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dc.contributor.advisorMargaret Mwihaki Ng’ang’aen_US
dc.contributor.advisorEthel O. Mondaen_US
dc.contributor.advisorAhmed Hassanalien_US
dc.contributor.authorMueni, Githinji Irene
dc.date.accessioned2021-09-23T09:31:47Z
dc.date.available2021-09-23T09:31:47Z
dc.date.issued2020
dc.identifier.urihttp://ir-library.ku.ac.ke/handle/123456789/22624
dc.descriptionA Thesis Submitted in Partial Fulfillment of the Requirements for the Award of the Degree of Doctor of Philosophy of in the School of Pure and Applied Sciences of Kenyatta University, December, 2020en_US
dc.description.abstractMycotoxins are secondary metabolites produced by fungi. The most toxic mycotoxins are particular secondary metabolites of Penicillium, Aspergillus and Fusarium fungi species that infect a variety of human food and animal feeds. Poultry farming has become one of the most profitable businesses in Kenya because of the growing demand of chicken and their eggs by households, hotels and restaurants. Besides creating employment, poultry meat and eggs are an alternative source of proteins for many people in both urban and rural areas. However, there is increased risk that poultry feeds may contain potential microbiological and toxicological contaminants that may compromise their safety and nutritional value. This study sought to quantify the levels of ochratoxin A (OTA), fumonisin B1 (FB1) and aflatoxin B1 (AFB1) in poultry feeds and chicken products using the Liquid chromatography-mass spectrometry technique, and to screen essential oils of selected ethnobotanical plants, individually and in different blends as potential inhibitors of fungi produced by Fusarium and Aspergillus species. Chicken feeds and chicken products were sampled from different agro-ecological zones in Kenya, where poultry farming is widely practiced. From the sampled chicken products and poultry feeds, 13.3 % and 46.9 % respectively were found to be OTA contaminated. All the poultry feed samples were found to be FB1 contaminated, while all the chicken products showed no detectable FB1 levels. AFB1 contamination occurred in 43.3% and 59.3 % of the sampled chicken products and poultry feeds, respectively. Contamination levels of OTA, AFB1 and FB1 differed significantly within the study regions and in different chicken feeds and products. Chicken feed and products from Kakamega County had the highest levels of OTA and AFB1 contamination. The mean levels of OTA in samples from Kakamega were 165.33±0.42 and 7.12±1.25 ng/g for chicken feeds and chicken products respectively. Kakamega had average levels of AFB1 of 32.44±1.54 ng/g in chicken feed and 4.10±1.33 ng/g in chicken products. Makueni County had the highest level of FB1 contamination in chicken feed (27700.00 ng/g). FB1 was not detected in all the chicken products. The mycelial diameter of A. niger, A. flavus and F. verticillioides decreased with increase in the concentration of each of the three plant essential oils, Lippia javanica, Ocimum gratissimum and Toddalia asiatica, from 1 μL/mL to 32 μL/mL. Essential oil of T. asiatica were most effective, followed by that of O. gratissimum, and lastly that of L. javanica. Of the blends of two essential oils, that of O. gratissimum and T. asiatica resulted in the least mycelia diameter, thus the best inhibitory activity against the growth of A. niger, A. flavus and F. verticillioides. On the other hand, the blend of O. gratissimum and L. javanica showed the least inhibition activity. A blend of all the three essential oils gave the highest growth inhibitory activity against the fungi, showing synergistic effects of various constituents of the three oils. Thus, this blend of L. javanica, O. gratissimum and T. asiatica at 32 μL/mL shows potential for use in the preparation of an efficient fungi inhibitor. Essential oils of L. javanica, O. gratissimum and T. asiatica contain phytochemicals that can be explored for mycotoxin causing fungi growth inhibition. However, further studies on the duration of efficacy, its toxicity, and constituents associated with the synergistc effect needs to be carried out.en_US
dc.description.sponsorshipKenyatta Universityen_US
dc.language.isoenen_US
dc.publisherKenyatta Universityen_US
dc.subjectMycotoxin Levelsen_US
dc.subjectChicken Feeds and Productsen_US
dc.subjectEffects of Exposing Associated Fungien_US
dc.subjectSelected Plant Essential Oilsen_US
dc.subjectKenyaen_US
dc.titleMycotoxin Levels in Chicken Feeds and Products and Effects of Exposing Associated Fungi to Selected Plant Essential Oils in Kenyaen_US
dc.typeThesisen_US


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