Previous reports have shown that some bacteria utilize a dissimilatory nitrate reductase enzyme (NR) in anaerobic environments. This enzyme reduces nitrate to nitrite and also has been shown to co-metabolize chlorate to cytotoxic chlorite. A commercially available competitive exclusion (CE) product was evaluated for its nitrate reductase activity and therefore its experimental chlorate product (ECP) sensitivity. Of the 29 constituent bacteria of the CE culture, 11 had slight utilization of NR, 3 had moderate utilization of NR; the remaining were NR negative (with slight and moderate utilization: >0.1 to < 1.0 mM and > 1.0 mM nitrate utilized within 6 h, respectively). In vivo studies utilizing CE and ECP showed significant reductions in Salmonella. Although some of the bacteria were affected by ECP, the combined effect of the CE culture and ECP were effective in reducing Salmonella. Clostridium perfringens (CP) is a pathogen in the commercial poultry industry, which is the etiologic agent of necrotic enteritis (NE). Day-of-hatch broilers were fed a wheat diet and assigned to the following groups: control, commercial coccidia vaccine, commercial bursal disease vaccine, or the combination of the two, and challenged with CP in order to develop a disease model. Broilers in each treatment group had significant increases (P≤ 0.05) in lesion scores, mortality, and CP incidence. As pressure mounts for discontinuing the use of antibiotics in the agriculture industry, it is important to develop new strategies to combat these costly enteric pathogens. In vitro investigations evaluated a mixed gut culture with CP and the ECP at 5 mM or a 10 mM concentrations, over time. By 3 h there was a reduction (P≤ 0.05) in the 5 mM ECP and 10 mM ECP treatment groups. In vivo studies showed significant reductions in the incidence of CP and populations of intrinsic E. coli in all of the chickens provided ECP in the drinking water. Birds administered ECP in the feed showed significant reductions in lesion scores, incidence of CP and also had reduced E. coli log10 values. These results show that an ECP could provide the industry with a new management tool for controlling NE.

Previous reports have shown that some bacteria utilize a dissimilatory nitrate reductase enzyme (NR) in anaerobic environments. This enzyme reduces nitrate to nitrite and also has been shown to co-metabolize chlorate to cytotoxic chlorite. A commercially available competitive exclusion (CE) product was evaluated for its nitrate reductase activity and therefore its experimental chlorate product (ECP) sensitivity. Of the 29 constituent bacteria of the CE culture, 11 had slight utilization of NR, 3 had moderate utilization of NR; the remaining were NR negative (with slight and moderate utilization: >0.1 to < 1.0 mM and > 1.0 mM nitrate utilized within 6 h, respectively). In vivo studies utilizing CE and ECP showed significant reductions in Salmonella. Although some of the bacteria were affected by ECP, the combined effect of the CE culture and ECP were effective in reducing Salmonella. Clostridium perfringens (CP) is a pathogen in the commercial poultry industry, which is the etiologic agent of necrotic enteritis (NE). Day-of-hatch broilers were fed a wheat diet and assigned to the following groups: control, commercial coccidia vaccine, commercial bursal disease vaccine, or the combination of the two, and challenged with CP in order to develop a disease model. Broilers in each treatment group had significant increases (P≤ 0.05) in lesion scores, mortality, and CP incidence. As pressure mounts for discontinuing the use of antibiotics in the agriculture industry, it is important to develop new strategies to combat these costly enteric pathogens. In vitro investigations evaluated a mixed gut culture with CP and the ECP at 5 mM or a 10 mM concentrations, over time. By 3 h there was a reduction (P≤ 0.05) in the 5 mM ECP and 10 mM ECP treatment groups. In vivo studies showed significant reductions in the incidence of CP and populations of intrinsic E. coli in all of the chickens provided ECP in the drinking water. Birds administered ECP in the feed showed significant reductions in lesion scores, incidence of CP and also had reduced E. coli log10 values. These results show that an ECP could provide the industry with a new management tool for controlling NE.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Bactérias da microbiota entérica de avestruzes foram isoladas e fermentadas (produto experimental denominado de ECOS). Em seguida, foram utilizadas na exclusão competitiva de Salmonella Typhimurium em pintinhos (\"Gallus gallus\") e em avestruzes recém nascidas (\"Struthio camelus\"). Os pintinhos e as avestruzes foram desafiados por via oral com a concentração de 1x104 UFC/ ave e 1x105 UFC/ ave, respectivamente. O ECOS reduziu significativamente a excreção de Salmonella Typhimurium em pintinhos e avestruzes recém nascidos infectados experimentalmente. O ECOS também reduziu significativamente os casos de enterites associadas à mortalidade em avestruzes, em testes de campo. Outros aspectos observados em avestruzes tratados a campo foram a redução do tempo de absorção do saco vitelínico e o aumento do ganho de peso. O ECOS mostrou ser uma importante ferramenta na melhoraria dos índices zootécnicos em estrutiocultura. / Bacterias of ostrich enteric microbiota were isolated and fermented (product called ECOS). Afterwards, they were used into a competitive exclusion of Salmonella Typhimurium in chicks (\"Gallus gallus\") and in ostriches chicks (\"Struthio camelus\"). The chicks and the ostriches were challenged by oral administration by 1x104 UFC/ chick e 1x105 UFC/ chick, respectively. ECOS reduced the excretion of Salmonella Typhimurium in chicks and ostriches chicks experimentaly infected. ECOS reduced, as well, cases of enteric diseases associated to ostrich mortality, in field tests. Another aspect observed in field treated ostrich, was the reduction of yolk sac absorption time and the increase of weight gain. ECOS showed to be an important tool to increase the zootecnical standards in ostrich farming.

Bactérias da microbiota entérica de avestruzes foram isoladas e fermentadas (produto experimental denominado de ECOS). Em seguida, foram utilizadas na exclusão competitiva de Salmonella Typhimurium em pintinhos (\"Gallus gallus\") e em avestruzes recém nascidas (\"Struthio camelus\"). Os pintinhos e as avestruzes foram desafiados por via oral com a concentração de 1x104 UFC/ ave e 1x105 UFC/ ave, respectivamente. O ECOS reduziu significativamente a excreção de Salmonella Typhimurium em pintinhos e avestruzes recém nascidos infectados experimentalmente. O ECOS também reduziu significativamente os casos de enterites associadas à mortalidade em avestruzes, em testes de campo. Outros aspectos observados em avestruzes tratados a campo foram a redução do tempo de absorção do saco vitelínico e o aumento do ganho de peso. O ECOS mostrou ser uma importante ferramenta na melhoraria dos índices zootécnicos em estrutiocultura. / Bacterias of ostrich enteric microbiota were isolated and fermented (product called ECOS). Afterwards, they were used into a competitive exclusion of Salmonella Typhimurium in chicks (\"Gallus gallus\") and in ostriches chicks (\"Struthio camelus\"). The chicks and the ostriches were challenged by oral administration by 1x104 UFC/ chick e 1x105 UFC/ chick, respectively. ECOS reduced the excretion of Salmonella Typhimurium in chicks and ostriches chicks experimentaly infected. ECOS reduced, as well, cases of enteric diseases associated to ostrich mortality, in field tests. Another aspect observed in field treated ostrich, was the reduction of yolk sac absorption time and the increase of weight gain. ECOS showed to be an important tool to increase the zootecnical standards in ostrich farming.

Cold seeps are areas of high biomass in the deep-sea, the impacts of these food-rich environments upon the sediment community is unknown in the Gulf of Mexico. The structure and function of benthic communities was investigated at food-rich and food-limited sites on the northern Gulf of Mexico continental slope. Cold seeps were richer in macrofauna densities and total sediment respiration, but were poorer in biomass and taxa diversity than normal slope communities. Decreased diversity is seen at most chemosynthetic communities and suggests a competition for resources. The spatial extent of these results at seeps is unknown and may be a localized, bioenhancement effect caused by seeping fluids.

Cold seeps are areas of high biomass in the deep-sea, the impacts of these food-rich environments upon the sediment community is unknown in the Gulf of Mexico. The structure and function of benthic communities was investigated at food-rich and food-limited sites on the northern Gulf of Mexico continental slope. Cold seeps were richer in macrofauna densities and total sediment respiration, but were poorer in biomass and taxa diversity than normal slope communities. Decreased diversity is seen at most chemosynthetic communities and suggests a competition for resources. The spatial extent of these results at seeps is unknown and may be a localized, bioenhancement effect caused by seeping fluids.

Under Gause's principle two species cannot indefinitely occupy the same niche. The north and south arms of Great Salt Lake are separated by a rail causeway, resulting in salinity differences and color variation between the arms. Farmington Bay is also separated from the south arm by a vehicular causeway to Antelope Island. These causeways allow examination of competitive exclusion of cyanobacteria in the hypersaline environment of the Great Salt Lake. Cyanobacterial distributions partially map salinity, with Aphanothece halophytica proliferating in the north arm, and Nodularia spumigena in the south arm. I hypothesized that cyanobacterial species abundant north of the railway causeway are competitively excluded from the south by other species, and that cyanobacterial species that thrive and bloom south of the Antelope Island causeway cannot grow in the high salinity of the north. To test these hypotheses, 129 flasks of autoclaved water from the north and south sides of each causeway were inoculated with Great Salt Lake water samples from the north and south sides of the causeways. Four genera of cyanobacteria, Aphanothece, Oscillatoria, Phormidium, and Nodularia were identified and counted from the culture flasks using comparative differential interference contrast, fluorescence, and scanning electron microscopy. Counts of the cyanobacteria found in each flask were totaled and two way Analysis of Variance tests as well as exact tests were performed. Rankings of median abundances were also calculated. These data support the first hypothesis because Aphanothece halophytica was found in all inocula, but appears to be suppressed by the presence of Nodularia spumigena, which periodically blooms. The second hypothesis is also supported by the data because N. spumigena was found only in inocula from the less saline waters south of Antelope Island causeway, and apparently cannot survive the high saline waters north of the railway causeway.

O efeito de sete tratamentos, contendo &beta;-glucano, um probiótico experimental, e um produto de exclusão competitiva assim como suas associações, foram avaliados frente a um desafio com Salmonella Typhimurium Nalr e na resposta imune, em frangos de corte. Dois experimentos foram realizados; o primeiro experimento apresentou seis tratamentos que consistiram de: a) produto de exclusão competitiva (EC); b) EC + probiótico experimental (LEB); c) EC + betaglucano (G); d) EC+LEB+G; e) controle negativo e f) controle positivo. O segundo experimento, foi delineado com nove tratamentos que consistiram em: a) EC; b) LEB; c) G; d) EC+LEB; e) EC+G; f) EC+LEB+G; g) LEB+G; h) controle negativo e i) controle positivo. Experimento 1: no dia 0 do experimento as aves foram tratadas com 0,1mL de EC por inoculação no inglúvio. No dia 1 do experimento as aves foram desafiadas com 107 CFU/mL de Salmonella Typhimurium (1796NR) Nalr. Durante o período de 1 ao 6 dia, as aves foram tratadas com o tratamento apropriado, e sacrificadas aos 7 dias de idade. Experimento 2: no dia 0 do experimento as aves foram tratadas com 0,1mL de EC por inoculação no inglúvio. Durante 28 dias as aves foram tratadas com o tratamento apropriado. Nos dias 1, 9, 16 e 23 do experimento as aves foram desafiadas com 107 UFC/mL de Salmonella Typhimurium (1796NR) Nalr, e sacrificadas uma semana após cada desafio. Nos dois experimentos, cecos, fígado e baço foram removidos assepticamente e examinados para Salmonellae; e foram colhidas amostras de soro e fluido intestinal, para se avaliar as concentrações de IgG e IgA totais. Os dados foram analisados por análise de variança de uma via, e as médias comparadas pelo teste de Duncan. Os tratamentos EC+LEB+G e LEB+G mostraram uma inibição significativa (p&lt;0,05) de invasão dos órgãos por Salmonella Typhimurium (1796NR) Nalr, com altos níveis de proteção. No segundo experimento, a colonização cecal foi reduzida somente após a segunda semana de tratamento. Os níveis de IgG não foram significativos no soro ou fluido intestinal, mas a concentração de IgA foi significativamente (p&lt;0,05) alta no soro e fluido intestinal, quando comparada com a do controle negativo. Estes resultados sugerem que os tratamentos associados usando produto de EC, probióticos e betaglucano são mais eficazes no controle de Salmonella, do que preparações individuais; estimulando a produção de IgA sistêmica e de mucosas. Outros estudos complementares são necessários para se determinar os mecanismos pelos quais as interações destas substâncias poderiam regular a resposta imune inata. / The effects of seven treatments, containing &beta;-glucan, experimental probiotic, competitive exclusion products and their associations were evaluated, on a Salmonella Typhimurium Nalr challenge and assessment of the immune response, in broiler chickens. Two sets of trials were performed; the first trial was arranged with six treatments. Treatments in the first set consisted of a) commercial competitive exclusion (EC), b) EC + experimental probiotic (LEB), c) EC + betaglucan (G), d) EC+LEB+G, e) negative control, and e) positive control. The second one, was designed with nine treatments consisted of a) EC, b) LEB, c) G, d) EC+LEB, e) EC+G, f) EC+LEB+G, g) LEB +G, h) negative control, and i) positive control. Trial 1: on day 0 birds were administered 0,1mL of the EC treatment by oral gavage. On day 1, birds were challenged with 107CFU/mL of Salmonella Typhimurium (1796NR) Nalr. During 1 to 6 days, birds were administered of appropriate treatment, and were sacrificed at 7 days of age. Trial 2: on day 0 birds were administered 0,1mL of the EC treatment by oral gavage. During 28 days, birds were administered of appropriate treatment. On day 1, 9, 16 and 23 birds were challenged with 107CFU/mL of Salmonella Typhimurium (1796NR) Nalr, and were sacrificed one week after challenge. In two sets of trials, ceca, liver and spleen were aseptically removed and examined for salmonellae; and were taken serum and intestinal fluid samples, in order to evaluate total antibody concentrations of IgG and IgA. Data were analyzed by one-way analysis of variance, and means compared by Duncan&prime;s test. Treatments EC+LEB+G and LEB+G resulted in a significant inhibition (p&lt;0,05) in Salmonella Typhimurium (1796NR) Nalr organ invasion offering a higher level of protection. In the second set of trial, colonization was reduced after the second week of treatment. IgG was no significantly in serum and intestinal fluid samples, but IgA was found significantly (p&lt;0,05) higher in serum and intestinal fluid samples, when compared to control ones. These results suggest that associated treatment using EC products, probiotics and betaglucans are more effective in Salmonella control, than individual preparations; stimulating the systemic and mucosal immune response mediated by IgA. Further research is necessary to determine the mechanisms by which the interaction of these substances could regulate avian innate immune response.

O objetivo deste estudo foi o de avaliar a eficiência da aderência de produtos de exclusão competitiva e de probiótico sobre a tonsila cecal de frangos SPF, com idade de um a doze dias. Através da microscopia eletrônica de varredura, verificou-se a ação destes produtos comerciais com relação a proteção ao epitélio, quando desafiados com Salmonella Enteritidis. O delineamento experimental foi dividido em cinco (05) grupos, sendo o grupo T1 o controle negativo, o grupo T2 recebeu o produto de exclusão competitiva Aviguard, o grupo T3 recebeu o produto de exclusão competitiva Broilact, o grupo T4 recebeu o probiótico Biotop e o grupo T5 o controle positivo. Após 12 horas do tratamento com os produtos de exclusão competitiva ou probiótico as aves foram infectadas, por via oral, com S. Enteritidis. Os resultados obtidos mostraram que os produtos de exclusão competitiva e probiótico apresentaram uma maior eficiência em estabelecer uma microbiota protetora contra S. Enteritidis, e que a adição destes pode produzir um efeito de melhor índice zootécnico, quando comparado com as aves que foram desafiadas com S. Enteritidis e que apresentaram um ganho de peso inferior. / The aim of this study was to evaluate the ultra structure of the cecal tonsil in SPF chicks using scanning electron microscopy, determining the efficacy of competitive exclusion products and probiotic and its protection in cecal epithelium against an oral challenge with Salmonella Enteritidis. The experimental design included five groups: T1 negative control, T2 chicks treated with Aviguard, T3 chicks treated with Broilact, T4 chicks treated with Biotop, and, T5 positive control. After 12 hours of treatment with competitive exclusion products or probiotic the chicks were infected orally with S. Enteritidis. Results showed that treated groups had a protective effect stimulating the establishment of the resident microflora against pathogenic bacteria. Treated chicks showed high weight gain when compared to chicks challenged.