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Fate of mitochondrial DNA (mtDNA) in zebrafish (Danio rerio)under oxidative stress
(University of Dhaka, 2017-05-02) Naher, Elmay
Stress in various formssuch as extreme drought, temperature, salt intrusion, emergence of new pathogens, industrial chemicals discharge in to the aquatic system causing serious health problem of the fishes, which ultimately affect the expected production level in fisheries sector. All these environmental stress factors increase cellular reactive oxygen species (ROS) levelmainly superoxide(O2•−), hydroxyl radicals (OH•), hydrogen peroxide (H2O2) leading to secondary oxidative stress effects in fish. Under oxidative stress, ROS might affect the cellular macromolecules like protein, lipid, DNA etc. This study focused to examine the secondary effects of the environmental pollutants that is the oxidative stress on mitochondrial DNA (mtDNA) in fish. Tropical freshwater zebrafish (Danio rerio) was used as experimental model in this study and the oxidative stress was induced by H2O2treatment. Firstly we examined the acute toxicity of H2O2on zebrafish by estimating LC50 value which was not reported yet. The fishes were exposed to different concentrations of H2O2 for static acute toxicity test. The concentration-mortality (%) data were analyzed through Probit analysis to estimate the 96 h median lethal concentration (LC50) which was 257.494 µM. Secondly, the oxidative stress effect on mtDNA was examined in both H2O2 treated and non-treated zebrafish during 96 hours period. We have designed two sets of mtDNA specific primers to observe H2O2 stress effect in two specific zone of mtDNA, one is from 1 bp to 8500 bp and the other is 8244 bp to 16585 bp. After polymerase chain reaction we observed a probable nucleotide loss in mtDNA in fish under oxidative stress with the primer set 2. This oxidative damage was observed from 8266 bp to 16563 bp in both brain and egg cell of H2O2treated zebrafish. After in silico analysis, we found that this particular sequence consists of several hot spots which are repeated sequences and prone to oxidative damage. This study finds a potential sequence in mtDNA to find the oxidative damage in fish. Our findings might be the basis to develop a molecular biomarker to study the secondary oxidative stress effect due to any environmental pollutants.
Anthropogenic and climatic impacts on the Kapotakkho river fisheries Bangladesh and adaptation strategies
(University of Dhaka, 2017-05-02) Tania, Hasna Ahmed
Bangladesh has been identified as one of the most vulnerable countries due to climate change. On the other hand, anthropogenic impact on land and nature fuses impacts on the biophysical environment, biodiversity and distinctive resources. The river fisheries are also vulnerable due to climate and anthropogenic changes. Available researches on river fisheries have focused mainly on fish production, fish biodiversity, fishing gear and fishermen's livelihoods. This study assessed the socio-economic status of fishers and present non-fishers (who were fishers before) and the impacts and adaptation strategies to anthropogenic and climatic changes in the Kapotakkho river fisheries of Chowgachaupazila of Jessore district, Bangladesh. Data were collected through household interviews, semi-structure questionnaire, focus group discussions (FGD), oral history interviews and interviews with key informants between June and July 2016 from two fishing communities (Hazrakhana and Kalitola) of the Kapotakkho river. Secondary data (Climatic parameter; temperature, rainfall) were collected from Bangladesh metrological department (BMD), Agargaon, Dhaka-1207. Socio-economic status of respondents was studied in term of age structure, religion, level of education, housing condition, homestead and cultivable savings. The socio-economic status of present day non-fishers was found better than that of fishers while occasional fishers and part-time fishers were found better than those of full-time fishers. On contrast, the socio-economic status of respondents was found better in 2016 than in 1998. Both fishing communities are being exposed to the impacts of anthropogenic variables (dam construction, riverbank land use and urban runoff) and climatic variables (high temperature and low precipitation). However, volumes of water and fish habitat are being reduced. Quality of the waters was found deteriorated in 2016 than in 1998. Fish abundance was found reduced in 2016 than in 1998. This study also identified that some fishes are locally extinct and/or going to be extincted from the surveyed river. It was also found that mean catch is reduced by 9.90-folds in 2016 than in 1998. Income from fisheries related activities were found reduced by reduction in fish catch which in turn affecting the livelihoods of the fishers thus affecting their socio-economic status. To cope with the changing climate and man-made variability both fishing communities have taken multiple adaptation strategies. Some 88.3% respondents adapted adaptation strategies while rest did not. While 86.3% adopted diversification of livelihoods others increased fishing duration and use extra efficient fishing gears. Diversification of livelihoods included agriculture, fish trading; fish farming, small business and vehicle driving as prominent in both study sites. This has clearly demonstrated that agriculture is the most common adaptation strategy for fishers and non-fishers. The socio-economic statusof the river Kapotakkho fishers and fisheries has been affected by a number of anthropogenic and climatic hazards, and are being traditionally adapted to those impacts which are not sufficient for sustainable livelihoods and fisheries. Over the next few decades this situation may worsen as predicted by the latest scientific research and an improved level of responsiveness would be required.
Genetic diversity of Hilsa and Chapila in Bangladesh using DNA barcodingand RAPD techniques
(University of Dhaka, 2017-04-30) Ray, Utpal Chandra
Fisheries is one of the most important sectors in the socio-economic context of our country. Fishes are the major source of animal protein and it contributes about 60% of the animal protein intake. Tenualosa ilisha is the national fish of Bangladesh. “Jatka” are captured in a large quantity by artisanal fishers and sold on local markets as “chapila”. The main purposes of the study were morphological identification and genetic characterization of “chapila” and different species of “hilsa”. Morphometric study and DNA barcoding were used for species identification. Species identification based on the DNA sequence of a fragment of the cytochrome c oxidase subunit I gene in the mitochondrial genome, DNA barcoding, is widely applied to assist in sustainable exploitation of fish resources. RAPD (Randomly Amplified Polymorphic DNA) analyses were used to find out the genetic distances by ten arbitrary oligonucleotide RAPD primers. Four different species of chapila (Gudusia chapra), hilsa (Tenualosa ilisha), toli shad (Tenualosa toli) and big eye ilish (Ilisha megaloptera) were identified by morphometric study. But DNA barcoding shows there were two different species of Indian oil sardine (Sardinella longiceps) and kelee shad (Hilsa kelee). A total of 134 bands were produced in RAPD analysis among four species where 23 bands were polymorphic indicating 18.48% polymorphisms. The molecular size of the amplified DNA fragments ranged between 200 to 1480bp and 83unique RAPD bands were observed among four populations.The values of pair-wise genetic distances ranged between 0.5077 and 0.9933with some degrees of genetic variation among the populations.The highest genetic distance (0.9933) was found between Gudusia chapra and Sardinella longiceps. While the lowest genetic distance (0.5077) was found between Sardinella longiceps and Hilsa kelee.The UPGMA dendrogramsegregated the four populations in three major clusters viz. C1, C2 and C3. Clusters C1 and C2 comprised Sardinella longiceps and Hilsa kelee. On the other hand, Gudusia chapra created the new distant cluster C3. Results show that DNA barcoding is a reliable tool for species identification. Genetic diversity information may be used for improved breeding programme and conservation of those four populations.
Molecular identification and characterization of Vibrio parahaemolyticus causing Acute Hepatopancreatic Necrosis Disease in cultured Shrimp
(University of Dhaka, 2017-04-30) Eshik, Md. Moatavi Enan
Acute Hepatopancreatic Necrosis Disease (AHPND), also called Early Mortality Syndrome (EMS), is a recently emergent shrimp bacterial disease caused by strains of Vibrio parahaemolyticus that contain a unique virulent plasmid, resulted in substantial economic losses since 2009.AHPND has caused severe mortalities up to100% in farmed populations of marine shrimp Penaeus monodon. The purpose of this thesis work was to identify and characterize the pathogenic strain of V. parahaemolyticus causing EMS in cultured shrimp using classical and molecular techniques. To conduct this work, shrimp samples were collected from three different locations of south-west shrimp farming region of Bangladesh viz.Sadar Upazilla of Satkhira district, Mongla and Morrelganj Upazilla under Bagerhat district. The shrimp samples were processed for microbial load count and to isolateV. parahaemolyticus strains. Four types of bacteriological culture media were used to enumerate the Total Bacterial count (TBC), Total Vibrio count (TVC). Besides Classical microbiology, molecular approaches (16S rRNAgene sequencing, pathogenic gene PCR using AP3 and AP4 primers) wereperformed to identify the pathogenic strains of V. parahaemolyticus causing AHPND in cultured shrimp. Shrimp suffering from AHPND showed significantly atrophy of hepatopancreas (HP), pale to white hepatopancreas due to pigment loss in connective tissue capsules and guts with discontinuous or no contents. In this study, TBC, TVC on TCBS and on HiChrome showed little variation of AHPND affected shrimp. TBC was found highest(6.37×108cfu/g) in shrimp of Satkhira Sadar Upazilla, whereas highest number of Total Vibrio on TCBS agar (2.40×107 cfu/g) was found in shrimp of Mongla Upazilla. In this study, among 46 isolates, representative eighteen isolates were checked for the species-specificdetection of V. parahaemolyticus using ldh primers; and tdhprimerswere used for the detection of human pathogenicity of V. parahaemolyticus. Detection of ldh gene fragment in the isolates showed positive result for ldhbut isolates were negative for human toxigenic gene tdh. The representative isolates were also subjected to 16S rRNA gene sequencing and were identified as V. parahaemolyticus. Multiple sequence alignment was performed to find out the polymorphic sites among the sequenced strains with considering 1386 bp nucleotides where 1.15 % dissimilarities were observed.Six strains (Vp2, Vp4, Vp21, Vp27, Vp35 and Vp39) were highly similar to each other but dissimilar to only two sites (34, 35 bp) on their polymorphic region. Phylogenetic analysis also confirmed the taxonomic positionof the isolates as V. parahaemolyticus. On the other hand, 18 V. parahaemolyticus isolates were further characterized to check the AHPND positivity using AP3 and AP4 primer. Twelve isolates showed positive result for AP3 and fourteen isolates for AP4 primer that indicate those isolates were AHPND positive which caused EMS in cultured shrimp.This study also reported that all the representative strainsof AHPND positive V. parahaemolyticuswere resistant to Gentamycin whereas all the strain showed sensitivity to Chloramphenicol, Nalidixic Acid,Nitrofurantion and Tetracycline. This report also agreed with the mortalities of shrimp that occurred within 30 days after stocking in shrimp farms of three different south-west regions of Bangladesh which caused by AHPND positive V. parahaemolyticus;and to the best of my knowledge, this is the first report of this shrimp pathogen in Bangladesh.
Species availability, price variation and marketing channel of fish in Dhaka city
(University of Dhaka, 2017-04-27) Shahariar, Md.
The study was conducted on species availability, price variation and marketing channel of fish in seven markets namely Showarighat, Kawran Bazar, Jatrabari, Anondo bazaar, Polashi Bazar, Mohakhali and Mogbazar and three super shops namely Meena Bazar, Shwapno and Agora in Dhaka for six months from May 2016 to October 2016. Data were collected through questionnaire interviews and focus group discussions. In Dhaka city a large number of people were involved in the fish marketing channel as bepari, aratdar, paiker, and retailer. Paiker and bepari bought fish from producer and finally sold fish to retailer through aratdar. Retailers were the last intermediaries of fish marketing channel and they had direct contact with the consumer.The most available fish in seven markets and three super shops in Dhaka city are golda chingri (Macrobrachium rosenbergii), bagda chingri (Penaeus monodon), bele (Glossogobiusgiuris), poa (Otolithoides pama), deshi pangus (Pangasius pangasius), rita (Rita rita), rupchanda (Pampus chinensis), common carp(Cyprinus carpio), grass carp(Ctenopharyngodon idella),taki(Channa punctatus),boal(Wallago attu), chapila(Gudusia chapra), shol(Channa striatus), catla(Catla catla),Koi (Anabas testudineus), rui (Labeo rohita), shing(Heteropneustes fossilis), shorputi(Puntius sarana), silver carp(Hypophthalmichthys molitrix), tilapia(Oreochromis mossambicus), big head(Hypophthalmichthys nobilis)mrigal(Cirrhina mrigala)etc.In the study area, marketing channel which comprise of Beparies, Aratdar, Paiker, Retailer and Consumer. The market chain from farmers to consumers covers mainly primary, secondary and retail markets, involving local agents, suppliers, wholesalers and retailers. Beparies bought fish from primary producer in primary markets that are located in Soarighat. Beparies sell their fish to Paiker and Retailer through Aratdar.Retailers were the last traders of fish marketing channel. The highest price was observed of Rupchanda 1278.33±386.67 Tk/kg at Meena bazar and lowest price was pangus 97.71±4.25 Tk/kg at Soarighat among Meena bazar, shwapno, agora, Jatrabari, Soarighat, Annanda bazar, Polashi bazar, Kaoran bazar, Mogbazar, Mohakhali. The highest price was observed of Chingri 585±115 Tk/kg at Mohakhali and lowest price was Big head 128.75±4.27 Tk/kg at Soarighat among Jatrabari, Soarighat, Annanda bazar, Polashi bazar, Kaoran bazar, Mogbazar and Mohakhali.Poor transport facilities and enormous number of intermediaries in the marketing channels were the main problems of fish marketing channel.During peak seasonprice was lower than that of lean season.
Seasonal variation in proximate, fatty acid and amino acid profile of freshwater mud eel, Monopterus cuchia (Hamilton, 1822)
(University of Dhaka, 2017-04-27) Rana, Sohel
Throughout the year, fish are subjected to considerable environmental changes and fluctuations in availability and compositions of feed that will affect their proximate, fatty acids and amino acids composition. The purpose of this study was to clarify the seasonal variation in proximate, amino acid and fatty acid profile of freshwater mud eel, Monopterus cuchia. The proximate compositions, total amino acid and fatty acid profile were determined by AOAC, HPLC and GC respectively. Results indicated that proximate (Moisture, Protein and Lipid), amino acid and fatty acid profile varied significantly (p<0.05) among these three seasons (pre-monsoon, monsoon and post-monsoon). However, ash content showed no significant variation among seasons. The amount of protein was higher in monsoon than in pre-monsoon and post-monsoon season. The fat and fatty acid as well as protein and amino acid contents of the investigated fish species showed a significant (p<0.05) seasonal dependency. Among the 14 recorded amino acids (Essential Amino Acid-6, Nonessential Amino Acid-8), the major amino acids in the total crude protein were lysine, glutamic acid, arginine, aspartic acid, leucine and methionine. The ratio of EAA/NEAA was higher in post-monsoon season than pre-monsoon and monsoon season. The findings of the present study also showed that unsaturated fatty acids represented 44.2142%, 57.2339%% and 66.0548% of the total fatty acids, whereas saturated fatty acids accounted for 55.7858%, 42.7661% and 33.9452% in pre-monsoon, monsoon and post-monsoon seasons. The major fatty acids in muscle ofM. cuchia were oleic acid (18:1), palmitic acid (16:0), linoleic acid (18:0),palmitoleic acid (16:1) and lauric acid (C12:0). Fatty acid profile resulted that some fatty acid: tridecanoic acid (C13:0), pentadecenoic acid (C15:1), eicosenoic acid (C20:1), eicosadienoic acid (C20:2), eicosapentaenoic acid (C20:5) and docosapentaenoic acid (C22:5) were not detected in pre-monsoon experimental fish. Most nutritionally important Docosahexaenoic Acid (DHA, C22:6 n-3) was dominant fatty acid in monsoon than post-monsoon. Linoleic acid was the most abundant Poly Unsaturated Fatty Acid (PUFA) in M. cuchia. Fatty acid composition and n-3/n-6 is higher in monsoon than pre-monsoon and post-monsoon season which indicates fishes caught in monsoon season arenutritionally rich, thus advantageous for human health. Therefore, a comprehensive study on Monopterus cuchia (Cuchia) is required for the further confirmation of the result of present study.
Studies on the fish marketing system and obstacles in Jessore district, Bangladesh
(University of Dhaka, 2017-04-27) Raihan, Md. Sharif
The study was carried out on fish marketing system of Jessore district to find out fish marketing system and obstacles in Jessore district from October to December, 2016 in sixteen different fish markets of Jessore District. Among them Jhikargacha and Doratana fish market were identified as the largest fish market based on daily fish marketing. In study area it was estimated that total marketing cost of fish for aratdar, paiker and retailer was 1.325, 6.052 and 1.829 Tk in per kg of fish respectively. Cost item of fish for different intermediaries was Tk. 9.965 total which included aratdar commission, transportation, personal expenses, wastage, icing, wages and salary, market toll, rent and electricity, packaging materials, loading and unloading, telephone bill, grading and security. The highest marketing costs (Tk. 6.052) were for Paiker as they had paid highest aratdari commission and transportation cost. Average Net profit varied among Paikers, Aratdars and Retailers during peak and lean period, which is Tk. 3.317 for Paikers at peak period and Tk. 2.90 at lean period; for Aratdars Tk. 1.627 at peak period and Tk. 1.494 lean period and for Retailers Tk. 5.229 at peak period and Tk. 5.347 at lean period in per kg of fish. Ilish (Hilsailisha) had high demand to consumers and available in the market with approximate price of Tk. 250 to Tk. 300 per piece. During the study different kind of obstacles were identified in traders and consumers such as uncontrolled transport costs, poor facilities in road communication, inadequate drainage system, poor supply of ice and water, unhygienic condition of fish market, poor sanitary facilities, highest demand of labors, lack of storage and marketing facilities and political disturbances etc. Therefore, to maintain a standard system in fish market cost control among Paikers, Aratdar, Retailers and consumers is essential as well as development in fish transport facilities, introduction of fish quality control measures were suggested to mitigate different problems and improve the fish marketing system in the study area.
Detection and molecular characterization of the Microsporidian parasites in cultured Shrimp
(University of Dhaka, 2017-04-26) Hossain, Md Munjur
Microsporidian parasite has emerged as a serious pathogen reported to be associated with retarded growth in cultured shrimp in many of the shrimp growing countries in Asia. As a part of ongoing disease surveillance among the farmed shrimp, this study investigated black tiger shrimp (Penaeus monodon) culturing in the south-west region especially Satkhira and Bagherhat district of Bangladesh for the prevalence of microsporidian parasite using light and scanning electron microscopy, histopathology and polymerase chain reaction (PCR). The evolutionary history among parasiteswere inferred using the Neighbor-Joining method. The optimal tree with the sum of branch length = 0.21208716 was shown. Evolutionary analyses were conducted in MEGA7. Squash preparation of hepatopancreas and stomach showed large number of microsporidian spores under light microscopy. Spores under scanning electron microscope appeared oval shapes. Histology of infected animals showed severe degeneration of hepatopancreatic tubules. Early and late stage of microsporidian parasites in hepatopancreatic tubules were also observed in some cases. Morphological dissimilarities among the parasites also observed. DNA extracted from hepatopancreas was subjected to PCR amplification using primers targeting microsporidian SSU rRNA gene. The PCR yielded an expected product of ~328 bp and the sequences showed 83% identity with the Paranucleospora theridion (GenBank no. FJ594971.1) reported from Vietnam, Thailand and China. Further screening of field samples was carried out using EHP-specific primers. Out of 10 P. monodon samples tested, none found to be positive. So the prevalence of EHP was not estimated. To understand the microsporidian parasite Enterocytozoon hepatopenaei (EHP) prevalence, samples should be drawn from more shrimp farms with information about their management strategies. This is the first report identifying microsporidian parasites in cultured shrimp farm along the South-west region especially Satkhira and Bagherhat district in Bangladesh.
Effects of some supplemented diets on the growth performance and nutrient contents of Gulsha, Mystuscavasius (Hamilton, 1822) in Bangladesh
(University of Dhaka, 2017-04-26) Islam, Md. Farukul
Gulsha (Mystuscavasius) is the most common aquaculture fish species in Bangladesh. The fish is consumed by the people for their rich protein and higher nutrient content. The objective of the present study was to estimate the growth performance and nutrient content of gulsha (Mystuscavasius). To estimate the effects of different diets on growth performance and nutrient content of gulsha .An experiment was conducted for fourth month in concrete small pond located in BCSIR (Bangladesh Council of Scientific and Industrial Research), Dhaka. This study was conducted during the month of June, 2016 to February, 2017. The nutrient content analysiswas done in Soil and Environmental section,Biological Research Division, BCSIR, Dhaka. The growth performance of gulshawas found to be maximum with rice bran +spirulinaand lowest with commercial feed. It can be stated that the growth performance of gulshacould be improved by rice bran + spirulina. The findings of the investigation showed that Condition factor found in treatment T1 was higher than of at fourth month culture period. Specific growth rate of treatment T1 with rice bran + spirulinawas higher than treatment T2 with commercial feed at fourth month of rearing. Treatment 1 has the best proximate composition and nutrient content for human nutritional interest and thus it was found to be better option to produce healthy fish for human consumption. The findings of this research suggest that raising gulsha with rice bran and Spirulina in ponds could help in better growth performance and improve nutrient content of gulsha.
Studies on the fish marketing system in Mawaghat, Munshiganj district, Bangladesh
(University of Dhaka, 2017-04-23) Rahman, Md. Hasibur
The present study was carried out on fish marketing system of Mawaghat,Munshiganj district to find out marketing channel,market infrastructure market,constraints of fish marketing,price of fish species,market recommendation for future management and development.This research was conducted from June 2016 to February 2017 in three selected fish markets in Mawaghat. The study was based on existing marketing system and economic features of marketing activities. Data were collected from three different markets. A total of 120 consumers, 30 from each market were interviewed at the market centre. The market chain from fishermen to consumer passes through a number of intermediaries: local traders, agents/ suppliers, retailers and consumers. There are some fish species available in three different markets, such as Indian major carps i.e. rohu, catla, mrigal and exotic carps silver carp, grass and common carp, tilapia, pangas etc. The price of fish depends on market structure, species, quality, size, weight. All traders in three markets made a considerable amount of profit. Traders have broadly improved their food consumption facilities, standards of living, purchasing power, choice and ability as an economic sector than previous time. However, concerns arise about the sustainable marketing system due to higher transport costs, poor road and transport facilities, inadequate supply of ice, lack of money for this business, poor institutional support. Basic infrastructure such as, clean water supply, sanitary facilities, adequate drainage system, icing, flooring etc. should be ensured for promotion of fish marketing system.In Mawaghat, almost all fish traded internally move through the privet sector where a large number of people are dealing with fish distribution and marketing system.On the basis of a sample of 30 traders from the market, the usual amount of the daily turnover of fish in this market is between Tk 2.5 and 3 million and the volume varies relying on the variation in catches during peak or off-season.Virtually most of the fish (near about 70%) is locally supplied, near about 30% brings in from all over the country including Cox’s Bazar, Teknaf, Chittagong, Mohangang, Chandpur, Barisal, Kuliarchar, Jessore and Satkhira, Khulna, Bicrompur, Mymensingh.The present study was carried out on fish marketing system of Mawaghat,Munshiganj district to find out marketing channel,market infrastructure market,constraints of fish marketing,price of fish species,market recommendation for future management and development.This research was conducted from June 2016 to February 2017 in three selected fish markets in Mawaghat. The study was based on existing marketing system and economic features of marketing activities. Data were collected from three different markets. A total of 120 consumers, 30 from each market were interviewed at the market centre. The market chain from fishermen to consumer passes through a number of intermediaries: local traders, agents/ suppliers, retailers and consumers. There are some fish species available in three different markets, such as Indian major carps i.e. rohu, catla, mrigal and exotic carps silver carp, grass and common carp, tilapia, pangas etc. The price of fish depends on market structure, species, quality, size, weight. All traders in three markets made a considerable amount of profit. Traders have broadly improved their food consumption facilities, standards of living, purchasing power, choice and ability as an economic sector than previous time. However, concerns arise about the sustainable marketing system due to higher transport costs, poor road and transport facilities, inadequate supply of ice, lack of money for this business, poor institutional support. Basic infrastructure such as, clean water supply, sanitary facilities, adequate drainage system, icing, flooring etc. should be ensured for promotion of fish marketing system.In Mawaghat, almost all fish traded internally move through the privet sector where a large number of people are dealing with fish distribution and marketing system.On the basis of a sample of 30 traders from the market, the usual amount of the daily turnover of fish in this market is between Tk 2.5 and 3 million and the volume varies relying on the variation in catches during peak or off-season.Virtually most of the fish (near about 70%) is locally supplied, near about 30% brings in from all over the country including Cox’s Bazar, Teknaf, Chittagong, Mohangang, Chandpur, Barisal, Kuliarchar, Jessore and Satkhira, Khulna, Bicrompur, Mymensingh.

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