The present investigation was concerned with the fish biodiversity of old Brahmaputra River under Mymensingh district of Bangladesh. Objectives of the study were to determine biodiversity and abundance of fish, and to assess seasonal abundance and variation of fish in the river. A semistructured questionnaire was used to collect the pertinent information from 40 randomly selected fishermen from the study area. A total of 55 species of fish and shell fish were recorded from study sites. Among them, 8 species of carps, 4 species of snakeheads, 8 species of perches, 3 species of eels, 13 catfishes, 8 species of barbs, 2 species of minnows and clupeid species, 3 species of shrimp and other miscellaneous 4 species. It was found that 13 species were abundant, 19 were common, 14 species were less common, and 9 species were rare. The fishermen and other local elites reported that fish population in the old Brahmaputra River has been declining very fast over the last decades may be due to change in water current, depth of water, over fishing, temperature etc.

Molluscs are the most important resources among all the seafood items in South-East Asian countries. However, very little information available on nutritional value of molluscs in these regions. In this study, we evaluated the 7 economically important species of molluscs in terms of proximate composition, amino acids profile, fatty acids profile, cholesterol and heavy metal contents in the bivalves (mussels, oysters, clams and cockles) and univalve (snail) collected from freshwater and marine environments of Bangladesh. The results of the proximate analyses revealed that significantly higher amount of crude protein contents were present in marine water oysters, clams and cockles (59.3 AE 0.3 to 75.4 AE 0.2%) than the freshwater mussels and snail (36.9 AE 0.4 to 49.6 AE 0.6%) on dry matter basis. However, carbohydrate contents were significantly higher in freshwater mussels and snail (30.2 AE 0.9 to 57.3 AE 0.2%) compared to the marine water bivalves (8.1 AE 0.4 to 20.2 AE 0.6%). Crude lipid contents were ranged from 2.5 AE 0.2 to 11.2 AE 0.1% and ash from 11.4 AE 0.1 to 16.8 AE 0.6% among the bivalves and snail species. The amino acid contents were comparatively higher in marine water bivalves than their freshwater counterparts. Saturated fatty acid contents were found to be higher in marine water bivalves than the freshwater mollusc species. The results also show that the omega-3 (eicosapentaenoic acid, EPA and docosahexaenoic acid, DHA) fatty acids were comparatively higher in oysters, clams and cockles in marine water than those in freshwater mussels and snail. However, omega-6 fatty acids like linoleic acid (LA), αlinolenic acid (ALA) and arachidonic acid (ARA) were higher in freshwater mussels and snail than in the marine bivalves. The n-3/n-6 ratio were significantly higher in oysters and cockle species than the other groups of bivalves and snail. The index of atherogenicity and index of thrombogenicity of the mollusc species ranged from 0.74 AE 0.1 to 1.74 AE 0.2 and 0.5 AE 0.1 to 2.6 AE 0.2, respectively. The results show that marine water bivalves contained higher amount of potassium, sodium, iron, chlorine especially oyster species contained significantly higher iodine than the freshwater bivalves and snail. However, freshwater mussels and snail showed significantly higher amount of zinc contents than the marine bivalves. The heavy metal contents such as arsenic, chromium and mercury were absent or present in very tiny amounts among the mollusc species. Significantly higher amount of cholesterol was present in marine bivalves and freshwater snail species than the freshwater mussels. Overall, the results indicate that marine bivalves can be good sources of high quality protein and lipid especially EPA and DHA. On the other hand, freshwater mussels and snails also could be good sources of protein, LA and ARA but scarcity of EPA and DHA.

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A study was conducted from July 2013 to June 2016 on production rate, quality, and color of pearl, cultured at Trishal, Fulbaria and BFRI (Bangladesh Fisheries Research Institute) of Mymensingh region. Freshwater pearl producing mussel, Lamellidens marginalis was used in this experiment. Eighty mussels per decimal were stocked in integration with fish culture. Three ponds from three locations were used. The area of each pond was 40 decimal having water depth of 1.5m in Trishal, Fulbaria and BFRI respectively. Water temperature, pH, Ammonia, Dissolve oxygen, Alkalinity, Ca2+ and Phytoplankton (× 103) ranged from 25.37-28.730C, 6.2-7.92, 0.02-0.3mg/l, 5.09-6.08mg/l, 100.17-191.50, 15.31-25.87and 48.99-63.45, respectively. Survival rate of the operated mussels were 30.62%, 34.62% and 40.25%, respectively. After 3 years of rearing, 53%, 76% and 93% pearls containing mussels were harvested from Trishal, Fulbaria and BFRI respectively. After final harvesting total pearl production, its quality and color were observed and found better at the location of BFRI, followed by Trishal and Fulbaria. Research study concluded that, the quality of pearl depends on intensive care, proper management, suitable water quality parameter, sunlight penetration, food availability and soil quality of the culture pond.  J Bangladesh Agril Univ 17(3): 424–429, 2019

The study was conducted to observe the biodiversity of Shorupdah Beel, fish species, non-piscine animal species and the aquatic vegetation. This beel riches with its biodiversity and most of them are consume by the people of surrounding area. This water body not so deep compare with its biodiversity, highest 5-6 feet in rainy season. A total fifty two species belong to ninteen families under nine orders were identified non-piscine biodiversity of Shorupdah Beel comprises five species of prawns, four species of mollusks, three species of arthropods, two species of amphibians and two species of reptiles. Only fish and prawn are consumed by local people and the highest catch found just after rainy season that is during August and September. Ten species of aquatic vegetation found in this beel. Among these some are edible and some are not. Fishermen and local people said that biodiversity has been declining very fast over the last decades due to change of water depth, over fishing, temperature, use of chemicals in agriculture etc.

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Serum Aeromonas hydrophilaRabbit FKC HKC MAS An experiment was conducted to prepare anti-Aeromonas hydrophila serum in two rabbits (Oryctolagus cuniculus). Formalin killed cell (FKC) and heat killed cell (HKC) were prepared by adding 0.5% formalin and 2.5 h heat treatment at 60°C of freshly cultured Aeromonas hydrophila (AQC810) isolated from naturally infected koi fish kidney respectively. Slide agglutination tests were performed for the determination of the presence of specific antibody against Aeromonas hydrophila in the serum collected from the blood of pre-immune rabbits or post immune rabbits. No agglutination of pre-immune serum with the homologous antigen proved that the rabbits had no previous Aeromonas contamination. Rabbits were injected subcutaneously with the FKC added with same amount of Freund's complete adjuvant. Three booster doses were given without the adjuvant at weekly intervals after second week of first injection. Agglutination titration of anti-Aeromonas hydrophila rabbit serum against HKC and FKC of homologous bacteria showed that the titers increased with the post inoculation days which rose at their peak during the fifth week of immunization and after three consecutive booster doses at weekly intervals starting from second week of first immunization. Rabbits were sacrificed after six weeks of immunization, whole blood, collected and centrifuged to accumulate the serum that were complementinactivated by heating to 58º C for 30 min and stored at -20°C in appendorph tubes, with the aim of rapid diagnosis of Aeromonas infections in fishes. Result of this study would initiate the way of vaccine development against MAS (motile Aeromonas septicemia) in the aquaculture fishes of Bangladesh. Development of anti-Aeromonas hydrophila serum from RabbitsRes.

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