The equine cecal microbiome is an incredibly diverse ecosystem that is critical to the overall health of the horse. It is of particular interest to equine researchers because of the link between colic and the bacterial profile residing within the cecum. We investigated ten probiotics for their ability to reduce numbers of previously identified pathogenic microorganisms: Streptococcus bovis/equinus complex (SBEC), Escherichia coli K-12, Escherichia coli general, Clostridium difficile, and Clostridium perfringens. A preliminary in vitro study was used to measure the reduction in opportunistic bacteria that are commonly found in the equine gastrointestinal tract. The second in vitro was designed as a titration study using the three most effective probiotics from the first project. In this second stage of testing, different dosage levels were utilized to determine if dosage had an effect on bacterial reduction potential. Dosage levels included manufacturer’s recommended dosage (1x), twice the recommended dosage (2x), and three times the recommended dosage (3x). Lastly, an in vivo study was conducted using three cecally-cannulated horses in a Latin square design in order to measure opportunistic bacteria reduction potential in the live horse model. Cecal fluid characteristics, pH, volatile fatty acids, and ammonia concentrations were measured, along with bacterial concentrations. In the initial in vitro experiment, we observed that all probiotic treatments numerically decreased the bacterial concentrations in comparison to the control. There were three products that decreased bacterial concentrations most consistently: Command FT, CRS, and SmartDigest Ultra. These probiotics were chosen for a titration in vitro study. Selected probiotics were dosed at the recommended dose (1x), as well as at two times the recommended dose (2x) and three times the recommended dose. In the titration in vitro experiment, SmartDigest Ultra increased (P < 0.01) bacterial concentrations of E. coli K12 and C. perfringens at 2x and 3x. Due to a lack of statistical significance for Command FT and CRS (P ≥ 0.10), cost efficiency was used as a selection criteria. Command FT was approximately $0.27 per dose and CRS was approximately $0.18 per dose. Therefore, CRS was chosen for further testing in the following in vivo experiment. In the in vivo experiment, CRS was dosed at one times (1x) and two times (2x) the recommended dose. We observed that blood parameters, cecal fluid characteristics, and bacterial concentrations were not statistically (P ≥ 0.10) altered by treatment. Numerical increases for bacterial concentrations were observed for SBEC at 1x and 2x, C. difficile at 2x, and C. perfringens at 2x. Numerical decreases were observed for E. coli K12 at 1x and 2x and E. coli general at 1x and 2x. Overall, this study suggests that the selected probiotics can be safely used at the recommended dose.

Twelve working horses were utilized in a completely randomized design to examine the efficacy of curcumin as an anti-parasitic, anti-inflammatory, and anti-microbial. Horses were randomly assigned to either the control (CON) containing no curcumin or to the curcumin (CUR) treatment which was dosed at 15 g of 500 mg/g of 95% curcumin per day (n = 6/treatment). Fecal samples were collected on day 0 before initiation of treatments and then daily for 30 days. Feces from working horses were evaluated for shedding of Streptococcus bovis/ equinus complex, Clostridium difficile, and Clostridium perfringens. Inflammation was observed through erythrocyte sedimentation rate (ESR) via jugular venipuncture every 3-4 days. Horses were fed treatments at 1100 daily and samples were collected prior to administration of treatments. Dosing curcumin at the recommended rate of 15 g per horse had no effect (P ≥ 0.58) on total fecal egg count, strongyles, or ascarids. There was a day effect (P ≤ 0.05) with parasite shedding mimicking the parasites life cycle. Treatment had no effect on ESR (P ≤ 0.42); however, a day effect (P ≤ 0.001) was observed with the CUR horses with ESR decreasing (P = 0.0006) on d 14 and d 21 compared to d 0. There was no treatment (P = 0.34) or day effect (P = 0.53) on concentration of Clostridium perfringens. Similarly, there was no treatment effect for Clostridium difficile (P = 0.51) or SBEC (P = 0.69). Day had an effect (P = 0.0001) on Clostridium difficile, for both CON and CUR horses with all horses having higher concentrations on d 0 and d 1 compared to all other days. Concentrations of SBEC were affected by day (P = 0.05) with concentrations increasing on different days for both CON and CUR horses. Data would suggest that curcumin has a potential benefit as an anti-inflammatory for working horses starting at d 14 when being dosed at 15 g of 500 mg/g of 95% curcumin. This dosage for 30 days however had no additional benefits as an anti-parasitic and anti-microbial. Curcumin has a potentially negative effect on the GIT by increasing opportunistic bacteria and more research is needed to further evaluate the anti-microbial and anti-parasitic effects of curcumin in horses.

Le tube digestif est la première barrière contre les agresseurs présents dans la nourriture (virus, bactéries, produits chimiques, pesticides etc...). Il doit donc maintenir au mieux son intégrité structurale et fonctionnelle tout au long de la vie de l'individu. Bien que l'impact délétère d'une intoxication aiguë puisse être surmonté par la capacité de défense et de régénération de la muqueuse digestive, une agression prolongée ou répétée peut compromettre l'équilibre physiologique (l'homéostasie) du tube digestif. Parmi les agresseurs pouvant être ingérés avec la nourriture, on trouve la bactérie Bacillus thuringiensis (Bt) et représente 70% des ventes de bioinsecticides. Bt est une bactérie Gram+ sporulante qui produit, pendant la sporulation, des toxines nommées Cry. Parmi les différentes souches de Bt, certaines ont été sélectionnées pour la spécificité d'action de leurs toxines Cry contre des nuisibles et sont commercialisées sous forme de sporanges. Certaines de ces souches sont utilisées en agriculture biologique en France et l'accroissement de leur utilisation fait qu'elles sont de plus en plus présentes dans la nourriture, source de contamination potentielle pour l'homme et l’environnement. La question qui se pose maintenant est de savoir si un tel accroissement de l’utilisation de Bt peut avoir des impacts sur des espèces non cibles. Mon projet de thèse a consisté en l’étude des conséquences de l'ingestion de Bt (sous forme végétative ou de sporanges) sur la physiologie intestinale de la drosophile (animal non sensible à Bt en termes de toxicité aigüe / The digestive tract is continuously subjected to multiple aggressions through virus, bacteria, toxins and chemicals mixed in the feed. Therefore the gut lining has established a mechanism of replenishment in order to maintain the physiological function of the organ called the gut homeostasis. Although the deleterious impact of acute poisoning can be overcome by the defense capacity and regeneration of the gut mucosa, prolonged or repeated intoxication can impair its homeostasis. Among the aggressors hidden in the feed, there is the bacterium Bacillus thuringiensis (Bt). Bt is worldwide used as bioinsecticide. Indeed the multitude of Bt strains produces a broad range of crystalline toxins, named Cry toxins, which certain have been selected in organic farming owing to their lethal properties against specific pests. Because of incentive programs for sustainable development, the use of Bt bioinsecticides as an alternative to chemical pesticides will further increase in the next decades. Although the specificity of the acute toxicity of Cry toxins has been proved since many years, data are scarce on adverse effects that could result from chronic exposure. The question now is how far non-target organisms will be potentially impacted by the resulting augmentation of the Bt bacterium and its Cry toxins in the environment. To answer this challenge, I used Drosophila (a non-target organism) to study the impacts of Bt bioinsecticides on the gut physiology because 1/ the digestive tract is the main entrance for feed contaminated by Bt bioinsecticides and 2/ Bt and its toxins are known to impair the gut epithelium of sensitive pests

Made available in DSpace on 2014-12-17T15:55:00Z (GMT). No. of bitstreams: 1 VivianeSFN_DISSERT.pdf: 1830875 bytes, checksum: cab92fad26402f8ffafa1b30a4f983b4 (MD5) Previous issue date: 2012-02-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Water is essential to life and all living organisms and their supply is necessary for economic development and quality of life of human populations, but their quality has been altered by human actions. In semi-arid northeast, the water is an issue of concern, especially its quality. This region is common to the construction of reservoirs that capture rain water, streams and temporary rivers in search of ease this situation, being intended for various purposes. Water scarcity is a limiting factor for the economic and social development of the region and contributes to the maintenance of waterborne diseases. About 80% of diseases that occur in developing countries are infected by waterborne pathogens. Therefore, this study aimed to determine in two environments that are part of semil?nticos Armando Ribeiro Gon?alves reservoir, and a stretch of the river Assu, all located in the semiarid RN, the occurrence of opportunistic pathogenic bacteria; check the conceptions of teachers and health workers about the issues "waterborne diseases" and "bacteria" and a diagnosis of diarrheal diseases that affect the population in some municipalities of the semi-arid region of RN from a survey of epidemiological data. For identification of bacteria using commercial kits and the diagnosis of diarrheal disease was based on information from databases. The previous conceptions of teachers and health workers were obtained through questionnaires. The results confirmed the presence of opportunistic bacteria in the studied area, showing the importance of monitoring water quality. There was an under-reporting of cases of diarrhea pointing out flaws in the monitoring of Diarrheal Diseases and indicating the need to improve it. It was felt also the need to implement educational activities on topics dealt with both with teachers and health workers, since they were identified misconceptions on the subject / A ?gua ? essencial ? vida e a todos os organismos vivos e o seu suprimento ? necess?rio para o desenvolvimento econ?mico e para a qualidade de vida das popula??es humanas, mas sua qualidade vem sendo alterada pelas a??es antr?picas. No semi?rido nordestino, a ?gua ? uma quest?o preocupante, especialmente a sua qualidade. Nessa regi?o ? comum a constru??o de reservat?rios, que captam ?guas de chuvas, c?rregos e rios tempor?rios, na busca de amenizar essa situa??o, sendo destinados para diversas finalidades. A escassez de ?gua ? limitante para o desenvolvimento econ?mico e social da regi?o e contribui com a manuten??o das doen?as de veicula??o h?drica. Cerca de 80% das doen?as que ocorrem em pa?ses em desenvolvimento s?o veiculadas pela ?gua contaminada por microrganismos patog?nicos. Nesse contexto, este trabalho objetivou determinar, em dois ambientes semil?nticos que fazem parte do reservat?rio Armando Ribeiro Gon?alves, e em um trecho do rio Assu, todos localizados no semi-?rido potiguar, a ocorr?ncia de bact?rias patog?nicas oportunistas; verificar as concep??es de professores e agentes de sa?de a respeito dos temas doen?as de veicula??o h?drica e bact?rias , e realizar um diagn?stico das doen?as diarr?icas que acometem a popula??o de alguns munic?pios do semi-?rido do RN a partir do levantamento de dados epidemiol?gicos. Para identifica??o das bact?rias utilizaram-se kits comerciais, e o diagn?stico das doen?as diarr?icas foi realizado com base em informa??es de bancos de dados. As concep??es pr?vias de professores e agentes de sa?de foram obtidas por meio da aplica??o de question?rios. Os resultados confirmaram a presen?a de bact?rias oportunistas nos ambientes estudados, evidenciando a import?ncia de vigil?ncia da qualidade da ?gua. Verificou-se uma sub-notifica?ao de casos de diarr?ias apontando falhas no Monitoramento das Doen?as Diarr?icas, e indicando a necessidade de aprimor?-lo. Percebeu-se, ainda, a necessidade de implementa??o de atividades educativas sobre os temas abordados, tanto com os professores como com os agentes de sa?de, uma vez que foram identificadas concep??es equivocadas sobre o tema