Interactions between increased intestinal viscosity, post-weaning colibacillosis and intestinal spirochaetosis in weaner pigs

Interactions between diet and enteric bacterial infections are complex and multifactorial. In production situations, more than one pathogen or disease may occur simultaneously. The intestinal environment in which pathogens proliferate can be altered by dietary manipulation and thereby can affect the outcome of disease (1). Post-weaning colibacillosis (PWC) affects newly-weaned pigs and is associated with excessive multiplication of enterotoxigenic Escherichia coli in the small intestine (2). Intestinal spirochaetosis (IS) is characterised by a mild typhylocolitis resulting from colonisation of the large intestine with the intestinal spirochaete Brachyspira pilosicoli (3). A previous study in weaner pigs found increased intestinal viscosity resulting from addition of carboxymethylcellulose to the diet may encourage intestinal proliferation of E. coli (4). There is also anecdotal evidence that pigs with PWC are then more commonly affected by IS. This study aimed to confirm the influence of viscosity on intestinal proliferation of E. coli, to investigate the influence of viscosity on proliferation of S. pilosicoli in the large intestine, and examine possible interactions between the two pathogens after weaning.