IN VITRO AND IN VIVO EVALUATION OF BACTERIA FROM SWINE-RELATED SOURCES AS DIRECT-FED PROBIOTICS FOR ENHANCED FEED UTILIZATION

Project Title: In Vitro and In Vivo Evaluation of Bacteria Isolated from Swine-Related Sources as Direct-Fed Probiotics for Enhanced Feed UtilizationGoals. The major goals of this project are to isolate bacteriafrom swine-related sources that have specific metabolic activities that can assist with feed utilization in farm animals (swine) by breaking down complex feed components to facilitate nutritional availability. When these probiotic bacteria are provided as feed additives, either through animal feed or water, the intention is that they colonize the intestinal tract and assist in the utilization of consumed feed, helping to break down complex feed components into those that are more readily absorbed, and this mayresultin improved animal weight gain. Weight gain in food production animals is an obvious benefit.Another issue that has been long to find a solution has been animal growth promotants whereby feeding food production animals subtherapeutic levels of antibiotics in their feed helps with weight gain, presumably by reducing bacterial inflammation that negatively impacts animal health and growth. The problem with providing even low levels of antibiotics is that they preferentially select antibiotic-resistant bacteria that increase in proportion to other bacteria. This could lead to food safety issues if there is a greater proportion of antibiotic-resistant foodborne pathogens associated with animal-derived meat products than would occur otherwise.The FDA has long attempted 'voluntary' programs to reduce the use of growth promotants and has also disallowed the use of some of them, but the best way to ween producers away from such products is to offer an effective alternative. Absent direct FDA actions against various growth promotants, an effective method has been consumer sentiment that drives large fast-food chains to adopt practices of buying meat from producers who do not use antibiotics as growth promotants.We hope that ourapproach can provide a sensible approach to animal weight gain during animal production that displacing traditional growth promotants would be an 'easy sell'.Objectives. In order to achieve these goalswe have defined specific objectives. These include multiple approaches to isolate swine-related bacteria that would have a greater likelihood of growing in the intestinal tracts of swine and using fermenter-based studies to better insure they can survive swine intestinal tracts and can breakdownthe animal feed components that we would like them to utilize in animal feed. Additional objectives are to use bioassay agar media involving various substrates to characterize and confirm metabolic activities of strains that we suspect aredesirable as potential probiotics. This would be followed by molecular identification of the isolates using 16S rRNA PCR and DNA sequencing to confirm the identities of the strains to make sure they are not pathogens that could be injurious to animals. We would also be looking to identify if the selected bacteria are beneficially affected by traditionally known 'prebiotics' (substances that facilitate the growth of probiotic bacteria) such that they may be given as additional dietary adjuncts to animals in addition to the probiotic bacteria. This could reduce the need to constantly provide the probiotic bacteria whereby the supplementation of prebiotics would boost probiotic growth in the animal. Finally, the last objective would be the direct use of the probiotic cultures and prebiotic additives as direct-fed supplements in animal studies as the 'proof is in the pudding'. We hope to demonstrate that this approach can enhance the growth of swine whose diets are supplemented with select probiotic bacteria that target the breakdown of specific components in animal feed.