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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Ácidos orgânicos no controle de Salmonella Enteritidis em frangos de corte desafiados experimentalmente com Salmonella Enteritidis e Eimeria tenella

CALAÇA, Gracinda Mariana 27 March 2009 (has links)
Made available in DSpace on 2014-07-29T15:07:50Z (GMT). No. of bitstreams: 1 Dissertacao Gracinda.pdf: 459529 bytes, checksum: 3fdb81b16ac7e68f80f7506af6bacaaf (MD5) Previous issue date: 2009-03-27 / This experiment was carried out using 504 one-day-old Hubbard female chicks, in order to evaluate the effect of a mixture of organic acids added to the ration, on the control of Salmonella in birds experimentally confronted with S. enteritidis and S. enteritidis associated with Eimeria tenella. The birds were distributed following a totally randomized sequence in factorial way 3x2, added or not the organic acid to the ration and the presence of challenge with S. enteritidis and E. tenella, isolated S. enteritidis or without challenge at all, totalizing six treatments with six repetitions each one, using 14 birds by experimental unit. The statistic data was analyzed using the program SAS, adopted to compare the averages, the Tukey test (quantitative variables) and Kruskal-Wallis (qualitative variables) to p< 0,05. The birds that received organic acid enriched ration had improvement in the performance at 7, 21 and 28 days. The birds inoculated only with S. enteritidis and the birds inoculated with S. Enteritidis and E. tenella presented worse levels of zootecnic performance (p<0,05) at 21, 28 and 35 days of life. The spleen weight and the thin intestine and cecum pH were not influenced (p>0,05) by the addition of organic acids to the ration. All the treatments challenged with S. enteritidis and which received acids presented minor frequency of bacteria isolation in the analyzed organs. It was also observed a reduction on the number of oocists of E. tenella in the excretes and in the cecum content in the treatments which had organic acids, as well as reduction of intestinal damage scores caused by infection with E. tenella. The organic acids promoted improvement on the zootecnic performance on cut chicken, improving intestinal health with positive consequences on control of S. enteritidis together with Eimeria tenella / Foi conduzido um experimento utilizando-se 504 pintainhas de um dia, de linhagem comercial Hubbard para corte, com o objetivo de avaliar o efeito de uma mistura de ácidos orgânicos adicionada à ração, no controle da Salmonella em aves experimentalmente desafiadas com S. Enteritidis e S. Enteritidis associada à Eimeria tenella. As aves foram distribuídas seguindo-se um delineamento inteiramente ao acaso em esquema fatorial 3x2, com a adição ou não de ácido orgânico na ração e a presença de desafio com S. Enteritidis e E. tenella, S. Enteritidis isolada ou sem nenhum desafio, totalizando seis tratamentos com seis repetições cada um, utilizando-se 14 aves por unidade experimental. Os dados estatísticos foram analisados empregando-se o programa SAS sendo adotado para comparação entre as médias, o teste de Tukey (variáveis quantitativas) e Kruskal-Wallis (variáveis qualitativas) para p<0,05. As aves que receberam ração contendo ácidos orgânicos apresentaram melhorias no desempenho zootécnico aos sete, 21 e 28 dias. As aves inoculadas apenas com S. Enteritidis e as aves inoculadas com S. Enteritidis e E. tenella apresentaram piores índices de desempenho zootécnico (p<0,05) aos 21, 28 e 35 dias de vida. O peso do baço e o pH do intestino delgado e dos cecos não foram influenciados (p>0,05) pela adição de ácidos orgânicos na ração.Todos os tratamentos desafiados com S. Enteritidis e que receberam ácidos apresentaram menor freqüência de isolamento da bactéria nos órgãos analisados. Foi também observada redução no número de oocistos de E. tenella nas excretas e no conteúdo cecal nos tratamentos que receberam ácidos orgânicos, bem como redução dos escores de lesão intestinal provocadas pela infecção por E. tenella. Os ácidos orgânicos promoveram melhorias no desempenho zootécnico dos frangos de corte, beneficiando a saúde intestinal com reflexos positivos no controle da Salmonella Enteritidis juntamente com a Eimeria tenella
42

Parasitoses e desempenho animal: estudo meta-analítico em frangos de corte e suínos em crescimento / Parasitosis and animal performance: meta-analytical study in broiler and growing pigs

Silva, Marcos Kipper da 01 December 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Two studies were carried out to evaluate, trough meta-analysis, the relationship between parasitosis and animal performance of broiler and growing pigs. Databases totaled 43,976 broilers (69 articles published between 1982 and 2010) and 1,279 growing pigs (18 articles published between 1971 and 2010). Meta-analyses followed three sequential analyses: graphic, correlation and variance-covariance. Pigs challenged by endoparasites presented reduction (P<0.001) of 5% on feed intake and 31% on weight gain. Broilers challenged by E. acervulina and E. tenella presented feed intake similar (P>0.05) to control group. However, the groups challenged by E. maxima and Pool presented increase on feed intake by 27% and 5% compared to control group. In relation to broilers weight gain, all challenged groups presented reduction (P<0.05) compared to control group. The average reduction was 10%, with the exception of the group challenged by E. maxima which showed a 23% reduction in daily weight gain compared to control group. The average age and average body weight of challenged animals, and the crude protein intake were the variables that most adjusted the determination coefficient in the equations for estimating the weight gain of parasitized pigs. Considering parasitized broilers, the reduction in feed intake was the variable that best explains the reduction in weight gain. Variance decomposition showed that parasitosis were responsible by a 6% reduction in weight gain for pigs and coccidiosis were associated by less than 1% for broilers. In addition, this analysis showed that most of the variation in weight gain was explained by the variation in feed intake (59% in pigs and 91% in broilers, on average). Parasitosis influences the performance of broilers and pigs. However, the magnitude of these effects varies with the parasite species, sex, age and line of the animal as well as nutritional factors. / Dois trabalhos foram desenvolvidos com o objetivo de estudar, através de meta-análise, a relação das parasitoses com o desempenho de frangos de corte e suínos. As bases de dados totalizaram 43.976 frangos de corte (69 artigos, publicados entre 1982 e 2010) e 1.279 suínos (18 artigos, publicados entre 1971 e 2010). A meta-análise foi realizada através de três análises sequenciais: estudos gráficos, de correlação e de variância-covariância. Suínos desafiados por endoparasitas apresentaram (P<0,001) redução de 5% no consumo de ração e de 31% no ganho de peso. Frangos de corte desafiados por E. acervulina e E. tenella apresentaram consumo de ração semelhante (P>0,05) em relação ao grupo controle. Já os grupos desafiados por E. maxima e Pool apresentaram aumento (P<0,05) no consumo de ração de 27% e 5% em relação ao grupo controle. Em relação ao ganho de peso dos frangos, todos os grupos desafiados apresentaram redução (P<0,05) quando comparados com o controle, A redução foi em média de 10%, com exceção do grupo desafiado por E. maxima que apresentou 23% de redução no ganho diário de peso em relação ao grupo controle. A idade média e o peso médio dos animais desafiados, bem como o consumo de proteína bruta, foram as variáveis que mais ajustaram o coeficiente de determinação nas equações para estimar o ganho de peso dos suínos parasitados. Para os frangos de corte parasitados, a redução no consumo de ração foi a variável que melhor explicou a redução no ganho de peso. Por decomposição da variância, foi verificado que as endoparasitoses foram responsáveis por 6% da redução no ganho de peso para os suínos, e as coccidioses foram responsáveis por menos de 1% para as aves. Além disso, a decomposição da variância mostrou que a maior parte da variação no ganho de peso foi explicada pela variação no consumo de ração (59% nos suínos e, em média, 91% nas aves). As parasitoses influenciam o desempenho dos frangos de corte e suínos. No entanto, a magnitude destes efeitos varia com o a espécie de parasita; o sexo, a idade e a linhagem do animal; bem como com fatores nutricionais.
43

Effects of Andrographis paniculata (Burm.F.) Nees on performance, mortality and coccidiosis in broiler chickens

Tipakorn, Naiyana 06 May 2002 (has links)
No description available.
44

Strategies to reduce the use of antibiotics in commercial broiler chickens : impacts on growth performance, intestinal health and microbiota

Parent, Eric 04 1900 (has links)
Il y a actuellement une pression mondiale pour revoir les pratiques d'utilisation des antimicrobiens (UAM) en production animale afin de limiter la propagation de bactéries résistantes aux antibiotiques. Conséquemment, les Producteurs de Poulet du Canada examinent la possibilité de réduire leur UAM en supprimant les antibiotiques médicalement importants en médecine humaine (AIM) des programmes préventifs avec la mise en place de leur stratégie de réduction de l’UAM. Cependant, les informations sont rares sur les conséquences de telles approches dans un contexte canadien. L'objectif de cette thèse était d'étudier les impacts sur les performances zootechniques, le contrôle des maladies intestinales et le microbiote cécal de deux stratégies de réduction de l'UAM dans des troupeaux commerciaux de poulets de chair par rapport à une UAM conventionnelle. Sur sept fermes commerciales de poulets de chair, un poulailler a été attribué aux traitements de réduction des antibiotiques pour six troupeaux consécutifs, tandis qu'un poulailler similaire sur le même site a été alloué à l'UAM conventionnelle (CONV) pour six troupeaux consécutifs (n = 84). Les stratégies de réduction des antibiotiques consistaient en l'utilisation continue d'ionophores dans l'alimentation sans (TX1) ou avec de l'acide butyrique (TX2). Aucune différence statistique (p > 0.05) n’a été notée entre TX1, TX2 et CONV sur les performances zootechniques et la santé intestinale. Les comptes d’oocystes d’Eimeria spp. étaient significativement (p < 0.05) inférieurs entre 22 et 34 jours d'âge dans les troupeaux CONV comparé aux TX1 et TX2. Le type de programme antibiotique a eu un impact relativement mineur (valeur R = 0.039), mais statistiquement significatif (p = 0.002), sur le microbiote cécal, tandis que les facteurs environnementaux ont montré les corrélations significatives (p = 0.001) les plus fortes avec le microbiote. Parmi les composantes du microbiote cécal associées à la croissance, le gain quotidien moyen (GMQ) était significativement associé à la Richesse bactérienne (p < 0.05). L’abondance relative de la famille bactérienne Lachnospiraceae fut la mesure la plus fortement corrélée à un GMQ augmenté, tandis que l’abondance relative de nombreuses familles bactériennes, incluant les Porphyromonadaceae, les Planococcaceae et les Veillonellaceae, fut corrélée à un faible GMQ. Ces taxons défavorables formaient un vaste réseau de corrélations positives entre elles, et négativement corrélées aux Lachnospiraceae. En conclusion, ces travaux ont contribué à améliorer la résilience de l'industrie avicole en fournissant des stratégies alternatives aux AIM pour prévenir les maladies intestinales. Des connaissances importantes sur le microbiote cécal des poulets de chair furent générées et pourront considérablement influencer les directions futures de la manipulation du microbiote pour favoriser la croissance. Par exemple, un paradigme important a été remis en question en illustrant que les additifs médicamenteux dans l'alimentation n’influencent que marginalement le microbiote cécal et que ce sont plutôt des facteurs environnementaux qui sont fortement impliqués dans la formation des communautés bactériennes cécales. La clé pour développer un microbiote cécal idéal chez les poulets de chair pourrait résider dans la capacité d'influencer ces facteurs, plus particulièrement l'exposition précoce à des communautés bactériennes bénéfiques et le contrôle de la flore résidente spécifique à la ferme. / There is a global pressure to review current antimicrobial use (AMU) practices in animal production and limit large-scale propagation of antibiotic resistant microorganisms. Consequently, the Chicken Farmers of Canada are examining the possibility to responsibly reduce AMU by discontinuing medically important antibiotics (MIAs) for humans from disease prevention programs of broiler chicken flocks through the implementation of their Antimicrobial Use Reduction Strategy. However, information is sparse on the consequences of such approaches in a Canadian commercial poultry production context. The general objective of this thesis was to investigate the impacts of two strategies reducing AMU in commercial broiler chicken flocks on zootechnical performance, control of intestinal diseases and the cecal microbiota compared to conventional AMU. On seven commercial broiler chicken farms, a house was allocated to the antibiotic reduction treatments for six consecutive flocks, while a similar house on the same premises was assigned to the conventional AMU (CONV) for six consecutive flocks (n = 84). The antibiotic reduction strategies consisted of continuous in-feed ionophores without (TX1) or with butyric acid (TX2). There were no statistical differences (p > 0.05) between TX1, TX2 and CONV for zootechnical performance and intestinal health. Predicted Eimeria spp. oocysts were significantly lower (p < 0.05) between 22 to 34 days of age in CONV flocks compared to TX1 and TX2. The type of antibiotic program had a relatively minor impact (R-value = 0.039), but statistically significant (p = 0.002), on the cecal microbiota composition, while environmental factors such as the farm and flock cycle showed the strongest statistically significant (p = 0.001) correlations with the microbiota composition (R-values of 0.239 and 0.374, respectively). Amongst the cecal microbiota components associated with weight gain, the average daily gain (ADG) was significantly associated with bacterial Richness (p < 0.05). The relative abundance of the bacterial family Lachnospiraceae was the most important measure correlated with ADG, while the relative abundance of numerous bacterial families, including Porphyromonadaceae, Planococcaceae and Veillonellaceae, were correlated with decreased growth rate. These unfavourable taxa formed a large network of positive correlations, indicating potential co-occurring synergies between these undesirable taxa. This network was also negatively correlated to Lachnospiraceae. In conclusion, the findings in this work contributed to improve the sustainability of the modern poultry industry by providing feasible alternatives to the practice of using MIAs for the prevention of intestinal diseases in broiler chickens. This project also generated important knowledge on the cecal microbiota of broiler chickens that could considerably influence future directions of microbiota manipulation in a perspective of improving zootechnical performance. For instance, an important paradigm was challenged by the indication that in-feed antibiotics and prebiotics may only influence marginally the microbiota during grow-out. Rather, this work suggests environmental factors are strongly involved in shaping the bacterial communities residing in the ceca of broiler chickens. Hence, the key to successfully develop an ideal cecal microbiota in broiler chickens may reside in the ability to influence such factors, more specifically the early exposure to beneficial bacterial communities and the control of farm-specific resident flora.
45

Étude de l'impact de deux traitements, dont un sans antibiotiques, sur la santé digestive et les populations de Clostridium perfringens dans des élevages de poulets de chair

Gaucher, Marie-Lou 05 1900 (has links)
No description available.

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