66 research outputs found

    Performance evaluation of hybrid thin layer solar tunnel-windmill dryer in the drying of brined and non-brined Tafi (Siganussutor) Fish

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    Studies were carried out to evaluate the performance of hybrid solar tunnel-windmill dryer in thin layer drying of brined and non-brined Tafi (Siganus spp.) fish. The fish were, eviscerated, and split into pieces of approximately 6cm by 4cm by 5mm was soaked in brine at 0 and 5% concentrations. The samples were dried in the dryer for 44 hours. The moisture content of the drying fish was evaluated by the AOAC oven drying procedure. In addition, analysis was carried out to establish the best thin layer drying model that describes the drying of fish in the hybrid wind-solar tunnel dryer. The moisture content of the drying fish was found to reduce linearly from 4.2 and 3.9kg/kg (db), respectively for brined and non-brined fish to 0.8kg/kg (db).  A two way Students t-test did not establish any significant difference in the drying of salted and unsalted fish (tstat=1.4032, tcrit, 5%=2.0687).  Further, the page thin layer drying model was found to be the best model describing the thin layer drying of Tafi  fish in the hybrd solar tunnel-windmill dryer (R2=0.9655 and 0.09434;  RMSE=0.0539 and 0.0840 for unsalted; c2=0.0032 and 0.0077, for salted and unsalted fish, respectively).  These results provide useful information in the modelling and design of solar drying systems for the drying of Tafi fish

    Key limitations of fish feeds, feed management practices, and opportunities in Kenya’s aquaculture enterprise

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    Profitability is key in fish farming, just as it is to any other enterprise. For the farmers to actualize high-profit margins, it is imperative to have access to well-balanced nutritive and cost-effective feeds, backed by sound on-farm feed management practices.  This paper audits Kenya’s fish feed industry and the on-going on-farm feed management practices, and emerging opportunities for fish farmers. The development of fish feed quality standards has boosted the aquaculture sector in Kenya, providing them hope that farmers will access high quality fish feeds. Much of the fish feed currently being used in Kenya is produced on-farm or by small-scale fish feed manufacturers within the East African region, while a few are imported directly from overseas countries, notably Israel, Netherlands, Mauritius and Denmark. Fish feeds produced by small-scale manufacturers are not closely monitored by quality standard agencies and not surprising that a majority are of poor quality. The improvement in the quality of these feeds is likely to lead to increased productivity and profitability because they are cheaper and readily available to fish farmers, compared to imported fish feeds. Besides feed quality, feed management practices markedly impact both the growth and economic performance of fish production. Adopting appropriate feed management strategies, therefore, is instrumental in the maximization of fish production and economic returns. Research has demonstrated several strategies for best feed management practices, which have not hitherto, been adopted by fish farmers in Kenya. Farmers have mainly focused on the mode of delivery of feeds to the fish. Furthermore, promoting natural pond productivity and supplementary feeding is still a common practice in the East African region. Provision of species-specific feeds and targeting the nutritional requirements of the different life stages of fish is still a major issue, although some local companies like Unga Farm Care (EA) have come up with a size and species-specific feed for catfish such as Fugo catfish®. To improve access to such information, public-private partnerships should be developed and, programmes that utilize the local media platforms such as extension service outlets must also be encouraged. Feed quality checks can also be carried out amongst fish feed suppliers. Lastly, farmers should be trained in various fish feed aspects like formulation, transportation and storage to sustain a steady fish feed supply and save on associated feed costs

    Genetic diversity study of Kenyan cassava germplasm using simple sequence repeats

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    Cassava (Manihot esculenta Cranzt) is an important food security crop for resource poor rural communities particularly in Africa. Little is however known about molecular diversity of Kenyan cassava germplasm. This led to a study whose objective was to identify genetic constitution of cassava accessions from different regions of Kenya using molecular tools. Seven pairs of micro satellite (SSR) primers previously developed from cassava were used to detect polymorphic 21 alleles in a sample of 69 accessions. The cluster analysis of similarity matrix obtained at 68% with SSR data showed that the 69 accessions were grouped into five marker based groups. This study proved that SSRs could be used to identify cassava accessions as well as in the assessment of level of genetic relatedness among accessions.Keywords: Cassava, simple sequence repeat (SSR) markers, genetic diversity

    Functional olfactory evolution in Drosophila suzukii and the subgenus Sophophora

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    Comparative analysis of multiple genomes has been used extensively to examine the evolution of chemosensory receptors across the genus Drosophila. However, few studies have delved into functional characteristics, as most have relied exclusively on genomic data alone, especially for non-model species. In order to increase our understanding of olfactory evolution, we have generated a comprehensive assessment of the olfactory functions associated with the antenna and palps for Drosophila suzukii as well as several other members of the subgenus Sophophora, thus creating a functional olfactory landscape across a total of 20 species. Here we identify and describe several common elements of evolution, including consistent changes in ligand spectra as well as relative receptor abundance, which appear heavily correlated with the known phylogeny. We also combine our functional ligand data with protein orthologue alignments to provide a high-throughput evolutionary assessment and predictive model, where we begin to examine the underlying mechanisms of evolutionary changes utilizing both genetics and odorant binding affinities. In addition, we document that only a few receptors frequently vary between species, and we evaluate the justifications for evolution to reoccur repeatedly within only this small subset of available olfactory sensory neurons

    Should first-line empiric treatment strategies cover coagulase-negative staphylococcal infections in severely malnourished or HIV-infected children in Kenya?

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    BACKGROUND: Bloodstream infection is a common cause of morbidity in children aged andlt;5 years in developing countries. In studies reporting bacteremia in Africa, coagulase-negative Staphylococci (CoNS) are commonly isolated. However, it is currently unclear whether children who are highly susceptible to infection because of severe acute malnutrition (SAM) or HIV should be treated with antimicrobials specifically to cover CoNS. We aimed to determine the clinical significance of CoNS amongst children admitted to a rural hospital in Kenya in relation to nutritional and HIV status. METHODS: Systematically collected clinical and microbiological surveillance data from children aged 6-59 months admitted to Kilifi County Hospital (2007-2013) were analysed. Multivariable regression was used to test associations between CoNS isolation from blood cultures and SAM (MUAC andlt;11.5cm or nutritional oedema (kwashiorkor)), and HIV serostatus; and among children with SAM or HIV, associations between CoNS isolation and mortality, duration of hospitalization and clinical features. RESULTS: CoNS were isolated from blood culture in 906/13,315 (6.8%) children, of whom 135/906 (14.9%) had SAM and 54/906 (6.0%) were HIV antibody positive. CoNS isolation was not associated with SAM (MUACandlt;11.5cm (aOR 1.11, 95% CI 0.88-1.40) or kwashiorkor (aOR 0.84, 95% CI 0.48-1.49)), or a positive HIV antibody test (aOR 1.25, 95% CI 0.92-1.71). Among children with SAM or a positive HIV antibody test, CoNS isolation was not associated with mortality or prolonged hospitalization. CONCLUSION: In a large, systematic study, there was no evidence that antimicrobial therapy should specifically target CoNS amongst children with SAM or HIV-infection or exposure

    COVID-19 vaccines under the international health regulations – we must use the WHO international certificate of vaccination or prophylaxis

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    The first vaccines against SARS-CoV-2 have now received emergency use authorization by the U.S. Food and Drug Administration (FDA), European Medicines Agency (EMA) and national authorities in China, India, UK, and Russia; and are rapidly being distributed in more than 30 countries since the end of the 2020. So far vaccines are being used by the respective countries after national approval based on promising efficacy reports and safety data, however, data on some of these vaccines have not yet been published in international peer-reviewed journals. The World Health Organization (WHO) has a role in “pre-qualifying” COVID vaccines, but WHO pre-qualification may not be necessary to record the use of immunization or prophylaxis in WHO Interna- tional Certificate of Vaccination or Prophylaxis (ICVP, aka Carte Jaune or Yellow Card) as this has not been the case with other vaccines which may not be WHO prequalified. Every dose of any COVID vaccine should be entered in the WHO Yellow Card.http://www.elsevier.com/locate/ijidam2022Veterinary Tropical Disease

    Genome sequence of the tsetse fly (Glossina morsitans):Vector of African trypanosomiasis

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    Tsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe the sequence and annotation of the 366-megabase Glossina morsitans morsitans genome. Analysis of the genome and the 12,308 predicted protein-encoding genes led to multiple discoveries, including chromosomal integrations of bacterial (Wolbachia) genome sequences, a family of lactation-specific proteins, reduced complement of host pathogen recognition proteins, and reduced olfaction/chemosensory associated genes. These genome data provide a foundation for research into trypanosomiasis prevention and yield important insights with broad implications for multiple aspects of tsetse biology.IS
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