Effect of dietary supplementation with inulin and/or benzoic acid on the incidence and severity of post-weaning diarrhoea in weaner pigs after experimental challenge with enterotoxigenic Escherichia coli

The purpose of this study was to evaluate the effects of feeding pigs with inulin and/or benzoic acid on post-weaning diarrhoea (PWD), indices of fermentation in the gastrointestinal tract, and production in pigs experimentally infected with an enterotoxigenic strain of Escherichia coli (ETEC). Forty-eight entire male pigs (Large WhitexLandrace) aged 21 +/- 3 days of age and weighing 4.97 +/- 0.08kg (mean +/- SE) were used in a 2x2 factorial experiment, with the respective factors being inulin (0 versus 8%) and benzoic acid (0 vs. 0.5%). Feeding inulin-supplemented diets improved (p=0.022) the faecal consistency (FC) and reduced (p=0.001) the incidence of PWD; however, the use of benzoic acid had no effects on PWD or faecal ETEC shedding. Wet faeces (a higher FC score) were associated with increased faecal ETEC shedding (R2=0.394, p=0.001). Inulin reduced the total concentrations of short chain fatty acids (p=0.029) in the proximal colon. The total concentration of lactic acid was increased by inulin in the caecum (p=0.007) and proximal colon (p=0.002). Feeding inulin or benzoic acid had no effects on production after weaning.