Browsing by Author "Nyaga, Justin M."

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    Effect of supplemental feeding on habitat and crop selection by wild boar in Sweden
    (Taylor & Francis, 2022-01) Muthoka, Cecilia M.; Andren, Henrik; Nyaga, Justin M.; Augustsson, Evelina; Kjellander, Petter
    The wild boar population has increased rapidly during the last 2 decades in Southern and Central Sweden. This rise in population size has caused severe damages to agricultural fields through their foraging behavior. Given the hierarch ical nature of habitat and resource selection, wildlife management needs to under stand the selection on both levels to better understand the ecology of nuisance species and mitigate the damages they infer. Thus, there is an urgent need for more knowledge on the factors that influence habitat selection as a tool in the evidence-based management of wild boar to reduce the losses they cause in the agricultural sector. This study aims to evaluate a common management action (feeding stations) influencing wild boar selection of (1) habitats and (2) resources i.e., crop types, in South-Central Sweden during summer. Eleven wild boars were fitted with GPS/GSM-collars to record movement among different habitats and crops. Wild boar shows a high preference for clear-cuts, agricultural fields, and deciduous forests. The animals showed a high preference for crop fields with oat, spring wheat, and mixed crops. A binary logistic model revealed both a positive and negative significant influence of distance to feeding stations on the selection of different habitats and crop fields. In general, feeding stations influenced the selec tion of different habitats and crops negatively i.e., the closer a habitat or crop field is to a feeding station, the higher the likelihood of its selection. The study recommends adjustments to wild boar management and cropping systems to reduce damages on highly selected crop fields.
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    In vitro anti-cancer efficacy and phyto-chemical screening of solvent extracts of Kigelia africana (Lam.) Benth
    (Heliyon, 2020) Mukavi, Justus Wambua; Mayeku, Philip Wafula; Nyaga, Justin M.; Kituyi, Sarah N.
    Background and objectives: Kigelia africana is a medicinal plant growing naturally in many parts of Africa. In Kenya, a water concoction of the plant is used to treat breast and prostate cancers. Laboratory data on its anti-cancer activity and active principles is limited, hence no scientific rationale for its medicinal use. This study reports on in-vitro toxic activities of dichloromethane and methanol extracts of the plant against human breast cancer cells and phytochemical screening of the two extracts. Methodology: Plant extracts were obtained by sequential solvent extraction of dry plant material (stem bark) using analytical grade dichloromethane: methanol (1:1) and methanol (Sigma Aldrich). In-vitro anti-cancer activities of the extracts were determined using the suphorhodamine (SRB) assay against a human breast cancer cell line (HCC 1937). Preliminary Thin layer chromatography of plant extracts was done using POLYGRAM® SIL G/UV254 plates (Merck) to establish presence of different classes of secondary metabolites. Results: In-vitro cytotoxic activities of the two extracts were significantly different (P ¼ 0.05). The methanol extract exhibited higher activity (IC50 ¼ 55.01 μg/ml). Phyto-chemical screening of the two extracts revealed the presence of terpenoids, phenols, steroids 26.02 μg/ml) compared to that of dichloromethane: methanol (1:1) (IC50 ¼ and flavonoids. Conclusion: The high in-vitro anti-cancer activities of solvent extracts of Kigelia africana justify its use in traditional medicine to manage breast cancer. Phytochemical analysis of the extracts reveal similar profiles hence the differences in their anti-cancer activities can be attributed to quantitative variations of various classes of secondary metabolites.