Doctor of Philosophy / Department of Grain Science and Industry / Praveen Vadlani / Whole stillage and thin stillage from the ethanol production process were evaluated as substrate sources for the production of [beta]-carotenes using Sporobolomyces Roseus (ATCC 28988). This product has the potential to be used as a novel feed ingredient for poultry, swine, or cattle diets. [Beta]-carotenes have been supplemented in animal diets to improve animal health, enhance meat color and quality and increase vitamin A concentrations in milk and meat. Microbial fermentations involving growth and product kinetics were performed in 500 mL baffled shake flasks and in a 5 L fermentation bioreactor. Media optimization was conducted in shake flasks to evaluate two carbon sources: glucose and glycerol, and two nitrogen sources: ammonium sulfate and urea. Final [beta]-carotene concentration of 272.57±4.34 [mu]g [beta]-carotene/g biomass was found to be highest for the whole stillage, with 10 g/L added glucose and 10 g/L nitrogen added through ammonium sulfate supplementation. Glycerol addition yielded no significant increase (P<.05) in [beta]-carotene yield, while urea addition significantly decreased (P<.05) the final [beta]-carotene concentrations. The resulting fermented product can be blended with regular feed using either whole stillage as a dry feed ingredient or thin stillage as a liquid feed additive. The fermentation of whole stillage significantly influenced the physical and flow properties of the material. Even though there was a significant decrease (P<0.05) in bulk density and increase (P<0.05) in tapped density between DDGS and fermented whole stillage, there was a less pronounced difference between the whole stillage and fermented whole stillage. The fermentation of whole stillage significantly influenced the physical and flow properties of the material. This showed that the fermentation process and resulting nutritional profile had a significant effect on the resulting fermented whole stillage. A 50 L bioreactor was specifically designed to evaluate the scalability of the process and to perform subsequent feed production trails. Pilot scale feed pelleting runs were conducted and the resultant product was put in environmental chambers to determine if [beta]-carotene concentration was reduced as a result of storage. There was a significant decrease (P<0.05) in [beta]-carotene levels after pelleting and after 28 d of storage at elevated temperature and humidity. These decreases were consistent with previous research.

Master of Agribusiness / Department of Agricultural Economics / Daniel M. O'Brien / In the manufacturing process one decision that is common to all industries is the sourcing of intermediate goods used in production. The decision to make internally verses to outsource can affect a firm's comparative advantage and increased company profits. This project deals with sourcing trace minerals used in the production of feed for the commercial production of food animals in the United States. From looking at the sources of minerals to the industry to the current market structure of the trace mineral production industry in the U.S. the question is asked whether trace minerals can be sourced differently for the client to gain this advantage. The specific objective of this research project is to determine whether it is more profitable either to purchase or manufacture trace mineral blends for use in feed ration formulations for a number of plants owned by a representative livestock feed company in western Kansas. The company has several feed plants in operation in the central Great Plains region. Does the company have enough volume of trace mineral usage to enable it to profitably produce its own mineral blends at one of its feed plants? If trace minerals can be profitably produced by the company, it will lead to a decrease in feed production cost for all of its plants. It is possible that this study will show that there is a large enough degree of consolidation in the U.S. mineral blending industry that there is little or no "room" or opportunity available in the competitive raw ingredient market to increase margin by self-producing trace minerals verses outsourcing. The rationale behind this perspective is that the supply of trace mineral blends is controlled tightly by a few existing suppliers / manufacturers who have enough market power and the subsequent ability to limit the entry of new firms. The raw ingredients required to produce these blends could not be purchased economically enough to realize any cost savings in the trace mineral production process.

L’objectif de ce travail était d’évaluer, les possibilités de diversification des matières premières utilisées en alimentation de la volaille et les conditions d’application des systèmes d’alimentation séquentielle et mélangée en milieu chaud. Une méta-analyse et deux expérimentations in vivo ont permis de conclure qu’il est possible de combiner sorgho/tourteau de coton et millet/sorgho dans l'aliment du poulet sans effet synergique sur les performances. Chez la poule pondeuse, une étude réalisée en milieu chaud et humide a permis de montrer que lorsque l’animal est soumis à des conditions thermiques et hygrométriques variables, les performances de production des poules en alimentation séquentielle et mélangée sont fortement affectées. En température chaude et constante, les poules en alimentation séquentielle ont une meilleure efficacité alimentaire que les poules en alimentation classique. Ce travail a permis de mettre en place des systèmes d’alimentation permettant de mieux valoriser des matières premières locales et d’améliorer l’ajustement des apports aux besoins des animaux. Les modèles présentés permettent ainsi de renforcer les liens entre filières avicole et végétale et de contribuer à leur développement. / The objective of this work was to evaluate the impact of alternative feed ingredients in poultry feeding and to determine bird’s responses to sequential and loose-mix feeding in hot climate. A meta-analysis and in vivo trials were performed on the use of millet. sorghum and cottonseed meal in poultry diets. Results showed that simple or combined utilization of these ingredients resulted in similar feed intake and growth performance as corn/soybean-based diets. In laying hens, a study conducted in warm conditions showed that when they are subjected 10 variable temperature and humidity throughout and within a day, laying and growth performance decreased in sequential and loose-mix feeding. A second study confirmed that high environmental temperature does not disable sequential feeding benefits. This work suggest feeding systems in which feed ingredients produced in hot climates could be directly included in birds diets have been proposed. This will thereby help consolidating the links between poultry and vegetable supply chains and contribute to their development.

O objetivo deste estudo foi avaliar a qualidade da glicerina produzida no Brasil e o seu efeito no valor de energia metabolizável e na digestibilidade para frangos de corte, bem como avaliar o desempenho e qualidade de carne, estudando os possíveis efeitos adversos e determinando o melhor nível de inclusão a ser adotado com segurança. Na primeira etapa foram coletadas 10 amostras de glicerina de diferentes fontes e origens para a análise da composição. Em seguida, foram selecionadas 4 glicerinas de composições contrastantes para a determinação da energia metabolizável e digestibilidade em ensaios de metabolismo com 200 frangos de corte durante o período de 21 a 29 dias de idade, através do método de coleta total de excretas. Na segunda etapa, as aves foram submetidas ao um delineamento inteiramente ao acaso, com 6 tratamentos e 6 repetições de 45 aves cada. Os tratamentos constituíam de uma ração controle e 5 rações com 2,5; 5,0; 7,5; 10,0 e 12,5% de glicerina, sendo que a glicerina utilizada foi a que apresentou melhor composição química e energia metabolizável de 3145 kcal/kg. A umidade da cama foi analisada aos 28, 35 e 40 dias de idade. Aos 40 dias de idade foram sacrificadas 6 aves por tratamento para determinação do rendimento de carcaça e partes, além de coleta do músculo do peito, perna e fígado. Nos músculos do peito e da perna foram realizadas as análises de qualidade de carne. Também foram determinados a composição centesimal e perfil de ácidos graxos da gordura no músculo do peito. As energias aparente metabolizável corrigida para o balanço de nitrogênio das glicerinas foram de 3145, 5026, 2828 e 2892 kcal/kg. Para o desempenho das aves o aumento do nível de glicerina na dieta até 10% não afetou negativamente, somente com a inclusão de 12,5% de glicerina houve piora no peso (P<0,05) para o período de 40 dias de idade. Não houve efeito significativo para o rendimento de carcaça e partes (P>0,05). Não foram encontradas diferenças (P>0,05) para a composição centesimal e perfil de ácidos graxos na gordura. Aos 35 e 40 dias de idade foram encontrados aumento no teor de umidade da cama (P<0,05) com a inclusão de 10 e 12,5% de glicerina. Não foram encontrados alterações nos fígados das aves com os maiores níveis de inclusão. Os resultados sugerem que dietas contendo a inclusão de até 5% não causam nenhum efeito negativo para as aves e cama. / The objective of this study was to evaluate the quality of the glycerin produced in Brazil and its effect on the value of metabolizable energy and digestibility, the performance and meat quality of broilers, studying the possible adverse effects and determining the best level of inclusion to be adopted safely. In the trial were collected 10 glycerin samples from different sources and analysis of the composition. In the following section, we selected four contrasting glycerins compositions for the determination of metabolizable energy and digestibility in metabolism trials with 200 broiler chickens during the 21-29 days of age, by the method of total excreta collection. In the second trial, the birds were subjected to a completely randomized design with 6 treatments and 6 replicates of 45 birds each. The treatments were a control diet and five diets with 2.5, 5.0, 7.5, 10.0 and 12.5% glycerin, and glycerin was used with the best chemical composition and metabolizable energy 3145 kcal / kg. The litter moisture was analyzed at 28, 35 and 40 days old. At 40 days of age were sacrificed 6 birds per treatment for determination of carcass yield and parts, and collection of the breast muscle, leg and liver. In the muscles of the chest and leg were performed the analyzes of meat quality. We also determined the composition and profile of fatty acid in breast muscle. The apparent metabolizable energy corrected for nitrogen balance of glycerins were 3145, 5026, 2828 and 2892 kcal / kg. For the performance of the birds increased level of glycerin in the diet up to 10% did not affect negatively only with the inclusion of 12.5% glycerin worsened in weight (P <0.05) for the period of 40 days old. There was no significant effect on carcass yield and parts (P> 0.05). There were no differences (P> 0.05) for the composition and profile of fatty acids in fat. At 35 and 40 days of age were found increase in moisture content of the bed (P <0.05) with the inclusion of 10 and 12.5% glycerin. No changes were found in the livers of the birds with the highest levels of inclusion. The results suggest that diets containing the inclusion of up to 5% do not cause any negative effects for the broilers, meat quality and litter

O objetivo deste estudo foi avaliar a qualidade da glicerina produzida no Brasil e o seu efeito no valor de energia metabolizável e na digestibilidade para frangos de corte, bem como avaliar o desempenho e qualidade de carne, estudando os possíveis efeitos adversos e determinando o melhor nível de inclusão a ser adotado com segurança. Na primeira etapa foram coletadas 10 amostras de glicerina de diferentes fontes e origens para a análise da composição. Em seguida, foram selecionadas 4 glicerinas de composições contrastantes para a determinação da energia metabolizável e digestibilidade em ensaios de metabolismo com 200 frangos de corte durante o período de 21 a 29 dias de idade, através do método de coleta total de excretas. Na segunda etapa, as aves foram submetidas ao um delineamento inteiramente ao acaso, com 6 tratamentos e 6 repetições de 45 aves cada. Os tratamentos constituíam de uma ração controle e 5 rações com 2,5; 5,0; 7,5; 10,0 e 12,5% de glicerina, sendo que a glicerina utilizada foi a que apresentou melhor composição química e energia metabolizável de 3145 kcal/kg. A umidade da cama foi analisada aos 28, 35 e 40 dias de idade. Aos 40 dias de idade foram sacrificadas 6 aves por tratamento para determinação do rendimento de carcaça e partes, além de coleta do músculo do peito, perna e fígado. Nos músculos do peito e da perna foram realizadas as análises de qualidade de carne. Também foram determinados a composição centesimal e perfil de ácidos graxos da gordura no músculo do peito. As energias aparente metabolizável corrigida para o balanço de nitrogênio das glicerinas foram de 3145, 5026, 2828 e 2892 kcal/kg. Para o desempenho das aves o aumento do nível de glicerina na dieta até 10% não afetou negativamente, somente com a inclusão de 12,5% de glicerina houve piora no peso (P<0,05) para o período de 40 dias de idade. Não houve efeito significativo para o rendimento de carcaça e partes (P>0,05). Não foram encontradas diferenças (P>0,05) para a composição centesimal e perfil de ácidos graxos na gordura. Aos 35 e 40 dias de idade foram encontrados aumento no teor de umidade da cama (P<0,05) com a inclusão de 10 e 12,5% de glicerina. Não foram encontrados alterações nos fígados das aves com os maiores níveis de inclusão. Os resultados sugerem que dietas contendo a inclusão de até 5% não causam nenhum efeito negativo para as aves e cama. / The objective of this study was to evaluate the quality of the glycerin produced in Brazil and its effect on the value of metabolizable energy and digestibility, the performance and meat quality of broilers, studying the possible adverse effects and determining the best level of inclusion to be adopted safely. In the trial were collected 10 glycerin samples from different sources and analysis of the composition. In the following section, we selected four contrasting glycerins compositions for the determination of metabolizable energy and digestibility in metabolism trials with 200 broiler chickens during the 21-29 days of age, by the method of total excreta collection. In the second trial, the birds were subjected to a completely randomized design with 6 treatments and 6 replicates of 45 birds each. The treatments were a control diet and five diets with 2.5, 5.0, 7.5, 10.0 and 12.5% glycerin, and glycerin was used with the best chemical composition and metabolizable energy 3145 kcal / kg. The litter moisture was analyzed at 28, 35 and 40 days old. At 40 days of age were sacrificed 6 birds per treatment for determination of carcass yield and parts, and collection of the breast muscle, leg and liver. In the muscles of the chest and leg were performed the analyzes of meat quality. We also determined the composition and profile of fatty acid in breast muscle. The apparent metabolizable energy corrected for nitrogen balance of glycerins were 3145, 5026, 2828 and 2892 kcal / kg. For the performance of the birds increased level of glycerin in the diet up to 10% did not affect negatively only with the inclusion of 12.5% glycerin worsened in weight (P <0.05) for the period of 40 days old. There was no significant effect on carcass yield and parts (P> 0.05). There were no differences (P> 0.05) for the composition and profile of fatty acids in fat. At 35 and 40 days of age were found increase in moisture content of the bed (P <0.05) with the inclusion of 10 and 12.5% glycerin. No changes were found in the livers of the birds with the highest levels of inclusion. The results suggest that diets containing the inclusion of up to 5% do not cause any negative effects for the broilers, meat quality and litter

Esta tese enfocou a validação de um sistema de recirculação para estudos de digestibilidade de camarões marinhos e a determinação dos coeficientes de digestibilidade de ingredientes protéicos em diferentes níveis de inclusão para a elaboração de dietas para camarões marinhos. O sistema de recirculação compreendeu o projeto de um tanque para estudos de digestibilidade com camarões e entre os diferentes sistemas avaliados, o Guelph-L foi o mais eficiente porque combinou uma alta eficiência de remoção de sólidos com um melhor perfil de velocidade da água e menor distância percorrida pelas partículas de fezes ou alimento não consumido. Os ensaios de digestibilidade com os seis ingredientes protéicos: farinha de peixe (FPX), concentrado protéico de soja (CPS), farinha de vísceras de frango (FVI), glúten de milho (GLM), farinha de carne e ossos (FCO) e farinha de penas hidrolisadas (PEN) incluídos na dieta referência nos níveis de 10, 20 e 30% mostraram que a digestibilidade aparente dos ingredientes foi significativamente influenciada pelo seu nível de inclusão nas dietas teste e esta influência foi mais intensa nos ingredientes glúten de milho e farinha de vísceras de frango, que apresentaram maiores desbalanços de aminoácidos. Os ingredientes que apresentaram os maiores coeficientes de digestibilidade aparente para a matéria-seca, proteína bruta, energia bruta e disponibilidade de aminoácidos foram a FPX e o CPS, enquanto que os menores custos para a proteína e energia digestível foram a FCO, CPS e PEN. O crescimento, sobrevivência e conversão dos camarões alimentar foram significativamente influenciados pelo tipo de ingrediente teste nas dietas, mas não pelo nível de inclusão e apresentaram a seguinte ordem de crescimento em g semana-1: FPX > CPS > PEN > FVI > FCO > GLM. Os coeficientes de digestibilidade aparente das dietas descreveram melhor o crescimento semanal do que os coeficientes de digestibilidade dos ingredientes, apesar da fraca correlação. / This thesis focused on the validation of an aquaculture recirculation system (RAS) for shrimp digestibility studies and the determination of the digestibility coefficients of protein sources at different inclusion levels for shrimp feeds. The recirculation system for digestibility studies proved to be adequate for its purpose and shrimp growth rates was equal to or higher than those experienced in the farms. The recirculated system comprised the Project of a tank for shrimp digestibility studies with marine shrimp which permitted the output of high quality faecal samples in quantity, reliability in the shorter time as possible. Among the systems evaluated the Guelph-L was the most efficient as it combined a high solids removal efficiency with an reasonable water velocity profile and the shortest distance for the feces and feed particles from the tank bottom to the collection tube. The digestibility trials were conducted with six protein sources: fish meal (FPX), soy protein concentrate (CPS), poultry by product meal (FVI), corn gluten meal (GLM), meat and bone meal (FCO) and hydrolyzed feather meal (PEN) at the inclusion rates of 10, 20 and 30% showed that the apparent digestibility of the protein sources was significantly affected by their inclusion levels in the test diets and this effect was more intense for the protein sources corn gluten meal and poultry by product meal, that displayed the greatest amino acids imbalance. The ingredients that presented the highest coefficients for the apparent dry matter, protein and energy digestibility and amino acids availability was fish meal and soy protein concentrate and the lowest cost for the digestible protein and energy was meat and bone meal, soy protein concentrate and hydrolyzed feather meal. The growth rates, survival and economical feed conversion ratio was significantly affected by the ingredient type, contrary to the inclusion level, and presented the following growth rate in g week-1 order: FPX > CPS > PEN > FVI > FCO > GLM. The diet apparent digestibility coefficients described weekly growth rate better than ingredient apparent digestibility coefficients, despite the weak correlation.

Esta tese enfocou a validação de um sistema de recirculação para estudos de digestibilidade de camarões marinhos e a determinação dos coeficientes de digestibilidade de ingredientes protéicos em diferentes níveis de inclusão para a elaboração de dietas para camarões marinhos. O sistema de recirculação compreendeu o projeto de um tanque para estudos de digestibilidade com camarões e entre os diferentes sistemas avaliados, o Guelph-L foi o mais eficiente porque combinou uma alta eficiência de remoção de sólidos com um melhor perfil de velocidade da água e menor distância percorrida pelas partículas de fezes ou alimento não consumido. Os ensaios de digestibilidade com os seis ingredientes protéicos: farinha de peixe (FPX), concentrado protéico de soja (CPS), farinha de vísceras de frango (FVI), glúten de milho (GLM), farinha de carne e ossos (FCO) e farinha de penas hidrolisadas (PEN) incluídos na dieta referência nos níveis de 10, 20 e 30% mostraram que a digestibilidade aparente dos ingredientes foi significativamente influenciada pelo seu nível de inclusão nas dietas teste e esta influência foi mais intensa nos ingredientes glúten de milho e farinha de vísceras de frango, que apresentaram maiores desbalanços de aminoácidos. Os ingredientes que apresentaram os maiores coeficientes de digestibilidade aparente para a matéria-seca, proteína bruta, energia bruta e disponibilidade de aminoácidos foram a FPX e o CPS, enquanto que os menores custos para a proteína e energia digestível foram a FCO, CPS e PEN. O crescimento, sobrevivência e conversão dos camarões alimentar foram significativamente influenciados pelo tipo de ingrediente teste nas dietas, mas não pelo nível de inclusão e apresentaram a seguinte ordem de crescimento em g semana-1: FPX > CPS > PEN > FVI > FCO > GLM. Os coeficientes de digestibilidade aparente das dietas descreveram melhor o crescimento semanal do que os coeficientes de digestibilidade dos ingredientes, apesar da fraca correlação. / This thesis focused on the validation of an aquaculture recirculation system (RAS) for shrimp digestibility studies and the determination of the digestibility coefficients of protein sources at different inclusion levels for shrimp feeds. The recirculation system for digestibility studies proved to be adequate for its purpose and shrimp growth rates was equal to or higher than those experienced in the farms. The recirculated system comprised the Project of a tank for shrimp digestibility studies with marine shrimp which permitted the output of high quality faecal samples in quantity, reliability in the shorter time as possible. Among the systems evaluated the Guelph-L was the most efficient as it combined a high solids removal efficiency with an reasonable water velocity profile and the shortest distance for the feces and feed particles from the tank bottom to the collection tube. The digestibility trials were conducted with six protein sources: fish meal (FPX), soy protein concentrate (CPS), poultry by product meal (FVI), corn gluten meal (GLM), meat and bone meal (FCO) and hydrolyzed feather meal (PEN) at the inclusion rates of 10, 20 and 30% showed that the apparent digestibility of the protein sources was significantly affected by their inclusion levels in the test diets and this effect was more intense for the protein sources corn gluten meal and poultry by product meal, that displayed the greatest amino acids imbalance. The ingredients that presented the highest coefficients for the apparent dry matter, protein and energy digestibility and amino acids availability was fish meal and soy protein concentrate and the lowest cost for the digestible protein and energy was meat and bone meal, soy protein concentrate and hydrolyzed feather meal. The growth rates, survival and economical feed conversion ratio was significantly affected by the ingredient type, contrary to the inclusion level, and presented the following growth rate in g week-1 order: FPX > CPS > PEN > FVI > FCO > GLM. The diet apparent digestibility coefficients described weekly growth rate better than ingredient apparent digestibility coefficients, despite the weak correlation.

Les Escherichia coli pathogènes de la volaille (APEC) font partie des E. coli extra-intestinaux pathogènes (ExPEC) et seraient un réservoir possible de gènes de virulence et de résistance aux antimicrobiens (RAM) des ExPEC chez l’humain. L’objectif de cette étude était d’évaluer l’effet d’un prébiotique et d’un mélange d’acide organique et d’huiles essentielles encapsulés sur la prévalence des gènes de virulence des ExPEC et de RAM, ainsi que les associations entre ces gènes chez E. coli de l’intestin du poulet sain. Des échantillons de contenus caecaux de poulets de 29 jours d’âge ayant reçu un de ces ingrédients alimentaires comparativement à des témoins ont été analysés pour la présence des gènes de virulence iucD, tsh, papC et des gènes de RAM blaTEM, blaSHV, tetA, tetC, blaCMY-2, aadA1, aac3 par PCR. La prévalence d’iucD était supérieure dans le groupe témoin comparativement aux groupes «prébiotique» et «acide organique» et la prévalence de papC était affectée dans le groupe «acide organique». La prévalence d’isolats d’E.coli positifs pour blaCMY-2 était supérieure dans le groupe témoin comparée aux groupes «prébiotique» et «acide organique», tel que démontré par la technique d’hybridation de l’ADN sur HGMF (Hydrophobic Grid Membrane Filter). De plus, la prévalence des isolats d’E. coli positifs pour tetA, blaTEM, aadA1 ou tsh était affectée par les ingrédients alimentaires. Dans l’ensemble, des associations entre la présence de tsh et iucD, blaTEM et aadA1, et iucD et blaCMY-2 ont été observées. .Cette étude démontre l’utilité de certains ingrédients alimentaires pour dimunier le risque d’exposition en santé publique. / Avian Pathogenic E. coli (APEC) belong to the extra-intestinal pathogenic E. coli (ExPEC) pathotype, and may be a virulence and antimicrobial resistance (AMR) gene reservoir for ExPEC in humans. The aim of this study was to evaluate the effect of addition to the feed of a prebiotic or an organic acid on the prevalence of ExPEC-associated virulence genes and antimicrobial resistance (AMR) genes and the association between these genes in E. coli of the intestinal microflora of healthy chickens. Caecal contents from 29-day-old chickens having received one of these feed ingredients in comparison to a control group were examined for the presence of virulence genes iucD, tsh, and papC and AMR genes blaTEM, blaSHV, tetA, tetC, blaCMY-2, aadA1, and aac3 by PCR. The prevalence of iucD was significantly higher in the control group than in the prebiotic and organic acid groups and prevalence of papC was affected by the use of the organic acid. The prevalence of blaCMY-2-positive E. coli isolates was higher in the control group than the prebiotic or organic acid groups, as demonstrated by Hydrophobic–grid membrane filter (HGMF) DNA probe colony hybridization. In addition, the prevalence of E. coli isolates positive for tetA, blaTEM, aadA1 or tsh was affected by the use of these feed ingredients. Overall, associations between the presence of iucD and tsh, blaTEM and aadA1, and iucD and blaCMY-2 were observed. This study demonstrates that the use of certain feed ingredients could reduce the risk of exposure in a public health perspective.

Les Escherichia coli pathogènes de la volaille (APEC) font partie des E. coli extra-intestinaux pathogènes (ExPEC) et seraient un réservoir possible de gènes de virulence et de résistance aux antimicrobiens (RAM) des ExPEC chez l’humain. L’objectif de cette étude était d’évaluer l’effet d’un prébiotique et d’un mélange d’acide organique et d’huiles essentielles encapsulés sur la prévalence des gènes de virulence des ExPEC et de RAM, ainsi que les associations entre ces gènes chez E. coli de l’intestin du poulet sain. Des échantillons de contenus caecaux de poulets de 29 jours d’âge ayant reçu un de ces ingrédients alimentaires comparativement à des témoins ont été analysés pour la présence des gènes de virulence iucD, tsh, papC et des gènes de RAM blaTEM, blaSHV, tetA, tetC, blaCMY-2, aadA1, aac3 par PCR. La prévalence d’iucD était supérieure dans le groupe témoin comparativement aux groupes «prébiotique» et «acide organique» et la prévalence de papC était affectée dans le groupe «acide organique». La prévalence d’isolats d’E.coli positifs pour blaCMY-2 était supérieure dans le groupe témoin comparée aux groupes «prébiotique» et «acide organique», tel que démontré par la technique d’hybridation de l’ADN sur HGMF (Hydrophobic Grid Membrane Filter). De plus, la prévalence des isolats d’E. coli positifs pour tetA, blaTEM, aadA1 ou tsh était affectée par les ingrédients alimentaires. Dans l’ensemble, des associations entre la présence de tsh et iucD, blaTEM et aadA1, et iucD et blaCMY-2 ont été observées. .Cette étude démontre l’utilité de certains ingrédients alimentaires pour dimunier le risque d’exposition en santé publique. / Avian Pathogenic E. coli (APEC) belong to the extra-intestinal pathogenic E. coli (ExPEC) pathotype, and may be a virulence and antimicrobial resistance (AMR) gene reservoir for ExPEC in humans. The aim of this study was to evaluate the effect of addition to the feed of a prebiotic or an organic acid on the prevalence of ExPEC-associated virulence genes and antimicrobial resistance (AMR) genes and the association between these genes in E. coli of the intestinal microflora of healthy chickens. Caecal contents from 29-day-old chickens having received one of these feed ingredients in comparison to a control group were examined for the presence of virulence genes iucD, tsh, and papC and AMR genes blaTEM, blaSHV, tetA, tetC, blaCMY-2, aadA1, and aac3 by PCR. The prevalence of iucD was significantly higher in the control group than in the prebiotic and organic acid groups and prevalence of papC was affected by the use of the organic acid. The prevalence of blaCMY-2-positive E. coli isolates was higher in the control group than the prebiotic or organic acid groups, as demonstrated by Hydrophobic–grid membrane filter (HGMF) DNA probe colony hybridization. In addition, the prevalence of E. coli isolates positive for tetA, blaTEM, aadA1 or tsh was affected by the use of these feed ingredients. Overall, associations between the presence of iucD and tsh, blaTEM and aadA1, and iucD and blaCMY-2 were observed. This study demonstrates that the use of certain feed ingredients could reduce the risk of exposure in a public health perspective.