| dc.description.abstract | Functional additives are used in poultry production to deliver benefits beyond the nutritive value of the additives. Although benefits of functional additive administration have been previously demonstrated, the mechanisms responsible for their beneficial action is not well characterized. We have explored mechanisms responsible for probiotic persistence in the gastrointestinal tract, effects of mineral source and administration on the gastrointestinal microbiota, intermittent administration of Lactic Acid Bacteria, and co-administration of functional feed additives. The results of these studies will provide insight on the mechanisms responsible for improved performance due to functional additives, and the administration methods needed to optimize benefits.
Lactobacillus species are common inhabitants of the gastrointestinal tract with a record of safe use as probiotics in animal health. While they are widely used, the mechanisms necessary for their persistence in the gastrointestinal environment are not well characterized. We characterized bile salt hydrolase (BSH) activity in poultry Lactobacillus and evaluated overexpression of BSH on survivability and growth of L. gallinarum. Overexpression increased deconjugation of tauro- conjugated bile acids in addition to increasing survivability in bile rich environments. Our results suggest poultry lactobacillus isolates possess a variety of BSH enzymes to combat the bile rich environment in the duodenum, and BSH activity may be beneficial for the persistence of probiotic bacteria in the gastrointestinal tract.
The gastrointestinal microbiota is an important modulator for animal health. Dietary inclusion of micronutrients is necessary for animal health and performance. Organic copper sources, such as Cu(HMTBa)2, may provide additional functionality beyond dietary copper and modulate the gastrointestinal microbiota. In this study, we investigated the administration of different copper sources, inclusion rates, and formulation methods on the gastrointestinal microbiota. We have demonstrated that dietary copper significantly effects populations of LAB and C. perfringens in the GI tract, and our data suggests a potentially mutualistic relationship between Clostridium and LAB. The inclusion rate and application of functional additives determines how they affect the gastrointestinal microbiota and may play a role in the scope of their non-nutritive benefit.
Alterations in nutrient and ingredient levels during feed changes is a cause of gastrointestinal stress during broiler production. Intermittent administration of probiotics may mitigate the perturbations caused during feed changes. In this study, we investigated the effects of intermittent administration of probiotic LAB during diet changes on growth performance, GI microbiota, and histomorphometry in broiler chickens. We have demonstrated the intermittent administration of LAB in drinking water improved growth performance, mitigated the decrease in LAB over feed changes, and mitigated the decrease in VH:CD over the feed change period. Our findings suggest targeted administration of functional feed additives during periods of stress may maximize their ability to improve animal health and performance.
Multiple feed additives are often administered to broilers in order to defend against a variety of stresses associated with commercial production. While their individual benefits have been characterized, the effect of co-administration is not well understood. Co-administration of Bacillus licheniformis with additional functional feed additive blends was investigated. Administration of B. licheniformis improves growth performance and additional functional feed additive blends improve gut health. However, there was insufficient data to suggest a synergistic rather than an additive effect of co-administration on broiler health and production. | en |
