Browsing by Author "Khamis, Fathiya M."

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    Biochar and gypsum amendment of agro- industrial waste for enhanced black soldier fly larval biomass and quality frass fertilizer
    (PloseOne, 2020) Beesigamukama, Dennis; Mochoge, Benson; Korir, Nicholas K.; Komi, K; Fiaboe, M.; Nakimbugwe, Dorothy; Khamis, Fathiya M.; Dubois, Thomas; Subramanian, Sevgan; Wangu, Musyoka M.; Ekesi, Sunday; Tanga, Chrysantus M.
    Black soldier fly (BSF) (Hermetia illucens L.) is one of the most efficient bio-waste recyclers. Although, waste substrate amendments with biochar or gypsum during composting process are known to enhance nutrient retention, their impact on agro-industrial waste have not been documented. Hence, this study focuses on a comparative effect of agro-industrial waste amended with biochar and gypsum on BSF larval performance, waste degradation, and nitrogen (N) and potassium retention in frass fertilizer. Brewery spent grain was amended with biochar or gypsum at 0, 5, 10, 15 and 20% to determine the most effective rates of inclusion. Amending feedstock with 20% biochar significantly increased wet (89%) and dried (86%) larval yields than the control (unamended feedstock). However, amendment with 15% gypsum caused decrease in wet (34%) and dried (30%) larval yields but conserved the highest amount of N in frass. Furthermore, the inclusion of 20% biochar recorded the highest frass fertilizer yield and gave a 21% increase in N retention in frass fertilizer, while biomass conversion rate was increased by 195% compared to the control. Feedstock amendment with 5% biochar had the highest waste degradation efficiency. Potassium content in frass fertilizer was also significantly enhanced with biochar amendment. At maturity, frass compost with more than 10% inclusion rate of biochar had the highest cabbage seed germination indices (>100%). The findings of this study revealed that initial composting of biochar amended feedstocks using BSF larvae can significantly shorten compost maturity time to 5 weeks with enhanced nutrient recycling compared to the conventional composting methods.
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    Biochemical changes in developing embryos of Schistocerca gregaria (Orthoptera: Acrididae) induced by pheromone produced by ovipositing gregarious females
    (2015) Khamis, Fathiya M.; Mireji, Paul O.; Osir, Ellie O.; Imbuga, Mabel O.; Hassanali, Ahmed
    Trans-generational transfer of gregarious-phase traits in the desert locust Schistocerca gregaria (Forska°l, 1775) is mediated by primer gregarizing pheromonal signals produced by ovipositing females that experience crowding. We monitored time-course proteomic events in eggs from solitary-reared locusts that had been exposed for 1, 3, 5, 7, 10 and 12 days to different levels of the sand-associated gregarizing signal originating from 0, 3, 5 or 10 ovipositions by crowd-reared females. Evidence for the phase transition was sought by comparing the protein patterns of embryos thus exposed with those from crowd-reared (gregarious) controls; this comparison was continued until the stage of the first instars. Expressed proteins were analysed by two-dimensional protein gel electrophoresis, and patterns from the different treatments within stages were compared by profile matching and x 2 analyses. Eggs derived from crowd- and solitary-reared females showed essentially similar protein patterns at early stages of embryogenesis; however, mature stages (particularly, days 10 and 12) and hatchlings demonstrated significantly different patterns. Protein patterns of eggs from solitary-reared females that were incubated in sand contaminated with the pheromonal signal and of the hatchlings that emerged were similar to those derived from gregarious females and dependent on the level of the pheromone to which the embryos had been exposed. The results confirm the gregarizing effect of the signal and constitute a useful basis for unravelling the mechanism of the signalling cascades associated with gene expressions triggered by the pheromone.
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    Biochemical changes in developing embryos of Schistocerca gregaria (orthoptera: acrididae) induced by pheromone produced by ovipositing gregarious females.
    (Cambridge University Press, 2015) Khamis, Fathiya M.; Mireji, Paul O.; Osir, E. O.; Imbuga, M.O.; Hassanali, A.
    Trans-generational transfer of gregarious-phase traits in the desert locust Schistocerca gregaria (Forska°l, 1775) is mediated by primer gregarizing pheromonal signals produced by ovipositing females that experience crowding. We monitored time-course proteomic events in eggs from solitary-reared locusts that had been exposed for 1, 3, 5, 7, 10 and 12 days to different levels of the sand-associated gregarizing signal originating from 0, 3, 5 or 10 ovipositions by crowd-reared females. Evidence for the phase transition was sought by comparing the protein patterns of embryos thus exposed with those from crowd-reared (gregarious) controls; this comparison was continued until the stage of the first instars. Expressed proteins were analysed by two-dimensional protein gel electrophoresis, and patterns from the different treatments within stages were compared by profile matching and x 2 analyses. Eggs derived from crowd- and solitary-reared females showed essentially similar protein patterns at early stages of embryogenesis; however, mature stages (particularly, days 10 and 12) and hatchlings demonstrated significantly different patterns. Protein patterns of eggs from solitary-reared females that were incubated in sand contaminated with the pheromonal signal and of the hatchlings that emerged were similar to those derived from gregarious females and dependent on the level of the pheromone to which the embryos had been exposed. The results confirm the gregarizing effect of the signal and constitute a useful basis for unravelling the mechanism of the signalling cascades associated with gene expressions triggered by the pheromone.
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    Contribution of Different Frass Fertilizer Products on Enhanced Growth, Yield and Nutrient Quality of Broccoli [Brassica Oleracea]
    (Frontiers in Plant Science, 2025-08) Kagehi, Noella; Beesigamukama,Dennis; Tanga, Chrysantus M.; Ngugi, Mathew P.; Subramanian, Sevgan; Khamis, Fathiya M.
    Vegetables are crucial for food security and income, but in developing countries their production is hindered by low soil fertility. Although the insect frass fertilizer is a potential solution, its use is constrained by limited product choices. Unlike conventional fertilizers, which are available in different forms, the insect frass fertilizer is mostly available in solid form. Here, we evaluated the effects of different black soldier fly frass fertilizer (BSFFF) products on broccoli [Brassica oleracea] growth, yield, and nutritional profiles. Solid, liquid BSFFF, chitin-fortified solid BSFFF, chitin-fortified liquid BSFFF, and commercial organic fertilizer (Safi) were applied at rates equivalent to 250 kg N ha-1 for two cropping seasons. The control treatment consisted of unfertilized soil. Results showed that solid and chitin-fortified solid BSFFF products significantly increased broccoli leaf growth and chlorophyll concentration by 54% and 11%, respectively, compared to the other BSFFF products. Soils amended with BSFFF products produced broccoli with higher number of heads (28 – 158%), fresh yield (26 – 138%), dry yield (17 – 60%), and aboveground biomass (7 – 117%) compared to Safi and control treatments. Broccoli grown in soil amended with BSFFF had higher nitrogen (84%), phosphorus (93%), potassium (51%) uptake, and agronomic use efficiency (4.6-fold) as compared to Safi and the control. Additionally, the application liquid BSFFF produced broccoli heads with higher levels of crude fat (61%), carbohydrates (16%), and calcium (38%) compared to other BSFFF products. Conversely, broccoli grown using chitin-fortified BSFFF exhibited the highest levels of crude protein, potassium, crush ash, and phosphorus. The net income and gross margin achieved with BSFFF treatments were 19 – 26-fold and 29 – 63-fold higher than values obtained Safi, respectively, with higher profitability achieved using chitin-fortified BSFFF formulations. These findings demonstrate the efficacy of different BSFFF formulations in supporting circular economy for safe vegetable production, and improved food and nutrition security
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    Distribution of indigenous strains of atoxigenic and toxigenic Aspergillus flavus and Aspergillus parasiticus in maize and peanuts agro‑ecological zones of Kenya
    (2015) Okun, Daniel O.; Khamis, Fathiya M.; Muluvi, G. M.; Ngeranwa, J.J.N.; Ombura, Fidelis O.; Yongo, Moses O.; Kenya, Eucharia U.
    Background: Grains of important food and export crops in Africa are susceptible to contamination by toxin-producing moulds. Aflatoxins are mycotoxins associated with liver damage and cancer in humans and animals. These toxic substances are produced by fungi (such as Aspergillus flavus and Aspergillus parasiticus) in food and feed exposed to poor conditions during crop cultivation, storage or processing of harvest. The presence of aflatoxins in especially maize and peanuts in Kenya is of great concern. Recent developments in the application of atoxigenic strains of these fungi as biological control agents against toxigenic strains could be a solution to the problem. The objective of this study was to isolate, identify and characterize atoxigenic and toxigenic strains of A. flavus and A. parasiticus in Kenya, and investigate possible application of atoxigenic strains in control of aflatoxin levels in maize and peanuts. Fungal communities in soils of maize and peanut fields were examined to determine the distributions of aflatoxin-producing Aspergillus species and to identify endemic atoxigenic strains. 220 isolates belonging to A. flavus and A. parasiticus were collected randomly from soils of maize and peanuts fields in seven agro-ecological zones and characterized using morphological and physiological examination. Results: Aspergillus section Flavi was detected in all the 57 soil samples collected in Kenya. Members of Aspergillus section Flavi L strain was the most common (54 %), followed by S-strains (35 %). Among Aspergillus, A. flavus was the most predominant (63.2 %), followed by A. parasiticus (27.7 %), A. tamari (5.5 %) and A. nomius (2.7 %). The mean CFU of the Aspergillus colonies per gram of soil was highly variable among the districts, ranging from 3.0 × 103 to 1.72 × 106 (p < 0.05). The mean pH across the collection sites also varied according to the respective agroecological zones (pH 5.5–6.8) which is within the optimal pH requirement for the members of section Flavi. There was no significant variation in temperature across the sampling sites (p > 0.05). The results also showed that A. flavus was detected in all the zones examined. Conclusions: Each of the regions had atoxigenic strains of potential value which can be employed as biological control agents in the management of aflatoxicoses.
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    Nitrogen Fertilizer Equivalence of Black Soldier Fly Frass Fertilizer and Synchrony of Nitrogen Mineralization for Maize Production
    (MPDI, 2020) Beesigamukama, Dennis; Mochoge, Benson; Korir, Nicholas; Musyoka, Martha W.; Komi, K. M. Fiaboe; Nakimbugwe, Dorothy; Khamis, Fathiya M.; Subramanian, Sevgan; Dubois, Thomas; Ekesi, Sunday; Tanga, Chrysantus M.
    The use of black soldier fly frass fertilizer (BSFFF) is being promoted globally. However, information on nitrogen (N) fertilizer equivalence (NFE) value and synchrony of N mineralization for crop production remains largely unknown. Comparative studies between BSFFF and commercial organic fertilizer (SAFI) were undertaken under field conditions to determine synchrony of N release for maize uptake. The BSFFF, SAFI, and urea fertilizers were applied at the rates of 0, 30, 60, and 100 kg N ha−1. The yield data from urea treated plots were used to determine the NFE of both organic inputs. Results showed that maize from BSFFF treated plots had higher N uptake than that from SAFI treated plots. High N immobilization was observed throughout the active growth stages of maize grown in soil amended with BSFFF, whereas soil treated with SAFI achieved net N release at the silking stage. Up to three times higher negative N fluxes were observed in SAFI amended soils as compared with BSFFF treated plots at the tasseling stage. The BSFFF applied at 30 and 60 kg N ha−1 achieved significantly higher NFE than all SAFI treatments. Our findings revealed that BSFFF is a promising and sustainable alternative to SAFI or urea for enhanced maize production. View
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    Nutritional evaluation of some Kenyan pumpkins (cucurbita spp.)
    (2014) Karanja, James K.; Mugendi, Jane Beatrice; Khamis, Fathiya M.; Muchugi, Alice N.
    The nutritional potential of thirteen varieties of Cucurbita fruits collected from selected regions of Kenya were evaluated for their proximate values, mineral and β-carotene content. The results indicated that the moisture content was high and it varied significantly (p<0.05) among the groups. Ash values were significantly different at (p<0.05) and ranged from 0.63 to 1.67%, crude protein was low in all the pumpkin groups and varied from 0.93 to 2.09%. The pumpkins also varied significantly (p<0.05) in crude fibre content (0.47- 1.95) among the groups. Potassium and sodium were the most prevalent minerals potentially useful amounts of potassium (199-172.3 mg/100g), sodium (56.39-118.28 mg/100g) and other essential minerals. The lowest micro-elements were copper and zinc. The results indicated that there were no significant differences among the groups in the β-carotene content (p<0.05). The nutrient information presented in this report should stimulate the nutritionists and agricultural officers in Kenya to consider the question of recommending the pumpkin to be consumed by adults and children alike in Kenya, including pregnant women and others with higher than normal nutritional requirements