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The accumulation trends of Cu, Zn, Pb and Ni and their effects on two native species, Etroplus suratensis and Villorita cyprinoides from Cochin estuary and their biomarker responses were explored. Bioaccumulation and metal selectivity index (MSI) in E. suratensis for gill and liver showed the highest accumulation for Zn (209.33 ± 17.14 mg kg−1) followed by Cu (64.16 ± 8.07 mg kg−1), while in V. cyprinoides Cu showed the highest accumulation (80.78 ± 6.92 mg kg−1) in gill tissue followed by Zn (65.28 ± 7.06 mg kg−1). Histological alterations were evaluated in gill and liver tissues of E. suratensis using histopathological index (Ih) method. Lamellar hyperplasia and deformed lamellar architecture were the evident changes in gill tissue, while the alterations in liver tissues were marked by the presence of melanomacrophage centers and necrotic lesions in liver parenchyma. The high target hazard quotient (THQ) obtained for Pb (0.94) indicated that the daily consumption of aquatic products contaminated with metals Pb, Cu and Zn has obvious health risk to human consumption. Thus, the elevated metal accumulation rate in the tissues with supportive histological changes suggests that these alterations can serve as definite signature of heavy metal contamination in native organisms of Cochin estuary.

Heavy metal contamination in aquatic ecosystems has become an emerging environmental issue. The stable physico-chemical properties of heavy metals could result in bioconcentration and bioaccumulation in different organs of freshwater fishes. The present study records the accumulation of Lead (Pb), Cadmium (Cd), Chromium (Cr), Copper (Cu) and Zinc (Zn) in the head, muscle and skin regions of seven fish species namely, Labeo rohita , Oreochromis mossambicus, Oreochromis niloticus, Etroplus suratensis , Heteropneustes fossilis , Oligolepsis acutipennis and Puntius dorsalis collected from Minnerya, Parakrama Samudraya and Kaudulla reservoirs in Polonnaruwa district, Sri Lanka. The results showed that both Pb and Cd accumulated in high concentrations in the head region compared to the skin and muscles of the fish samples. The highest amounts of Pb (22.44±5.48 mg/Kg) and Cd (4.98±0.86mg/Kg) were recorded from the head parts of the H. fossilis in Minneriya and O. niloticus in Kaudulla respectively, whereas the highest amount of Cr (30.87±4.51mg/Kg) was detected in head part of the O. acutipennis in Minneriya. The Cu concentration was the highest (2.92±0.001 mg/Kg) in head regions of H. fossilis from Minneriya. Zn was the most abundant heavy metal detected in the head, muscle and skin regions of fish in all three reservoirs. The highest amount of Zn (118.93±10.55mg/Kg) was detected in the head part of O . acutipennis from Minneriya. The Pb, Cd, Cr, Cu and Zn concentrations detected in the head part of popular edible freshwater species, O. mossambicus, O. niloticus and E. suratensis were higher than the provisional tolerable weekly intake (PTWI) of Pb (0.025 mg/Kg), Cd (0.007 mg/Kg), Cr (0.1 mg/Kg), Cu (3.5 mg/Kg) and Zn (7 mg/Kg) specified by the FAO/WHO. Therefore, long-term consumption of these fish species especially the head parts may lead to accumulation of these heavy metals in tissues and lead to chronic diseases which may risk the health of consumers especially in the north-central province of Sri Lanka.

The upper Malwathu Oya is a seasonal river. The main livelihood of people living in the immediate vicinity of the river is paddy cultivation, and chronic kidney disease is reported among them. Farmers utilize different types of agricultural chemicals in their fields expecting bumper harvests. Several agricultural chemicals have been reported to contain toxic trace elements in Sri Lanka. Therefore, arsenic and cadmium might end up in the river water. The presence of these trace elements in the river water and sediments can result in their bioaccumulation in fish tissues. The main purpose of this study was to investigate the presence of two trace elements in water and sediments, as well as in fish tissues (gills, kidney, liver and muscle) of three food fish species, Etroplus suratensis, Anabas testudineus and Channa striata during cultivating and non-cultivating seasons of the year. Further, the level of bioaccumulation of two trace elements in fish tissues in relation to the contamination level of water and sediments was assessed. Data were gathered for 43months. Arsenic and cadmium concentration in water showed a significant (P

Copper (Cu) and zinc (Zn) play a vital role in the growth and development, however increased uptake causes deleterious effects in normal functioning of organisms. We have demonstrated in this contribution the tolerance limit of Cu and Zn on Etroplus suratensis (pearl spot) by Continuous Flow Through (CFT) bioassay and the biomarker responses. The accumulation for Cu, Zn and selected trace metals (Cr, Cd, Ni and Pb) from field conditions, as well Geo-accumulation index (I geo) and Contamination factor (C.F) suggested moderate to heavy pollution in the Cochin estuarine system. The 96 h LC50 values for Cu was 1.74 ± 0.04 mg L−1and that for Zn was 24.36 ± 0.58 mg L−1 at 95% confidence interval. No observed effect concentration (NOEC) and low observed effect concentration (LOEC) for Cu and Zn were derived based on the survival rates. Chronic toxicity values for Cu and Zn were 0.23 mg L−1 and 2.005 mg L−1 respectively for 30 days period. The histological, biochemical, hematological and behavioral parameters showed significant variations at sublethal concentrations. Lamellar hyperplasia in gills, vacuolation combined with necrosis in liver, increased occurrence of melanomacrophage centres in spleen were noticed at chronic levels for both Cu and Zn. Tissue specific bioconcentration was observed for zinc and copper in gill and liver respectively, with least rate of bioconcentration observed in muscle tissues. Malaonate Dehydrogenase (MDH), Super oxide dismutase (SOD), Nonspecific esterase (EST) activity significantly varied compared to control at NOEC and LOEC values in both the metals. The hematological and genotoxic alterations as decrease in erythrocyte count, lymphocytes, hemoglobin concentration and hematocrit percentage were significantly reduced (p

An experiment was conducted to compare the efficiency of biofilm production in natural and artificial substrates and to study their effect on water quality and growth of Etroplus suratensis. Four different substrates were used for biofilm formation: paddy straw (T1), sugarcane bagasse (T2), polyvinylchloride (PVC) pipe (T3) and plastic sheet (T4). The experiment was carried out in mud-bottomed fibre-reinforced plastic tanks (300 L) in triplicates. About 3000 cm2 surface area (600 g) of each substrate was suspended in water supplemented with fertilizers. Only cow dung and urea were applied in control tanks. The tanks were stocked with 25 fishes with average weight of 9.1 ± 0.22 g. The overall mean value of heterotrophic bacteria in substrate was found higher in straw followed by bagasse, plastic and PVC. The dominant genera of bacteria in the substrate were Bacillus, Pseudomonas and Micrococcus in that order of preponderance. The mean phytoplankton and zooplankton density on the substrates were higher in bagasse followed by straw, plastic and PVC. The biofilm developed on the substrate significantly reduced the ammonia nitrogen and nitrite-nitrogen content of water. The growth of fishes was significantly (P

Fishes are always exposed to various environmental stresses and the chances of succumbing to such stresses are of great physiological concern. Any change in temperature from the ambient condition can induce various metabolic and physiological changes in the body. The present study evaluates the effects of temperature induced stress on the antioxidant profile of Etroplus suratensis such as superoxide dismutase, catalase, glutathione peroxidase and lipid peroxidation. Fishes of same size were kept in a thermostatized bath at three different temperature regimes viz 16 °C, 27 °C (ambient temperature) and 38 °C for 72 h. These temperatures were selected based on the CT Max (Critical Thermal Maximum) and CT Min (Critical Thermal Minimum) exhibited by E. suratensis. Superoxide dismutase and catalase activity was found maximum in brain and muscle respectively during the 48th hour of exposure in fishes kept at 38 °C. At 16 °C the antioxidant response of glutathione peroxidase was maximum in muscles, whereas the lipid peroxidation rate was found to be high in gills compared to other tissues. The profound increase in the levels of oxidative stress related biomarkers indicate that the thermal stressors severely affected oxidative state of E. suratensis by the second day of experiment. Such down-regulation of redox state accompanied with the induction of oxidative stress cascade may lead to physiological damage in various tissues in fishes, in vivo. However current data indicate that a transition to low and high temperature environment from ambient condition severely affected the levels and profile of the antioxidant markers overtime in E. suratensis.

The study was conducted to document the biochemical changes in the different body parts of Etroplus suratensis when feeding them with herbal maturation diets. Three different herbal maturation diets, such as Mucuna pruriens: Withania somnifera:Moringa oleifera (MP:WS:MO) in 1:1:1 ratio (Experimental Diet-1 - EXD1), MP:WS:MO in 2:1:2 ratio (Experimental Diet-2 - EXD2), MP:WS:MO in 1:2:1 ratio (Experimental Diet-3 - EXD3) and a control diet(without herbal extracts) were prepared by mixing the said proportions of the herbal extract with other feed ingredients and fed to the adult female animals. The effects of herbal maturation diet on biochemical parameters such as level of triglyceride, total protein, cholesterol and carbohydrate in blood, liver, gonad and body tissue were analyzed in the experimental fish. The results showed that the level of triglyceride, total protein, cholesterol and carbohydrate were significantly increased in EXD3 herbal maturation diets fed fishes than the other experimental and control diet fed animals. The results proved that the administration of the herbal maturation diet EXD3 enhanced the level of the triglyceride, total protein, cholesterol and carbohydrate which can in turn leads to quick maturation and reproductive success in E. suratensis.

With the objective to develop an indoor tank seed rearing system for pearlspot (Etroplus suratensis), effects of three stocking densities in presence or absence of soil base were evaluated on growth, weight variation, survival and body composition in a 60-day trial. The experiment had a 3 × 2 factorial design with three levels of stocking density (150, 300 and 450 fish m−3) and two levels of soil base (with and without) in triplicates. Pearlspot fry (27.5 ± 0.5 mm/0.39 ± 0.02 g) were stocked in experimental tanks (Length×Breadth×Height: 0.65 × 0.50 × 0.48 m) and fed with a formulated diet containing 29.85% crude protein. Increasing the stocking density from 150 to 450 fish m−3 significantly decreased the growth (average body weight and total length), daily weight gain, specific growth rate and survival (P 0.05). A significant positive interaction effect of stocking density and presence or absence of soil base was observed on average body weight (P

Cell lines of Etroplus suratensis established in our laboratory were evaluated for their potential use as screening tools for the ecotoxicological assessment of tannery effluent. The cytotoxic effect of tannery effluent in three cell lines derived from eye, kidney and gill tissue of E. suratensis was assessed using multiple endpoints such as Neutral Red (NR) assay, Coomassie Blue (CB) protein assay and Alamar Blue (AB) assay. Acute toxicity tests on fish were conducted by exposing E. suratensis for 96 h to tannery effluent under static conditions. The toxic effect of tannery effluent on the survival of fish was found to be concentration and time dependent. The tannery effluent at the concentration of 15% caused 100% mortality at 96 h whereas the lower concentration (0.5%) caused 13.33% mortality. The cytotoxicity of tannery effluent was found to be similar in the three cell lines tested, independent of the toxic endpoints employed. EC(50) values, the effective concentration of tannery effluent resulting in 50% inhibition of cytotoxicity parameters after 48 h exposure to tannery effluent were calculated for eye, kidney and gill cell lines using NR uptake, AB and cell protein assays. Statistical analysis revealed good correlation with r(2)=0.95-0.99 for all combinations between endpoints employed. Linear correlations between each in vitro EC(50) and the in vivo LC(50) data, were highly significant p0.001 with r(2)=0.977, 0.968 and 0.906 for AB(50), NR(50), and CB(50), respectively.

Mercury, a global pollutant, has become a real threat to the developing countries like India and China, where high usage of mercury is reported. Mercury and other heavy metals deposited in to the aquatic system can cause health risk to the biota. The common edible fishes such as Mugil cephalus, Arius arius, Lutjanus ehrenbergii, Etroplus suratensis were collected from Cochin backwaters, Southwest India and analysed for mercury and other heavy metals (zinc, cadmium, lead and copper) in various body parts. Kidney and liver showed highest concentration of metals in most fishes. The omnivore and bottom feeder (E. suratensis) showed high concentration of mercury (14.71 mg/kg dry weight) and other metals (1.74 mg/g—total metal concentration). The average mercury concentration obtained in muscle was 1.6 mg/kg dry weight (0.352 mg/kg wet weight), which is higher than the prescribed limits (0.3 mg/kg wet weight). The concentration of other heavy metals in the muscles of fishes were found in a decreasing order Zn>Cu>Cd>Pb and are well below WHO permissible limits that were safe for human consumption. Metal selectivity index (MSI) obtained for all the metals except mercury showed that both carnivores and omnivores have almost same kind of affinity towards the metals especially Zn and Cd, irrespective of their feeding habit. The MSI values also indicate that the fishes have the potential to accumulate metals. High tissue selectivity index (TSI) values were reported for kidney, muscle and brain for all metals suggests that the metal concentration in these tissues can serve as an indication of metal polluted environment. Even if the daily intakes of Zn, Cd, Pb and Cu from these fishes are within the provisional maximum daily intake recommended by WHO/FAO, the quality is questionable due to the high hazard index obtained for mercury (>1). Fishes like E. suratensis being a favourite food of people in this region, the high consumption of it can lead to chronic disorders as this fish has high concentration of metals.

Highly popular and delicious fish of Kerala (India), pearlspot, Etroplus suratensis is known for its ability to tolerate wide range of salinity, omnivorous feeding behavior. Present report documents the occurrence and management of Caligus rotundigenitalis in brackishwater pond meant for culture demonstration of pearlspot in Gujarat, (India). A brackishwater aquaculture pond (1,500 sq m) was stocked with pearlspot fry (2.60 ± 0.83 g; 4.31 ± 0.82 cm) @ 25,000 ha(-1). On the 46th day of culture couple of dead fish were observed which gradually increased to 120 per day by 52nd day. Following the close observation parasitic infestation was noticed on gills cavities ranging from 15 to 20 numbers per fish. These characteristic features confirmed the parasite as C. rotundigenitalis. As a therapeutic measure the infested pond was successfully treated with Butox(®) @ 300 ml/ha (Deltamethrin 12.5 mg) and repeat dose was administered 2 weeks later. The results of the study suggest the possible therapeutic value of Deltamethrin in treatment of caligid infestation in pond cultured pearlspot.

The effects of sodium acetate dip treatment, followed by vacuum-packaging, on the shelf life of beheaded, scaled and gutted Pearlspot (Etroplus suratensis) during chill storage were examined. Sodium acetate (2%, w/v) solution was used for the dip treatment. Pouches (size: 15 x 22 cm) made of 12μ-polyester laminated with 300 gauge low-density polyethylene were used for packing fish. After packing, all the packs were iced with flake ice in the ratio (1:1) fish: ice in an insulated box and were kept in a cold room maintained at 0-2 °C. The control and the treated packs were analysed periodically for chemical (pH, TBA, TMA, TVB-N), microbiological (total viable count), textural and sensory characteristics. Changes in Staphylococcus aureus, Enterobacteriacea and Feacal streptococci were determined for fresh fish and for fish samples at the time of sensory rejection. Air packed samples were found to have a shelf life of about 8 days; vacuum-packed samples were found to be acceptable up to 10 days, whereas sodium acetate-treated vacuum packed samples were found to be acceptable up to 15 days. Thus, vacuum-packaging, in combination with sodium acetate, was found to delay the spoilage, thereby significantly extending the shelf life of Pearlspot at refrigeration temperatures.

Aims: This study aimed to determine the effect of packaging [air, modified atmosphere (MA)] on microbial growth, sensory and chemical parameters and also on shelf life of fresh pearl spot (Etroplus suratensis Bloch) and on the selection of microbial association. Methods and Results: Fresh pearl spot (whole, gutted) were packaged under both 100% air and MAs (40%CO2/60% O2, 50%CO2/50%O2, 60% CO2/40%O2, 70% CO2/30% O2 and 40% CO2/30% O2/30% N2) and stored at 0°C. Microbial growth (counts of total aerobic bacteria, H2S–producing bacteria, Lactic acid bacteria, Brochothrix thermosphacta, yeast and mould), chemical spoilage indicators (pH, total volatile basic nitrogen) and sensory characteristics were monitored. Microbial changes in Pearl spot packed under 100% air and 40% CO2/30%O2/30% N2 were similar. The total volatile basic nitrogen values increased, but the values never exceeded the acceptability limit of 25 mg 100 g−1. Conclusions: MA 60% CO2 : 40%O2 was found to be better with a shelf life of 21 days whereas air stored samples had a shelf-life of 12–14 days only. Significance and Impact of the Study: Storage of pearl spot under MAs 60% CO2 : 40%O2 is a promising method to extend shelf-life. Longer shelf life expands the market potential of pearl spot and reduces waste during distribution and retail display.

In the present study growth promoting, potential of Clitoria ternatea leaves, Flowers, Roots and Seeds the Pearl spot Etroplus suratensis was evaluated. The ingredients basal diet (control) 40% rice flour, 20% Soy bean meal, 10% corn gluten meal, 12% wheat flour, 3% starch -potato starch, and 6% carbohydrate and lipid sources, 5% fish oil, and vitamin and 3% mineral premix. Significant improvements in the nutritional indices, concentrations of biochemical constituents, activities of digestive enzymes. All the statistical values significantly at p

Chemical partitioning of heavy metals (Fe, Mn, Cu, Cr, Pb, Zn, Ni) were determined in surface sediments of three reservoirs at the Delta region of Cauvery River, India. The abundance of metals in sediments varied in the following descending order: Fe, Mn, Cr, Zn, Cu, Ni, and Pb. Higher concentrations of Zn, Pb, Fe, Mn and Cu in exchangeable and carbonate fraction indicated toxicity risk to the biota. Therefore, to understand the extent of bioaccumulation, six commercial fish species were collected from the same sites and analyzed for heavy metals distribution in different organs. Among the metals found in fish samples, iron was observed in the highest concentration, followed by Zn, Pb, Cr, Mn, Cu, and Ni. Concentrations of Pb, Cr and Zn in many fish samples exceeded the permissible limits of Food and Agriculture Organization. The concentrations of Pb (17.7-31.7%), Cr (6.2-15.1%), Cu (15.2-30.5%) and Zn (30-40%) associated with exchangeable and carbonate fractions had significant positive correlation with the respective metal concentrations in fish. Among the fish species, Catla catla and Etroplus suratensis showed the highest accumulation of metals suggesting risk for human consumption.

The genotoxic potential of methyl parathion and phosphamidon, two commercial formulations of organophosphorus pesticides, was evaluated through induction of sister chromatid exchanges (SCE) and chromosome aberrations in fish gill tissues. Fishes exposed to the medium containing 0.05, 0.1 and 0.2 ppm of methyl parathion or 0.5, 1.0, and 2.0 ppm of phosphamidon for a duration of 96 h revealed significant increase in the number of SCE and chromosome aberrations against control values. This demonstrates the feasibility of the fish in vivo system in detecting genotoxic potential of pollutants.

Sister chromatid exchange (SCE) test was applied to a tropical cultured fish, Etroplus suratensis by exposing to known mutagens. Intramuscular injections of methyl methane sulphonate (MMS) and cyclophosphamide (CP) for an exposure period of 96 h resulted in significant increase in the frequency of SCE in gill tissues. MMS induced dose dependent increase in SCE. The findings revealed that the test species in the present study may be used in mutagenicity assays for screening environmental pollutants.

Quality changes in Mullet ( Liza corsula ) and Pearlspot ( Etroplus suratensis ) stored at ambient temperature and in ice were studied by sensory, nucleotide and volatile base nitrogen analysis. The K-value increased linearly with storage time and appeared to be a good index of freshness for the two brackish water fish. Inosine monophosphate bears a significant positive correlation with ( P ≤ 0.001) flavour score. Hypoxanthine increased exponentially with time and volatile base nitrogen showed a slow increase during the early periods of iced storage.

The digestibility of the aquatic macrophyte Hydrilla verticellata by the Asian cichlid, Etroplus suratensis was estimated using three indigenous markers viz. hydrolysis resistant organic matter (HROM), crude fibre (CF) and hydrolysis resistant ash (HRA). In the fodder HROM showed the least variation and HRA the highest. The recovery of HRA in the faeces was always higher than 100% whereas HROM was the nearest to 100%. The total digestibility varied between 34·6% and 51·9%, and the digestibility estimates were higher when HRA was considered as the marker. The overall protein and lipid digestibility varied between 59·2%–70·9% and 65·0%–70·1 % respectively. It is suggested that HROM is a better reference marker in comparison CF and HRA. Daily variation in protein digestibility ranged from 51·2% to 81·8%.

Summary Therapeutic control of crustacean ectoparasite Ergasilus ceylonensis on gills of Asian cichlid Etroplus suratensis inhabiting Negombo estuary and its tributaries on the west coast of Sri Lanka was investigated using formalin, gammexane, potassium permanganate, 3,4 Dichloropropyoanilyde and fenitrothione. Potassium permanganate (3–5 ppm) and 3,4 Dichloropropyoanilyde (3–5 ppm) were observed to be successful as therapeutic chemicals. Infected fish were not able to tolerate low concentrations of formalin (50–500 ppm), gammexane (5 ppm) and fenitrothione (0.1–5.0 ppm).

The proximate compositions and amino acid make-up of silver jew fish (Johnius argentatus), Indian halibut (Psettodes erumei), grey mullet (Mugil cephalus) and pearl spot (Etroplus suratensis) are reported. Calorific values of these fishes have been calculated from their proximate compositions and their amino acid make-up compared with the available data for beef and egg. From the study, pearl spot is adjudged to be the most nutritive among the fishes studied, followed by Indian halibut, grey mullet and silver jew fish.