Inclusion body hepatitis (IBH) has been occurring as an economically important, emerging disease of broiler chickens in several countries. Historically, IBH has been identified as a secondary disease, often associated with common immunosuppressive diseases. However, few studies have identified IBH as a primary disease with no apparent association with immunosuppressive diseases. The objectives of this study were to develop an animal model of IBH in commercial broilers, to demonstrate vertical transmission of fowl adenoviruses (FAdVs) in broiler breeders and to control IBH in broilers by vaccinating their parents with an inactivated FAdV vaccine. In order to develop an animal model of IBH in commercial broilers, fourteen-day old broilers were inoculated intramuscularly with 1x104 1x107 CCID50 of either FAdV x11a-like virus, two strains of FAdV-8a (FAdV-8a strain TR-59 and FAdV-8a strain T8-A) or FAdV-11strain 1047. Four days following FAdV inoculation, 5% - 15% mortality was observed and dead birds showed histologic lesions of hemorrhagic necrotizing hepatitis. This animal model reproduced the clinical disease, and pathological lesions of IBH that have been described in commercial broilers. In order to demonstrate vertical transmission of the FAdV, 35-week-old broiler breeders were inoculated with 1x106 CCID50 of either FAdV x11a-like virus, FAdV-8a strain TR-59, FAdV-8a strain T8-A or FAdV-11 strain 1047. Eggs from infected breeders were collected and hatched seven days post-inoculation. Clinical signs or mortality were not observed in parents; however broiler progeny derived from broiler breeders inoculated with FAdV-8a strain T8-A had 30% IBH mortality by seven days of age. The hexon gene loop 1 sequence of the virus isolated from affected broiler progeny showed 100% identity to FAdV-8a strain T8-A. In order to demonstrate protection of broilers against IBH by vaccination of their parents, four groups of broiler breeders were vaccinated with either FAdV-8a strain T8-A (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion, or FAdV x11a-like virus (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion at the age of 12 and 15 weeks. The control group was inoculated with 20% oil-in-water emulsion. Broiler progeny were challenged with FAdV-8a strain T8-A to study the immunoprotective effect of the vaccine. Although, survival of broilers following FAdV-8a strain T8-A challenge was not significantly different among vaccinated and non-vaccinated groups (P>0.05), immunoprotective effect was enhanced by the increase dose of FAdV antigens (P>0.05). Further studies are necessary to improve the vaccine efficacy to protect broilers against IBH.<p> In conclusion, the results of this study support the hypothesis that IBH in broilers in Canada is a vertically-transmitted primary disease with no known immunosuppressive involvement. The results also demonstrated that inactivated antigens of FAdV are able to partially protect broilers against IBH by vaccinating their parents. Further studies with different formulations, and priming the immune system of broiler breeders with live FAdV prior to vaccination with inactivated FAdV vaccines are necessary to improve the efficacy of inactivated IBH vaccine.

Inclusion body hepatitis (IBH) has been occurring as an economically important, emerging disease of broiler chickens in several countries. Historically, IBH has been identified as a secondary disease, often associated with common immunosuppressive diseases. However, few studies have identified IBH as a primary disease with no apparent association with immunosuppressive diseases. The objectives of this study were to develop an animal model of IBH in commercial broilers, to demonstrate vertical transmission of fowl adenoviruses (FAdVs) in broiler breeders and to control IBH in broilers by vaccinating their parents with an inactivated FAdV vaccine. In order to develop an animal model of IBH in commercial broilers, fourteen-day old broilers were inoculated intramuscularly with 1x104 1x107 CCID50 of either FAdV x11a-like virus, two strains of FAdV-8a (FAdV-8a strain TR-59 and FAdV-8a strain T8-A) or FAdV-11strain 1047. Four days following FAdV inoculation, 5% - 15% mortality was observed and dead birds showed histologic lesions of hemorrhagic necrotizing hepatitis. This animal model reproduced the clinical disease, and pathological lesions of IBH that have been described in commercial broilers. In order to demonstrate vertical transmission of the FAdV, 35-week-old broiler breeders were inoculated with 1x106 CCID50 of either FAdV x11a-like virus, FAdV-8a strain TR-59, FAdV-8a strain T8-A or FAdV-11 strain 1047. Eggs from infected breeders were collected and hatched seven days post-inoculation. Clinical signs or mortality were not observed in parents; however broiler progeny derived from broiler breeders inoculated with FAdV-8a strain T8-A had 30% IBH mortality by seven days of age. The hexon gene loop 1 sequence of the virus isolated from affected broiler progeny showed 100% identity to FAdV-8a strain T8-A. In order to demonstrate protection of broilers against IBH by vaccination of their parents, four groups of broiler breeders were vaccinated with either FAdV-8a strain T8-A (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion, or FAdV x11a-like virus (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion at the age of 12 and 15 weeks. The control group was inoculated with 20% oil-in-water emulsion. Broiler progeny were challenged with FAdV-8a strain T8-A to study the immunoprotective effect of the vaccine. Although, survival of broilers following FAdV-8a strain T8-A challenge was not significantly different among vaccinated and non-vaccinated groups (P>0.05), immunoprotective effect was enhanced by the increase dose of FAdV antigens (P>0.05). Further studies are necessary to improve the vaccine efficacy to protect broilers against IBH.<p> In conclusion, the results of this study support the hypothesis that IBH in broilers in Canada is a vertically-transmitted primary disease with no known immunosuppressive involvement. The results also demonstrated that inactivated antigens of FAdV are able to partially protect broilers against IBH by vaccinating their parents. Further studies with different formulations, and priming the immune system of broiler breeders with live FAdV prior to vaccination with inactivated FAdV vaccines are necessary to improve the efficacy of inactivated IBH vaccine.

Despite their beneficial effects, concerns have been raised about the role of antimicrobial growth promoters (AGP) in the emergence of antibiotic resistant bacteria. This study evaluated the effects of approved AGP on the emergence of antibiotic resistance in commensal E. coli and foodborne pathogen Salmonella. A survey of antibiotic resistance levels in commercial broiler chicken farms in the Fraser Valley (B.C.) and an experimental feeding trial were conducted from May 2004 to February 2005 and May to November 2005, respectively. The latter examined the effects of ten AGP formulations (bambermycin, penicillin, salinomycin, bacitracin, combination of salinomycin and bacitracin, chlortetracycline, virginiamycin 11ppm, virginiamycin 22ppm, monensin and narasin) on bird performance as well. Multiple antibiotic resistant commensal E. coli and Salmonella carrying virulence genes were found at commercial broiler chicken farms and therefore may serve as reservoirs for these genes. There was no significant difference between feed formulations on the phenotypic or genotypic characteristics of the isolates, except for tetracycline resistance gene tet(B). In the experimental feeding trial, broiler chickens were fed a diet including or excluding AGP. Birds were sampled prior to and weekly during feeding of the control and the AGPP containing diets. Although not detected on day 0, E. coli increased after day 7 to more than 9.9 log10 CFU/g in ceca. Multi-drug resistant E. coli were isolated from birds fed the ten AGP containing diets as well as the control diet. Except for penicillin, none of the AGP containing diets significantly improved bird performance compared to the control diet (P>0.05). Good management practices can significantly improve broiler chickens performance and decrease the mortality rate.

Despite their beneficial effects, concerns have been raised about the role of antimicrobial growth promoters (AGP) in the emergence of antibiotic resistant bacteria. This study evaluated the effects of approved AGP on the emergence of antibiotic resistance in commensal E. coli and foodborne pathogen Salmonella. A survey of antibiotic resistance levels in commercial broiler chicken farms in the Fraser Valley (B.C.) and an experimental feeding trial were conducted from May 2004 to February 2005 and May to November 2005, respectively. The latter examined the effects of ten AGP formulations (bambermycin, penicillin, salinomycin, bacitracin, combination of salinomycin and bacitracin, chlortetracycline, virginiamycin 11ppm, virginiamycin 22ppm, monensin and narasin) on bird performance as well. Multiple antibiotic resistant commensal E. coli and Salmonella carrying virulence genes were found at commercial broiler chicken farms and therefore may serve as reservoirs for these genes. There was no significant difference between feed formulations on the phenotypic or genotypic characteristics of the isolates, except for tetracycline resistance gene tet(B). In the experimental feeding trial, broiler chickens were fed a diet including or excluding AGP. Birds were sampled prior to and weekly during feeding of the control and the AGPP containing diets. Although not detected on day 0, E. coli increased after day 7 to more than 9.9 log10 CFU/g in ceca. Multi-drug resistant E. coli were isolated from birds fed the ten AGP containing diets as well as the control diet. Except for penicillin, none of the AGP containing diets significantly improved bird performance compared to the control diet (P>0.05). Good management practices can significantly improve broiler chickens performance and decrease the mortality rate.

Despite their beneficial effects, concerns have been raised about the role of antimicrobial growth promoters (AGP) in the emergence of antibiotic resistant bacteria. This study evaluated the effects of approved AGP on the emergence of antibiotic resistance in commensal E. coli and foodborne pathogen Salmonella. A survey of antibiotic resistance levels in commercial broiler chicken farms in the Fraser Valley (B.C.) and an experimental feeding trial were conducted from May 2004 to February 2005 and May to November 2005, respectively. The latter examined the effects of ten AGP formulations (bambermycin, penicillin, salinomycin, bacitracin, combination of salinomycin and bacitracin, chlortetracycline, virginiamycin 11ppm, virginiamycin 22ppm, monensin and narasin) on bird performance as well. Multiple antibiotic resistant commensal E. coli and Salmonella carrying virulence genes were found at commercial broiler chicken farms and therefore may serve as reservoirs for these genes. There was no significant difference between feed formulations on the phenotypic or genotypic characteristics of the isolates, except for tetracycline resistance gene tet(B). In the experimental feeding trial, broiler chickens were fed a diet including or excluding AGP. Birds were sampled prior to and weekly during feeding of the control and the AGPP containing diets. Although not detected on day 0, E. coli increased after day 7 to more than 9.9 log10 CFU/g in ceca. Multi-drug resistant E. coli were isolated from birds fed the ten AGP containing diets as well as the control diet. Except for penicillin, none of the AGP containing diets significantly improved bird performance compared to the control diet (P>0.05). Good management practices can significantly improve broiler chickens performance and decrease the mortality rate. / Land and Food Systems, Faculty of / Graduate

Orientadores: Irenilza de Alencar Naas, Marta dos Santos Baracho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-14T11:27:11Z (GMT). No. of bitstreams: 1 Menezes_AdrianaGomesde_M.pdf: 3659236 bytes, checksum: 9ed106bcdf2c0254a5318139cf5e3141 (MD5) Previous issue date: 2009 / Resumo: O presente trabalho propôs um estudo exploratório para determinar os pontos críticos de controle, gargalos e possíveis riscos do incubatório e da granja de produção de frango de corte. A pesquisa foi conduzida em um incubatório e em dois aviários na região do interior do Estado de São Paulo. O experimento foi conduzido nas seguintes salas do incubatório: sala de ovos, câmera fria, pré-aquecimento, incubadora e nascedouro. Os seguintes dados foram coletados no incubatório e nos aviários: dados de temperatura (T,?C) e umidade (UR,%), velocidade do ar (VA, m s-1), temperatura superficial do ovo e do pintinho (tS,?C), níveis de amônia (NH3) e luminosidade. Na avaliação dos aviários foi aplicado o questionário do manual de Boas Práticas de Produção de Frango de Corte, bem como entrevistas com os colaboradores/produtores e posterior aplicação da matriz de análise de risco para determinar os pontos críticos de controle. Após a coleta dos dados foi aplicado o Controle Estatístico do Processo (CEP), através da análise de Índice de Capacidade do Processo utilizando o software Minitab15®. Os pontos críticos identificados no incubatório e nas duas granjas analisadas foram a temperatura ambiente e umidade relativa. As categorias que se configuraram como pontos críticos de controle foram: cama de aviário, alimentação, água, higiene e saúde do trabalhador, manejo e biosseguridade, normas e legislações, instalações e planejamento das atividades. Pôde-se concluir que a análise dos PCCs associada às ferramentas de controle CEP, às diretrizes de boas práticas de produção e às demais literaturas consultadas, contribuíram para a garantia da segurança alimentar da produção avícola industrial, resultando em maior confiança na cadeia de produção. / Abstract: This research presents an exploratory study to determine the critical control points, bottlenecks and possible risks of the incubation process and farm production of broilers. The research was conducted in an incubatory and two aviaries in the state of São Paulo. The experiment was conducted in the following rooms of the incubatory: egg room, cold camera, pre-heating and hatchery. The following data were collected in the incubatory and in the aviaries: temperature (T?C), humidity (% RH), air velocity (AV m s-1), surface temperature of the egg and the chick (ST), ammonia levels and light intensity. In the assessment of the aviaries, the following tools were applied: the questionnaire from the Manual of Good Practices for Broiler Production, interviews with employees/producers and subsequent application of the matrix of risk analysis to determine the critical control points. After collection of data, the Statistical Process Control (SPC) was applied, through the analysis of the Process Capability Index PCI and PC, using the software Minitab15®. The critical points identified in the incubatory and in the two farms were T(ºC) and RH(%). The topics that were taken into consideration as critical control points were: poultry litter, food, water, hygiene and health of workers, husbandry and biosecurity, legislation, facilities and planning of activities. It was observed that the analysis of PCCs associated with statistical control tools, guidelines of good practices for production as well as information from existing literature, contributed to ensuring the food safety of the poultry production industry, resulting in higher levels of trust in the production chain. / Mestrado / Construções Rurais e Ambiencia / Mestre em Engenharia Agrícola

No presente trabalho foram realizadas análises de enterobactérias e Salmonella em cecos e papos de frangos de corte criados sem reaproveitamento de cama e com baixa densidade, submetidos a períodos de jejum de 3, 6, 9, 12, 15 e 18 horas; também foram feitas análises das mesmas bactérias, incluindo esporos de Bacillus subtilis e bactérias ácido lácticas em papos e cecos de frangos de corte alimentados com probióticos (bactérias lácticas, Bokashi e esporos de B. subtilis) e antibiótico (bacitracina de zinco) nas rações. Não houve diferença significativa entre as populações de enterobactérias nos períodos de jejum analisados, e não foram isoladas cepas de Salmonella nos diferentes tratamentos. Houve diminuição significativa na população de enterobactérias nos cecos em relação ao grupo controle quando os frangos foram alimentados com bactérias ácido lácticas nas rações. Com Bokashi e antibiótico nas rações, a população de enterobactérias nos cecos foi maior que no grupo controle. Nos papos, não houve diferença significativa entre as populações de enterobactérias para os diferentes tratamentos, mas o tratamento com Bokashi foi o que obteve menor população das enterobactérias nesse habitat. As contagens de bactérias ácido lácticas e esporos de B. subtilis dos cecos e papos analisados não sofreram alteração significativa devido aos diferentes aditivos presentes nas rações, quando comparadas ao grupo controle. Novamente não foram isoladas cepas de Salmonella nos cecos e papos dos frangos analisados. A ausência de Salmonella pode ter explicação no modo de criação dos frangos, com baixa densidade (12 aves/m2) e sem reaproveitamento de cama, pois foi um resultado encontrado nas duas fases do trabalho. A diminuição de enterobactérias nos cecos por parte das bactérias ácido lácticas administradas na ração pode ter sido devido à exclusão competitiva, apesar da população dessas bactérias não ter aumentado significativamente neste habitat. O tratamento com administração de Bokashi obteve menor contagem de enterobactérias no papo possivelmente devido ao fato de ser um produto fermentado, com pH baixo, que poderia agir prontamente no papo. A administração de esporos de B. subtilis não surtiu efeito nas populações das bactérias analisadas nos cecos e papos dos frangos de corte. / This study analyzed the population of enterobacteria and Salmonella in the crop and caeca of broiler chickens submitted to 3, 6, 9, 12, 15 and 18 hours of feed withdrawal, and raised without reutilization of the litter, in low density. The same bacteria were analyzed, plus Bacillus subtilis spores and lactic acid bacteria, in the crop and caeca of broiler chickens fed rations with probiotics (lactic acid bacteria, Bokashi and B. subtilis spores) and antibiotic (zinc bacitracin). There were no significant differences between enterobacteria populations on the analyzed withdrawal periods, and Salmonella and antibiotic (zinc bacitracin). There were no significant differences between enterobacteria populations on the analyzed withdrawal periods, and B. subtilis spores populations from the caeca and crops of analyzed broiler chickens did not differ from the control group when the different additives were fed through the ration. Again there were no Salmonella isolates in the analyzed crop and caeca. The absence of Salmonella may have an explanation on the way that chickens were raised, with low density (12 birds/m2) and no litter reutilization, because this result was found on the two phases of the study. The lower caeca enterobacteria population found when the broilers were fed lactic acid bacteria may have been due to competitive exclusion, even though the lactic acid bacteria counting did not increase significantly in this habitat. Treatment with Bokashi administration had lower counting of enterobactérias in the crop, possibly due to the fact that Bokashi is a fermented product, with low pH, that could act readily in the crop. The administration of B. subtilis spores did not have any effect on the populations of the analyzed bacteria, in the crop and caeca of broiler chickens.

Several studies were designed to investigate effect of cold winter transportation on broiler meat quality and physiological parameters. The first study assessed the effect of microclimate environment during winter transportation (-27 to +11ºC) from farm to the processing plant (3-4 h) on core body temperature (CBT) and breast meat quality parameters of 522 broiler chickens using an actively ventilated transport vehicle. Temperatures below freezing during transportation resulted in significantly (P < 0.05) higher ultimate pH (pHu) and darker color breast meat, which led to 8% incidence of dark, firm and dry (DFD) breast meat (pH > 6.1; L*< 46).<p> The effects of extreme cold conditions (-18 to -4ºC) along with age (5 and 6 wk), gender and lairage (0 and 2 h) on physiology parameters, breast muscle metabolites and meat quality of 360 birds using a simulated transport system were investigated. Five and 6 wk birds exposed to temperatures below -8 and -14ºC, respectively, showed significantly (P < 0.05) lower CBT and blood glucose and higher live shrink with breast meat that was darker in color, higher in pHu, water holding and water binding capacity compared to breast meat of birds exposed to warmer temperatures. A high incidence of DFD breast meat (> 50%) was observed for 5 and 6 wk birds exposed to temperatures below -8 and -14ºC respectively. Lairage following acute cold exposure caused an increase of up to 20% in DFD breast meat following exposure of the birds to temperatures below -8ºC.<p> Characteristics of cold-induced DFD breast meat were investigated in broiler chickens. DFD breast meat was significantly darker, redder, and less yellow in color and had higher pH, water binding capacity, processing cook yield and lower thaw and cook loss compared to normal meat. However, no significant difference in initial energy reserves was observed between DFD and normal breast meat.<p> Effect of extreme cold-stress (-15 to -9ºC) was further assessed on thigh meat quality and incidence of DFD from 160 male broilers. A greater impact of cold stress was observed on muscle metabolites and pH of thigh compared to breast meat, with 85% DFD incidence in thigh compared to 42% in breast meat of cold-stressed birds.<p> Biochemical basis of cold-induced DFD breast and thigh meat was investigated by measuring muscle metabolites at different times post-mortem. Lack of energy reserves at slaughter clearly explained the incidence of DFD thigh meat, but other factors might contribute to DFD breast meat aside from glycogen reserve at slaughter. However, the factors leading to DFD breast meat still remain unresolved and association of post-mortem enzyme activity and development of DFD breast meat merits further investigation.

Several studies were designed to investigate effect of cold winter transportation on broiler meat quality and physiological parameters. The first study assessed the effect of microclimate environment during winter transportation (-27 to +11ºC) from farm to the processing plant (3-4 h) on core body temperature (CBT) and breast meat quality parameters of 522 broiler chickens using an actively ventilated transport vehicle. Temperatures below freezing during transportation resulted in significantly (P < 0.05) higher ultimate pH (pHu) and darker color breast meat, which led to 8% incidence of dark, firm and dry (DFD) breast meat (pH > 6.1; L*< 46).<p> The effects of extreme cold conditions (-18 to -4ºC) along with age (5 and 6 wk), gender and lairage (0 and 2 h) on physiology parameters, breast muscle metabolites and meat quality of 360 birds using a simulated transport system were investigated. Five and 6 wk birds exposed to temperatures below -8 and -14ºC, respectively, showed significantly (P < 0.05) lower CBT and blood glucose and higher live shrink with breast meat that was darker in color, higher in pHu, water holding and water binding capacity compared to breast meat of birds exposed to warmer temperatures. A high incidence of DFD breast meat (> 50%) was observed for 5 and 6 wk birds exposed to temperatures below -8 and -14ºC respectively. Lairage following acute cold exposure caused an increase of up to 20% in DFD breast meat following exposure of the birds to temperatures below -8ºC.<p> Characteristics of cold-induced DFD breast meat were investigated in broiler chickens. DFD breast meat was significantly darker, redder, and less yellow in color and had higher pH, water binding capacity, processing cook yield and lower thaw and cook loss compared to normal meat. However, no significant difference in initial energy reserves was observed between DFD and normal breast meat.<p> Effect of extreme cold-stress (-15 to -9ºC) was further assessed on thigh meat quality and incidence of DFD from 160 male broilers. A greater impact of cold stress was observed on muscle metabolites and pH of thigh compared to breast meat, with 85% DFD incidence in thigh compared to 42% in breast meat of cold-stressed birds.<p> Biochemical basis of cold-induced DFD breast and thigh meat was investigated by measuring muscle metabolites at different times post-mortem. Lack of energy reserves at slaughter clearly explained the incidence of DFD thigh meat, but other factors might contribute to DFD breast meat aside from glycogen reserve at slaughter. However, the factors leading to DFD breast meat still remain unresolved and association of post-mortem enzyme activity and development of DFD breast meat merits further investigation.

Breeding success in the broiler chicken has been accompanied by gait problems which are detrimental to productivity and welfare. Although these gait issues have not been reported to the same extent in Pekin ducks, there is concern that such problems will manifest if the duck continues on its current selection trajectory. In order to understand how changes in morphology due to selection have affected gait in both species, divergent lines were objectively assessed for gait using a pressure platform (12 birds per line at three, five and seven weeks of age). The broiler chicken was compared to the slower growing layer chicken and the Pekin duck to its slower growing ancestor, the mallard. Two breeding lines of Pekin duck were also assessed. After gait assessment, the leg bones (femur and tibiotarsus) were scanned by computed tomography to measure morphological changes which have occurred due to selection for high growth and meat yield. Results were analysed by ANOVA, accounting for age and sex. During walking, heavy lines walked at a slower velocity, displayed a wider stance and spent more time supporting their mass on both feet than their lighter conspecifics, strategies which are likely to improve balance. The foot angle while walking differed between lines; all duck lines rotated their feet internally whereas the layer chickens’ feet were aligned with the direction of travel. Conversely the broiler chicken rotated its feet externally by seven weeks of age. Morphologically, the main differences were between species. Duck lines reached adult leg size earlier than chickens, which may be a response to differing adaptive environments prior to domestication. This early cessation of bone growth in ducks may provide more opportunity for the bones to remodel to handle the loads imposed on them. Lower levels of porosity and a unique cortical architecture observed in ducks endow relatively greater bone strength. Bone curvature also differed between species; the tibiotarsus curved more laterally in ducks than in chickens and may be a swimming adaptation that hinders locomotion on land in the modern production bird. In order to improve the objectivity of selection for better gait in poultry, the genetic parameters of gait components selected on the basis of results in this thesis were estimated using a linear mixed model in a population of Pekin ducks of known pedigree. As they are a simpler measure, similar or improved heritability estimates were estimated for these gait components when compared with the standard commercial gait score which is based on a subjective view of walking ability. Intense selection for economic traits has altered gait in similar ways in both species. To improve gait in poultry, greater breeding success may be achieved by focussing on those components of gait which have changed through selection, rather than using a subjective overall visual gait score. Furthermore, in both species, adaptations for pre-domesticated life may have affected the ability with which the selected lines have accommodated their gait to other morphological changes associated with increasing body mass.