Title : Development of Molecular Tools to Assess the Impact of Growth Promotants on Animals and Public Health NPB # 04 - 078

The overall goal of this project was to develop molecular based tools to measure the diversity and content of the bacterial microflora in the pig intestinal tract. The approach was to create DNA libraries based on the presence of a signal sequence found in all bacteria: 16S rRNA. This is a standard means used to classify bacteria. Because the intestinal bacteria are not uniformly distributed and are present in hugely differing quantities, the means to measure diversity required the development of a technique to detect microbes present at low concentrations. To accomplish this a DNA renaturation kinetic technique was used. The results of this limited study identified a set of microbes, 56% of which have never been described. The value of this research is to develop ways to alter the intestinal microflora of pigs in a way to produce healthier pigs containing fewer food borne pathogens and reducing producer reliance on sub-therapeutic antibiotics.