exposed to cypermethrin as compared with control. Fish previously fed for 60 d with a diet supplemented by high level of ascorbic acid (1.0 g kg(-1)) could significantly reverse these effects. Fish fed a low level of dietary ascorbic acid (0.5 g kg(-1)) failed to counter the stress of cypermethrin.

Toxicity of Methanol to Fish, Crustacean, Oligochaete Worm, and Aquatic Ecosystem

Static renewal bioassays were conducted in the laboratory and in outdoor artificial enclosures to evaluate toxic effects of methanol to one teleost fish and two aquatic invertebrates and to limnological variables of aquatic ecosystem. Ninety-six-hour acute toxicity tests revealed cladoceran crustacea Moina micrura as the most sensitive to methanol (LC50, 4.82 g/L), followed by freshwater teleost Oreochromis mossambicus (LC50, 15.32 g/L) and oligochaete worm Branchiura sowerbyi (LC50, 54.89 g/L). The fish, when exposed to lethal concentrations of methanol, showed difficulties in respiration and swimming. The oligochaete body wrinkled and fragmented under lethal exposure of methanol. Effects of five sublethal concentrations of methanol (0, 23.75, 47.49, 736.10, and 1527.60 mg/L) on the feeding rate of the fish and on its growth and reproduction were evaluated by separate bioassays. Ninety-six-hour bioassays in the laboratory showed significant reduction in the appetite of fish when exposed to 736.10 mg/L or higher concentrations of methanol. Chronic toxicity bioassays (90 days) in outdoor enclosures showed a reduction in growth, maturity index and fecundity of fish at 47.49 mg/L or higher concentrations of methanol. Primary productivity, phytoplankton population, and alkalinity of water were also reduced at these concentrations. Chronic exposure to 1527.60 mg/L methanol resulted in damages of the epithelium of primary and secondary gill lamellae of the fish. The results revealed 23.75 mg/L as the no-observed-effect concentration (NOEC) of methanol to freshwater aquatic ecosystem.

Acute toxicity of synthetic pyrethroid cypermethrin to freshwater catfish Heteropneustes fossilis (Bloch)

Lethal concentrations of cypermethrin, dissolved either in water or acetone, were determined for freshwater catfish Heteropneustes fossilis at different hours of exposure by static bioassays. Up to 48 hours, there was no difference between LC50 values of aqueous and acetone solublized cypermethrin. Seventy-two-hour LC50 values of aqueous cypermethrin and acetone solublized cypermethrin to H. fossilis were 0.67 and 1.27 μg/L, respectively. Lethal values remained unchanged beyond 72 hours. The fish exposed to even lower concentration of cypermethrin (0.5 μg/L) showed hyperactivity.

Effects of Aniline–An Aromatic Amine to Some Freshwater Organisms

We determined the acute and chronic toxicity of aniline to tilapia (Oreochromis mossambicus), cladoceran crusatcea (Moina micrura) and oligochaete worm (Branchiura sowerbyi) using static bioassay tests. The 96 h LC50 values of aniline for O. mossambicus, M. micrura and B. sowerbyi were 69.4, 0.6 and 586 mg l−1 respectively. Tilapia responded to even low concentrations of aniline: the fish lost appetite at aniline concentrations as low as 0.02 mg l−1. A 90 d outdoor bioassay with tilapia showed that 0.02 mg l−1 aniline reduced fish yield, specific growth rate and food conversion efficiency. Reproductive functions of fish were affected by aniline at a concentration of 0.5 mg l−1 and above. Dissolved oxygen, primary productivity and plankton population of the test medium also were significantly reduced at 2.65 and 6.94 mg l−1 aniline.

Evaluation of fermented fish offal in formulated diet of the Indian major carp, rohu, Labeo rohita [Hamilton]

There has been a considerable research effort towards utilization of less expensive renewable ingredients in fish diet formulations to alleviate problems related to shortage of quality fish meal (Pongmaneerat et al. 1993, El Sayed 1994, Rangacharyulu et al. 2003, Yang et al. 2004, Mukhopadhyay and Mitra 2007). Fish offal, which is generated in large quantities on a daily basis in the urban and sub-urban markets in India, has immense potential to be used as a predominant nutrient source in fish diet formulations. Very few studies have evaluated its efficacy, so far (Giri et al. 2000). In a preliminary investigation we observed the viscera of carps, which are discarded in bulk as offal in the retail fish markets contain a substantial amount of crude protein (31.5%–38.9%) and lipid (40.6%–43.8%) on a dry matter basis (Mondal et al. 2006). Collection of these wastes from the urban and suburban markets, treating them suitably to preserve their nutrients and finally recycling them into fish diet production can have a significant benefit in terms of abatement of pollution of environment as well as reduction in the recurring cost of fish production. Although dried fish, chicken viscera, and related animal by-products have been evaluated previously as protein resource in fish diet formulations (Saha and Ray 1998, Giri et al. 2000), efficacy of fish offal as such has not been ACTA ICHTHYOLOGICA ET PISCATORIA (2007) 37 (2): 99–105 DOI: 10.3750/AIP2007.37.2.06

Combined effects of cadmium and composted manure to aquatic organisms

To evaluate the interactive toxicity of cadmium (Cd) and composted manure to aquatic organisms 96 h static bioassays were conducted in the laboratory with fry of common carp (Cyprinus carpio), copepod (Diaptomusforbesi) and oligochaete worm (Branchiura sowerbyi). Five concentrations of composted manure (0, 0.25, 0.5, 1.0 and 6.7 g/l) were prepared from the aquatic weed, Pistia stratiotes and each of them was combined with several concentrations of Cd to determine 96 h LC-50 values of Cd for the test organisms. Addition of composted manure, irrespective of concentration, significantly reduced the LC-50 value of Cd to the copepod and common carp fry while it increased the LC-50 value of Cd to the worm. Increased susceptibility of the worm to combined treatment of composted manure and small concentrations of Cd could be revealed only from the dose mortality curve. Results of acute toxicity bioassays were different from the results of bioassays conducted with small concentrations of Cd. Worms, exposed to 2.5 mg/l Cd, accumulated more Cd than did the carp fry and copepod. Accumulation of Cd by worms was increased by the addition of 6.7 g/l composted manure while it decreased in the carp fry and copepod. Food consumption rate of common carp fingerling was significantly reduced relative to the control by exposure to 2.5 mg/l Cd. No change in feeding rate was observed when Cd was combined with composted manure (6.7 g/l).

Toxicity of the pyrethroid pesticide fenvalerate to freshwater catfish clarias gariepinus: Lethality, biochemical effects and role of dietary ascorbic acid

Static bioassays were made in the laboratory to determine lethal concentration of the pyrethroid pesticide fenvalerate [(RS)-alpha-cyano-3-phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate] for the freshwater catfish Clarias gariepinus and effects of sublethal concentrations of the pesticide on some biochemical parameters of the fish. For exposure periods of 24 to 96 h, LC50 values of fenvalerate ranged from 5.83–4.76 μ g/L and 4.24–2.94 μ g/L, respectively for water and acetone soluble fenvalerate. Two sublethal concentrations of fenvalerate were used in the bioassays for biochemical parameters: 2.1 μ g/L for 24 h and 1.4 μ g/L for 96 h exposure, both concentrations representing 50% of LC50 value of acetone soluble fenvalerate for the respective exposure period. Hepatosomatic index, liver glycogen, alkaline phosphatase of liver and ascorbic acid of blood, liver, and kidney decreased while haemoglobin (Hb) %, plasma glucose levels and acid phosphatase level of liver increased after 24 h exposure to 2.1 μ g/L fenvalerate. Longer exposure (96 h) to even a lower concentration (1.4 μ g/L) of fenvalerate resulted in reduction of all the parameters (except Hb %) tested as compared with control. Fish previously fed for 60 days with a diet supplemented by a high level of ascorbic acid (100 mg/100 g diet) could reverse most of the effects caused by 24 h exposure to 2.1 μ g/L fenvalerate. A lower level of ascorbic acid (50 mg/ 100 g diet) supplement could not influence these effects of fenvalerate. Even the higher dose of ascorbic acid supplementation (100 mg/100 g diet) could not relieve the stress parameters, except for Hb% and HSI, when the pesticide was applied at 1.4 μ g/L for a longer time period (96 h).

Acute toxicity of cadmium to fish Labeo rohita and copepod Diaptomus forbesi pre-exposed to CaO and KMnO4.

96-h LC50 values of cadmium (Cd) to fish Labeo rohita and the copepod Diaptomus forbesi, determined by static bioassays, were, respectively, 89.5 and 10.2 mg/l. LC50 values increased significantly when fish pre-exposed to 100-350 mg/l CaO or 0.5-1.5 mg/l KMnO4 for 4 d and the copepod to 20-70 mg/l CaO or 0.25-1.0 mg/l KMnO4 for same period. The LC50 values also increased when the pre-exposure period of CaO was increased to 12 d at concentration 100 mg/l for fish and 20 mg/l for copepod. All fish died when pre-exposed to 1.5 mg/l KMnO4 for 8 d. But LC50 values of Cd to copepod increased when pre-exposure period of 0.5 mg/l KMnO4 was increased from 4 to 8 d.

Susceptibility of epigeic earthworm Eisenia fetida to agricultural application of six insecticides.

Ecotoxicological risks of agricultural application of six insecticides to soil organisms were evaluated by acute toxicity tests under laboratory condition following OECD guidelines using the epigeic earthworm Eisenia fetida as the test organism. The organochlorine insecticide endosulfan (LC(50) - 0.002 mg kg(-1)) and the carbamate insecticides aldicarb (LC(50) - 9.42 mg kg(-1)) and carbaryl (LC(50) - 14.81 mg kg(-1)) were found ecologically most dangerous because LC(50) values of these insecticides were lower than the respective recommended agricultural dose (RAD). Although E. fetida was found highly susceptible to the pyrethroid insecticide cypermethrin (LC(50) - 0.054 mg kg(-1)), the value was higher than its RAD. The organophosphate insecticides chlorpyrifos (LC(50) - 28.58 mg kg(-1)), and monocrotophos (LC(50) - 39.75 mg kg(-1)) were found less toxic and ecologically safe because the LC(50) values were much higher than their respective RAD.