Thesis (M.Sc. (Zoology)) --University of Limpopo, 2010 / Refer to document

The state of diseases in South African domestic pigs drastically changed when Porcine reproductive and respiratory syndrome (PRRS) was introduced in the Western Cape Province during 2004 and was followed by an outbreak of Classical swine fever (CSF), primarily in the Eastern Cape, in 2005. These outbreaks occurred mostly in rural and backyard pig populations. Subsequent to an intensive culling operation, it became necessary to implement country-wide surveillance to substantiate that freedom from these two diseases had been achieved. Samples for a country-wide cross-sectional study were collected from commercial and non-commercial pig establishments in a combined effort between the South African Pig Producers Organisation (SAPPO) and the National and Provincial Departments of Agriculture, Veterinary Services. The survey targeted the high-risk sector of the pig population and included rural pig populations, pigs from “grey” herds (commercial farms with inadequate bio-security) and commercial establishments. Samples were also tested for Swine influenza (SI), Transmissible gastroenteritis (TGE), Aujeszky’s Disease (Aujeszky’s), Foot-and-mouth Disease (FMD) and African swine fever (ASF). The first objective of this study was to evaluate the validity of the survey design. The second objective was to evaluate the results and, thereafter, make valid inferences regarding the disease status of the domestic pig population. This also included the confidence level of the overall survey. The third objective was to qualify and quantify sample losses to enable improved future survey design and execution. The outcome of the survey indicated that the results were sufficient to conclude that the non-commercial pig population is free from CSF, PRRS and SI at the expected minimum prevalence of 1%. The calculations also indicated that the results were adequate to conclude that the commercial pig population is free from CSF, PRRS and SI at the expected minimum prevalence of 5%. The outcome of the calculations done on the second phase test results allows South Africa to conclude that the non-commercial pig sector is free from FMD, ASF, Aujeszky’s and TGE, at the expected minimum prevalence of 2%. The sample sizes for Aujeszky’s, TGE, ASF and FMD tests in the commercial sector were too small to allow for a decision to be made and, as a result, it was not possible to declare this sector free of disease. However, the non-commercial sector is much larger and the risk of disease introduction higher, therefore, if the non-commercial sector tested negative for the disease, it is highly likely that the commercial sector will be free of the disease as well. It is recommended that passive surveillance be augmented and that a national pig survey be conducted every 3 years to provide proof of disease freedom. It is important to conduct a risk analysis to qualify and quantify the risk of CSF and PRRS introduction. This could improve future surveys by providing a scientific basis for targeted surveillance. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Production Animal Studies / unrestricted

This diploma thesis deal with the neonatal sibling competition during nursing within first day after farrowing, focusing on maternal reaction on neonatal sibling competition during nursing. We predicted that the sow will terminate nursing by a changing posture or by a non- nutritive nursing (i.e. nursing without milk ejection) with increasing number of fights and screams. A total of 19 healthy sows and their litters were directly observed and video recorded during first day after farrowing for 6 h. The behaviour of piglets (fighting, screaming, presence at the udder) in the pre massage and the post massage was scored every 15 seconds. Piglets which missed milk ejection, posture changing of the sow and whether the nursing involve milk ejection were noted. A sum of fighting and screaming piglets in the pre massage and the post massage was calculated. A higher sum of fighting and screaming piglets correlated with a higher proportion of non-nutritive nursing (P<0.001) as well as with a higher proportion of sow posture changing in the pre massage (P<0.01). However, a higher sum of fighting and screaming piglets did not increase the probability of sow posture changing in the post massage. The results show a positive correlation between the litter size and the sum of fighting and screaming piglets in the...

Hos grisar finner man flera stereotypiska beteenden, som rörbitning och svansbitning. Dessa beteenden är relativt vanliga hos grisar. En miljöberikning definieras som förbättring av ett djurs välfärd, både psykologisk och fysiologiskt, genom förändringar hos djurets omgivning. Denna studie har undersökt om miljöberikningar kan minska stereotypiska beteenden hos grisar. De två olika miljöberikningar som har använts är en jutesäck fylld med halm och en Jolly Ball™. De tre stereotypiska beteendena som studerades var rörbitning, svansbitning och bukmassage. Studien utfördes på 107st grisar uppdelade på 12 boxar, under totalt tre veckor. Alla tre stereotypiska beteenden minskade statistiskt signifikant . Detta visar att båda miljöberikningarna hade en positiv effekt på grisarna då de minskade deras stereotypiska beteenden. De interagerade mer med jutesäcken fylld med halm än vad det gjorde med Jolly Ball™.  Grisarna föredrog den miljöberikningen som var omformbar, förstörbar, ätbar, tuggbar, vilket går i linje med liknande studier. / Among fattening pigs you find several stereotypical behaviours, such as bar-biting and tail-biting. These behaviours are quite common among domestic pigs. Environmental enrichments are often used to reduce stereotypical behaviours in animals.  An environmental enrichment is defined as an improvement of an animal’s welfare, both psychologically and physiologically, through changes in the environment of the animal. With this study, different environmental enrichments were studied to see if they can reduce stereotypical behaviour among fattening pigs. The two different environmental enrichments used were a jute sack filled with straw and a Jolly Ball™. The stereotypical behaviours that were looked at were bar-biting, tail-biting and belly-nosing. The study was carried out on 107 pigs divided into 12 pig boxes, during 3 weeks in total. All three stereotypical behaviours decreased significantly. This shows that the environmental enrichments had a positive effect on the pigs, since they reduced their stereotypical behaviour. The pigs interacted more with the jute sack than they did with the Jolly Ball™.  The pigs preferred the environmental enrichment that was destructible, edible, deformable and chewable, which fits well into similar studies that have been executed.

The intracellular sperm injection (ICSI) technique is a very effective tool for the fertilization research. In the newly established laboratory at the Faculty of Science of the Charles University it was necessary to introduce this method and define the early developmental potential of fertilized oocytes. After fertilization oocytes were incubated to the blastocyst stage with a success comparable with other laboratories (17%). The ubiquitin-proteasome system which plays a major role in a protein degradation within cells is involved in a regulatory mechanism of sperm maturation. It is also responsible for a penetration of a vitelline membrane. In these processes ubiquitin residues are localized extracellulary. High level of sperm ubiquitination correlates with their low quality. Hypotetically it can be expected that the ubiqutination of impaired sperm cells can be used as a negative marker for their recognition and degradation by 26S proteasome complex localized. Experiments in this diploma thesis were designed based on the hypothesis that the executive part of the selective mechanism is the 26S proteasome. Therefore the effect of MG132 peptide inhibition of the 20S proteasome on the pronuclei formation and subsequent early embryonic development after ICSI was studied. Inhibition of 20S proteasome...

La vue est sans doute le plus important des sens. L'anatomie, l'histologie et la physiologie de l'œil normale chez les espèces de laboratoire adultes ont généralement été bien documentées. Cependant, les références décrivant les caractéristiques histomorphologiques du développement oculaire postnatal chez les animaux de laboratoire demeurent sporadiques et incomplètes. L'évaluation de tissus oculaires provenant d'animaux immatures peut être nécessaire lors d’études précliniques juvéniles de toxicité effectuées dans le but d’évaluer l'innocuité de médicaments destinés à la population pédiatrique. En effet, les données découlant d'études précliniques réalisées avec des animaux matures ne sont pas toujours jugées appropriées pour évaluer la toxicité d'un composé lorsqu'il est administré à des enfants. Cependant, la rareté des références histologiques sur le développement postnatal chez les animaux, ainsi que l'absence courante de témoins appariés selon l'âge pour les animaux sacrifiés de façon précoce lors d’études juvéniles, peuvent rendre difficile l'analyse des structures de l’œil en développement. Ainsi, l'objectif de cette thèse était de fournir des connaissances histologiques et immunohistochimiques (IHC) sur le développement oculaire postnatal, de la naissance au stade prépubère, chez le rat Sprague Dawley (SD), cochon domestique (DP), cochon miniature Göttingen (MP) et chien Beagle (BG). Les résultats de cette thèse ont démontré l'immaturité marquée de toutes les structures oculaires chez les rats SD et les chiens BG à la naissance et pendant la période postnatale. À la naissance, la rétine chez ces espèces altriciales était encore composée de la couche neuroblastique externe fœtale, et plusieurs étapes cruciales de la rétinogenèse, mises en évidence avec l’IHC, se sont produites lors des premières semaines de vie. D’autres évidences d'immaturité oculaire chez ces espèces incluaient la stratification de l’épithélium cornéen lors de l'ouverture des paupières et la présence de vestiges de la vascularisation hyaloïde. En revanche, les yeux des DP et MP, considérés comme une espèce précoce, étaient davantage développés à la naissance, néanmoins, d'importants changements de morphogenèse ont été observés lors de la période postnatale. Par exemple, la rétine du cochon néonatal présentait des photorécepteurs peu développés. Chez toutes les espèces examinées, la prolifération cellulaire et l'engagement des cellules dans le cycle cellulaire, mis en évidence avec Ki-67 et/ou PHH3, étaient prédominants dans la majorité des structures oculaires en développement. L'apoptose, démontrée avec l'IHC contre caspase-3 activé et/ou l'histochimie TUNEL, s’est avérée une caractéristique histologique clé à des âges précis de la rétinogenèse chez les rats SD et les chiens BG. Ce changement était aussi notable dans l'épithélium immature du cristallin du rat SD, ainsi que dans les vestiges hyaloïdes chez toutes les espèces. Enfin, des évidences d’activation non-apoptotique de caspase-3 ont été observées dans différents types cellulaires chez toutes les espèces. Les connaissances présentées dans cette thèse pourront servir de référence pour les pathologistes devant évaluer des structures oculaires en développement dans le cadre d'études précliniques de toxicité. Par ailleurs, les résultats de cette thèse ouvrent la voie pour des investigations plus approfondies sur le développement oculaire, particulièrement chez le chien et le cochon, qui pourront servir à des recherches futures en ophtalmologie pédiatrique. / Vison is arguably the most important of senses. The normal anatomy, histology, and physiology of the eye in mature laboratory species have generally been well documented, particularly in rodents. However, references addressing the histomorphological features of the postnatal ocular development in laboratory animals, notably in nonprimate large animal models, remain sporadic and incomplete. From a veterinary toxicologic pathology perspective, the evaluation of ocular tissues from immature animals may be needed during different types of preclinical juvenile animal toxicity studies conducted to assess the safety of xenobiotics on the pediatric population. Data from preclinical studies conducted in mature animals are often not deemed appropriate to evaluate the toxicity of a drug when administered to children, thus warranting the need to use juvenile animals. However, the paucity of histological references describing the postnatal development of laboratory animals, along with the common lack of age-matched controls when animals are unexpectedly sacrificed (or found death) early during juvenile studies, can render the analysis of developing ocular structures challenging. Thus, the objective of this thesis was to provide comprehensive histological and immunohistochemical (IHC) knowledge on the postnatal ocular development, using several age timepoints from birth to the peripubertal stage, in the Sprague Dawley (SD) rat, domestic pig (DP), Göttingen minipig (MP) and Beagle (BG) dog. Overall, the results from this thesis demonstrated the marked immaturity of all ocular structures in SD rats and BG dogs at birth and during the postnatal period. Notably, the retina at birth in these altricial species still contained the highly proliferative fetal outer neuroblastic layer, and critical retinogenesis events, highlighted with IHC, occurred rapidly during the first few weeks of life. Other noteworthy features of ocular immaturity in these species included the corneal epithelial stratification happening around the time of eyelid opening, the presence of hyaloid vascular remnants, and the globally poorly developed eye anterior segment. Contrastingly, the eyes of the DP and MP, considered a precocial species, were appreciably more developed at birth, although important ocular morphogenesis changes still occurred after birth. Importantly, the neonatal pig retina presented poorly developed cone and rod photoreceptors. In all examined species, cellular proliferation and the engagement of cells in the cell cycle, highlighted by Ki-67 and/or PHH3 IHC, were prominent in nearly all developing ocular structures for variable periods of time. Physiologically occurring apoptosis, highlighted by cleaved-caspase-3 IHC and/or TUNEL histochemistry, was a key histological feature of retinogenesis at specific age timepoints in SD rats and BG dogs, and was notable in the SD rat immature lens epithelium, as well as in regressing hyaloid vasculature remnants of all species. Lastly, evidence of nonapoptotic activation of caspase-3 was observed in different ocular cell types in all species. The information presented in this thesis will hopefully serve as general reference material for pathologists evaluating immature ocular structures in the context of preclinical toxicity studies. Moreover, the results pave the way for more in-depth investigations of specific ocular developmental events in nonprimate large animal models that may be useful for pediatric ophthalmology translational research.