FEED INGREDIENTS, PATHOGEN COLONIZATION AND GUT HEALTHIN PIGS

摘要

Increased regulatory control and market demand are driving considerable investigation to identify non-antibiotic feed additives to promote animal health. It is clear however, that effective management of gut health in production animals must include anumber of nutritional and management strategies. Although feed ingredients are generally selected based on nutritional value, other considerations such as bioactive compounds, fibre and protein composition may also have implications for health, including intestinal microbial ecology, mucosal physiology and exclusion of (zoo)-pathogens. We have studied Western Canadian barley varieties that are characterized by a broad range of fibre content, especially (3-glucan, and starch type (amylase:amylopectin ratio). Based on an in vitro fermentation model for pig hindgut and in vivo feeding studies this variation in carbohydrate content can be associated with changes in intestinal microbial profile and metabolites. Furthermore, in atrojan salmonella challengemodel, hulless barleys appear to have some advantage over hulled barleys in minimizing salmonella transmission. In contrast, salmonella transmission was not affected by fibre or yeast content when comparing wheat and wheat DDGS. The carbohydrate composition of feed ingredients may also have interactive effects with other feed components such as protein. Several studies examining the interaction of fibre and fermentable (non-digestible) protein on animal performance report mixed results, probably due t othe difficulty in balancing diets for all factors. We have focused on ef fects of protein fermentation on m icrobial fermentation products and distal gut ecophysiology. Preliminary results show that fermentable protein can influence colonic microbial ecology and mucosal physiology. Further work will determine whether these changes affect response to bacterial challenge.