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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.
1

Untersuchungen zur Induktion und zum Transfer der Vancomycin-Resistenz vom VanA-Typ sowie zur Flavophospholipol-Resistenz in Enterococcus faecium / Investigations concerning the induction and the transfer of VanA-type glycopeptide resistance in Enterococcus faecium

Riedl, Sabine January 2002 (has links) (PDF)
Enterokokken gelten primär als opportunistische Erreger mit geringer Pathopotenz. Sie zeichnen sich allerdings durch ausgeprägte natürliche und erworbene Resistenzen gegen eine Vielzahl von Antibiotika aus. Besorgniserregend ist hierbei insbesondere das Auftreten von Vancomycin-resistenten Enterokokken. Glycopeptidantibiotika, wie Vancomycin und Teicoplanin, werden als Reserveantibiotika gegen multiresistente gram-positive Erreger, wie zum Beispiel Methicillin-resistente Staphylococcus aureus-Stämme (MRSA) eingesetzt. Der VanA-Typ der Glycopeptidresistenz, welcher zuerst in Enterococcus faecium beschrieben wurde, ist die in Zentraleuropa vorherrschende Variante der Glycopeptidresistenz. Das Transposon Tn1546, das die vanA-Resistenzdeterminante kodiert, liegt häufig auf großen konjugativen Plasmiden vor und kann zwischen Enterokokken-Stämmen transferiert werden. In dieser Arbeit wurde der direkte Einfluss von Vancomycin und eines weiteren Antibiotikums, Flavophospholipol (FPL), auf die Rate des konjugativen Transfers des vanA-Operons in E. faecium untersucht. Das Phosphoglycolipidantibiotikum FPL wird derzeit als Leistungsförderer in der Tiermast eingesetzt. Beide Antibiotika induzieren die Expression der Glycopeptidresistenz vom VanA-Typ. Es konnte gezeigt werden, dass Flavophospholipol in unterschiedlichen Konzentrationen die Häufigkeit des Transfers von konjugativen VanA-Plasmiden sowohl in klinischen E. faecium-Isolaten, als auch in E. faecium-Stämmen aus Tierfaeces signifikant hemmte. Vancomycin zeigte keinen signifikanten Effekt auf die Transferrate der VanA-Plasmide. Somit konnte nachgewiesen werden, dass in E. faecium kein funktionaler Zusammenhang zwischen der Induktion des vanA-Operons durch Vancomycin und FPL und der Transferfrequenz der konjugativen VanA-Plasmide unter dem Einfluss der beiden Antibiotika besteht. Weiterhin wurde die Induktion des vanA-Operons unter dem Einfluss verschiedener Antibiotika in einem E. faecium-Isolat näher untersucht. Hierbei wurde die Expression des 39 kDa VanA-Ligase Proteins direkt durch das Western Blot-Verfahren dargestellt. Eine Induktion der Expression des VanA-Ligase Proteins erfolgte durch Inhibitoren der späten Phase der Zellwandsynthese, wie Vancomycin, Flavophospholipol, Bacitracin und Tunicamycin. Außerdem konnte eine leichte Induktion des VanA-Ligase Proteins durch Fosfomycin, Cefalexin und Cefuroxim, Meropenem und Clindamycin nachgewiesen werden. Somit konnte gezeigt werden, dass Cefuroxim und Clindamycin zwei Antibiotika, die in klinischen Studien eine Besiedelung mit VRE begünstigen, auch eine geringe Zunahme der VanA-Ligase Expression bewirken. Zudem wurde deutlich, dass durch den Einfluss von Hitzestress und osmotischem Stress keine Induktion der 39 kDa VanA-Ligase Bande erfolgt. Ein weiteres Ziel dieser Arbeit war die Identifizierung einer putativen Resistenz-determinante gegen Flavophospholipol. Die Eigenschaft der FPL-Resistenz konnte nicht durch in vitro-Filterkonjugation von FPL-resistenten auf FPL-sensitive E. faecium-Stämme übertragen werden. Zur molekularen Untersuchung der Resistenz gegen Flavophospholipol wurde ein resistenter E. faecium-Stamm durch das konjugative Transposon Tn916 mutagenisiert. In allen identifizierten FPL-sensitiven Mutanten war die Insertionstelle des Transposons und dessen Orientierung im Chromosom identisch und es deletierte ein 1,5 kb großer genomischer Bereich „downstream“ der Transposon-Insertionsstelle. Dieser Bereich umfasste das 3´-Endes des Gens für eine putative Threonyl-tRNA Synthetase und den Genlocus für einen putativen Transkriptionsregulator. Die Sequenzen in allen Mutanten begannen ca. 200 bp vor dem Startcodon eines Gens für ein putatives Penicillin-Bindeprotein (PBP). In Northern Blot-Analysen konnte gezeigt werden, dass die Transkription des putativen PBP in der Mutante 64/3-1 schwächer war als im Wildtyp 64/3. Außerdem wurden durch 3H Penicillin-Markierung von PBP-Extrakten Unterschiede im Expressionsmuster der Penicillin-Bindeproteine im Wildtyp und in der Mutante deutlich. Während im Wildtyp fünf Penicillin-Bindeproteine zu erkennen waren, fehlten PBP2 und PBP3 in der Mutante 64/3-1. Die Größe von PBP3 entsprach hierbei der geschätzten Größe des putativen PBP von 79 kDa. In der Mutante 64/3-1 fand wahrscheinlich durch den Verlust eines putativen Regulators oder wichtiger regulatorischer Bereiche eine Veränderung im Expressionsmuster der Penicillin-Bindeproteine statt, welche zum FPL-sensitiven Phänotyp führte. In dieser Arbeit konnte zudem gezeigt werden, dass Flavophospholipol in E. faecium an PBP2 und PBP3 bindet und es sich hierbei um bifunktionale „high molecular weight“ Penicillin-Bindeproteine mit Transglycosylase- und Transpeptidase-Untereinheit handeln muss. / Enterococci are primary opportunistic pathogens. Species of this genus are inherently resistant to many antimicrobial agents and readily acquire additional resistances, which is likely the reason why enterococci have become prominent nosocomial pathogens. Glycopeptides, such as vancomycin and teicoplanin are the antibiotics of last resort for the treatment of methicillin-resistant staphylococci (MRSA). In Central Europe, the VanA-type is the most frequent genotype of acquired glycopeptide resistance. The vanA gene cluster is located on transposons of the Tn1546 type, which are integrated into conjugative plasmids, and can therefore be transferred among enterococcal strains. In this study, the influence of vancomycin and flavophospholipol (FPL) on the conjugative transfer of vanA plasmids was determined in several Enterococcus faecium strains. FPL is a phosphoglycolipid antibiotic used as a growth promoter in animal husbandry. Both antibiotics have an inducing effect on the vanA operon. We showed that subinibitory concentrations of FPL inhibit the tranfer of vanA plasmids. This inhibitory effect is dose-dependend and was observed both in clinical and animal isolates of E. faecium. Vancomycin had no significant effect on the transfer rate of vanA plasmids. These results suggest that there is no functional link between the induction of vancomycin resistance of VanA-type and the frequency of transfer of conjugative vanA plasmids in E. faecium. Furthermore, the influence of some antibiotics on the VanA ligase protein expression was examined by Western-blotting analysis. Induction of the 39 kDa protein could be detected after addition of some cell-wall active agents such as vancomycin, flavophospholipol, bacitracin and tunicamycin. Fosfomycin, cefalexine and cefuroxime as well as meropenem and clindamycin had a weaker inducing effect on the VanA ligase protein expression. Heat- and osmotic stress had no effect on the expression of the VanA ligase. A further objective of this study was the identification of a putative Flavophospholipol resistance determinant. Transfer of the FPL resistance between E. faecium strains could not be detected in filter mating experiments. For the molecular analysis of the Flavophospholipol resistance an insertional mutagenesis was carried out in a FPLr E. faecium strain using the conjugative transposon Tn916. The chromosomal insertion sites of the transposon were identical in all identified mutants with a 1.5 kb sequence deletion downstream of Tn916. Sequence analysis of the deleted area revealed homolgy to the 3´-end of a putative threonyl-tRNA synthetase gene and the gene of a putative regulator. The sequences in all mutants began about 200 bp upstream of the startcodon of a putative penicillin-binding protein (PBP) gene. The transcription of this penicillin-binding protein was weaker in the transposonmutant 64/3-1 than in the wildtype 64/3 as could be shown by Northern hybridisation. Further, binding-studies using 3H penicillin showed differences in the expression pattern of the penicillin-binding proteins between wildtype and mutant 64/3-1. The wildtype contained five PBP, while PBP2 and PBP3 where not marked in mutant 64/3-1. The size of PBP3 corresponds with an estimated size of the putative penicillin-binding protein of 79 kDa. This results suggest that the change in the penicillin-binding protein expression pattern of FPLs mutant 64/3-1 may be caused by the loss of a putative regulator or an important regulatory sequence. The PBP studies also show that FPL binds to PBP2 and PBP3 in E. faecium and these are likely bifunctional high molecular weight penicillin-binding proteins with transglycosylase- and transpeptidase-modules.
2

Reavaliação nas doses de flavomicina para frangos de corte / Reassessment of flavophospholipol dosis for broiler chickens

Barros, Rafael de January 2012 (has links)
A flavomicina é um antimicrobiano registrado no Ministério da Agricultura do Brasil e que tem sido amplamente utilizado na avicultura e suinocultura. Seu uso foi intenso até o final dos anos 1990, sendo este reduzido posteriormente. Este produto está registrado como promotor de crescimento até a dose máxima de 2 ppm no Brasil. A definição desta dose provêm de trabalhos executados há muitas décadas e, portanto, é possível que as doses que otimizem seu uso sejam diferentes na avicultura atual, especialmente em um cenário de limitadas ferramentas para melhora de desempenho de frangos de corte. O objetivo deste trabalho foi reavaliar a utilização da flavomicina em frangos de corte a partir de um experimento dose-resposta. Foram utilizados 900 frangos de corte machos Cobb x Cobb 500 de um dia de idade, divididos em 5 tratamentos com 12 unidades experimentais cada. Os tratamentos foram constituídos de doses crescentes de flavomicina formuladas com níveis similares de EMAn e nutrientes baseados em níveis utilizados pela indústria brasileira: 0, 2, 4, 8 e 16 ppm de flavomicina. A avaliação de desempenho foi feita semanalmente até os 42 dias com avaliações de ganho de peso, conversão alimentar corrigida para mortalidade, consumo de ração e mortalidade. No período de 1 a 21 dias de idade, as dosagens ótimas calculadas pela equação de regressão foram de 16 ppm , 12,17 ppm e 14,68 ppm para consumo de ração, conversão alimentar e ganho de peso, respectivamente. De 22 a 42 dias, as dosagens foram de 10,31 e 9,83 ppm para conversão alimentar e ganho de peso. Pela equação de regressão do período acumulado de 1 a 42 dias, houve uma melhora crescente até o platô de inclusão de 10,9 e 10,14 ppm, para ganho de peso e conversão alimentar. O estudo nos mostra que, nas condições experimentais, o desempenho de modernas linhagens de frangos de corte podem ser maximizados de dosagens que variam de 9,83 até 16 ppm, acima dos padrões estabelecidos na legislação brasileira. / Flavophospholipol is an antimicrobial registered in Ministério of Agricultura of Brazil that has been widely used in poultry and swine production. Its use was intense until the end of 1990, which was later reduced. This product is registered as a growth promoter until the maximum dosis of 2 ppm in Brazil. These doses derived from research performed many decades ago and, therefore, this dose is likely to different from the one that optimizes broiler performance, especially in a scenario of limited tools for improvements of performance of broilers. The objective of this study was to reassess the use of flavophospholipol for broilers in a dose-response trial. A total of nine hundred male Cobb x Cobb 500 broilers were placed across five treatments with 12 replications each. The treatments consisted of increasing doses of flavophospholipol: 0, 2, 4, 8, 16 ppm. The diets were formulated with similar levels of metabolizable energy based on levels and nutrients used by the Brazilian industry. Performance evaluation was done weekly until the day 42. The evaluated parameters were: body weight gain, feed conversion ratio corrected for mortality, feed intake and percentage of mortality. In the period equation were 16 ppm, 12.17 ppm and 14.68 ppm for feed intake, feed conversion ratio and body weight gain, respectively. From 22 to 42 days, the estimated doses were 10.31 and 9.83 ppm for feed conversion and body weight gain. In the cumulative period from 1 to 42 days it was found an increased improvement until the plateau which was 10.9 and 10.14 ppm, for body weight gain and feed conversion ratio. The study showed that under the experimental conditions used, the performance of modern broilers could be optimized from 9.83 to 16 ppm, above the standards established by Brazilian legislation.
3

Reavaliação nas doses de flavomicina para frangos de corte / Reassessment of flavophospholipol dosis for broiler chickens

Barros, Rafael de January 2012 (has links)
A flavomicina é um antimicrobiano registrado no Ministério da Agricultura do Brasil e que tem sido amplamente utilizado na avicultura e suinocultura. Seu uso foi intenso até o final dos anos 1990, sendo este reduzido posteriormente. Este produto está registrado como promotor de crescimento até a dose máxima de 2 ppm no Brasil. A definição desta dose provêm de trabalhos executados há muitas décadas e, portanto, é possível que as doses que otimizem seu uso sejam diferentes na avicultura atual, especialmente em um cenário de limitadas ferramentas para melhora de desempenho de frangos de corte. O objetivo deste trabalho foi reavaliar a utilização da flavomicina em frangos de corte a partir de um experimento dose-resposta. Foram utilizados 900 frangos de corte machos Cobb x Cobb 500 de um dia de idade, divididos em 5 tratamentos com 12 unidades experimentais cada. Os tratamentos foram constituídos de doses crescentes de flavomicina formuladas com níveis similares de EMAn e nutrientes baseados em níveis utilizados pela indústria brasileira: 0, 2, 4, 8 e 16 ppm de flavomicina. A avaliação de desempenho foi feita semanalmente até os 42 dias com avaliações de ganho de peso, conversão alimentar corrigida para mortalidade, consumo de ração e mortalidade. No período de 1 a 21 dias de idade, as dosagens ótimas calculadas pela equação de regressão foram de 16 ppm , 12,17 ppm e 14,68 ppm para consumo de ração, conversão alimentar e ganho de peso, respectivamente. De 22 a 42 dias, as dosagens foram de 10,31 e 9,83 ppm para conversão alimentar e ganho de peso. Pela equação de regressão do período acumulado de 1 a 42 dias, houve uma melhora crescente até o platô de inclusão de 10,9 e 10,14 ppm, para ganho de peso e conversão alimentar. O estudo nos mostra que, nas condições experimentais, o desempenho de modernas linhagens de frangos de corte podem ser maximizados de dosagens que variam de 9,83 até 16 ppm, acima dos padrões estabelecidos na legislação brasileira. / Flavophospholipol is an antimicrobial registered in Ministério of Agricultura of Brazil that has been widely used in poultry and swine production. Its use was intense until the end of 1990, which was later reduced. This product is registered as a growth promoter until the maximum dosis of 2 ppm in Brazil. These doses derived from research performed many decades ago and, therefore, this dose is likely to different from the one that optimizes broiler performance, especially in a scenario of limited tools for improvements of performance of broilers. The objective of this study was to reassess the use of flavophospholipol for broilers in a dose-response trial. A total of nine hundred male Cobb x Cobb 500 broilers were placed across five treatments with 12 replications each. The treatments consisted of increasing doses of flavophospholipol: 0, 2, 4, 8, 16 ppm. The diets were formulated with similar levels of metabolizable energy based on levels and nutrients used by the Brazilian industry. Performance evaluation was done weekly until the day 42. The evaluated parameters were: body weight gain, feed conversion ratio corrected for mortality, feed intake and percentage of mortality. In the period equation were 16 ppm, 12.17 ppm and 14.68 ppm for feed intake, feed conversion ratio and body weight gain, respectively. From 22 to 42 days, the estimated doses were 10.31 and 9.83 ppm for feed conversion and body weight gain. In the cumulative period from 1 to 42 days it was found an increased improvement until the plateau which was 10.9 and 10.14 ppm, for body weight gain and feed conversion ratio. The study showed that under the experimental conditions used, the performance of modern broilers could be optimized from 9.83 to 16 ppm, above the standards established by Brazilian legislation.
4

Reavaliação nas doses de flavomicina para frangos de corte / Reassessment of flavophospholipol dosis for broiler chickens

Barros, Rafael de January 2012 (has links)
A flavomicina é um antimicrobiano registrado no Ministério da Agricultura do Brasil e que tem sido amplamente utilizado na avicultura e suinocultura. Seu uso foi intenso até o final dos anos 1990, sendo este reduzido posteriormente. Este produto está registrado como promotor de crescimento até a dose máxima de 2 ppm no Brasil. A definição desta dose provêm de trabalhos executados há muitas décadas e, portanto, é possível que as doses que otimizem seu uso sejam diferentes na avicultura atual, especialmente em um cenário de limitadas ferramentas para melhora de desempenho de frangos de corte. O objetivo deste trabalho foi reavaliar a utilização da flavomicina em frangos de corte a partir de um experimento dose-resposta. Foram utilizados 900 frangos de corte machos Cobb x Cobb 500 de um dia de idade, divididos em 5 tratamentos com 12 unidades experimentais cada. Os tratamentos foram constituídos de doses crescentes de flavomicina formuladas com níveis similares de EMAn e nutrientes baseados em níveis utilizados pela indústria brasileira: 0, 2, 4, 8 e 16 ppm de flavomicina. A avaliação de desempenho foi feita semanalmente até os 42 dias com avaliações de ganho de peso, conversão alimentar corrigida para mortalidade, consumo de ração e mortalidade. No período de 1 a 21 dias de idade, as dosagens ótimas calculadas pela equação de regressão foram de 16 ppm , 12,17 ppm e 14,68 ppm para consumo de ração, conversão alimentar e ganho de peso, respectivamente. De 22 a 42 dias, as dosagens foram de 10,31 e 9,83 ppm para conversão alimentar e ganho de peso. Pela equação de regressão do período acumulado de 1 a 42 dias, houve uma melhora crescente até o platô de inclusão de 10,9 e 10,14 ppm, para ganho de peso e conversão alimentar. O estudo nos mostra que, nas condições experimentais, o desempenho de modernas linhagens de frangos de corte podem ser maximizados de dosagens que variam de 9,83 até 16 ppm, acima dos padrões estabelecidos na legislação brasileira. / Flavophospholipol is an antimicrobial registered in Ministério of Agricultura of Brazil that has been widely used in poultry and swine production. Its use was intense until the end of 1990, which was later reduced. This product is registered as a growth promoter until the maximum dosis of 2 ppm in Brazil. These doses derived from research performed many decades ago and, therefore, this dose is likely to different from the one that optimizes broiler performance, especially in a scenario of limited tools for improvements of performance of broilers. The objective of this study was to reassess the use of flavophospholipol for broilers in a dose-response trial. A total of nine hundred male Cobb x Cobb 500 broilers were placed across five treatments with 12 replications each. The treatments consisted of increasing doses of flavophospholipol: 0, 2, 4, 8, 16 ppm. The diets were formulated with similar levels of metabolizable energy based on levels and nutrients used by the Brazilian industry. Performance evaluation was done weekly until the day 42. The evaluated parameters were: body weight gain, feed conversion ratio corrected for mortality, feed intake and percentage of mortality. In the period equation were 16 ppm, 12.17 ppm and 14.68 ppm for feed intake, feed conversion ratio and body weight gain, respectively. From 22 to 42 days, the estimated doses were 10.31 and 9.83 ppm for feed conversion and body weight gain. In the cumulative period from 1 to 42 days it was found an increased improvement until the plateau which was 10.9 and 10.14 ppm, for body weight gain and feed conversion ratio. The study showed that under the experimental conditions used, the performance of modern broilers could be optimized from 9.83 to 16 ppm, above the standards established by Brazilian legislation.
5

Desempenho de novilhos Nelore em pastagem suplementados com diferentes aditivos / Performance of Nellore calves on pasture with different feed additives

Roger Tito Abal 30 November 2016 (has links)
O objetivo do trabalho foi avaliar o desempenho de novilhos Nelore mantidos em pastagem de Brachiaria decumbens, suplementados com três tipos de aditivos, usados como promotores de crescimento na época das águas, durante 112 dias. Foram utilizados 60 bezerros da raça Nelore, com 12 meses de idade e 259,2 ± 10,68 kg de peso corporal médio. O delineamento experimental foi inteiramente casualizado, com quatro tratamentos (15 animais cada): controle (mistura mineral), mistura mineral com monensina (1.000 mg kg-1), mistura mineral com salinomicina (1.111 mg kg-1) e mistura mineral com flavomicina (333 mg kg-1). Os animais foram divididos em quatro piquetes de Brachiaria decumbens (com 6,7 ha) e submetidos a rodízios semanais. Foram avaliados consumo de suplemento, composição do pasto, desempenho e análise econômica. Os dados foram analisados pelo PROC GLM do SAS (2009) e as médias comparadas pelo teste de Tukey a 5% de significância. O consumo de suplemento mineral dos tratamentos com salinomicina e monensina foram menores em 27,5 e 38,8 %, respectivamente, em relação ao tratamento controle (P <0,01). Não houve diferença no ganho de peso dos animais que receberam aditivos e esses foram maiores que o tratamento controle (P <0,01). A suplementação mineral com monensina, salinomicina e flavomicina apresentou menor custo por arroba produzida em referência ao controle de 53,5; 42,1 e 18,3%, respectivamente. A eficiência do suplemento com flavomicina, salinomicina e monensina foi 56,1%; 88,2% e 142,3% maior em relação ao controle respectivamente. Foi concluído que a adição de monensina, salinomicina e flavomicina no suplemento mineral de bovinos Nelore, em pastagem de Brachiaria decumbens na época das águas, melhora o desempenho dos animais e aumentou o retorno econômico. / The objective of this research was to evaluate the performance of Nellore steers grazing on Brachiaria decumbens, supplemented with three types of additives used as growth promoters in the rainy season for 112 days. The total of 60 Nellore calves with 12 months and 259.2 ± 10.68 kg of body weight were divided randomly in four treatments (15 animals each one): control (mineral supplement mixture), mineral supplement with monensin (1000 mg kg-1), mineral supplement with salinomycin (1111 mg kg-1) and mineral supplement with flavomycin (333 mg kg-1). The animals were divided into four paddocks of Brachiaria decumbens (with 6.7 ha) and subjected to weekly rotation. It was evaluated the supplement intake, pasture composition, performance and economic analysis. Experimental data were analyzed using PROC GLM of SAS (2009) and the means was compared by Tukey test at 5% significance. The consumption of mineral supplement of the treatments with monensin and salinomycin were 27,5 % and 38,8 %, respectively, lower than the control (p <0,01). There was no difference in weight gain of the animals supplemented with additives but their gain was higher than the control treatment (P <0.01). The mineral supplementation with monensin, salinomycin and flavomycin presented less cost of meat production in reference to the control of 53,5; 42,1 and 18,3 %, respectively. The feed efficiency of the supplement with flavomycin, salinomycin and monensin was 56.1%; 88.2% and 142.3% higher than the control respectively. It was concluded that the feed additives increased the animal performance and the profit.
6

Desempenho de novilhos Nelore em pastagem suplementados com diferentes aditivos / Performance of Nellore calves on pasture with different feed additives

Abal, Roger Tito 30 November 2016 (has links)
O objetivo do trabalho foi avaliar o desempenho de novilhos Nelore mantidos em pastagem de Brachiaria decumbens, suplementados com três tipos de aditivos, usados como promotores de crescimento na época das águas, durante 112 dias. Foram utilizados 60 bezerros da raça Nelore, com 12 meses de idade e 259,2 ± 10,68 kg de peso corporal médio. O delineamento experimental foi inteiramente casualizado, com quatro tratamentos (15 animais cada): controle (mistura mineral), mistura mineral com monensina (1.000 mg kg-1), mistura mineral com salinomicina (1.111 mg kg-1) e mistura mineral com flavomicina (333 mg kg-1). Os animais foram divididos em quatro piquetes de Brachiaria decumbens (com 6,7 ha) e submetidos a rodízios semanais. Foram avaliados consumo de suplemento, composição do pasto, desempenho e análise econômica. Os dados foram analisados pelo PROC GLM do SAS (2009) e as médias comparadas pelo teste de Tukey a 5% de significância. O consumo de suplemento mineral dos tratamentos com salinomicina e monensina foram menores em 27,5 e 38,8 %, respectivamente, em relação ao tratamento controle (P <0,01). Não houve diferença no ganho de peso dos animais que receberam aditivos e esses foram maiores que o tratamento controle (P <0,01). A suplementação mineral com monensina, salinomicina e flavomicina apresentou menor custo por arroba produzida em referência ao controle de 53,5; 42,1 e 18,3%, respectivamente. A eficiência do suplemento com flavomicina, salinomicina e monensina foi 56,1%; 88,2% e 142,3% maior em relação ao controle respectivamente. Foi concluído que a adição de monensina, salinomicina e flavomicina no suplemento mineral de bovinos Nelore, em pastagem de Brachiaria decumbens na época das águas, melhora o desempenho dos animais e aumentou o retorno econômico. / The objective of this research was to evaluate the performance of Nellore steers grazing on Brachiaria decumbens, supplemented with three types of additives used as growth promoters in the rainy season for 112 days. The total of 60 Nellore calves with 12 months and 259.2 ± 10.68 kg of body weight were divided randomly in four treatments (15 animals each one): control (mineral supplement mixture), mineral supplement with monensin (1000 mg kg-1), mineral supplement with salinomycin (1111 mg kg-1) and mineral supplement with flavomycin (333 mg kg-1). The animals were divided into four paddocks of Brachiaria decumbens (with 6.7 ha) and subjected to weekly rotation. It was evaluated the supplement intake, pasture composition, performance and economic analysis. Experimental data were analyzed using PROC GLM of SAS (2009) and the means was compared by Tukey test at 5% significance. The consumption of mineral supplement of the treatments with monensin and salinomycin were 27,5 % and 38,8 %, respectively, lower than the control (p <0,01). There was no difference in weight gain of the animals supplemented with additives but their gain was higher than the control treatment (P <0.01). The mineral supplementation with monensin, salinomycin and flavomycin presented less cost of meat production in reference to the control of 53,5; 42,1 and 18,3 %, respectively. The feed efficiency of the supplement with flavomycin, salinomycin and monensin was 56.1%; 88.2% and 142.3% higher than the control respectively. It was concluded that the feed additives increased the animal performance and the profit.
7

EFFECT OF FLAVOMYCIN (FLAVOPHOSPHOLIPOL) ON THE ACQUISITION AND LOSS OF ANTIMICROBIAL RESISTANCE IN MULTIDRUG-RESISTANT SALMONELLA ENTERICA SEROVAR ENTERITIDIS IN BROILER CHICKENS

Lim, Kelvin Z. 02 June 2015 (has links)
No description available.

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