Publications by authors named "Sheila Okoth"

This study examined the effects of fumonisins (FBs) and aflatoxin B1 (AFB1), alone or in combination, on the productivity and health of laying hens, as well as the transfer of aflatoxins (AFs) to chicken food products. The efficacy and safety of mycotoxin detoxifiers (bentonite and fumonisin esterase) to mitigate these effects were also assessed. Laying hens (400) were divided into 20 groups and fed a control, moderate (54.

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The study aimed to screen fungal diversity and ochratoxin A levels on culinary spice and herb samples sold in open-air markets and supermarkets in Nairobi County, Kenya. All herbs were grown in Kenya, while locally-produced and imported spices were purchased from both types of retail outlet. The results showed a high frequency of and species contaminating the samples.

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Article Synopsis
  • * Researchers conducted a 35-day experiment with 401-day-old chicks assigned to various diets, measuring impacts on feed intake, weight gain, and health through blood tests and organ examinations.
  • * Results showed that high AFB1 diets negatively impacted feed conversion ratios, while combinations with FBs improved protein levels; however, overall health was worse in contaminated groups, highlighting the effectiveness of potential detoxifiers like bentonite and fumonisin esterase.
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Diseases contribute to attainment of less than 50% of the local groundnut potential yield in Kenya. This study aimed to evaluate the agronomic characteristics (flowering and germination), disease incidence, yield performance (biomass, harvest index, 100-pod, 100-seed, and total pod weight), and aflatoxin accumulation in six peanut varieties. A field experiment was conducted using four newly improved peanut varieties: CG9, CG7, CG12, and ICGV-SM 90704 (Nsinjiro), and two locally used varieties: Homabay local (control) and 12991, and in a randomized complete block design with three replications.

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Aflatoxins (AFs) frequently contaminate food and animal feeds, especially in (sub) tropical countries. If animals consume contaminated feeds, AFs (mainly aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2) and their major metabolites aflatoxin M1 (AFM1) and M2 (AFM2)) can be transferred to edible tissues and products, such as eggs, liver and muscle tissue and milk, which ultimately can reach the human food chain. Currently, the European Union has established a maximum level for AFM1 in milk (0.

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The objective of the study was to investigate the efficacy of bentonite and fumonisin esterase, separately or combined, in mitigating the effects of aflatoxins (AF) and fumonisins (FUM) in Boran and Friesian-Boran crossbreed cattle. These effects were studied by measuring mycotoxins, their metabolites, and biomarkers that relate to animal health, productivity, and food safety. The study was divided into three experiments each lasting for 2 weeks.

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Warm and humid climatic conditions coupled with poor agricultural practices in sub-Saharan Africa favor the contamination of food and feed by and fungi, which subsequently may produce aflatoxins (AFs) and fumonisins (FBs), respectively. The growth of fungi and the production of mycotoxins are influenced by physical (temperature, pH, water activity, light and aeration), nutritional, and biological factors. This study aimed at optimizing the conditions for the laboratory production of large quantities of AFs and FBs for use in the animal experiments.

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This study investigated 65 (35 in summer and 30 in winter) smallholder dairy cattle feeds from Free State and Limpopo provinces in South Africa from 2018 to 2019 for fungal contamination and assessed the impacts of seasonal variation on fungal contamination levels, isolation frequency, and diversity. Samples were examined for fungal contamination using macro- and microscopic approaches, and their identities were confirmed by molecular means. A total of 217 fungal isolates from 14 genera, including Aspergillus, Fusarium, and Penicillium, were recovered from feeds from both seasons.

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Mycotoxin food contamination data is scattered, isolated, and poorly described. Reporting mycotoxin contamination data in a standardized manner is essential for collaborative research and integrated large-scale data analysis. The present study aimed to complement the existing European Food Safety Authority (EFSA) and Global Environment Monitoring System (GEMS) mycotoxin contamination data descriptors for application in low- and middle-income countries in particular.

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This study assessed the levels of mycotoxins in maize from Kenyan households. Further, local open pollinated maize varieties were compared with commercial hybrids to evaluate which variety is less susceptible to mycotoxin contamination. Four hundred and eighty (n = 480) maize samples were collected in the years 2018-2020 from households in Eastern, Western, Coastal and Lake Victoria regions of Kenya.

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The poultry industry in sub-Saharan Africa (SSA) is faced with feed insecurity, associated with high cost of feeds, and feed safety, associated with locally produced feeds often contaminated with mycotoxins. Mycotoxins, including aflatoxins (AFs), fumonisins (FBs), trichothecenes, and zearalenone (ZEN), are common contaminants of poultry feeds and feed ingredients from SSA. These mycotoxins cause deleterious effects on the health and productivity of chickens and can also be present in poultry food products, thereby posing a health hazard to human consumers of these products.

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Mycotoxins are common in grains in sub-Saharan Africa and negatively impact human and animal health and production. This study assessed occurrences of mycotoxins, some plant, and bacterial metabolites in 16 dairy and 27 poultry feeds, and 24 feed ingredients from Machakos town, Kenya, in February and August 2019. We analyzed the samples using a validated multi-toxin liquid chromatography-tandem mass spectrometry method.

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Article Synopsis
  • * Common mycotoxins include aflatoxins, fumonisins, zearalenone, T-2 toxin, deoxynivalenol, and ochratoxin A, which can lead to mycotoxicoses in animals and significant losses in the animal industry.
  • * The review discusses the prevalence and effects of these mycotoxins in dairy cattle diets, their implications for animal health and productivity, and presents current strategies to mitigate contamination in feed.
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The rapid population growth in developing countries has led to strong pressure on capture fisheries. However, capture fisheries have reached their maximal limits of fish production and are supplemented by farmed fish. The growth in aquaculture has led to high demand for fish feeds, which play a very important role in fish nutrition and health.

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This study evaluated the effect of dietary aflatoxin B (AFB) on growth, milt and egg quality in matured Nile tilapia (). Triplicate groups of Nile tilapia (initial body weight 24.1 ± 2.

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Insect damage on trees can severely affect the quality of timber, reduce the fecundity of the host and render it susceptible to fungal infestation and disease. Such pathology weakens or eventually kills the host. Infestation by two insect woodborer species (a moth and a beetle) is causing mortality of Sonneratia alba, a wide-ranging pioneer mangrove species of the Indo-Pacific.

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Article Synopsis
  • * Fungi were identified and characterized using PCR-sequence analysis, confirming their species and revealing that 87% were one species and 13% another.
  • * The research indicated that while the presence of specific biosynthesis genes did not strongly correlate with fungal species or regions, there was a notable association with aflatoxin production, particularly in the newly discovered species prevalent in Eastern Kenya.
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Aflatoxins continue to be a food safety problem globally, especially in developing regions. A significant amount of effort and resources have been invested in an attempt to control aflatoxins. However, these efforts have not substantially decreased the prevalence nor the dietary exposure to aflatoxins in developing countries.

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Zearalenone (ZEA) can widely contaminate crops and agricultural products. The ingestion of ZEA-contaminated food or feed affects the integrity and functions of the intestines. In this study, we aimed to find the potential protective mechanism against ZEA ingestion.

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Different methods have been applied in controlling contamination of foods and feeds by the carcinogenic fungal toxin, aflatoxin, but nevertheless the problem remains pervasive in developing countries. Curcumin is a natural polyphenolic compound from the spice turmeric (Curcuma longa L.) that has been identified as an efficient photosensitiser for inactivation of Aspergillus flavus conidia.

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colonisation of maize can produce mycotoxins that are detrimental to both human and animal health. Screening of maize lines, resistant to infection, together with a biocontrol strategy, could help minimize subsequent aflatoxin contamination. We developed a qPCR assay to measure biomass and showed that two African maize lines, GAF4 and KDV1, had different fungal loads for the aflatoxigenic isolate (KSM014), fourteen days after infection.

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Fungal contamination and the consequent mycotoxin production is a hindrance to food and feed safety, international trade and human and animal health. In Africa, fungal contamination by and is heightened by tropical climatic conditions that create a suitable environment for pre- and postharvest mycotoxin production. The biocontrol of and its associated fusariotoxins has stagnated at laboratory and experimental levels with species of , and atoxigenic being tested as the most promising candidates.

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Fungal species recovered from fermented foods and beverage from Nigeria and South Africa were studied to establish their toxigenic potential in producing an array of secondary metabolites including mycotoxins ( = 49) that could compromise human and animal safety. In total, 385 fungal isolates were grown on solidified yeast extract sucrose agar. Their metabolites were extracted and analyzed via ultra-performance liquid chromatography tandem mass spectrometry.

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Article Synopsis
  • Toxigenic Aspergillus species are harmful fungi that produce mycotoxins, causing serious health issues like cancer and liver damage in both humans and animals, particularly seen in outbreaks like the deadly one in Kenya in 2010.
  • A study focused on the diversity and characteristics of Aspergillus flavus across different Kenyan agricultural regions identified 20 unique vegetative compatibility groups, with some groups being more prevalent than others.
  • The research offered new insights into aflatoxin distribution in counties like Nandi, Homa Bay, and Kisumu, providing valuable data for future biocontrol strategies to combat aflatoxin contamination.
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