Histoarchitecture effect of cypermethrin was investigated in the gills and liver of freshwater catfish, Pangasianodon hypophthalmus (weight 60-70g) over an exposure period of 96 h as an endpoint of toxicity. The fish were exposed to five acute concentrations (0.00ml/L, 0.025ml/L, 0.050ml/L, 0.075ml/L and 0.10ml/L) and the 96 h LC 50 was 0.075 ml/L. The physical reactions observed in the treated fish were erratic swimming, discolorations of the skin, loss of reflex, hyperactivities, surfacing, increasing opercula ventilation and these effects increased with increasing concentration of the toxicants and duration of exposure. The most common changes in gills histoarchitecture at all doses of cypermethrin were curl shape gill lamellae, bulged with the fusion of secondary gill lamellae, severe epithelial necrosis in gill lamellae and hypertrophy. The changes observed in the liver tissues were cloudy swelling, focal necrosis and hypertrophy of hepatocytes, degeneration of hepatocytes and cytoplasmic, extensive vacuolation of hepatocytes and pyknotic nuclei. The results of this histoarchitecture analysis of gills and liver tissues indicate a direct correlation between cypermethrin exposure and the histoarchitecture disorders.

The adsorption of levafix red (LR) dye from waste water via batch adsorption onto treated jute stick powder was investigated. Studies concerning the factors influencing the adsorption such as adsorbent dosage, pH, contact time and temperature were systematically investigated and discussed. The results revealed that the maximum removal of levafix red was ~91% from water. The kinetics data were analyzed using pseudo-first order and pseudo-second order models. It was best described by the pseudo-second order model. The adsorption equilibrium follows Langmuir isotherm. This result indicates that treated jute stick powder could be employed as low-cost alternatives to commercial activated carbon for the removal of levafix red (LR) from waste water. Rapid industrialization in Bangladesh has resulted in increased water pollution that has higher dye level. Waste water from dyeing and finishing factories is a significant source of environmental pollution. The waste water is typically characterized by high levels of COD (chemical oxygen demand) concentration, high concentration of coloring material, large amount of suspended solids, highly fluctuating pH and high temperature. Dyes may therefore present an ecotoxic hazard and introduces the potential danger of bioaccumulation that may eventually affect man by transport through the food chain. As pharmaceutical industries use lots of water and intake of this type of water might have adverse effects on human health. Therefore, water purification is extremely essential for human and animal health and dye free water may be farther purified for its proper use.

Abstract:The investigation was conducted on traditional fish drying activities of the Atrai upazila under Naogaon district from July 2011 to December 2011. There was only one fish drying point was found in study area. The observed fish drying points are seasonal (from July to December). There are sixteen fish species were identified for drying among study area. Most of the raw fish collect from local market or Atria River. Transportation of raw fish was done by non-mechanized van or by head load of the labour. Price of the raw fish varied according to the species, size and availability. It is observed that September-October peak period for drying. The rate of mixing salt in the study area was found as 1kg salt for 12 kg of raw fish. At normal weather condition drying duration recorded to be varied from 2-5 days depend on the size of the raw fish. Plastic, jute sack and sometimes bamboo baskets were used for packaging purpose. The marketing channel is too small here. It was found that all the dried fish product in study areas, carried to the Sayadpur dry fish wholesale market in Nilphamary district directly by producers. The annual production of dried fish range 6000-8000 Kg. The highest price per kg dried fish was found as 400-550 Tk (Baim) and the lowest was found as 90-120 Tk (Punti, Darkina, Colisa). The cost benefit ratio for fish drying activities of study area was 1:0.671. The dry fish trader faced some problem such as insufficient credit, lack of raw fish insect infestation, storage and marketing facilities. From the present study some recommendations were also formulated to minimize the problem.

Abstract:Freshwater aquaculture is by far the most ancient aquatic living resource production system known in the world. An experiment was conducted to evaluate the growth performance of prawn and tilapia (male) under different sex (male and female) contribution of prawn in polyculture ponds for a period of four months from September 2010 to December 2010. The experiment was designed with 3 treatments like T 1 (All male Tilapia-4938/ha + All male Prawn 19,753/ha), T 2 (All male Tilapia -4938 / ha + All female Prawn 19,753/ha) and T 3 (All male Tilapia -4938/ decimal + all male Prawn 19876 + all female prawn 19876/ha), each with 2 replications. The mean stocking weight of prawn was 2.87 g and that of tilapia was 37.36 g. Total stocking density of prawn and tilapia (24,691/ha), basal fertilization (Cowdung 2470kg/ha, Urea 50kg/ha and TSP 50kg/ha), periodic fertilization (Cowdung 50kg/ha/day, urea 1.25kg/ha/day and TSP 1.25kg/ha/day) and feeding regime (diet containing 30% protein level at the rate of 2-5% of prawn and fish body weight twice daily) were same for all the treatments. Water quality parameters (water temperature, transparency, dissolved oxygen, pH, NH 3 -N and alkalinity) were monitored fortnightly and the growth parameters were monitored monthly. Mean values of water quality parameters were found within the suitable range. Treatment T 1 varied more significantly (P<0.05) than that of others for the mean values of growth parameters (final weight, weight gain, SGR, survival rate and yield) of prawn and tilapia.

Abstract:The study was carried out to explore the impact of probiotics on shrimp (Penaeus monodon) in the Shrimp Research Station ponds during the culture period of 90 days. The experiment was set in 9 on-station ponds having an area of 0.052-0.064 ha. Three treatments of the experiment were: super Ps probiotics broadcast all over the ponds mixed with clay (T 1 ), probiotics broadca Zymetin st over the pond mixed with feed (T 2 ) and control (without probiotics) the ponds (T 3 ) and each treatments having 3 replicates. All Juvenile of shrimp were stocked at a density of 6.0 juv/m 2 and was fed with quality feed (gold plus-grower) twice daily at the rate of 10.3% of shrimp biomass. Water quality parameters namely temperature, water depth, dissolved oxygen, pH, salinity, ammonia, nitrate, total alkalinity and transparency were within suitable range for shrimp growth without finding any stress. Growth of shrimp was measured and feed was adjusted after every fortnight. The average weight of shrimp in T 1 , T 2 and T 3 was 22.065 ±5.52, 19.87 ±4.98 and 11.01 ±0.86g, respectively. Higher growth was obtained from T 1 followed by T 2 and T 3 . Day after 90 of husbandry, all shrimp were harvested. The survivality rate of shrimp production was reckoned 80%. The production of shrimp was found 760 kg/ha in T 1 , 665 kg/ha in T 2 and 205.19 kg/ha. in T 3 . So the highest production was found using super PS (T 1 ). Food conversion ratio (FCR) of prawn was found higher (2.48) in T 3 compared to T 1 (1.83) and T 2 (2.01). The result of the study is therefore revealed that probiotics paly a most important role in growth, survival and production of shrimp by maintaining good water quality environment throughout the culture period. It may be therefore concluded that probiotics can be utilized well the shrimp ponds to get higher growth and production keeping the congenial environment.