Thesis (M.S.)--University of Pretoria, 2005. / Title from PDF t.p. (viewed on Apr. 14, 2007). Includes bibliographical references.

DNA sequencing and restriction fragment length polymorphism analysis (RFLP) of polymerase chain reaction (PCR) amplified mitochondrial DNA fragments, and random amplified polymorphic DNA sequence (RAPD) analysis were techniques evaluated in this study for applicability in the investigation various aspects of genetic diversity within the ostrich (Struthio camelus). The genetic aspects that were investigated were (i) relationships between ostrich subspecies, (ii) genetic variability between and within domesticated populations of southern African ostriches (Struthio camelus australis), (iii) linking egg production in domesticated ostriches to RAPD profiles, and (iv) determining the zygosity of twin ostriches. In the first part of this study DNA sequencing and the polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) methods were evaluated for resolving genetic differences in the small mtDNA fragments ofthe ostrich. DNA sequencing ofPCR amplified 450 bp 12S rRNA gene fragments of representatives from the southern African population ostrich (S.c. australis) did not reveal any differences between the populatiohs from different geographical areas, representing ostrich lineages with different breeding histories. The PCRRFLP analysis ofmtDNA fragments (450 bp 12S rRNA gene fragment and 550 bp D-loop region) also did not reveal any genetic variability between the domesticated s.,c. australis populations included in this study. PCR-RFLP analysis of a 450 bp 12S rRNA gene fragment, however, showed differences between the subspecies s.c. australis and s.c. molybdophanes. The proportion of shared fragments (F) between these two subspecies was 0.286 and nucleotide sequence divergence estimated at 8.9 %. Divergence time between these two subspecies was estimated at 4.5 million years ago. The data presented from this study are comparable to the data from a previous study in which the entire mitochondrial genome and a larger number of restriction enzymes were used. The PCR-RFLP method thus demonstrated its usefulness for genetic studies of ostriches at thesubspecies level. The sequences used in this study could not reveal any markers that were useful for genetic studies of ostriches at the population level. In the second part of the study the RAPD method was evaluated for application in the genetic studies of ostriches. RAPD profiles, based on three RAPD primers, revealed differences between three subspecies of ostriches and indicated relationships between these subspecies that are consistent with observations from other studies. The numerical analysis of pooled and individual primer data demonstrated that the subspecies s.c. australis is more closely related to s.c. massaicus than to s.c. molybdophanes. RAPD marker differences between s.c. molybdophanes on the one hand, and s.c. massaicus and s.c. australis on the other is also consistent with observations from studies that proposed separate specie~ status for s.c. molybdophanes. RAPD analysis by five primers revealed geographic variation between s.c. australis populations. The clustering patterns observed in the dendrograms and Neighbour Joining Trees generated by computer programs showed trends of separating ostric1;t populations into geographical groups, possibly reflecting their different breeding histories. In the RAPD profiles of the inbred population, band-sharing was generally greater than in the outbreeding group. RAPD analysis thus showed that it may be a useful method in the population studies of domesticated S. c. australis. RAPDs also generated data that grouped ostriches according to trends in egg production capabilities. Analysis ofRAPD profiles by computer software showed a Neighbour Joining Tree and a dendrogram that predominantly grouped ostriches into clusters associated with either good or poor egg production. Evidence supporting the suitability of RAPDs as a tool in breeding programmes of ostriches was thus provided by this study. RAPDs also provided data, demonstrating that two sets of ostrich twins were non-identical twins. It was demonstrated by this study that RAPDs analysis may be a useful technique for applying to (1) systematic (2) population (3) breeding and (4) twin studies of ostriches (Struthio camelus).

Thesis (MMedVet (Hygiene))--University of Pretoria, 2001. / Includes bibliographical references.

Dissertation (PhD (Agric))--Universiteit van Stellenbosch, 1992. / Bibliography. Also available via the Internet.

Adequate and appropriate nutrition is essential for the production of high quality commercially farmed animal species. Although South Africa has had a well-established ostrich industry for over a century, little information on ostrich nutrition, in particular the specific nutritional requirements at different stages of production, is available. The industry has consequently relied heavily on data derived from poultry and pigs, but this has often proved to be unsatisfactory for ostriches and has resulted in serious nutritional-related problems. Recent studies on the metabolisable energy of specific components of diet formulations and balanced diets have indicated that ostriches have enhanced digestibility compared with poultry and pigs. At the same time, in the present economic climate, it is necessary to find cost-effective diets for breeding birds without compromising egg and chick production. This study primarily assessed the effect of different dietary protein and energy levels on production parameters and body condition of breeding female and male ostriches. The energy content of the diet appears to be the main constraint to egg production and breeders on low energy diets laid fewer eggs and lost more body condition compared with breeders fed higher energy diets. A diet with 8.5 MJ/kg DM and 10% protein with well balanced amino acids appears to be sufficient for female breeders without compromising production and a diet with 7.5 MJ/kg DM and 10% protein appears suitable for breeding male ostriches. Different dietary energy and protein levels similarly had little or no effect on egg quality and composition. This study also assessed the carry-over effect of the nutritional regime in one year on the production in the following breeding season. Females fed diets as low as 7.5 MJ/kg ME in the previous breeding season produced significantly fewer eggs in the next breeding season, which resulted in lower chick production. Energy had no effect on the percentage infertile eggs or on the initial egg weight. Different levels of dietary protein had no effect on egg production, egg weight, fertility, hatchability and initial chick weight.

Thesis (MScAgric)--University of Stellenbosch, 1985. / Bibliographical references. Also available via the Internet.

Thesis (M. A.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (leaves 214-228). Also available via the World Wide Web.

Ostrich organs/tissue/fluids were screened for plasma kallikrein-like, tissue kallikrein-like and tonin-like activity in a continuous-fluorogenic-assay system using Pro-Phe-Arg-7-amino-4-methylcoumarine, Phe- Arg-7-amino-4-methylcoumarine and Val-Leu-Arg--7-amino-4-trifluoro-methylcoumarine as substrates. Ostrich liver and kidney showed the highest specific plasma kallikrein-like activity. Ostrich adrenal glands and kidney showed the highest specific tissue kallikrein-like and tonin-like activity. Ostrich high molecular weight kininogen was purified from plasma and low molecular weight kininogen was partially purified. The N-terminal amino acid sequences of both high- and low molecular weight kininogens from ostrich plasma were determined. Ostrich plasma high molecular weight kininogen was purified as a 118 kD protein. The purified high molecular weight kininogen inhibits the cysteine proteinase papain at a ratio of one molecule HKG to two molecules of papain. Ornitho kinin-like molecules were detected in ostrich urine using reverse phase HPLC.

Different management techniques were studied, at the Kromme Rhee Experimental Farm near Stellenbosch, in order to stimulate feed intake of ostrich chicks and to determine the effect on their growth rate. A first experiment was conducted to determine the effect of different dietary flavourants on the feed intake of ostrich chicks. Ostrich chicks (1-28 days of age), with no previous exposure to flavourants showed a strong preference for salty feed. Another experiment determined the effect of different colourants on the feed intake of ostrich chicks. Exposure of chicks to feed coloured artificially in different colours (green, red, blue and yellow) had no impact on the feed intake of ostrich chicks (1-28 days of age). Throughout the study the dry matter intake was the highest for the control diet, indicating that the provision of coloured feed to ostriches, as practised in this study, will not stimulate feed intake. The effect of feed processing and restriction of water availability for ostrich chicks was also examined. Extrusion reduced microbial counts in feed by 99.7 percent. Feed intake as well as average daily gain of chicks were lowered by both the pelleting and the extrusion process practised in this study. Processing did not have a positive influence on the production of ostrich chicks 6-15 weeks of age. Dry matter intake for chicks subjected to water restriction were the same as for birds receiving water ad libitum. Similarly growth rate as well as feed conversion ratio was not effected by restriction of water, as practised in this study. Another technique studied was to determine the effect of 24h artificial light on feed intake, growth and the behaviour of ostrich chicks (1-28 days of age). A Timeactivity budget revealed that chicks subjected to 24 hours of light spent more time eating (14.7 percent) than those subjected to normal day and night cycles (11.4 percent). In spite of this, no significant difference in feed intake, growth rate and feed conversion ratio was observed for ostrich chicks subjected to different light regimes. The effect of different dietary salt levels on the production of ostrich chicks (8-12 weeks of age) was also determined. The performance of chicks was the best on a diet with a salt inclusion of 1.4 percent.

The aim of this study was to investigate the components of the ovary in the sexually immature ostrich by using immunohistochemistry, light microscopy and electron microscopy. The light and electron microscopic studies carried out, revealed that the oocyte in the sexually immature ostrich is surrounded by seven layers which included the zona radiata,lamina perivitellina, stratum granulosum, basal lamina, thecal layers (theca interna and theca externa), connective tissue layer and superficial epithelium (see details in Chapter Two and Three). Several morphological and immunohistochemical changes occurred as the follicles developed and regressed, suggesting that ovarian follicles in the sexually immature ostrich undergo a cycle of growth and degeneration as reported in other avian species. In the present study, thecal gland cells in the ovary of the sexually immature ostrich were common. In addition, interstitial gland cells were a notable feature in atretic follicles as described in the ovary of the crow, common myna and dove (Guraya and Chalana, 1976). Further investigations on the interstitial gland cells will provide an insight into the process of steroidogenesis in the sexually immature ostrich. As discussed in Chapter five, various cells in the ovary showed immunoreactivity to oestrogen, progesterone and androgen receptors. These observations indicated that the ovarian tissue in the sexually immature ostrich is a potential target for gonadal hormones. Thus, it can be assumed that steroid hormones regulate ovarian functions in the ostrich. The use of immunohistochemical procedures proved to be an excellent method to investigate the distribution of nerves in the ovary. The results of this study have shown that the ovary in the sexually immature ostrich is well-innervated. However, further studies are required to differentiate between cholinergic and adrenergic nerve fibres. / Dissertation (MSc(Anatomy and Physiology))--University of Pretoria, 2005. / Anatomy and Physiology / unrestricted