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Haemophilus parasuis is a Gram-negative bacterium responsible for Glasser's Disease in pigs, though little is known regarding its antigenic or virulence factors. Our goals were to characterize the H. parasuis capsular polysaccharide (CP), determine its role in serotype-specificity and virulence, determine if CP is immunogenic, and develop diagnostic and protective products to prevent rampant H. parasuis infection within swine herds. Material from H. parasuis was purified using carbohydrate isolation techniques and compared to CPs from other Pasteurellaceae. Rabbits were immunized with CPs to generate antisera for microscopy, immunoassays, and bactericidal assays. CP antisera were conjugated to latex particles to create an agglutination assay for detection and typing of H. parasuis. CP was conjugated to Cholera Toxin B, and used to immunize mice and piglets before challenge with H. parasuis to determine its protective efficacy against Glasser's Disease. Broth-grown cells expressed CP, which reacted with antisera in microscopy and immunoassays. Broth-grown H. parasuis cells were serum-resistant unless homologous anti-CP serum was present. In contrast, agar-grown cells did not react with antisera in immunoassays, and cells were susceptible to killing by normal swine serum. CP was not expressed on the surface of agar-grown cells unless supplemented with bicarbonate. The addition of bicarbonate also contributed to the variability in CP quantity and upregulation of genes in the CP locus. Sensitized latex particles agglutinated strongest with homologous H. parasuis CPs, cells, and agar-grown cell lysates, but also reacted weakly with higher concentrations of heterologous CPs. The latex beads did not agglutinate with non-H. parasuis swine bacterial pathogens. Mice immunized with the CP-CTB conjugate produced a significantly higher IgG2/Th2 response than unimmunized mice or mice immunized with only CP, and immunized mice had fewer bacteria in their tissues that unimmunized mice. The CP conjugate produced a robust IgG antibody response to CP when used to immunized piglets, but because the control animals also survived H. parasuis challenge, the protective efficacy remains inconclusive. Therefore, the H. parasuis CP is the antigen that confers serotype identity, and can be implemented in methods and help direct future research in disease prevention and serotype tracking in H. parasuis infections. / Ph. D.

Thesis (MPhil (Animal Sciences))--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: A trial was done to determine if there are any differences in the growth performance of finisher pigs in the old conventional type of housing with disease infected pigs, pigs in multi unit housing that were also disease infected and high health pigs in multi unit type of housing. The high health pigs gave the best results when factors like A.D.I., A.D.G., F.C.R., margin over feed cost and carcass weight are compared with the results of the other two treatments. The difference in achievement between the disease infected pigs and the high health pigs were not the same for all the production factors but it was still in favour of the high health pigs. The trial results show just how dynamic pig production has become. From the results it is very clear that there is not any place anymore for the old conventional type of housing in any modern piggery. The time has also come for every pig farmer to look at and evaluate the health status of his piggery and to consider changing over to a high health herd. From a production as well as an economic viewpoint it makes good sense.

Made available in DSpace on 2016-12-08T16:24:16Z (GMT). No. of bitstreams: 1 PGCA14MA126.pdf: 1502489 bytes, checksum: 114ec2bccc4079c0c854d6aabdb2add0 (MD5) Previous issue date: 2014-02-25 / The study aimed to evaluate the health, zootechnical and economic behavior of pigs housed in the "wean-to-finish" system (WF) compared to the conventional production system. Two groups of pigs from the same sow farms, born and weaned in the same week, were evaluated. One group was housed in a conventional production system and the other in a WF adapted barn, both in collective pens. After the end of the nursery phase part of the WF group was transferred and housed in a conventional barn and replaced by part of the conventional group (CC), forming four groups (WF ,CC1 ,CC2 and CC3). For analysis of production was calculated the average daily feed intake (DFI), average daily gain (ADG) and feed conversion ratio (FCR). For economic analysis were determined the cost of ration per kilogram of live weight gain, the index of economic efficiency (IEE) and cost index (CI) . The health examination consisted of clinical monitoring (incidence of diarrhea, cough and sneezing), laboratory monitoring (necropsy and sample collection for histology and bacteriology) and slaughter, with the rates of pneumonia (IPP), atrophic rhinitis (RAP), kidney and liver lesions. Data were subjected to analysis of variance using the SAS statistical package, previously tested for normality of the residuals using the Shapiro-Wilk test, and the means of groups were compared by the Tukey test (5 %). Mortality was low in all groups, with the main reason of death the circovirosis. The rates of diarrhea were also not significant, with the highest incidence in nursery phase for the WF group. During the grow/finish the lowest index was of the WF, who not suffered transfer. Data from cough and sneezing were also not considered significant in all stages of review. In the slaughter-house the highest rates of RAP and IPP were of the WF group. The highest production rates for final body weight, ADG and CDR in nursery phase were of the WF group, but feed conversion ratio was better in CC. During the grow/finish the WF and CC3 group ended with similar final body weights and higher than the other groups. The ADG and FCR were equal to WF, CC1 and CC3 groups. In the economic aspect WF group had the lowest costs, with a difference of up to R$ 0.09 per kilogram of live weight gain compared to the other groups. The results of productive performance mainly linked with the economic aspect, shows that WF system can be a viable alternative for the pork industry / O trabalho teve como objetivo avaliar o comportamento zootécnico, econômico e sanitário de suínos alojados no sistema wean-to-finish (WF) em comparação ao sistema convencional de produção. Foram avaliados dois grupos de suínos provenientes das mesmas unidades produtoras de leitões, nascidos e desmamados na mesma semana. Um grupo foi alojado em um sistema convencional de produção e o outro em um galpão WF adaptado, ambos em baias coletivas. Após o termino da fase de creche parte do grupo WF foi transferido e alojado em um galpão convencional, e substituído por parte do grupo convencional (CC), formando-se quatro grupos (WF, CC1, CC2 e CC3). Para análise de produção foi calculados o consumo médio diário de ração (CDR), o ganho médio de peso diário (GPD) e a conversão alimentar (CA). Para análise econômica foram determinados o custo em ração por quilograma de ganho de peso vivo, o índice de eficiência econômica (IEE) e o índice de custo (IC). A análise sanitária consistiu em monitoria clínica (incidência de diarreia, tosse e espirro), monitoria laboratorial (necropsia com coleta de material para histologia e bacteriologia) e de abate, com os índices de pneumonia (IPP), rinite atrófica (RAP), lesões renais e hepáticas. Os dados foram submetidos à análise de variância utilizando-se o pacote estatístico SAS, previamente testados para normalidade dos resíduos pelo teste de Shapiro-Wilk, e as médias dos grupos comparadas pelo teste de Tukey (5%). A mortalidade foi baixa em todos os grupos, tendo como principal causa mortis a circovirose. Os índices de diarreia também não foram significativos, com maior incidência na fase de creche para o grupo WF. Nas fases de crescimento e terminação o índice mais baixo foi do WF que não sofreu transferência. Os dados de tosse e espirro também não foram considerados significativos em todas as fases de avaliação. No frigorífico os maiores índices de RAP e IPP foram do grupo WF. Os maiores índices produtivos para peso médio e GPD e CDR finais na fase de creche foram do grupo WF, porém a conversão alimentar do CC foi melhor. Nas fases de crescimento e terminação o grupo WF e o CC3 terminaram com peso médio final semelhante e maiores que os outros grupos. O GPD e a CA foram iguais para os grupos WF, CC1 e CC3. No aspecto econômico o grupo WF apresentou os menores custos, com diferença de até R$ 0,09 por quilograma de ganho de peso vivo em comparação aos demais grupos. Os resultados do desempenho produtivo associados principalmente ao aspecto econômico ajudaram a concluir que o sistema WF é uma alternativa viável dentro da cadeia produtiva de suínos