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Introduction: Seed production has experienced significant growth in Bangladesh over the last decade, driven by the increasing number of hatcheries. The hatchery segment plays a crucial role in the overall growth and development of aquaculture in the country. Understanding its structure, conduct and performance is essential for assessing its impact on the productivity and profitability of aquaculture farms. However, there is a limited number of methodologically rigorous studies focusing on the hatchery segment in Bangladesh. The study aimed to fill the gap in the exiting literature by conducting a methodologically analysis of the hatchery segment of aquaculture value chain in Bangladesh. Methods: This study was conducted in seven of the main aquaculture producing districts in southern Bangladesh. A comprehensive structured survey was conducted between May and August 2022 with 66 enterprises, including 42 carp+catfish, 16 tilapia, and 8 crustacean hatcheries. Results and discussion: The major findings and their implications are as follows. (1) The number of hatcheries increased by 15% over the past decade, with a 27% increase in fish hatcheries and a 47% decrease in crustacean hatcheries. (2) Carp and tiger shrimp were the most commonly produced fish and crustacean seeds, contributing 67% and 99% of volume and 66% and 97% of sales value, respectively. (3) The hatcheries were family-owned and operated enterprise, and generated a total 2,491 full time equivalent (FTE) jobs. (4) Hatcheries used 86% of their broodstock annually and replaced them regularly for improving quality and avoiding inbreeding. (5) 18% of hatcheries reported facing diseases and/or water quality problems, but mean economic loss was only 0.71% of seed sales value, which is a low level of loss and waste. (6) Average annual net profit margin was relatively modest, averaging 54% of the gross revenue, which suggests the existence of competitive seed production and marketing. The results showed that the hatchery segment in southern Bangladesh appears to be dynamic, well developed, efficient, and relatively competitive. [ABSTRACT FROM AUTHOR]

Water quality has recently emerged as one of the utmost severe ecological problems being faced by the developing countries all over the world, and Bangladesh is no exception. Both surface and groundwater sources contain different contaminants, which lead to numerous deaths due to water-borne diseases, particularly among children. This study presents one of the most comprehensive reviews on the current status of water quality in Bangladesh with a special emphasis on both conventional pollutants and emerging contaminants. Data show that urban rivers in Bangladesh are in a critical condition, especially Korotoa, Teesta, Rupsha, Pashur, and Padma. The Buriganga River and few locations in the Turag, Balu, Sitalakhya, and Karnaphuli rivers have dissolvable oxygen (DO) levels of almost zero. Many waterways contain traces of NO3, NO2, and PO4−3 pollutants. The majority of the rivers in Bangladesh also have Zn, Cu, Fe, Pb, Cd, Ni, Mn, As, and Cr concentrations that exceed the WHO permissible limits for safe drinking water, while their metal concentrations exceed the safety threshold for irrigation. Mercury poses the greatest hazard with 90.91% of the samples falling into the highest risk category. Mercury is followed by zinc 57.53% and copper 29.16% in terms of the dangers they pose to public health and the ecosystem. Results show that a considerable percentage of the population is at risk, being exposed to contaminated water. Despite hundreds of cryptosporidiosis cases reported, fecal contamination, i.e., Cryptosporidium, is totally ignored and need serious considerations to be regularly monitored in source water. [ABSTRACT FROM AUTHOR]

Introduction: Seed production has experienced significant growth in Bangladesh over the last decade, driven by the increasing number of hatcheries. The hatchery segment plays a crucial role in the overall growth and development of aquaculture in the country. Understanding its structure, conduct and performance is essential for assessing its impact on the productivity and profitability of aquaculture farms. However, there is a limited number of methodologically rigorous studies focusing on the hatchery segment in Bangladesh. The study aimed to fill the gap in the exiting literature by conducting a methodologically analysis of the hatchery segment of aquaculture value chain in Bangladesh. Methods: This study was conducted in seven of the main aquaculture producing districts in southern Bangladesh. A comprehensive structured survey was conducted between May and August 2022 with 66 enterprises, including 42 carp+catfish, 16 tilapia, and 8 crustacean hatcheries. Results and discussion: The major findings and their implications are as follows. (1) The number of hatcheries increased by 15% over the past decade, with a 27% increase in fish hatcheries and a 47% decrease in crustacean hatcheries. (2) Carp and tiger shrimp were the most commonly produced fish and crustacean seeds, contributing 67% and 99% of volume and 66% and 97% of sales value, respectively. (3) The hatcheries were family-owned and operated enterprise, and generated a total 2,491 full time equivalent (FTE) jobs. (4) Hatcheries used 86% of their broodstock annually and replaced them regularly for improving quality and avoiding inbreeding. (5) 18% of hatcheries reported facing diseases and/or water quality problems, but mean economic loss was only 0.71% of seed sales value, which is a low level of loss and waste. (6) Average annual net profit margin was relatively modest, averaging 54% of the gross revenue, which suggests the existence of competitive seed production and marketing. The results showed that the hatchery segment in southern Bangladesh appears to be dynamic, well developed, efficient, and relatively competitive. [ABSTRACT FROM AUTHOR]

Fish plays an essential role in Bangladesh people's diet, being the leading and sometimes easily replaceable food of low-income households. Major and minor elements in fish are crucial for the biological process in the human body. The analyses of 18 distinct elements (Na, Mg, Al, Ca, V, Cr, Mn, Fe, Cu, Zn, Se, Br, Rb, Sr, Cd, I, Pb) in 6 selected fishes consumed by the people who live in the Savar region of Dhaka city in Bangladesh were conducted. The objective of the present analysis is to assess the concentration of heavy and trace elements in these fishes and provide up-to-date information if these fishes are safe to eat. The Proton-Induced Gamma Emission technique and the High Purify Germanium detector were used to detect the characteristic Gamma-rays from the target and then calculate the concentration of elements. In general, the highest concentrations range was typically found in K, Ca, and Fe, while the lowest concentrations range were found in V, Cd, and Pb. The findings were compared with the allowable limits of the International Atomic Energy Agency (IAEA-407) and the World Health Organisation/Food and Agriculture Organization (WHO/FAO).Fish are a key source of protein for millions of Bangladeshi citizens, particularly households with low incomes, so monitoring the toxicity level of fish is very crucial. The present analysis results indicate that these fishes are not entirely free of health hazards in consumption. Further study will provide crucial information on the relationship between the concentration of elements and human health. [ABSTRACT FROM AUTHOR]

The present study aimed to characterize and compare the skin and gut microbial communities of rohu at various post‐harvest stages of consumption using quantitative real‐time polymerase chain reaction and 16S rRNA‐based amplicon sequencing. Real‐time PCR amplification detected higher copy numbers for coliform bacteria—Escherichia coli, Salmonella enterica and Shigella spp. in the marketed fish—compared to fresh and frozen samples. The 16S rRNA data revealed higher alpha diversity measurements in the skin of fish from different retail markets of Dhaka city. Beta ordination revealed distinct clustering of bacterial OTUs for the skin and gut samples from three different groups. At the phylum level, Proteobacteria was most abundant in all groups except the Fusobacteria in the control fish gut. Although Aeromonas was found ubiquitous in all types of samples, diverse bacterial genera were identified in the marketed fish samples. Nonetheless, low species richness was observed for the frozen fish. Most of the differentially abundant bacteria in the skin samples of marketed fish are opportunistic human pathogens enriched at different stages of postharvest handling and processing. Therefore, considering the microbial contamination in the aquatic environment in Bangladesh, post‐harvest handling should be performed with proper methods and care to minimize bacterial transmission into fish. [ABSTRACT FROM AUTHOR]

The aim was to assess the efficacy of prophylactic health products (PHPs) on shrimp (Penaeus monodon) post larvae (PL) during the nursery phase. This included five treatments: infeed probiotic (F_PRO), water probiotic (W_PRO), a combination of water and infeed probiotic (FW_SYN), biofloc, a combination of biofloc and infeed probiotic (F_PRO&biofloc), and a no‐treatment control, five replicates each. Each tank was filled with 450 L water and stocked with 700 PL15, weight 0.008 ± 0.00 g at a density of 1.56 PL/L, reared for 27 days. There were no significant differences in water temperature, dissolved oxygen, alkalinity, and total ammonia nitrogen among treatments and control. pH and nitrite were lower in biofloc and F_PRO&biofloc compared to other treatments. The final body weight, weight gain, specific growth rate and food conversion ratio were significantly higher (p ≤.05) in F_PRO&biofloc compared to other treatments and control. A salinity stress test showed a significantly higher survival rate in F_PRO&biofloc followed by biofloc than other treatments and control. Our study indicated that rearing shrimp in biofloc alone or combined with infeed probiotic might increase growth and resistance to environmental stressors. Further on‐farm trials are required to confirm the efficacy of the PHPs. [ABSTRACT FROM AUTHOR]

Vibriosis caused by luminous Vibrio species is one of the biggest challenges to shrimp industry in Bangladesh. This study aimed to characterize whole microbial communities from Vibrio‐infected black tiger shrimp (Penaeus monodon) using 16S rRNA‐based amplicon sequencing. A total of 36 disease‐free and infected shrimp were collected from six different hatcheries in Bagerhat, Bangladesh. A final pool of 12 samples (n = 6) was created by homogenization of the hepatopancreas samples from three shrimps collected from each hatchery for the same group. The amplicon sequencing data revealed significant (p <.05) decrease of alpha diversity measurements and subsequent effects (p <.05) on the hepatopancreas microbiota in the infected group, compared to control shrimp. Proteobateria and Aeromonas were the most dominant bacteria at phylum and genus level in both groups and identified as core microbiota in the community. Two bacterial groups at phyla level and eight at genus level were found associated with the alteration of hepatopancreas microbial communities and associated gene functions in vibriosis‐infected shrimp, revealed by differential abundance and KEGG pathway analysis. The overwhelming abundance of Citroibacter, Shewanella and Candidatus lineages in vibriosis‐infected shrimp needs further investigations. [ABSTRACT FROM AUTHOR]

This work has been conducted at the electrical machines lab in European University of Bangladesh (EUB) for both the experimental and analytical determination of the performance parameters of the transformer for practical utilization. No-load and short-circuit tests were done for calculating the various performances parameters, such as core loss(Hysteresis loss and Eddy current loss), winding copper loss (I2R loss), no load current (Io),active component of no load current (Iw),magnetizing component of no load current (Iµ), no load resistance (Ro), no load reactance (Xo), equivalent resistance referred to primary (R01), reactance referred to primary (X01) and impedance referred to primary (Z01) and efficiency (η) of the practical transformer. Insulation resistance test was done to check the insulation level, which can identify the presence of major faults. The vector group tests also performed to identify the group numbers for various connection facilities of practical transformer. The subject under consideration was a 1.5 kVA small size, dry type practical transformer. This type of research work like 1.5 kVA practical transformer is not yet done before anywhere. This study will be the guide line for practical utilization of transformer for different purposes. [ABSTRACT FROM AUTHOR]

A beautiful method based on solar energy to heat and melts the paraffin or bees wax has been developed to manufacture the candles by a linear fresnel reflecting solar concentrating collector and a bucket. The solar method has several advantages over the conventional candle making methods. This process is likely to generate the employment particularly in the rural complex areas in Bangladesh. This paper reports a few modifications made on the solar system to enhance the daily candle production. Candles are used by all section of the society for various purposes. Candles are made from paraffin or bees wax which is heated by Fresnel reflecting concentrating collector and method to make candles. A few other materials are also added to make good quality of candles. So far the older methods based on conventional fuels are in practice for candle production. These old manual methods are troublesome, unhygienic and needs continuous attendance and care during the melting of wax besides having other drawbacks. To overcome these drawbacks, a completely new system for candle production has been developed at Solar Energy Research Centre, Department of Physics, Jagannath University, Dhaka in Bangladesh. This system is based on solar energy which accumulates sufficient solar heat by Fresnel reflecting solar concentrating collector to melt wax for making candles. The new solar system, besides saving the fuels, has several advantages over the conventional candle making methods and also obviates the continuous attendance during wax melting. The reports about the solar system and there after the few modifications made over it to improve the candle production. It is shown that in the semi-cloudy day the efficiency of the solar candle production machine is 41.52% and 59.75% for single glazed and double glazed respectively. In the clear day the efficiency of the solar candle machine is 43.135% and 63.775% for single glazed and double glazed system respectively. [ABSTRACT FROM AUTHOR]

The rapid growth of aquaculture in Bangladesh over the past three decades has been facilitated by increasing supplementary feed use and increasing numbers of feed suppliers, but little is known about the organization and behavior of the feed supply segment of aquaculture value chain. We conducted a comprehensive survey with 79 feed suppliers of two types: 'dealers' linked to feed companies (n = 34) and independent retailers (n = 45), in the seven main aquaculture producing districts of southern Bangladesh in 2021 to address this knowledge gap. We found the following. (1) Over the past 10 years, the number of traders increased 70% and the volume of feed traded almost doubled. (2) Feed supply is shifting from traditional agricultural byproducts to formulated feeds (47% of total feed), and floating feeds as a subset of those (54% of formulated feed), contributing to increasing farm productivity. (3) The formulated fish feed market in Bangladesh is diverse, but quite concentrated. Feed suppliers sold formulated feed produced by 35 companies, with eight companies accounting for 74% of sales. (4) Feed handling practices are efficient. Traders sell feeds quickly (average turnover time 10 days) and storage practices are adequate to maintain quality. (5) No traders reported experiencing any waste or loss of feed during their most recent completed transaction, and only 5% of traders reported losing a small portion of feed (1.7%) during transport. (6) The average profit margin earned by feed suppliers is a modest 6.2%. (7) Feed trading creates substantial employment: 43,937 full time equivalent (FTE) jobs in the seven surveyed districts. In sum, the feed supply segment of the aquaculture value chain in southern Bangladesh is dynamic, well-developed, and relatively competitive and efficient. This finding is contrary to the conventional wisdom, which often portrays the sector as inefficient and beset by problems. • Feed trading businesses in Bangladesh have enabled the intensification of aquaculture. • Trader feed handling practices are efficient with rapid stock turnover minimizing spoilage and feed loss and waste. • Feed trading creates substantial employment: approximately one FTE job in feed supply for every 10 FTEs on-farm. • Feed trader profit margins are modest, and traders appear to reduce credit constraints for farms by offering credit in-kind. • The feed supply segment of the aquaculture value chain in Bangladesh is dynamic, well-developed, competitive, efficient. [ABSTRACT FROM AUTHOR]

The article presents a study about the anti-diarrheal, anti-inflammatory, thrombolytic and cytotoxic activities of the methanol extract from the leaves of the ornamental medicinal plant Persicaria orientalis.

Production of the mola carplet ( Amblypharyngodon mola ), a small vitamin A rich fish, has the potential to reduce human malnutrition in Bangladesh. However, although efforts have been made to promote mola culture, the factors affecting its production are poorly understood. Therefore, this study was undertaken to identify factors contributing to mola productivity in polyculture systems. A total 177 farms in three sub-districts of Barisal district, Bangladesh, were surveyed. Production of carp was higher ( P < 0.05) in demo farms (3.42 ± 1.64 t ha − 1 ) than non-demo farms (2.49 ± 1.46 t ha − 1 ) and also differed significantly ( P < 0.05) by sub-district. The productivity of mola ranged from 0.08 to 0.68 t ha − 1 (mean; 0.26 ± 0.10 t ha − 1 ). Mola yields differed significantly ( P < 0.05) by sub-district, but no significant difference in yields was observed between demo (0.28 ± 0.10 t ha − 1 ) and non-demo (0.25 ± 0.10 t ha − 1 ) farms. Annual costs, gross income and net income were significantly different ( P < 0.05) between demo and non-demo farms. A Cobb-Douglas production function model was used to identify which inputs affect fish yields. Stocking density, feed inputs, labor and pond depth were found to significantly affect total fish production, whereas mola production was significantly influenced by inputs of inorganic fertilizer, mustard oilcake, the number of months water was retained in the pond, labor and pond depth. A financial analysis showed the benefit-cost ratio of mola polyculture was higher than 1, indicating the investment efficiency of this technology for rural farmers. The study indicates that application of appropriate inputs could be considered to maximize production of mola in future projects attempting to promote its culture. Statement of relevance This paper assesses the productivity of vitamin A rich mola carplet, farmed in polyculture with carp in Bangladesh, and identifies factors contributing to mola carplet productivity to support the design of attempts to promote mola culture in future. [ABSTRACT FROM AUTHOR]

The aim of this study is to describe current chemical use practices in the aquaculture sector of Bangladesh and to identify the factors that influence them. A survey on the use of chemical and biological products was conducted between November 2011 and June 2012 using structured questionnaires administered to operators of nine farm groups, including homestead ponds, carps, tilapias, koi fish, shrimps, shrimps and prawns, prawns, rice and fish, and pangas. Farm type and farm owner characteristics were used as independent variables to explain observed chemical use. Forty-six chemical and biological products (7 water and sediment treatment compounds, 13 disinfectants, 7 antibiotics, 7 pesticides, 8 fertilizers and 4 feed additives and probiotics) were reported to be applied in aquaculture. The use of disinfectants and antibiotics was found to be highest in intensive koi and pangas farms as compared to other farm groups, whereas the use of fertilizers was lowest in these farm groups. A higher percentage of prawn and shrimp/prawn farmers applied pesticides than other farm groups. A multivariate analysis showed that patterns of use of chemical and biological products were significantly different across aquaculture farm groups, with the largest number of chemical compounds used by the intensive koi farm group. The study shows that, despite rapid expansion of commercial aquaculture in Bangladesh, use of chemical and biological products is still relatively low compared to other aquaculture producing countries in Asia. However, despite this finding, the study identified a large number of compounds that are currently in use, and that require further regulation and evaluation regarding their potential environmental and human health impacts, as already done in most developed countries. Statement of relevance Chemical use practices in Bangladesh [ABSTRACT FROM AUTHOR]

Environmental flows have scarcely been considered in river water management in Bangladesh. This study attempts to assess the environmental flow requirements in the Halda River, Bangladesh. Thus, the objectives are to estimate the Halda River flow with different return periods/probabilities, which was done using the log-Pearson Type III distribution (LPIII), and to mitigate the environmental problems in the Halda River using the building block method. The LPIII distribution was used to estimate the expected extreme and satisfactory flows for fish habitat at Panchpukuria station and the expected extreme water levels at Panchpukuria, Narayanhat, Telpari and Enayethat stations. It was found that floods are likely to occur at least once in 2.1, 1.02, 1.75 and 1.25 years at Panchpukuria, Narayanhat, Telpari and Enayethat stations, respectively. The results of flow and water quality analyses suggest that environmental flow requirements cannot be achieved in this river throughout the year. The environmental flow requirements and conservation of fish resources can be achieved by implementing the suggestions provided in conjunction with a comprehensive awareness programme, investigations and trade-off analyses being among the suggestions. Editor Z.W. Kundzewicz; Associate editor B. Sivakumar Citation Akter, A. and Ali, Md. H., 2012. Environmental flow requirements assessment in the Halda River, Bangladesh. Hydrological Sciences Journal, 57 (2), 326–343. [ABSTRACT FROM PUBLISHER]

Background: Worldwide people in disorder of sex development (DSD) faces multiple barriers while seeking their social rights, particularly healthcare services. We aimed to explore the healthcare opportunities available to them, using patterns of healthcare utilization and difficulties faced by DSD population in accessing healthcare services in Bangladesh.Methods: Data from a total of 945 DSD population and 71 medical staff were analyzed, collected from three major divisions (Dhaka, Chittagong, and Rajshahi) in Bangladesh during the period of January to December of 2017. A structured questionnaire was used to collect data via face-to-face interviews. Descriptive statistic was used to determine the frequencies of the visit by the DSD population in healthcare facilities as well as to analyze difficulties experienced by the DSD population in getting healthcare services. Multivariate regression analysis was used to explore the association between perceived barriers in getting healthcare services and failures of the DSD population to receive the healthcare services.Results: Present data revealed that around 80% of DSD population sought healthcare services from government healthcare facilities, where the overall success rate in getting healthcare services was less than 50%. The DSD population reported a number of reasons for failures in getting healthcare services, including non-friendly interaction by non-clinical hospital's staff, non-friendly interaction by physicians, public fright as general people do not want to mingle with a DSD person, undesirable excess public interest in DSD individuals, and limitation of the treatment opportunities of hospitals to merely male or female patients. Among the stated reasons, the most frequently reported reason was non-friendly interaction by physicians (50.27%), followed by undesirable excess public interest in DSD individuals (50.16%).Conclusion: DSD population in Bangladesh have limited access to healthcare facilities and facing multiple barriers to get healthcare services. Initiatives from the government and social organizations are important to ensure their access to healthcare services. [ABSTRACT FROM AUTHOR]