Metabolomics is a discipline where metabolites are assessed, identified and quantified in different samples. Metabolites are crucial components of the biological system and highly informative about its functional state due to the closeness to functional endpoints and to the organism’s phenotypes. 1H NMR and LC-MS, the commonly used metabolomics analytical platforms were used to annotate the metabolites found in Sclerocarya birrea (S. birrea) leaves from five South African provinces, Limpopo (L), Gauteng (G), North West (NW), Mpumalanga (M) and KwaZulu-Natal (KZN). Supervised Orthogonal Partial Least Square – Discriminant Analysis (OPLS-DA) of the full spectra revealed a clear differentiation of S. birrea leaves from five provinces. In addition, the level of common metabolites were measured and compounds previously found to have anti-diabetes potential ((-)-epicatechin 3-0-galloyl ester, myricetin-3-0-α-L-rhamnopyranoside, gallic acid and Kaempferol-3-0-α-L-rhamnopyranoside) were annotated in the samples. The samples from the five provinces showed anti- diabetic activity when exposed to an in-vitro glucose uptake assay, with the highest activity observed in male samples from M. The sample presented high concentrations of (-)-epicathechin 3-0-galloyl ester, one of the metabolites with anti-diabetes activity. Overall 1H NMR and LC-MS metabolic profiling were successfully applied to discriminate all five sources of S. birrea leaves, and obtained qualitative information of many common metabolites / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

MaxEnt modelling uses only the known locations of a species to predict the overall distribution of a species. Large trees are important for the functioning of savanna ecosystems, bringing nutrients to the surface, providing shelter to animals and providing a number of ecological functions. Large trees have been identified as declining in density in many southern African reserves, making the conservation of large trees within reserves an issue in park management, such as in Kruger National Park (KNP) and Hluhluwe iMfolzi Parks (HiP). Two species of primary concern are Acacia nigrescens and Sclerocarya birrea, which have similar distributions in Southern Africa. Effective management of large trees requires understanding their distribution within reserves and any potential distribution changes. By determining the current locations of a species, and using GIS layers of environmental variables to predict the extent of habitats that could support the species, niche models can predict species distribution. Maximum Entropy techniques evaluate the probability of finding the species in raster squares, with values for environmental factors controlling distribution. For this study, the locations of A. nigrescens and S. birrea trees higher than 5 m were recorded in KNP and HiP, and were used in conjunction with MaxEnt to produce distribution probability maps for both species in each reserve. In HiP, the distribution map was compared with an independent existing data set to determine if the predicted distributions were accurate. The factors effecting their distribution were compared between HiP and KNP to determine why the species were found together in KNP but not in HiP. MaxEnt could predict the locations of the species within HiP, but predictions were better for A. nigrescens than S. birrea. In both Reserves, rainfall was the best predictor of tree location, along with elevation. The niche overlap was higher in KNP, where both species are well within their total species range, than in HiP where A. nigrescens was at the edge of its distribution. These variables that are limiting distribution at a reserve scale will have an influence on the overall distribution of the species. Niche models can be used to inform the establishment of botanical reserves or other management strategies that can help preserve large trees within reserves. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

The current research was done to evaluate the nutritive values and the ruminal degradation of dry matter (DM) and crude protein (CP) from three non-conventional oil cakes, viz: amarula (Sclerocarya birrea) (AOC), macadamia (Integrifolia) (MOC) and baobab (Adansonia digitate L.) (BOC). The oil cakes were collected from biodiesel producers in Limpopo Province, transported to the ARC-Animal Production campus, where proximate and ruminal nutrient degradation analysis were conducted. Triplicates samples from each oil cake were analyzed for the nutritive values, mineral and amino acids contents. Three rumen cannulated mid-lactating (days in milk; DIM: 180±5) Holstein cows weighing 667±43 kg body weight were allocated to determine the in situ ruminal dry matter (DM) and crude protein (CP) degradation. The cows were offered a totally mixed ration (TMR) (60 concentrate: 40 forage ratio) that was compounded according to their daily nutrient requirements, and were milking was done twice per day at 12 hrs intervals. The three oil cake samples were ground using a 2-mm screen after which sub-samples (6.5 g) were put in 10 x 20 cm; 50 μm pore size polyester bags to achieve 15 mg/cm² (ratio of the sample size to surface area). The bags were then fistulated in each cow’s rumen in triplicate for a period of 2, 4, 8, 16, 24, or 48 hrs. After being incubated, the bags were removed from the rumen and washed with cold (4°C) water in 20-L buckets. Following immersing in cold water, the bags were machine washed until clean water was obtained. The bags were then dried at 60 °C in an oven for 48 hrs. The dried bags were individually weighed, and the content of each bag were removed and stored into glass vial until analysis. The remaining two duplicate sets of each sample were rinsed using cold water in order to determine solubility at 0 hrs. The AOC had higher (P<0.05) ether extract (EE) and CP content than both BOC and MOC. Macadamia oilcake (MOC) and BOC had higher (P<0.05) fractions of fibre (NDF, ADF and ADL) compared to the AOC. The AOC had greater (P<0.05) content of essential amino acids than in the BOC and MOC. Additionally, AOC had a high (P<0.05) phosphorus, but low calcium and potassium concentration. While AOC had high effective degradability of DM, it also had high water soluble as well as DM and CP rapidly degradable fractions. Effective degradation of CP was higher in AOC and BOC than in MOC. However, BOC had a high insoluble but degradable fraction of CP. Further work to determine the toxicology of these non-conventional oil cakes and animal feeding experiments is needed / Agriculture and  Animal Health / MSc. Agriculture