Abstract
Swine dysentery (SD) is a severe diarrhoeal disease of pigs caused by Serpulina hyodysenteriae. Certain components of large intestinal microflora facilitate colonisation by the spirochaete, but reduced fermentation in the large intestine protects pigs from SD. In this experiment, we treated wheat based diets by extrusion and/or addition of exogenous enzymes to reduce the amount of substrate reaching the large intestine, and monitored the microflora. Six pigs on each dietary were then infected with S. hyodysenteriae. Both the addition of enzyme and extrusion caused a small but significant reduction in total numbers of anaerobes. No consistent changes were observed in the distribution of specific bacterial species and pigs in all treatments groups developed SD. Neither extrusion, enzyme addition, nor the combination of both reduced fermentation sufficiently to inhibit colonisation by S. hyodysenteriae.