21 research outputs found

    Analysis of microbial communities associated with Tilapia Aquaculture in Malawi

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    Aquaculture is of major and increasing importance to global food security, particularly in Low Income, Food Deficit Countries (LIFDCs), where it also serves as a significant contribution to poverty alleviation. Disease is widely acknowledged as the prominent bottleneck to achieving global food security and poverty alleviation targets relating to aquaculture, with annual losses exceeding >$6bn (Food and Agriculture Organization 2014). Outbreaks of disease caused by endemic and emerging pathogens impact directly on farmer income and their nutritional security. Avoidance of yield-limiting disease outbreaks is a fundamental requirement for future growth and resilience of aquaculture in LIFDCs. Advances in molecular techniques coupled with next-generation sequencing have provided a step-change in understanding the role of host-associated bacteria, archaea, protists and viruses (the microbiome) in host homeostasis. Shifts in microbiome communities under stressful conditions can contribute to disease states. However, the role of microbiomes in the emergence of diseases in aquaculture, where stressors include feeding, antibiotic and disinfectant use and over-stocking, is poorly studied. Here our study presents an evaluation of the microbiomes (bacteria and viruses) associated with tilapia and their pond environments in aquaculture, using 16S rRNA community profiling techniques and viral amplicon sequencing. Samples investigated in this project were collected from Malawi tilapia fish farms; their skin community composition and diversity were examined across geographical scales. The high variability observed of the microbial communities in small geographic regions, showed that future sampling to detect shifts due to dysbiosis will require time-resolved sampling of ponds under study. Nanopore sequencing of full length 16S rRNA genes, using MinION, allowed us to examine the microbial communities at higher taxonomic resolution than short read sequencing techniques. Its success lays the foundation for in-situ microbial profiling of aquaculture ponds for disease, and offers independence to farmers to monitor their own ponds. Successful amplification of the T4-like Myoviridae phylogenetic markers from one rearing water sample was achieved, although the required degeneracy of the primers inhibited multiplexing. Therefore, our findings suggest that inclusion of bacteriophages in microbiome studies is better served using shotgun metagenomic methods, rather than amplicon sequencing. Finally, we investigated the use of skin swabbing as an alternative to bucket incubations to minimise animal stress when categorising the fish skin microbiome. Skin swabbing successfully captured similar microbial communities in comparison to bucket incubations, with greater diversity and variance between fish

    An integration of uml use case diagram and activity diagram with Z language for formalization of library management system

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    Unified Modeling Language (UML) is the effective standard for modeling object-oriented software systems. However, the ambiguity of semantics and the absence of consistency among UML diagrams lead to lack of precisely defining the requirements of a system. On the other hand, formal methods are techniques and tools use the mathematical notations, and they involve the precise syntax and semantics of the unambiguous software requirements specification. It applied in early stages of Software Development Life Cycle (SDLC). Therefore, an integrated between UML specification and formal specification is required to reduce the requirements' ambiguity and error, and to improve the quality and security of software systems. This paper proposes an approach involves the combining UML use-case diagram and activity diagrams with Z language for formalization of Library Management System (LMS). The focus of this paper is on consistency between the UML diagrams to Z Schema, and then verified by using the Z / EVEs tool

    Relationships between pond water and tilapia skin microbiomes in aquaculture ponds in Malawi

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    This is the final version. Available on open access from Elsevier via the DOI in this recordData availability: Raw sequencing reads were deposited in the European Nucleotide Archive under the accession PRJEB46984. Data processing, analysis scripts and final ASV tables are accessible at https://github.com/jamiemcm/Malawi_Tilapia_MicrobiomesIntensification of fish farming practices is being driven by the demand for increased food production to support a rapidly growing global human population, particularly in lower-middle income countries. Intensification of production, however, increases the risk of disease outbreaks and thus the likelihood for crop losses. The microbial communities that colonise the skin mucosal surface of fish are poorly understood, but are important in maintaining fish health and resistance against disease. This skin microbial community is susceptible to disruption through stressors associated with transport, handling and the environment of intensive practices, and this risks the propagation of disease-causing pathogens. In this study, we characterised the microbial assemblages found on tilapia skin — the most widely farmed finfish globally — and in the surrounding water of seven earthen aquaculture ponds from two pond systems in distinct geographic regions in Malawi. Metabarcoding approaches were used to sequence the prokaryotic and microeukaryotic communities. We found 92% of prokaryotic amplicon sequence variants were common to both skin and water samples. Differentially enriched and core taxa, however, differed between the skin and water samples. In tilapia skin, Cetobacterium, Paucibacter, Pseudomonas and Comamonadaceae were enriched, whereas, the cyanobacteria Cyanobium, Microcystis and/or Synechocystis, and the diatom Cyclotella, were most prevalent in pond water. Ponds that clustered together according to their water prokaryotic communities also had similar microeukaryotic communities indicating strong environmental influences on prokaryotic and microeukaryotic community structures. While strong site-specific clustering was observed in pond water, the grouping of tilapia skin prokaryotes by pond site was less distinct, suggesting fish microbiota have a greater buffering capacity against environmental influences. The characterised diversity, structure and variance of microbial communities associated with tilapia culture in Malawi provide the baseline for studies on how future intensification practices may lead to microbial dysbiosis and disease onset.Biotechnology & Biological Sciences Research Council (BBSRC)Newton FundWorldFis

    Interaction between Dietary Fat Intake and Metabolic Genetic Risk Score on 25-Hydroxyvitamin D Concentrations in a Turkish Adult Population

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    From MDPI via Jisc Publications RouterHistory: accepted 2022-01-14, pub-electronic 2022-01-17Publication status: PublishedFunder: Scientific and Technological Research Council of Turkey; Grant(s): 216S272Previous studies have pointed out a link between vitamin D status and metabolic traits, however, consistent evidence has not been provided yet. This cross-sectional study has used a nutrigenetic approach to investigate the interaction between metabolic-genetic risk score (GRS) and dietary intake on serum 25-hydroxyvitamin D [25(OH)D] concentrations in 396 unrelated Turkish adults, aged 24−50 years. Serum 25(OH)D concentration was significantly lower in those with a metabolic-GRS ≥ 1 risk allele than those with a metabolic-GRS 1 risk allele (p = 0.020). A significant interaction between metabolic-GRS and dietary fat intake (energy%) on serum 25(OH)D levels was identified (Pinteraction = 0.040). Participants carrying a metabolic-GRS ≥ 1 risk allele and consuming a high fat diet (≥38% of energy = 122.3 ± 52.51 g/day) had significantly lower serum 25(OH)D concentration (p = 0.006) in comparison to those consuming a low-fat diet (38% of energy = 82.5 ± 37.36 g/d). In conclusion, our study suggests a novel interaction between metabolic-GRS and dietary fat intake on serum 25(OH)D level, which emphasises that following the current dietary fat intake recommendation (35% total fat) could be important in reducing the prevalence of vitamin D deficiency in this Turkish population. Nevertheless, further larger studies are needed to verify this interaction, before implementing personalized dietary recommendations for the maintenance of optimal vitamin D status

    Developing Field-based Methods for Real-time Genomic Surveillance of Viral Outbreaks in Tilapia

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    Viral pathogens are having a significant impact on Tilapia health, threatening global food security. It is critical to increase biosecurity measures, diagnostic testing, and sequencing to better understand their evolution and spread in aquaculture. Yet, this is not feasible or adapted in many countries, as numerous fish farms are situated in resource limited regions with reduced access to diagnostic labs. Delays in turn-around time for results reduces the capacity for timely interventions. One way to avoid devastating outcomes of viral outbreaks in aquaculture is real-time whole genome sequencing (WGS) of isolates, using in-field tools to rapidly resolve chains of transmission and implement control measures. Here, we investigate the feasibility of a tiled PCR method for genomic surveillance of Infectious spleen and kidney necrosis virus (ISKNV), a powerful tool successfully adapted for genomic surveillance of important human pathogens. We perform a complete phylogeographic analysis on isolates collected from Lake Volta, Ghana, since 2018. ISKNV, a slow evolving double stranded DNA virus has been causing mass mortalities in Ghana, and is capable of infecting a wide range of marine and freshwater fish. In addition, an in-field, non-destructive water sampling method was developed to monitor viruses in tilapia fish cages, by concentrating viral fraction on filters. Challenges were encountered when applying these methods in the field in Ghana, and the technical and economic issues are discussed. We evaluate our developed method on an equally important single stranded RNA virus, known as Tilapia Lake Virus (TiLV), which has been affecting the growth of tilapia for more than a decade. Finally, we highlight the challenges faced during a field -based genomic surveillance campaign performed on Lake Volta. This work is the first of its kind to develop and test a valuable in-field, routine monitoring and detection tool for viral outbreaks impacting the prosperity of aquaculture.Cefas-Exete
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