43 research outputs found
The biofloc technology (BFT) in indoor tanks: Water quality, biofloc composition, and growth and welfare of Nile tilapia (Oreochromis niloticus)
No full textThe present study evaluates the biofloc technology (BFT) in light-limited tank culture of Nile tilapia (Oreochromis niloticus). Two biofloc treatments and one control were managed in 250 1 indoor tanks: BFT fed a diet of 35% crude protein (CP), BFT fed a diet of 24% CP, and clean water control without biofloc with 35% CP. BFT tanks were aerated and agitated using a dome diffuser. Three kg of Nile tilapia were stocked in each tank. Feed was applied at 1.5% of the total fish biomass daily in each tank. Wheat flour was added in BFT tanks to maintain an optimum C:N ratio for heterotrophic production. The total suspended solid (TSS) level was maintained at around 500 mg l(-1) in BFT tanks. The nutritional quality of biofloc was appropriate for tilapias. Fish survival was 100%. Net fish production was 45% higher in the BFT tanks than in the control tanks confirming the utilization of biofloc by fish as food. There was no difference in fish growth/production between 35% and 24% CP fed tanks under BFT. Welfare indicators in terms of fin condition, gill histology, proximate composition, blood haematocrit and plasma cortisol levels were compared and no significant differences between BFT and control tanks were recorded indicating no increased fish stress due to the presence of biofloc. However, overall fish growth and production was poor in terms of commercial feasibility. A modified system design that would allow enhanced feed and biofloc utilization is proposed
Microbial protein production in activated suspension tanks manipulating C:N ratio in feed and the implications for fish culture
No full textThe present experiment investigated the possibility of microbial protein production in 2501 indoor tanks by manipulating C:N ratio in fish feed applied. Two different levels of protein feed (35% and 22% CP) resulting in C:N ratio of 8.4 and 11.6, respectively, were applied at 25 g daily in each tank. Tanks were aerated and agitated continuously using a dome diffuser. The experiment was carried out for eight weeks. The biofloc development in terms of VSS and BOD5 was better in the low protein fed tanks than in the high protein fed tanks. An estimated biofloc productivity ranged 3-5 g C m(-3) day(-1). A 3-D image stained with DAPI indicates that the biofloc is comprised of hundreds of bacterial nuclei, size being ranged from 100 to 200 mu m. Biofloc quality was independent of the quality of feed applied and contained more than 50% crude protein, 2.5% crude lipid, 4% fibre, 7% ash and 22 kJ g(-1) energy on dry matter basis. The dietary composition and size of biofloc can be considered as appropriate for all omnivorous fish species. The underlying ecological processes are explained through factor analysis. The potential of using biofloc in fish culture is also discussed
Measurement of Control parameters for Omnidirectional Treadmills using RGBD camera
No full textOmnidirectional treadmill systems are an effective platform that allows unconstrained locomotion possibilities to a user for effective VR exploration.
There are two most common problems associated with Omnidirectional tread- mill systems. First one is the mechanical design of it. The second one is con- trolling algorithm that controls the treadmill. This thesis focuses on the second problem and presents an algorithm which measures important parameters for controlling the direction and speed of omnidirectional treadmills. The primary objective is to collect skeleton data from Kinect Sensor(RGBD) and measure speed, acceleration and orientation vectors of lower body joints. From these measurements, it is possible to calculate the control parameters for omnidirec- tional treadmills. Using these parameters, the treadmill will try and compensate user motion, to keep the user close to the platform center. Another objective is to validate the parameters found from the algorithm and determine the accu- racy of the algorithm using Kinect camera. Also, this article explores whether the kinect can be a viable replacement for current motion capture systems used for this purpose. Usage of Kinect camera can make VR experience non-invasive and low-cost.Engineerin
Towards integration of environmental and health impact assessments for wild capture fishing and farmed fish with particular reference to public health and occupational health dimensions
No full textThe paper offers a review and commentary, with particular reference to the production of fish from wild capture fisheries and aquaculture, on neglected aspects of health impact assessments which are viewed by a range of international and national health bodies and development agencies as valuable and necessary project tools. Assessments sometimes include environmental health impact assessments but rarely include specific occupational health and safety impact assessments especially integrated into a wider public health assessment. This is in contrast to the extensive application of environmental impact assessments to fishing and the comparatively large body of research now generated on the public health effects of eating fish. The value of expanding and applying the broader assessments would be considerable because in 2004 the United Nations Food and Agriculture Organization reports there were 41,408,000 people in the total ‘fishing’ sector including 11,289,000 in aquaculture. The paper explores some of the complex interactions that occur with regard to fishing activities and proposes the wider adoption of health impact assessment tools in these neglected sectors through an integrated public health impact assessment tool
Scoping a public health impact assessment of aquaculture with particular reference to tilapia in the UK
No full textBackground. The paper explores shaping public health impact assessment tools for tilapia, a novel emergent aquaculture sector in the UK. This Research Council’s UK Rural Economy and Land Use project embraces technical, public health, and marketing perspectives scoping tools to assess possible impacts of the activity. Globally, aquaculture produced over 65 million tonnes of food in 2008 and will grow significantly requiring apposite global public health impact assessment tools.<p></p>
Methods. Quantitative and qualitative methods incorporated data from a tridisciplinary literature. Holistic tools scoped tilapia farming impact assessments. Laboratory-based tilapia production generated data on impacts in UK and Thailand along with 11 UK focus groups involving 90 consumers, 30 interviews and site visits, 9 visits to UK tilapia growers and 2 in The Netherlands.<p></p>
Results. The feasibility, challenges, strengths, and weaknesses of creating a tilapia Public Health Impact Assessment are analysed. Occupational and environmental health benefits and risks attached to tilapia production were identified.<p></p>
Conclusions. Scoping public health impacts of tilapia production is possible at different levels and forms for producers, retailers, consumers, civil society and governmental bodies that may contribute to complex and interrelated public health assessments of aquaculture projects. Our assessment framework constitutes an innovatory perspective in the field
CSR practices of private commercial bank's in Bangladesh: A comparative study
No full textCSR movement has gathered great momentum over the past number of years and is now regarded as being at this most prevalent. CSR is presently one of the most discussed topics by government, by non-government and by business itself. The purpose of the study is to provide deep understanding of the practices of CSR of PCBs in Bangladesh. The study has been taken to observe different regulatory framework (CSR areas) of CSR of PCBs and its contribution. This study found CSR practices of PCBs are quite scant rather than profit. The study reveals that PCBs are trying to swell their contribution in accordance with Bangladesh Bank proper guidelines.Corporate Social Responsibility; Private Commercial Bank; Profit; Sustainability
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No full textI hereby declare that I am the sole author of this thesis. I authorize the University of Waterloo to lend this thesis to other institutions or individuals for the purpose of scholarly research. Signature I further authorize the University of Waterloo to reproduce this thesis by photocopying or by other means, in total or in part, at the request of other institutions or individuals for the purpose of scholarly research
Periphyton-based pond polyculture system: a bioeconomic comparison of on-farm and on-station trials
No full textA bioeconomic study of periphyton-based aquaculture in Bangladesh was carried out through comparison of on-farm and on-station trials. Five treatments, three on-farm and two on-station, each with four replications, were tried in a completely randomized design: on-farm control without substrate or feed (control), on-farm bamboo substrate only (treatment B-farm), on-farm substrate plus feed (BF-farm), on-station substrate only (B-station) and on-station substrate plus feed (BF-station). All ponds were stocked with three native major carps, rohu (Labeo rohita), catla (Catla catla) and mrigal (Cirrhinus mrigala) at a ratio of 60:40:15 and a stocking density of 11,500 juveniles ha−1. All ponds were fertilized fortnightly with urea and triple super phosphate (TSP) at the same rate of 50 kg ha−1. In substrate treatments, ponds were provided with bamboo poles as periphyton substrates. In fed treatments, rice bran and mustard oil cake (ratio 2:1 by weight) were applied. The environmental conditions of on-station ponds were better than on-farm ponds. Under on-farm condition, substrate plus feed (BF-farm) and substrate only (B-farm), respectively, resulted in 59% and 28% higher production over control. Under on-station condition, supplemental feed did not contribute significantly to the total fish production. However, on-station trial resulted in 77% higher combined net yield than on-farm trial. The cost–benefit analysis indicated that well-managed periphyton-based aquaculture practices might be a profitable business. The sustainability issues of this novel technology needs to be carefully assessed during the design and planning of aquacultural developmental efforts
Photosynthetic and growth responses of Japanese sasabamo (<i>Potamogeton wrightii</i>Morong) under different photoperiods and nutrient conditions
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