Soluble fibre and insoluble fibre sources added to enterotoxigenic Escherichia coli-challenged pigs after weaning influence production and β–hemolytic E. coli excretion

Abstract Text:

Different dietary and (or) feeding strategies to ameliorate the post-weaning malaise are being examined given increased scrutiny of the use of antimicrobial agents in diets. The extent to which dietary fiber, and the balance between soluble and insoluble fiber, might modify gastrointestinal tract structure and function to influence performance and health after weaning in the absence of dietary antimicrobials has not been fully established. An experiment using 96 individually-housed male pigs was conducted having a 2 x 4 factorial arrangement of treatments, with factors being added (mostly) soluble fiber (≈ 8 versus 48 g/kg), and four levels of high insoluble fiber (added as wood cellulose; 0, 30, 60 and 90 g/kg). Ground white rice was used as the cereal. Antimicrobial-free diets were fed for two weeks after weaning, after which time all surviving pigs were fed a commercial diet for another week. All pigs were orally inoculated with an enterotoxigenic E. coli strain (0149:K91:F4) on days 5, 6 and 7 after arrival to induce diarrhea. On days 8 and 9 after weaning, a sub-sample of pigs from each treatment was humanely euthanized. There were positive linear effects (P = 0.046 and P = 0.019) of wood cellulose inclusion level on bodyweight at d 14 and d 21, respectively. In the first 14 days after weaning, each 10 g/kg increase in the analyzed dietary NDF content (to ≈ 100 g/kg) increased average daily gain (ADG) and average daily feed intake (ADFI) by 6.4 and 8.1 g/day (R²=0.84, P = 0.085; R²=0.89, P = 0.056, respectively), whilst each 10 g/kg increase in the analyzed dietary ADF content (to ≈ 50 g/kg) increased ADG and ADFI by 10.6 and 13.3 g/day (R²=0.89, P = 0.058; R²=0.95, P = 0.027, respectively). There were significant main effects of wood cellulose level on the feed conversion ratio (FCR) in the first 7 (P = 0.018) and 14 (P = 0.028) days after weaning, but FCR from days 15-21 and over the entire 21-day period was determined by an interaction between soluble and insoluble fiber sources (P = 0.035 and P = 0.038, respectively). At day 9 post-weaning, increasing amounts of insoluble fiber linearly decreased (P = 0.010) the fecal excretion of β-hemolytic E. coli, however there were no differences (P> 0.05) between fiber treatments for the diarrhea index or the number of therapeutic antibiotic treatments given.

Keywords: weaning; fiber; diarrhea