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Item A study on the medicinal potential of Artemisia afra, a traditionally used herb in Namibia(University of Namibia, 2024) Farmer, Wennyth Luzaann; Bruwer, IwanetteThe use of plants as medicines to relieve various symptoms, as well as to manage and cure ailments has been recorded since ancient times. Much interest in these ethnomedicinal plants stems from their long-standing use in traditional medicine. They are still regarded as making important contributions to health care even though great advances have been made in modern medicine. Traditionally, Artemisia afra (‘Wilde als’) is used to treat the common cold, flu and coughs, as well as nasal congestion. During the COVID-19 pandemic, communities in Namibia used ‘Wilde als’ as a treatment for the disease. Little is known about the efficacy and safety of ‘Wilde als’ found in Namibia. This study aimed to identify the bioactive classes of compounds for ‘Wilde als’; as well as to determine the antioxidant, anti-inflammatory, and antiviral activities and the cytotoxic properties of the plant. Extracts of ‘Wilde als’ were prepared by aqueous and organic extraction methods, using water and a mixture of methanol and dichloromethane (1:1 v/v). The phytochemical profile was determined using thin-layer chromatography. The total flavonoid content within the extracts was also determined. The albumin denaturation assay was used for determining the in vitro anti-inflammatory response of the extracts of ‘Wilde als’ using egg albumin derived from a fresh hen’s egg as the protein source. The DPPH antioxidant assay was used to determine the radical scavenging activity of the plant extracts using 2,2-diphenyl-1- picryl-hydrazyl-hydrate also known as DPPH, and the MTT cytotoxicity assay was used to determine the cellular reduction of the tetrazolium salt, 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide, also known as MTT. The Vero E6 cell line, a kidney epithelial cell line was used to determine cell proliferation and survival during the MTT assay. The in vitro antiviral effects of the plant extracts against a pseudovirus of SARS-CoV-2 were determined by calculating the reduction of the SAR-CoV-2 in ii the Vero E6 cells. The extracts of the ‘Wilde als’ possessed flavonoids, coumarins, saponins, steroids and terpenoids, with TFC with the highest at 19.89 % for the organic extracts of the twigs. The extracts of A. afra exhibited significant antioxidant activities ranging from 0.1029 to 9.4197 μg/ml with the highest activity observed for the aqueous extract of the leaves. The extracts of A. afra also exhibited significant anti- inflammatory activity. The highest anti-inflammatory activity of the plant extracts was observed for the organic extract from the combination of the leaves and twigs (87.5 % at 100 μg/ml). The plant extracts displayed antiviral potential against the beta-strain of the SARS-CoV 2 virus, with the organic extracts exhibiting higher inhibition of the viral load with EC50 values of 48.84 μg/ml (leaf extracts), 24.65 μg/ml (twig extracts) and 251.67 μg/ml (combination of the leaves and twigs extracts). The results of the MTT cytotoxicity assay indicated that the aqueous extracts showed little to no cytotoxicity; the organic extracts on the other hand showed high cytotoxicity with IC50 values of 134.12 μg/ml (leaves and twigs), followed by 151.53 μg/ml (twigs) and 182.31 μg/ml (leaves). The findings of this study suggest that ‘Wilde als’ has the potential to be used as an antiviral agent with antioxidant and anti-inflammatory activities as the possible mechanisms of action, with low cytotoxic effects for the aqueous extracts. The organic extracts, however, were cytotoxic, but when used in the correct doses, they can have significant health benefits. This study also provides evidence that the use of ‘Wilde als’ an herbal remedy in the south of Namibia is rational and consistent with research from other regions of AfricaItem Assessment of fishers’ catches on a Kavango River floodplain, Namibia(University of Namibia, 2023) Tiyeho, Deon Cain; Hay, ClintonFloodplains in the Kavango River sustain an important fishery that provides riparian communities with a source of food, seasonal employment and income for those that sell their catches. This study was conducted to investigate the effort, fishing gear, and fish catches of the fishers on the Kamutjonga floodplain along the Kavango River, Namibia. Fishers were monitored daily for two annual flood cycles of 2018 and 2020 (February to June). A total of 254 and 462 fisher days were recorded during the 2018 and 2020 flood cycles, respectively, where females dominated the fishing in both years. In 2018, the catch per unit effort (CPUE) in number (fish/set) (set = 60 min) were highest for mosquito nets (93 fish/set) followed by plastic containers (12 fish/set), hook and line (10 fish/set), and traditional traps (7 fish/set). In 2018, CPUE in weight (kg/set) was also highest for mosquito nets (0.21 kg/set), but followed by hook and line (0.17 kg/set), traditional traps (0.03 kg/set), and plastic containers (0.02 kg/set). In 2020, the CPUE in numbers was the highest in mosquito nets (275 fish/set), followed by hook and line (18 fish/set), plastic containers (10 fish/set) and traditional traps (7 fish/set). In 2020, CPUE in weight (kg/set) was the highest in mosquito nets (0.73 kg/set) followed by hook and line (0.63 kg/set), traditional trap (0.06 kg/set) and plastic containers (0.03kg/set). In 2018, a total of 27 fish species were caught and the five most important species according to the index of relative importance (%IRI) were Oreochromis andersonii (79.6%), Coptodon rendalli (9.9%), Pseudocrenilabrus philander (3.8%), Hydrocynus vittatus (2.3%) and Serranochromis angusticeps (1.4%). In 2020, 23 fish species were caught on the and the five most important species according to %IRI were Oreochromis andersonii (65.5%), Coptodon ii rendalli (29.9%), Hydrocynus vittatus (1.8%), Serranochromis macrocephalus (0.9%) and Pharyngochromis acuticeps (0.7%). In 2018, the estimated catch was 150.53 kg constituiting of 79.00 kg during the rising phase, 68.49 kg during the receding phase and 2.99 kg during the high phase. In 2020, the estimated catch was 1 607.00 kg constituiting of 415.25 kg during the rising phase, 1 215.01 kg during the high phase and during the 123.65 kg receding phase. Most of the fish species caught on the floodplain were juvenile of larger fish species, while other fish species were from small sized fish species. It is suggested that harvesting of juvenile fish contributes to food security of riparian communities. The continuous monitoring of the exploitation partterns of the Kamutjonga floodplain is encouraged to enusure that managers are timely informed of any changes in fishing activities that might negatively impact the fish stocks and make management recommendationItem Anti-hyperglycemic, Anti-oxidant, and Cytotoxicity activity of selected Ethno medicinal plants from the Hardap region of Namibia(University of Namibia, 2024) Kaitjizemine, Kaveire; Mumbengegwi, DavisDiabetes mellitus is a multifactorial non-communicable metabolic disorder, characterized by the perpetual manifestation of hyperglycemia as a consequence of the disturbed metabolism of carbohydrates, fat, and protein, due to defects in insulin secretion and/or its effectiveness. Currently prescribed medication such as the derivatives of Biguanides, have excellent therapeutic benefits but cause impaired liver and kidney due to lactic acidosis. Based on the historic success of medicinal plants as remedies for many ailments and the increasing need for alternative medication for diabetes, plants from the Hardap region, in Namibia, were evaluated as potential Complementary and Alternative Medicine (CAM) for diabetes. In Namibia, medicinal plants are used as primary health care to manage diabetes, especially by those in resource-poor settings. However, there is a paucity of data supporting the use of these plants for this purpose. Scientific data must be generated to support the use of Namibian plants as complementary and alternative medicines for managing diabetes. To this end, a survey on the use of medicinal plants for the management of diabetes in the Hardap region of Southern Namibia was conducted. The survey revealed eleven plants belonging to nine different families, that is Asphodelaceae, Malvaceae, Pedaliaceae, Apocynaceae, Lamiaceae, Geraniaceae, Zygophyllaceae, Tiliaceae, and Fabaceae as authenticated by the National Herbarium. However, of the eleven plants, only five were available for collection for laboratory analysis, namely Corchorus tridens, Sarcocaulon salmoniflorum, Zygophylum decumbens, Hermannia fruticulosa, and Hoodia gordonii. The plant materials were air-dried at room temperature before being ground to a powder for extraction using ethanol, methanol, and water. The plant extracts were iii subjected to Thin Layer Chromatography (TLC) screening, followed by quantification of total flavonoid content (TFC) and total phenolic content (TPC). The biological properties of the extracts; antioxidant activity involving DPPH and reducing power; antihyperglycemic activity using α amylase and α glucosidase assay; and in vitro cytotoxicity assay using MTT assay, were evaluated. The study demonstrated the presence of alkaloids, flavonoids, phenols, saponins, steroids, tannins, and terpenoids in plants. Quantification of phytochemicals showed high TPC content in C. tridens, methanol extracts (23.58 ±0.41) mgQE/g, and ethanol extracts (22.79 ±0.16). High TFC was observed in ethanol extracts of C.tridens (96.90±7.04) mgGAE/g, followed by Z. decumbens (49.98±2.97) mg GAE/g then S. salmoniflorum (44.55±0.44) mg GAE/ g. Data showed a statistically significant difference between TFC and TPC (p < 0.05). Plants showed free radical scavenging potential, with C. tridens ethanol extracts exhibiting the highest scavenging activity with IC50 0.0312±21.05 mg/ml followed by methanol extracts of H. fruticulosa with IC50 of 0.0339±24.64 mg/ml when compared with the positive control (ascorbic acid) with IC50 of 0.0279±17.09 mg/ml. The different solvents used for plant extraction significantly influenced the free radical scavenging potential of plants (p < 0.05) while no significant difference was demonstrated across the different concentrations (p >0.05). The reducing power of extracts showed no significant concentration dependence (p > 0.05). High reducing activity was recorded in methanol extracts of S. salmoniflorum 1.84 ± 0.025726834 and C. tridens 1.5± 0.014854405 when compared with the ascorbic acid of 3.16 ± 0. 026394. iv Antihyperglycemic potency of plant extracts was evident with the inhibition of α- amylase recorded for aqueous extracts of Z. decumbens and H. gordonii, 96.3% and 93.9 % respectively when compared with the positive control (acarbose) inhibition capacity of 64.2 % at 1 mg/ml. The inhibition of α-amylase is not significantly influenced by the concentration (p > 0.05), though showed significant reliance on the solvent used for extraction (p < 0.05). Aqueous extracts of H. gordonii revealed potency with the lowest IC 50 of 0.1667 mg/ ml. A qualitative α-glucosidase inhibition potential was demonstrated by all the tested plant extracts, through the ability to prevent the degradation of starch in the presence of α-glucosidase and starch that was evident by the stain that was produced on the agar. The cell line of 3T3 proliferated 90 % and above in the presence of the studied plant extracts. The Kruskal- Wallis test revealed that the growth of 3T3 cell lines wassignificantly influenced by the difference in extract concentrations (p < 0.05). Moreover, these cells proliferate differently in the presence of the different studied plants (p < 0.05). The safety data of cytotoxicity indicate less toxicity to none except for C. tridens with IC 50 0.2014±5.491 μg / μl. The demonstrated anti-hyperglycemic activity of the studied plants, especially aqueous extracts of Z.decumbens and H. gordonii can be attributed to the presence of the tested phytochemicals and may infer that they have potential anti-hyperglycemic agents as well as validate their use in the traditional setting. Further in vivo and detailed phytochemical analysis is recommended to identify active components of the plants and their mechanism of action.Item Antioxidant, Antimicrobial, and Antibiofilm properties of Opuntia stricta and Vachellia erioloba, and chemical characterization of volatile compounds(University of Namibia, 2023) Jackson, Junias Natangwe; Kapewangolo, PetrinaVachellia erioloba, commonly known as Acacia erioloba belongs to the family Fabaceae and is native to Namibia, Botswana, and South Africa. The plant is used traditionally to treat ear infections, headaches, and toothaches. Opuntia stricta belongs to the family Cactaceae and is found in Namibia. The plant is used in the management of diseases such as diabetes, obesity, and cancer. This study was designed to investigate the antioxidant, antimicrobial, antibiofilm activity, and chemical characterization of V. erioloba and O. stricta. The radical scavenging capacity of extracts was estimated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the reducing power was determined using ferric reducing power assay. Moreover, the antimicrobial activities of the extracts of these medicinal plants were tested against Staphylococcus aureus, Streptococcus mutans, Escherichia coli, and Candida albicans. On the other hand, antibiofilm activity was determined against Staphylococcus aureus. The phytochemical analysis of V. erioloba and O. stricta was done using qualitative and quantitative phytochemical analysis. Moreover, the characterization of the volatile constituents was done for the seed extract of V. erioloba. Furthermore, chemical characterization of the volatile constituents of the extract was performed using gas chromatography-mass spectrometry (GC–MS). The radical scavenging assay revealed IC50 values of 1.973 ± 0.012 and 972.0 ± 22.3 μg/mL for the seed pods and seed of V. erioloba, respectively, while the IC50 values for the extracts of O. stricta were 53.74 ± 0.18, 153.8 ± 0.9, 258.7 ± 0.7, and IC50 ˃ 1000 μg/mL for the seeds, flowers, fruits, and leaves of O. stricta, respectively. In addition, the reducing power of both V. erioloba and O. stricta extracts increased as the concentration of the extracts increased, which confirmed the presence of antioxidants in the extracts. The antimicrobial assay revealed that the various extracts of V. erioloba and O. stricta ii exhibited moderate antimicrobial activity with inhibition zones (IZ) ranging from 0 to 12 mm. Moreover, the MIC obtained from this study ranged from ≤ 0.63 to 10 mg/mL. The biofilm inhibition demonstrated BIC50 values of V. erioloba and O. stricta extracts ranged from ˂ 0.08 to 0.498 ± 0.017 mg/mL. Moreover, biofilm eradication revealed BEC50 values ranged from < 0.08 to 0.172 ± 0.008 mg/mL. The GC-MS analysis of V. erioloba seed extracts revealed the presence of phytosterols, acids, esters, α- tocopherol and α-amyrin, which comprises a number of known bioactive compounds. The results from this study show that V. erioloba and O. stricta extracts possess antioxidant, antimicrobial, and antibiofilm properties, making these plants good potential sources of antioxidants and antimicrobial agents. The findings of this study support the traditional uses of V. erioloba and O. stricta.Item Acetylcholinesterase inhibition and Cytotoxic activity of extracts and a novel compound isolated from flowers of the wild everlasting (Helichrysum Argyrosphaerum DC)(University of Namibia, 2024) Mtuleni, Etuhole; Louw, StefanHelichrysum argyrosphaerum is a poisonous plant responsible for livestock losses in southern Africa. Helichrysum species primarily affect the central nervous system when ingested by livestock. However, previous attempts to identify the toxins produced by these plants resulted in only tentative identification of some chemical constituents. This study aimed to isolate and characterize compounds from the flowers of H. argyrosphaerum and to determine the in vitro acetylcholinesterase inhibitory activity and cytotoxicity of the methanol (MeOH) and dichloromethane (DCM) flower extracts and isolated compounds. Several flavonoid glycosides (tentatively identified as apigenin-O-glycosides) as well as an unknown chlorogenic acid analogue were isolated from the methanol extract of H. argyrosphaerum flowers using semi- preparative high-performance liquid chromatography (HPLC). The chemical structures of three isolated compounds were elucidated as apigenin, chamaemeloside, and a novel compound, 14-acetyl chamaemeloside, based on their high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance spectroscopy (NMR) data. Interestingly, both the MeOH and DCM H. argyrosphaerum flower extracts as well as 14-acetyl chamaemeloside induced acetylcholinesterase activity. In the cytotoxicity assay, neither the MeOH and DCM extracts nor 14-acetyl- chamaemeloside exhibited toxicity against HeLa cells. This research marks the initial report of acetylcholinesterase activity and cytotoxicity in both H. argyrosphaerum MeOH and DCM flower extracts, as well as the isolated compound, 14-acetyl- chamaemeloside, against HeLa cells. Consequently, these findings will contribute to future toxicological studies and aid in developing preventative agents that can be used in the treatment of animals poisoned by H. argyrosphaerumItem Rodent species composition, abundance, richness, and diversity amongst different habitats in two villages in the Mukwe Constituency, Kavango East region of Namibia(University of Namibia, 2024) Kayala, Ester N.Rodents are habitat bio-indicators because their population dynamics respond to changing environmental and habitat alteration such as environmental disturbances. Some rodent species such as Mastomys natalensis are agricultural pests and have caused a lot of damage to crop harvests and peoples’ belongings. Additionally, rodents serve as vectors for deadly diseases which they can transmit to humans. The aim of this study was to examine variations in the rodent species composition, abundance, richness and species diversity amongst different habitats (fallow land, less disturbed land and in the houses) in Bagani and Diyogha village, in the Mukwe Constituency. Trapping was conducted over a period of twelve months using PVC live traps, for three consecutive nights in each habitat. A total number of 285 rodent captures were recorded in 16,272 trap nights; comprising of five different rodent species, which were Mastomys natalensis, Gerbilliscus leucogaster, Thallomys paedulcus, Saccostomus campestris and Steatomys pratensis. A Kruskal-Wallis H test showed that there was no statistically significant difference in rodent species abundance amongst the three habitats in Bagani (χ2 = 1.665, df = 2, p = 0.4101), and Diyogha (χ2 = 1.715, df = 2, p = 0.3978). Whereas the same test has also revealed that there was a statistically significant difference in the rodent species richness between the fallow land (SR = 4) and the less disturbed land (SR = 2) as well as the less disturbed land (SR = 2) and houses (SR = 3) in Bagani (χ2 = 10.81, df = 35, p = 0.0026), and between the fallow land (SR = 2) and houses (SR = 3) in Diyogha (χ2 = 12.18, df = 35, P = 0.001). Additionally, the test revealed that there was no significant difference in the rodent species diversity amongst the three habitats in Bagani (χ2 = 2.551; df = 35, p = 0.147), however, there was a significant difference in the rodent diversity amongst the habitats in Diyogha (χ2 = 4.97; df = 35, p = 0.029). Dunn’s post hoc test was used for all the iii parameters to further explore the differences within the habitats. It showed that there was a significant difference in the rodent species richness between the fallow land and the less disturbed land (p = 0.006) as well as between less disturbed land and the houses (p = 0.001) in Bagani. Whereas in Diyogha, there was a significant difference in the species richness between the fallow land and the houses (p = < 0.002). Lastly, the post hoc test showed a significant difference in rodent species diversity between the fallow land and the houses (p = 0.0084). An HCA based on a Bray Curtis Similarity Index showed that there was a 30% and a 22% similarity in the rodent species composition amongst the three habitats in Bagani and Diyogha, respectively. The Spearman’s correlation (Rs) test revealed that rodent species abundance was weakly positively correlated with the rainfall (r= 0.146, n = 12, p = 0.650) and relative humidity (r = 0.403, n = 12, p = 0.193), however, the temperature (r = -0.05, n = 12, p = 0.87) had a negative influence on the rodent numbers in Bagani. Furthermore, in Diyogha, all three weather parameters had positive correlations to the rodent numbers during different seasons or months. The following study revealed that the different habitats in both villages did not influence the rodent species abundance. A similar study to the current one should be conducted for a period longer than two years in order to compare the influence climatic variables have on the rodent numbers in both Bagani and Diyogha village. However, the study should use a capture-mark-recapture (CMR) technique instead of euthanizing the rodentsItem Analysis of seasonal variation in dietary composition and behaviour of wild chacma baboons (Papio ursinus) in two habitats of different human influence around windhoek, central Namibia(University of Namibia, 2024) Mukuve, Bernhard Z.M.Diet composition of an organism gives a holistic picture of what an organism forages on in its environment to maximize energy intake for all its essential activities that contribute to survival and successful reproduction. Chacma baboons have the ability to modify their broad omnivorous diet and behavior under changing environmental and climatic conditions. However, the ever-increasing environmental and anthropogenic pressures on baboon populations are likely to affect both the diet composition and foraging behavior of these animals. Moreover, Namibia being one of the driest countries in the Sub Saharan Africa, and coupled with accelerated anthropogenic changes, baboon populations, especially those thriving in and around the city of Windhoek are facing constant threats of habitat destruction and fragmentation due to the rapid expansion of the city and are under pressure to adapt to these changes in order to survive. With limited research carried out on primates in the central highlands of Namibia, this study was carried out in an effort to bridge the knowledge gap and obtain insight into the influence humans have on the ecology of these primates around the city of Windhoek. The study investigated the activity budget and diet of the baboons using data collected from two contrasting habitats (Dobra and farm Krumhuk) that are influenced by human activities. A total of 166 baboons were observed during 2 seasons (wet & dry) at two sites using a focal animal method. Forty-nine (49) scat samples were collected between the seasons, separated in the laboratory, weighed, and placed into four categories (fruits and seeds, roots, stems, and leaves, invertebrates, and others). Results showed that baboons consumed plant materials more than any other food type and that they maintained their diet profile across the seasons. Furthermore, their behavior was found to be reactional to seasonal changes. The study further confirmed the ii broad diet and selectivity that exists in the so-called “generalist diet” of these well documented old-world monkeys while also providing an alternative method to enhance scat analysis techniques in the laboratory. The study noted that the human-disposed food waste, stable and constant water supply, preserved wild flora and minimal disturbance regimes around human settlements, all contribute to increased contact with humansItem Development of a “greener” hplc-uv method for the analysis of reducing sugars in apple juice and indigenous fruits using acetone as an alternative solvent(University of Namibia, 2023) Iyambula, Aina KChromatographic techniques can be made more environmentally friendly, i.e., “greener”, by a number of different strategies. One approach is to replace the toxic mobile phase solvents such as acetonitrile with greener alternatives. Acetone, in particular, has proven to be a suitable alternative to acetonitrile, since the two solvents have similar physicochemical properties, including solubility, miscibility and viscosity properties. However, due to acetone’s high ultraviolet (UV) cut–off wavelength (330 nm), it normally cannot be used as a mobile phase solvent when performing high performance liquid chromatography (HPLC) analysis with UV detection. In this study, a reversed-phase HPLC–UV method using acetone-containing mobile phase was developed for the determination of reducing sugars in apple juice and two indigenous fruits, Berchemia discolor and Hyphaene petersiana. Pre-column derivatisation of analytes via reductive amination with p-aminobenzoic acid ethyl ester (ABEE) was performed to enable photometric detection at 307 nm. The method was directly compared to a method that utilised acetonitrile-containing mobile phase. Although the detection wavelength of the ABEE derivatives is below the UV cut–off wavelength of acetone, it is high enough above acetone’s absorbance maximum (~280 nm) to enable satisfactory detection of the derivatives. Hence, the method compared well with the acetonitrile method, providing similar resolution and selectivity, as well as sufficient sensitivity to facilitate the quantitation of glucose and fructose in all the fruits and juice investigated in this study. Although the method was only validated in terms of precision, linearity, limit of detection and quantitation but no other aspects such as accuracy, it shows potential to be used as a greener alternative for sugar analysis for laboratories that only have access to HPLC–UV instrumentsItem Comparative study on the quality of Namibian commercial oyster mushrooms cultivated on encroacher bushes as substrates(University of Namibia, 2023) Haukongo, KristineHumans need a wide range of nutrients to have a well-balanced diet, nutritious edible mushrooms can be part of a healthy lifestyle. The objectives of the study were to evaluate the yield and yield components, to determine antioxidant activity, total phenolic content (TPC), total flavonoid content (TFC) and nutrient composition of different mushroom species cultivated on four different bush encroacher substrates. To provide mushroom cultivation training to farmers in Okondjatu district. Mushrooms were cultivated in 2kg bags of dry substrate, harvested, dried and powdered. Mushrooms powder was extracted in 99.9% methanol. Antioxidant activity of the mushroom extracts were analysed by reducing power and 2, 2 Diphenylpicrylhydrazyl (DPPH) assay. The TPC and TFC were quantified. Crude protein was calculated (N x 6.25) from determining the amount of nitrogen (N) in mushroom powder using the Dumas combustion method. Potassium and Phosphorus were determined by using the flame emission spectroscopy, while Phosphorus was determined by colorimetry. Neutral detergent fibre (NDF) and Acid detergent fibre (ADF) were analyzed using the Ankom 220 fibre analyzer unit. Mushroom cultivation training was conducted at three randomly selected villages. There was a significance difference in weight of fresh mushrooms, days to first harvest and number of fruiting bodies which was due to mushroom species used at p=0.002, p<0.001 and p=0.019 respectively. Pleurotus florida (PF) yielded more mushrooms with 350 g, followed by PS with 322 g, followed by Pleurotus ostreatus (PO) with 314 g, and the least was on HK 35 with 243 g. The inhibitory concentration at 50% (IC50) values ranged from 0.380±0.098 mg/ml to 0.780±0.007 mg/ml on different mushroom species grown. The inhibition of the DPPH radical by PO extracts cultivated on Terminelia sericea ii (0.380±0.007 mg/ml) showed the highest activity. All Mushroom species grown on different bushes showed an appreciable ability to reduce ferricyanide complex to ferrous form at different concentrations (0.063–1.00 mg/mL). The TPC varied from 3.93 mg GAE/g to 8.016 mg GAE/g. TFC ranged from 0.515 mg QE/g to 12.1 mg QE/g, which showed a significant difference on the bush species (p-value < 0.01). Crude protein content ranged from 28.0% to 39.0%. A significant difference in % NDF on mushroom species was found, where a variation was detected in HK35 while PF, PO, and PS showed a similar performance in % NDF. The study showed that ash content ranged from 5.77% to 17.9%. Percentage moisture ranged from 86.0% to 87.5%. A significant difference in mineral composition, with PO showing a high content of potassium (2.292%), PF showing a high content of sodium (0.059%), and PS showing a high content of phosphorus (0.746%) as compared to other mushroom species. A total of 45 community members participated in the training. In conclusion, all four encroaching bushes can be used as the substrate for mushroom cultivation. All mushroom species showed antioxidant activity and appreciable nutrient and mineral composition, thus can be used as a remedy to illnesses and a supplement to human diets. Therefore, it is essential to promote awareness and train farmers on mushroom cultivationItem Rhizobia inoculant effects on bambara groundnut growth and yield in Namibia(University of Namibia, 2023) Fwanyanga, Felicitas MantjodiBambara groundnut (Vigna subterranea (L.) Verdc) is the third most significant food legume in Africa after groundnut (Arachis hypogea) and cowpea (Vigna unguiculata). It is normally grown in poor soils, is drought tolerant, and has a high potential for nitrogen fixation. Despite that, Bambara groundnut yields are on a gradual decline due to a combination of abiotic and biotic stresses such as erratic annual rainfall and climate induced changes in soil microbial community compositions, which negatively impacting food security. Thus, the application of rhizobial inoculants at planting significantly improves yields in many leguminous crops. Moreover, symbiotic inoculants are mainly used in developed countries to improve nitrogen fixation and improve productivity of grain legumes. Sub-Saharan African countries like Namibia, however, still under-utilise the above practice. Three (3) studies were conducted, of which two were conducted in 2021, and in 2021/22 season. The first study was on farmer’s appraisal, which was aimed to assess Bambara groundnut production systems in Kavango East Region. Bambara groundnut farming systems, farming inputs, and production constraints were explored in the two constituencies in Kavango East region. Subsequently, an experiment in a greenhouse of the ZERI at the University of Namibia using soil from the Kavango region to ascertain how well the various Bradyrhizobium strains promote nodulation and yield components among three varieties of Bambara groundnut was conducted. The study also evaluated the strains that are most competitive to reach the roots and promote nodulation in a given period. For the greenhouse experiment, the treatments included three different Bambara groundnut varieties that were inoculated with two types of inoculants (MIX inoculant with 7 Bradyrhizobium strains [1-7; 3B 4-1; 9-5, 36 1-1; 36 3-2; 55 1-1 and 60 2-1] and inoculant with Bradyrhizobium vignae 9-5 only), both of which were obtained from the University of Bremen in Germany the third treatment was an absolute control. The treatments were set up in a randomized complete block design with three replications. In comparison to the single strain 9-5, the mixed strains were found to be more productive and contagious (p=0.05). Moreover, the two inoculants outperformed the non-inoculated cultivars in terms of plant height, shoot dry weight. The brown variety, which was not inoculated, nevertheless, showed some nodules. Hence, in the next season (field ii experiment) the mixed inoculant strains of Bradyrhizobium were applied as single inoculants. The field experiment was conducted at Mashare Agricultural Development Institute (MADI) in Kavango East Region. The same three Bambara groundnut varieties which were used in the greenhouse were treated with chemical fertilizer (urea), 7 Bradyrhizobium strains, and negative control with no treatment. After 130 days of planting the cultivars were harvested and different yield parameters were assessed. The control Var03 (red) yielded the greatest grain at 1311.7 kg ha-1 , followed by Var01 (brown) treated with In1-7 at 1237.3kg ha-1 , while Var01 and Var02 (cream) inoculated with In36 3-2 yielded 1171.3kg ha-1 each. Based on the results, farmers are advised to consider inoculating Bambara groundnut seeds with Bradyrhizobium strains prior to planting, as this has been shown to have a positive impact on nodulation, grain yield, and biomass production compared to using urea fertilizer which is expensive and environmentally unfriendly. However, it is important to note that the control variety Var03 performed the best, likely due to its compatibility with native soil rhizobia. Therefore, it may be worthwhile for more studies to investigate and identify the unidentified strains used in the study as potential bio-inoculants. Additionally, it is recommended that farmers monitor the performance of different varieties in their specific soil conditions and choose the most suitable one for their crop management. Finally, it is important to adhere to best practices for inoculant application, such as using high-quality inoculants and ensuring proper handling and storageItem The spatial, temporal and vertical fish species composition of the kamutjonga floodplain, Kavango river, Namibia(University of Namibia, 2023) Muunda, Vilio TuutileniThe present study investigated the variations in fish species composition on a floodplain during a flood pulse on the floodplain along Kavango River, Namibia. Specifically, the study aimed at comparing the species composition, the catch per unit effort, and the body length of two selected species (Pseudocrenilabrus philander and Tilapia sparrmanii) across periods during the flood, across depth intervals and sites on the floodplain. Further, the study also aimed at determining any correlation between the catch per unit effort and the physio-chemical parameters of the water. A throw trap net was used to sample six (6) sites along the peripheries of the Kamutjonga floodplain during its inundated period (20 February 2020 to 09 June 2020), with each site subdivided into three depth intervals – 0- 29 cm, 30-59 cm and 60-99 cm. Three flooding periods (early, middle and late) were identified during the flood pulse. A total of 48 throws were cast at each site per flooding period, with each depth interval sampled 16 times per site. A total of 30 species were recorded on the floodplain, with the highest number of species (17) recorded during the early flooding period, in the deepest section sampled (60 – 99 cm) (21 species) and at site 2 (20 species). Cichlids dominated the floodplain, with Oreochromis andersonii and Pseudocrenilabrus philander being the most important species during the early and late flooding period, respectively. Few but large specimens were on the floodplain during early flooding, whilst a lot of small (by weight) specimens were during the late flooding periods. More specimens, yet large (by weight) were found on the shallow section (0 – 29 cm) of the floodplain. The findings uphold the significance of the peripheries of newly inundated areas, which are documented to serve as breeding, nursery and forage grounds for most riverine species. A large proportion (83%) of individuals such as those of P. philander were above sexual maturity during the early flooding period, which coincided with the highest number of small-sized specimens during the late flooding period – further hinting at the use of the floodplain as a breeding groundItem Determination of the prevalence and density of true plasmodium falciparum infections and gametocyte carriage during two malaria outbreaks in Zambezi region, Namibia(University of Namibia, 2023) Eloff, LydiaMalaria is a disease caused by parasites from the genus Plasmodium, which are transmitted to humans by the bite of an infected female Anopheles mosquito. Malaria remains as one of the leading causes of mortality globally. Namibia has successfully reduced the malaria burden by over 90% between 2004 and 2014 and aimed to eliminate the disease by 2020, however, this progress has stalled and it has experienced outbreaks. New approaches are needed to understand and address the reasons for persistent transmission and outbreaks. Accurate diagnosis is a challenge with the routinely used Rapid Diagnostic Tests (RDTs) at low transmission settings as they have been reported to give both false-positive and false-negative results, both outcomes compromise the detection and treatment of all malaria cases. Furthermore, RDTs do not give much information about epidemiological parameters that affect malaria transmission and can be used to assess and mitigate against onward transmission of the disease which includes transmission intensity and risk of transmission. Molecular tools have been reported as being able to identify true malaria infections. This includes parasite species and strains as well as being able to give a more accurate and quantitative reflection of the malaria burden and potential risk of transmission, additional information that RDTs cannot provide. This study was conducted to confirm and identify the Plasmodium species confirmed by RDTs; quantify parasite densities and gametocytes during the 2017 and 2021 outbreak seasons to determine the importance of these parameters in assessing transmission intensity and risk. A total of 589 malaria RDT positives, (251 from the 2017 malaria outbreak and 338 from the 2021 outbreak) from the Zambezi region with corresponding dried blood spots (DBS) were analysed using DNA extracted using the Chelex method for conventional PCR. Only 223/589 (38%) RDT positive samples were confirmed as being true malaria positive: (71/251, 28% for 2017 and 152/338, 45% for 2021). All confirmed samples were identified as Plasmodium falciparum only. The QIAamp DNA kit was used to extract DNA from the 223 confirmed malaria positive samples for quantitative PCR to calculate parasite density for each malaria outbreak season (71 for 2017 and 152 for the 2021 season, a total of 223). The parasitaemia of the samples from each season was calculated and classified as follows: for 2017, low - 13%, moderate - 24%, high - 51%, hyperparasitaemia - 13%; for 2021 low - 24%, moderate - 29%, high - 40%, hyperparasitaemia - 7%. The mean parasite density was higher in 2017 (46088 p/μL) as compared to 2021 (35211 p/μL) (Mann-Whitney, p=0.008). Gametocyte carriage was determined by RTqPCR to detect and quantify the presence of Pfs25 transcripts for female gametocytes. The study showed that as parasitaemia increased, there was a higher chance of detecting gametocytes. Gametocyte detection was found in 59/71 (83%) for 2017 and 98/152 (64%) for 2021 using a Ct value of ≤35 as a cut-off point. There was a significant difference in gametocyte mean for 2017 (116 g/μL) and 2021 (892 g/μL) (Mann-Whitney, p=0.003). There was a moderate correlation between parasitaemia and gametocyte carriage during the 2017 outbreak (rho = 0.6) and a strong correlation for the 2021 outbreak (rho = 1) using Spearman’s Correlation. The Median test showed that during the 2021 outbreak there was no significant difference (p=0.910) between gametocyte carriage in low parasitaemia infections and moderate parasitaemia infections. This showed that low density infections are actually a risk factor for onward transmission of malaria. This study confirmed that P. falciparum is the dominant parasite causing malaria in the Zambezi region during the 2017 and 2021 outbreaks. It also showed that the use of RDTs for Reactive Case Detection (RACD) does not give an accurate picture of true malaria cases during outbreaks, only 38% of cases were confirmed by PCR. Both outbreaks showed moderate parasite density on average although both had high parasitaemia and hyper parasitaemia cases, signals indicative of an outbreak. Parasitaemia also correlated with gametocyte carriage showing that the parasite density was linked with higher transmission risk through gametocyte carriage. Thus, parasite density and gametocyte carriage as determined through the use of molecular tools can be used to assess the risk of transmission. However, further studies should be conducted in dry seasons to have a better understanding of residual transmission, parasite reservoir, and malaria epidemiology as a comparison to the outbreak seasons. The use of additional molecular analysis such as the Multiplicity of Infection (MOI), heterozygosity index and parasite transmission networks can also enrich the data collected during molecular surveillance and its usefulness in heterogeneous malaria transmission settings. It is recommended that molecular surveillance be used during passive surveillance at clinics; used during reactive case detection and Mass Screen and Treat and when targeting interventions to high-risk groups to understand the drivers of sustained transmission. This will contribute to the tailoring of cost-effective interventions and not a one-size fits all blanket intervention.Item Human impact on the biodiversity of macroinvertebrates in intertidal rocky shores along the Namibian coast(University of Namibia, 2023) Ochs, KellyThe intertidal rocky shores along the central coast of Namibia provide multiple microhabitats supporting a high species biodiversity and a unique heterogeneous environment. Extreme anthropogenic disturbance such as harvesting and trampling due to human visitors may reduce biodiversity, modifying species genetic variability and overall ecosystem functioning. This research compares macroinvertebrate assemblage structures, size and diversity between disturbed and less disturbed sites. The study was conducted in March and June 2022 at six different sites along the coast – four disturbed sites and 2 control (less disturbed) sites. At each site, three line transects were used with a 0.5m x 0.5m quadrat placed at 5m intervals for 50m. In each quadrat, samples were counted and collected for identification and measurements. There was a significant difference in species assemblages in March (R = 0.557, P = 0.001) and June (R = 0. 618, P = 0.001) among all sites. There was a correlation between macroinvertebrate communities and sites due to environmental differences such as the type of habitat, water temperatures and human harvesting. Alien invasive mussels such as M. galloprovincialis and S. patagonicus had a significant reduced size (P < 0.05) in disturbed sites compared to control sites in both months. Majority of the limpet species such as S. argenvillei and C. granatina only had a significant smaller size (P < 0.05) in March and showed no significant difference in June. Oxystele variegata had larger sizes at control sites compared to disturbed sites in both months. There was a significant difference in species diversity between disturbed and less disturbed sites in both March (Z = -2.905, P = 0.002) and June (Z= -3.373, P < 0.001) indicating that both control sites had a greater species diversity than the disturbed sites. Human harvesting and trampling along with natural variation may play a crucial role in species assemblage structure, size and species diversity along the Namibian intertidal rocky shore. This study may be useful in filling the knowledge gap about the rocky intertidal structure along the Namibian coast and possibly identifying coastal management requirements.Item Feeding ecology of the African tigerfish Hydrocynus vittatus castelnau, 1861 in the floodplains of the Kavango river, Namibia(University of Namibia, 2023) Tshimwandi, Filippus S.The feeding ecology of the African tigerfish Hydrocynus vittatus was investigated in the floodplains of the Kavango River, Namibia. A total of 275 samples of tigerfish were caught, using a seine and an experimental multifilament gillnet, during the annual flooding period between February and May 2020. The result of the study shows a significant ontogenetic dietary shift (P < 0.05) between size classes of tigerfish. The study also find a significant different (P < 0.05) in the diet composition of different size classes of tigerfish, where small size class tigerfish (20 mm -149 mm) fed predominately on aquatic macro invertebrates, which contributed by percentage number 94.5 % (N%), feeding mainly prey on the group of Corixidae 42.5%, Notonectidae 25.5% and Letophilebiidae 18.2%. Medium size class tigerfish (150 mm – 190 mm) fed on both portions of fish (Enteromius spp) and aquatic macro invertebrates (Trichoptera and Libellulidae)and the large size class tigerfish (200 mm - 585 mm) were predominately piscivorous (68.2 % N), feeding mainly on Cichlidae 34.9% and M. altisambesi 15.9 %. Overall, the results of the study show that tigerfish did not consume prey larger than 150 mm in total length (TL), and the predator - prey length ratio was approximately 23%. The study findings show that tigerfish on the Kamutjonga floodplains feed predominately on aquatic macro invertebrates when in the early stages of life and are piscivorous in the adult stage life. The study results provide important information in understanding the dietary requirement of tigerfish in the Kamutjonga floodplains. Such information is important in conservation measure of tigerfish. Henceforth, the study recommended multi-species modeling studies based on predator-prey interactions, in order to better understand, resource use and partitioning among species on the Kamutjonga floodplain.Item Phytochemical analysis and acetylcholinesterase inhibition activity of medicinal plants used in the traditional treatment of mental disorders in Kavango east region of Namibia(University of Namibia, 2022) Nghilalulwa, Theodor Nande N.In Namibia, various plants are used in the treatment of various illnesses in traditional healing systems, however the majority of these plants have not been characterised in terms of chemical constituents, and therefore, their safety and efficacy are unknown. The present study focused on the phytochemical analysis and evaluation of the acetylcholinesterase (AChE) inhibition activity of the extracts of five medicinal plants (Laggera decurrens, Ficus glumosa, Psendolachnostylis maprounifolia, Ochna pulchra and Ozoroa longipes) used in the traditional treatment of mental disorders in Kavango east region. Extracts were prepared from the powdered roots and leaves of the plants using dichloromethane/methanol (50/50, %v/v) and ethanol. Extracts were screened for the presence of alkaloids, saponins, diterpenes and flavonoids using standard methods. Saponins, diterpenes and flavonoids were found to be present in all the extracts, except for the leaves of O. longipes, while no alkaloids were detected in any of the plant extracts. Diterpenes appeared to be the most abundant phytochemicals for most of the samples. Leaf extracts exhibited varying levels of AChE inhibition activity. The L. decurrens proved to be the most potent plant species with percentage inhibition ranging from 74–101% for the dichloromethane/methanol (DCM/MeOH) extract and 93–106% for the ethanol extract. The highest inhibition percentages were observed at concentrations of 200 and 100 µg/mL for the DCM/MeOH and ethanol extracts respectively. Compounds were be tentatively assigned to chemical classes based on their ultraviolet absorption spectra. Future studies should employ spectroscopic techniques such as mass spectroscopy (MS) and nuclear magnetic resonance (NMR) spectroscopy to identify the chemical compounds present in these extractsItem Potential of selected microalgae in bioremediation of wastewater polluted dam water: A case of Goreangab dam in Windhoek, Namibia(University of Namibia, 2022) Ndura, JenniferThe study was aimed at determining the efficacy of freshwater microalgae in the treatment of polluted dam water with respect to the reduction of pathogen loads, as well as the concentrations of heavy metals and nutrients. Microalgae collected to treat water samples from the Goreangab Dam were collected from the Klein Windhoek River, Avis Dam as well as the Goreangab Dam. Identification of the microalgae species revealed the presence of the Microcystis species in the Goreangab Dam (control), Anabaena species in the Klein Windhoek River (treatment 1) and the Scenesdesmus species as well as the Anabaena species in the Avis Dam (treatment 2). The water samples in 12 L conical flasks each containing 1.5 L of Goreangab Dam water were treated in a greenhouse facility at the University of Namibia for a period of 12 days. Triplicate 100 ml samples were collected from the flask at day 0, day 6 and day 12 and quantitatively assessed for faecal and total coliform bacteria, heavy metals (Pb and Cd) as well as nutrients (phosphorous and nitrates). A one-way analysis of variance (ANOVA) indicated that there were no statistical differences between the mean values of Pb (p = 0.346) and Cd (p = 0.940) concentrations after treatment with microalgae. The Kruskal Wallis tests indicated statistical differences between the mean values of the nitrate levels (H(3) = 8.597 , p = 0.035) after treatment with microalgae. And the Pair Wise Comparisons indicated significant differences in nitrate uptake between treatment 1 and treatment 2 (p = 0.039) and also between treatment 2 and treatment 3 (p=0.005). However, the ANOVA indicated that there were no significant differences between the mean values of total phosphate uptake (p = 0.052) after treatment with microalgae. The results for pathogen loads in the wastewater samples indicated that there were statistical differences between the mean values of total coliform ((H(3) = 10.352 , p = 0.015) after treatment with microalgae. Further, the Pair Wise Comparisons indicated significant differences in total coliform removal between the control and the consortium (p = 0.040), between the control and treatment 2 (p=0.002) and between treatment 1 and treatment 2 (p = 0.040). Additionally, for faecal coliform presence the results indicated statistical differences between the mean values (H(3) = 10.421 , p = 0.015) after treatment with microalgae and the Pair Wise Comparisons indicated significant iii differences in faecal coliform removal between the control and treatment 2 (p = 0.002), between the control and the consortium (p=0.041) and also between treatment 1 and treatment 2 (p = 0.041). Given this evidence the use of microalgae in bioremediation is effective in the removal of pathogen loads and excessive nutrients from wastewater.Item The effects of prebiotics on the growth performance and gastrointestinal microflora modulation in oreochromis mossambicus in Hardap region, Namibia(University of Namibia, 2022) Salushando, KauloAquaculture across the world is growing exponentially, and has certainly gained popularity among small scale farmers in Namibia. Aquaculture aims to take on the increasing demand of fish as a food source in light of depleting fish stocks in natural water systems. Therefore, studies aiming to improve aquaculture production in eco-friendly and sustainable ways, such as, adopting measures that improve fish performance and health are necessary, for example, the use of feed additives such as prebiotics, probiotics and synbiotics. This study aimed to investigate the prebiotic effect of dietary inulin and Termitomyces schimperi mushroom powder incorporated in fish feed on the growth performance and modulation of gastrointestinal microflora in Oreochromis mossambicus. Three experimental diets; inulin, inulin+ mushroom and control were made at 1% dry weight of feed inclusion level. Furthermore, initial and final body mass and daily feed consumption records were used to determine growth performance and feed utilization parameters; while fish tissue samples were used to determine proximate composition analyses. 16S metagenomics sequencing of the bacterial communities available in the intestinal samples were carried out on Illumina Miseq with primers targeting the V3-V4 region of ribosomal ribonucleic acid (rRNA). The results of this study showed that the weight gain rate (WGR) and specific growth rate (SGR) of fish fed the control diet (152.59 ± 9.61 & 2.15 ± 0.09 respectively) were significantly higher (P value ≤ 0.05) than those fed the inulin diet (117.25 ± 6.20 & 1.80 ± 0.07 respectively). However, the results indicated that there were no significant differences (P values ≥ 0.05) among the experimental diets in terms of feed conversion ratio (FCR), survival rate (SR), fat, moisture, ash and protein contents. The colony-forming units (CFU) in the inulin group ii (3.54 ± 0.05 log 10 CFU/g) were significantly lower (P value ≤ 0.05) than the control group (3.54 ± 0.05 log 10 CFU/g). On the other hand, it was discovered that I group showed higher alpha and beta diversity indexes in comparison to the control and inulin + mushroom groups. Typical examples of phyla identified include Firmicutes, Actinobacteria, Proteobacteria and Bacteroidetes. At the genus level, relative abundance showed higher variation in the most abundant genera between samples. This study established that the inclusion of inulin and T. schimperi powder had no significant effect on the growth performance and proximate composition of O. mossambicus. On the other hand, the inclusion of inulin powder resulted in the reduction of viable gut microbiota counts in culture dependent methods, as well as higher alpha & beta diversity indices in culture independent methods in comparison to mushroom powder and the control. To the best of our knowledge, this is the first study to document the inclusion of T. schimperi powder as a prebiotic in fish feed. This study recommends the incorporation of prebiotics in fish feed before extrusion to ensure homogeneity of prebiotics and feed mixture. In addition, future studies should consider doing stress challenges to the fish to test the health benefit (resistance to stress) of fish fed with prebiotics. Moreover, further sequence analyses are recommended to identify the amplicon sequence variants (ASVs) without taxonomic classification in this study.Item Antimicrobial activity of fungal secondary metabolites isolated from pearl millet on gut microflora(University of Namibia, 2022) Nghaamwa, Pamela M.N.Pearl millet also known as mahangu in Namibia is a crop commonly found regions in the Northern part of Namibia such as Zambezi and Ohangwena region. Pearl millet is a common staple food of a certain percentage of Namibians. Traditional methods used for processing millet comprise of threshing, cleaning, washing, soaking, germination, wet and dry milling and fermentation. The fungal species gain access to grain matrices, depending on the type of environmental conditions certain secondary metabolites are generated this may occur during the pre-harvest, storage, transportation, processing, and marketing stages. Hazardous secondary metabolites with antimicrobial properties for instance polyketide, non-ribosomal peptides, alkaloids, and terpenes are produced by fungi and can cause food poisoning and possibly affect the microflora in the gut. It is important to identify and document whether fungi that produce antimicrobial secondary metabolites are present in mahangu that may affect the microflora. Even though sophisticated machinery exist, traditional methods of food storage and preparation are still being used in certain parts of the country. These traditional methods are seldom done in unhygienic conditions resulting in contamination of the food. The effect of food poisoning by fungi in Namibia is unknown, to the best of my knowledge there are fewer studies in Namibia that focused on the effect of antimicrobial fungi secondary metabolites on the microflora found in the gut. For this reason this study focused on isolating fungal species from pearl millet and testing their antimicrobial ability on four gut microflora E. coli ATCC 33849, K. pneumoniae ATCC BAA- 2146, L. monocytogenes and L. plantarum ATCC 8014. The pearl millet was bought from the local market and serial dilution was performed using distilled water. The solution of pearl millet with a dilution of 1:100 000 was plated on Sabouraud Dextrose Agar, it was then sub cultured until pure fungal isolates was obtained. Fungi were identified on the basis of colony characteristics and microscopic examinations. The following six types of fungi were identified Aspergillus flavus, Aspergillus niger, Saccharomyces sp., Rhodotorula sp., Trichosporon sp. and Saccharomyces sp. Ethyl acetate was used for extraction of the secondary metabolites and agar well diffusion was used to test for ii antimicrobial activity. Then Minimum Inhibitory Concentration was carried out only with fungi which produced zones of inhibition against the selected bacteria, lastly Minimum Bactericidal Concentration was carried out. The analytic test used showed that there was a significant difference in the antimicrobial activity among different fungal species p= 0.019. The fungus A. niger did not show any form of antimicrobial activity while Saccharomyces sp. showed the highest inhibitory effects with a mean value of 12.16 ± 0.21. The fungus A. flavus showed more inhibitory activity against the following bacterial strain L. plantarum, L. monocytogenes and K. pneumoniae at 7.5 mg/ml when MIC was carried out. The extract from A. flavus was the only extract exhibiting bactericidal effects and this was seen against K. pneumoniae and L. plantarum. It is evident that gut microflora can be affected by secondary metabolites of fungi from pearl millet which can lead to detrimental effects in humans. Further studies are required to detect secondary metabolites that could cause harm to the gut microflora also what dosage level is required to cause an effect in vivo on gut microflora.Item Antimicrobial effect of selected probiotic strains on salmonella typhimurium and e. coli o157:h7 isolated in a commercial slaughterhouse in Windhoek, Namibia(University of Namibia, 2022) Shapwa, Kalihulu MarthaIn recent years, Lactic Acid Bacteria (LAB) have gained popularity due to their preservative and antimicrobial activities. Therefore, there has been a growing interest in researching and developing new antimicrobial agents from various sources to control and eliminate pathogens such as Salmonella typhimurium and E. coli O157:H7 in food niches. The two pathogens are the major causative agents of foodborne diseases especially in meat products. Therefore, this study aimed to evaluate the antimicrobial activity of selected commercial probiotic strains of P. acidilactici and P. pentosaceus against S. typhimurium and E. coli O157:H7 isolated from beef samples using monoculture and co-cultures design. Beef samples were collected from Meatco Abattoir and antimicrobial activity of the probiotics strains was evaluated using pour plate methods over general and selective media such as Salmonella Shigella (SS) agar and MacConkey agar. The optical density (OD) was measured at 600 nm to study the growth kinetics of microbial mass for the probiotic and pathogenic strains in mono and co-cultures models. The co-cultures of S. typhimurium and P. acidilactici gave the significant reduction of 1.2 log cfu in S. typhimurium population, indicating that, it is more sensitive to the tested Pediococcus strains than E. coli O157:H7. Both LAB strains showed antagonistic activities against S. typhimurium and E. coli O157:H7, although none of the LAB showed a complete inhibition. However, P. acidilactici had a greater antimicrobial activity compared to P. pentosaceus. The OD value of S. typhimurium co-culture decreased with 2.24 log cfu when it was co-cultured with P. acidilactici and 2.28 log cfu when it was co-cultured with P. pentosaceus. Meanwhile, OD value of E. coli O157:H7 decreased significantly with 2.22 log cfu when it was co-cultured with P. pentosaceus and 2.33 log cfu with P. acidilactici showing their potential bio-preservation in meat products. However, further confirmatory tests are ii needed especially in their permitted concentration on the surface of cow carcasses and meat cuts during the storage.Item Analysis of food safety and food handling knowledge among street food vendors in selected local food markets in Windhoek(University of Namibia, 2022) Ngalangi, PaulusContaminated food leads to foodborne disease outbreaks (FDO) that cause millions of deaths among people every year. In Namibia, many low and middle-income consumers use street-vended foods (SVF) with compromised quality of raw materials, degraded handling and storage conditions that do not meet food safety standards. Therefore, this study was conducted by means of a descriptive, cross-sectional study of six Windhoek locations of Okuryangava, Katutura, Klein Windhoek, Kleine Kuppe, Prosperita, and Otjomuise. Food samples were purchased for laboratory analysis to determine pH, moisture and total plate count (TPC). Systems-Theoretic Accident Models and Processes (STAMP) was adopted, informed by data gathered based on event chain models drawn from street food handlers (SFH). Food-handlers were knowledgeable about the need for hygienic practices such as hand washing (94.6%), and cleaning of utensils (83.5%). Knowledge on food pathogens revealed that 72.1% did not know food pathogens such as Salmonella, Listeria, Campylobacter, and E. coli, meanwhile, only 28.4% did not know that parasites, fungi, and viruses act as agents to cause food poisoning. There is a none-consistent pattern of SFH knowledge with regard to hygienic practices during food handling and processing. pH values were lower (3.21±0.29) for liquid beverage than all solid foods that ranged from 6.81±0.10 to 7.54±0.16. The moisture percentage was higher (90.97±0.85) for liquid beverage than all solid foods that ranged from 37.66±1.20 to 63.28±0.89. High TPC of 5.28±0.49 Log CFU/g was detected in matangara, followed by sausage (5.06±0.99), kapana (3.07±0.47), and oshifima (2.66±1.99). STAMP with ready to use scenarios was introduced to deal with accidents that lead to FDO. Moreover, an assessment of the potency and appropriateness of food preservation methods and preservatives are ii recommended. A robust food safety regulatory regime, including a strong component of food safety training for contamination prevention should be pursued and is recommended for SVF handlers