Oxidative stress biomarkers of exposure to deltamethrin in freshwater fish, Channa punctatus Bloch
The pyrethroid class of insecticides, including deltamethrin, are being used as substitutes for organochlorines and organophosphates in pest-control programs because of their low environmental persistence and toxicity. Ecotoxicological consequences of deltamethrin, particularly its effects on antioxidants in fish and other aquatic organisms, are not well understood. We investigated the effect of deltamethrin (0.75 μg/L) on antioxidants in a freshwater fish, Channa punctatus Bloch, using standard laboratory conditions. A single exposure for 48 h caused induction of various antioxidant enzymes and nonenzymatic antioxidants in kidney and liver. The induction of these antioxidants was not very prominent in gills. In fact, certain antioxidants were found to be depleted in gills. Catalase activity was decreased in all the tissues. Deltamethrin also induced lipid peroxidation in all the tissues, gills showing the highest levels. Glutathione, which is an established nonenzymatic antioxidant in fish, was significantly (P<0.001) increased in all the tissues. Ascorbic acid content increased in kidney and liver while it decreased in gills. The findings of the present investigation show that deltamethrin has oxidative-stress-inducing potential in fish, and gills are the most sensitive organs. It is also interesting to note that gills are the primary sites of deltamethrin absorption and their antioxidant potential is also very poor. The various parameters studied in this investigation can also be used as biomarkers of exposure to deltamethrin. It is suggested that appropriate ecotoxicological risk assessment should be made in the areas where deltamethrin is proposed to be used in pest control activities. 
Arsenic-induced histopathology and synthesis of stress proteins in liver and kidney of Channa punctatus
As3+, considered effective for aquatic weed control, has been found to be harmful to several species of freshwater teleosts. Channa punctatus (Bloch) exposed for 14 days to nonlethal concentrations (1/20 LC50 and 1/10 LC50) of As2O3 were sampled on days 0, 1, 2, 7, and 14. Tissue disorientation, peliosis, and vacuolization accompanied by karyolysis, apoptosis, and necrosis of hepatocytes were significant on days 1, 2, and 7. In the kidney shrinkage of the glomerulus and increase in the Bowman’s space were observed on days 1, 2, and 7. Irregularities in the renal tubule including apoptotic and necrotic cells were also common. Decreased intertubular space and enlargement of the height of the brush border cells were noteworthy. Corresponding with the histopathological lesions, dose-dependent disturbances in liver and renal functions and induction of heat shock protein 70 were significant at the early phase of arsenic treatment while metallothionein was induced at a later phase of treatment. 
Induction of hepatic antioxidants in freshwater catfish (Channa punctatus Bloch) is a biomarker of paper mill effluent exposure
Enzymatic and non-enzymatic antioxidants serve as an important biological defense against environmental oxidative stress. Information on antioxidant defense in fish is meager despite that fish are constantly exposed to a myriad of environmental stress including the oxidants. This study, therefore, assesses the activities of antioxidant enzymes viz., glutathione peroxidase, catalase and glutathione S-transferase and the non-enzymatic antioxidants viz., glutathione and metallothionein in various tissues of freshwater fish Channa punctatus (Bloch), in response to short-term and long-term exposures to paper mill effluent. The fish were exposed to the effluent at a concentration of 1.0% (v/v) for 15, 30, 60 and 90 days. The exposure caused a time-dependent increase in glutathione level (P<0.001), activities of glutathione peroxidase (P<0.05 to P<0.001), glutathione S-transferase (P<0.001) and a marginal initial decrease in catalase activity in the liver (P<0.01 to P<0.001). Metallothionein was induced in liver after 60 days of exposure. Two isoforms of metallothionein were detected. Catalase activity also increased 60 days afterwards. Antioxidant pattern was different in gill and kidney showing that liver was more resistant to oxidative damage as compared to gills and kidney. Our results demonstrate a pollutant-induced adaptive response in fish. In addition, levels of enzymatic and non-enzymatic tissue antioxidants may serve as surrogate markers of exposure to oxidant pollutants in fish. 
Probiotic Properties Profiling of Isolated Lactic Acid Bacteria from the Intestine of Channa punctata
Aims: This study was conducted for isolation, identification and probiotic profiling of Lactobacillus spp. from the intestine of indigenous and non-indigenous Channa punctata species.
Study Design: Lactobacillus spp. from the intestine of Channa punctata fish was isolated and cultured as well as screened for probiotic properties and profiling.
Place and Duration of Study: The research work was carried out in Biotechnology Laboratory, Department of Genetic Engineering and Biotechnology, Jessore University of Science and Technology, Jessore-7408, Bangladesh, from July to October, 2015.
Methodology: Lactic Acid Bacteria (Lactobacillus spp.) were isolated from the intestine of dissected Channa punctata by using MRS agar medium following spread plate method. Isolated bacteria were subjected to gram staining, microscopic observation and biochemical tests example catalase for identification of Lactobacillus spp. Thereafter, bile salt tolerance test, phenol tolerance test and antibiotic sensitivity test were done for probiotic profiling.
Results: Two Lactic Acid Bacteria were isolated from indigenous and non-indigenous Channa punctata species where total bacterial cell was counted as 2.1×1010 and 1.9×109 cfu/gm. Both the fish intestines contain bacteria having gram positive, non-sporulating, catalase negative rods which were confirmed to be Lactobacillus. They were able to survive in bile salt and phenol at 0.1, 0.2, and 0.3% concentration. The Lactobacillus isolated from indigenous Channa punctata was resistant to Azithromycin, Cefuroxime, Ciprofloxacin, Tetracycline, Ampicillin, Erythromycin, Vancomycin, Chloramphenicol and Co-trimoxazole while Lactobacillus from non-indigenous C. punctata showed almost same resistant except Cefotaxime and Gatifloxacin. They are claimed as probiotics.
Conclusion: Thus, the study claimed that the isolated, counted and identified Lactobacillus spp. are belong to probiotic that can exert beneficial health action for human. 
Consequences of Environmental Stressors on Hematological Parameters, Blood Glucose, Cortisol and Phagocytic Activity of Nile Tilapia Fish
Introduction: Under intensive fish culture of Tilapia, there appears to be susceptible various environmental stressors. Stress factors normally reduce growth and damage the biological system of the fish resulting in a great economic loss.
Aims: The study aimed at elucidating effects of lack of feedstuffs, overcrowding and protein deficiency on Tilapia physiology and production.
Study Design: Ninety Tilapia fish, half males and half females were randomly allocated into four treatments [control (C), protein deficiency (P), fasting (F) and overcrowding (O)].
Materials and Methods: Three aquaria were used for each treatment. Each aquarium has 6 fishes except in case of overcrowding each aquarium contained 12 fishes. Treatment lapsed for 30 days in C and P, 21 days for F and 14 days for O. Blood was collected for hematological traits and for biochemical attributes.
Results: There exists significant increase (p<0.05) in MCV values in fishes (males & females) exposed to deprivation of food. Moreover, males exhibited significant high MCV value when they were overcrowded. Mean values for MCV in males were 112.93, 123.45, 118.41 and 121.68 µm3 for C, F, P and O, respectively. Males didn’t express changes in MCH due to treatment. The values for MCH (pg) were; 35.15, 35.45, 34.15 and 35.74 pg for C, F, P and O, respectively. On the other hand, there exist significant (p<0.05) decreases in MCH values in overcrowded and protein deficiency-group. The respective MCH values in females were; 37, 35.05, 34.35 and 34.46 for C, F, P and O, respectively. Percentage of MCHC showed significant decreases (p<0.05) in treated males and females compared with control fish. Values of mean corpuscular hemoglobin concentration in males were 31.11, 28.92, 28.98 and 29.42 mg/dl for C, F, P and O, respectively. Similarly in females the respective values were; 30.99, 27.84, 28.16 and 29.21 mg/dl, respectively.
Conclusions: Adverse environmental stressors had negative impacts on different physiological parameters of Tilapia fish causing severe reduction in the productivity and consequent severe economic losses. 
 Sayeed, I., Parvez, S., Pandey, S., Bin-Hafeez, B., Haque, R. and Raisuddin, S., 2003. Oxidative stress biomarkers of exposure to deltamethrin in freshwater fish, Channa punctatus Bloch. Ecotoxicology and environmental safety, 56(2), pp.295-301.
 Roy, S. and Bhattacharya, S., 2006. Arsenic-induced histopathology and synthesis of stress proteins in liver and kidney of Channa punctatus. Ecotoxicology and Environmental Safety, 65(2), pp.218-229.
 Ahmad, I., Hamid, T., Fatima, M., Chand, H.S., Jain, S.K., Athar, M. and Raisuddin, S., 2000. Induction of hepatic antioxidants in freshwater catfish (Channa punctatus Bloch) is a biomarker of paper mill effluent exposure. Biochimica et Biophysica Acta (BBA)-General Subjects, 1523(1), pp.37-48.
 Naser, R.-A.-, Mamun, M., Hossain, M., Saikot, F., ., S. and Arifuzzaman, M. (2016) “Probiotic Properties Profiling of Isolated Lactic Acid Bacteria from the Intestine of Channa punctata”, Microbiology Research Journal International, 17(4), pp. 1-8. doi: 10.9734/mrji/2016/v17i45181.
 Zeitoun, M. M., El-Azrak, K. M., Zaki, M. A., Nemat Allah, B. R. and Mehana, E. E. (2017) “Consequences of Environmental Stressors on Hematological Parameters, Blood Glucose, Cortisol and Phagocytic Activity of Nile Tilapia Fish”, Journal of Agriculture and Ecology Research International, 10(3), pp. 1-11. doi: 10.9734/JAERI/2017/29133.