Modulation of intestinal cell differentiation in growing pigs is dependent on the fiber source in the diet

Feeding high-fiber diets decreases cost, but also caloric and nutritional efficiency by modifying intestinal morphology and function. We analyzed the changes in intestinal cell composition, nutrient transporters and receptors, and cell differentiation induced by fibers from different sources. Forty-six finishing pigs (BW 84 ± 7 kg) were fed 1 of 4 diets: corn-soybean (Control; n = 12), 23% wheat straw (WS; n = 11), 55% corn distillers dried grains with solubles (DDGS; n = 11), and 30% soybean hulls (SBH; n = 12). Pigs were fed 2 meals daily to an amount equivalent to 2.5% of initial BW for 14 d in metabolism cages. Ilea were collected for histological and gene expression analysis after euthanasia. Data were analyzed using the Kruskal–Wallis test followed by Dunn’s multiple comparisons and differences considered significant when P < 0.05. The enterocyte marker was increased (P < 0.03) by feeding SBH compared with Control and WS diets. Goblet cells presence was greater (P < 0.01) in pigs fed WS and DDGS compared with Control, and in pigs fed WS compared with SBH (P = 0.02). Mucin 2 expression was greater (P < 0.05) in pigs fed DDGS and SBH compared with Control diet. No changes were observed for endocrine and Paneth cells markers, vil- lus and crypt length, or proliferation index. Compared with the Control, gene expression of receptors for oligopeptides, calcium, glucose, fructose, free fatty acid receptor 1, and G protein-coupled receptors 119 and 84 was increased (P < 0.05) by feeding WS and DDGS diets. Feeding SBH diet repressed (P < 0.005) the umami receptor compared with WS and DDGS diets, while DDGS repressed (P = 0.02) its expression compared with Control. Pigs fed DDGS had reduced (P < 0.001) fatty acid receptor 2, and those fed SBH showed increased (P < 0.05) fatty acid translocase expression compared with WS and DDGS pigs. Feeding WS and DDGS diets induced (P < 0.01) the expression of stem cell marker r-spondin receptor (LGR5), while olfactomedin 4 was reduced (P < 0.02) by feeding DDGS compared with Control. The expression of delta-like Notch ligand 4 was induced (P < 0.05) by all fibers compared with Control. Transcription factors atonal factor 1 and Wnt family 3A were suppressed (P < 0.001) by WS and DDGS compared with Control. In conclusion, feeding diets containing WS and DDGS modulated intestinal differentiation by promoting goblet cells and altered expression of nutrient receptors and transporters in growing pigs, while feeding SBH had less effect.