Dietary fermented soybean meal inclusion improves growth performance and ileal barrier function of the weaned piglets challenged by enterotoxigenic Escherichia coli K88

Abstract

The present study was performed to investigate whether dietary fermented soybean meal (FSBM) inclusion could improve growth performance and ameliorate diarrhea via improving ileal barrier function in weaned piglets challenged by enterotoxigenic Escherichia coli (ETEC) K88, and further analyze the potential roles for inflammatory response and epithelium apoptosis. A total of 32 crossbred barrows (Duroc × Landrace × Large White), 21 ± 2 day of age, and initial body weight of 6.86 ± 0.54 kg) were assigned to 2 diets (basal diet with or without FSBM, 60 g/kg at the expense of soybean meal) and subsequently challenged or not with ETEC K88 (5 × 1010 CFU/piglets) on day 15 of experiment in a 2 × 2 factorial arrangement of treatments. The results showed that weaned piglets fed FSBM had a tendency for greater average daily gain (ADG) compared to piglets fed SBM during day 1–14 (P = 0.081). After ETEC K88 challenge, the challenged piglets had higher (P < 0.01) feed conversion ratio (FCR) and incidence of diarrhea compared to the nonchallenged piglets. Dietary FSBM inclusion improved the ADG (P = 0.047), and decreased the FCR and incidence of diarrhea (P < 0.05) of weaned piglets. Piglets challenged with ETEC K88 had increased (P < 0.001) plasma D-lactate concentration and a tendency (P = 0.094) for increase plasma diamine oxidase concentration. ETEC K88 challenge decreased ileal villus height (P = 0.011) and tended to decrease ileal villus height to crypt depth (P = 0.058). Dietary FSBM inclusion tended to increase ileal villus height (P = 0.068). Ileal zonula occludens-1 (ZO-1), occludin, and claudin-1 mRNA and protein expression were decreased (P < 0.01) by ETEC K88 challenge, while increased by dietary FSBM inclusion (P < 0.05). There were no effects of either treatment on the ileal mRNA and protein expression of genes associated with mucin production (mucin 1 and mucin 2). ETEC K88 challenge increased ileal tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) mRNA expression (P < 0.01), while dietary FSBM inclusion alleviated the increase of ileal TNF-α mRNA expression (P = 0.042) and tended to relieve the increase of ileal IL-6 mRNA expression (P = 0.069). The decreased (P < 0.001) ileal B-cell lymphoma-2 (Bcl-2) mRNA expression were observed in ETEC K88-challenged piglets. Dietary FSBM inclusion increased ileal Bcl-2 mRNA expression of weaned piglets (P = 0.002), especially that of piglets without ETEC K88 challenge (P = 0.065). In conclusion, dietary FSBM inclusion improved growth performance, ameliorated diarrhea and enhanced ileal tight junction protein expression, which was concomitant to decreased pro-inflammatory cytokine expression and ileal mucosal cell apoptosis.