Effects of prefermented cereals or the end products of fermentation on growth and metabolism of enterocyte-like Caco-2 cells and on intestinal health of restrictedly fed weanling pigs

Abstract

To unravel the underlying mechanisms that explain the positive effects of prefermented cereals on in vivo gastrointestinal (GI) architecture and function, an in vitro experiment using a human small intestinal epithelial cell model (Caco-2) was performed. A range of dilutions (0% to 10%) of the supernatants of three liquid experimental diets, as well as Na-lactate were used in an in vitro experiment to assess their effect on cellular growth, metabolism, differentiation and mucosal integrity using Caco-2. The experimental diets contained, in addition to a protein rich basal diet (60%), (1) a liquid control diet (C) containing 40% of a mixture of barley and wheat (ratio 3 : 1) or (2) a liquid diet (F) containing 40% prefermented barley and wheat or (3) C with the addition of the fermentation end-products (organic acids and ethanol) in concentrations similar to those in the fermented diet (FP). For F, the mixture of barley and wheat was fermented at 358C for 48 h. Parallel to the in vitro experiment, 18 groups of eight weanling pigs were assigned to one of the experimental diets during a 14-day in vivo experiment. Each group was fed restrictively. The results of the in vitro experiment showed that the lowest dose of both F-and FP-supernatants had no clear effects on the cell proliferation, but incubation with 5% and 10% of the F-and FP-supernatants decreased the cell numbers at day 19. DNA, RNA, protein and glycoprotein synthesis in differentiated Caco-2 cells were stimulated by incubation with the lower concentrations (0.5% to 2.5%) of F-and FP-supernatants whereas the higher concentrations (5% and 10%) had no effect. Both the F-and FP-supernatants decreased the specific sucrase-isomaltase activity in a dose-dependent manner, but the effects on the specific aminopeptidase activities were less clear. Mucosal integrity initially decreased after incubation with the highest F-and FP-supernatants and started to recover between 24 and 48 h. The results of the in vivo experiment showed no dietary effects ( P . 0.1) on GI morphology and brush-border enzyme activities at day 5 or at day 14. Time related changes in GI characteristics followed a normal pattern. In conclusion, the supernatants of diets containing either prefermented cereals or their fermentation end-products clearly modulate cellular growth, metabolism, differentiation and mucosal integrity in an in vitro model, although these effects were not observed in the in vivo characteristics measured in weanling pigs.Keywords: Caco-cell, fermented cereals, intestine, pigs ImplicationsThe described in vitro experiment showed that fermentation end products within the range of realized intake in the in vivo study, affect metabolism of intestinal cells. Measurements point at an initial damaging effect followed by repair.The described in vivo experiment did not show effects on intestinal physiology on day 5 and 14 after weaning. It seems that the provision of fermented cereals has several effects of which the net outcome is not always beneficial for the animal. The in vitro...

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“…The addition of 5-FU is necessary to stabilize and standardize DXR action, reducing the variability of epithelial damages in this model mimicking medium-term chemotherapy-induced effects on the intestinal mucosa, in particular, morphology and cellular population alterations and junctional systems integrity [24,28-30]. Intestinal epithelium from mice treated with the two chemotherapeutics was extensively damaged (Figure 4A-F).…”

Performance and energy metabolism in restrictively fed weanling pigs are not affected by feeding either fermented cereals or their end-products

“…In an accompanying manuscript on this experiment (Bruininx et al, 2009), we concluded that neither the inclusion of 40% fermented cereals nor their fermentation end-products affected the in vivo characteristics whereas we saw clear effects on cellular growth and metabolism in an in vitro model. The absence of in vivo effects on intestinal health is likely due to small differences in short chain fatty acid intake between the experimental groups (Bruininx et al, 2009) that may also have masked dietary effects on fecal digestibility of dry matter, crude ash, nitrogen and energy in this experiment. Because losses of fermentation products due to freeze-drying are not accounted for, the digestibility figures in both the F-and FP-groups are underestimated assuming that these products will be absorbed completely.…”

“…It was hypothesized that the observed effects on digestion and energy metabolism of feeding fermented cereals are largely due to the presence of the fermentation end-products organic acids and ethanol as commonly found in fermented cereals but not to the presence of a high microbial load as suggested earlier (Geary et al, 1999). The effects on structure and function of the gastrointestinal tract are reported elsewhere (Bruininx et al, 2009).…”

“…Each trial comprised an initial 5-day period followed by a second period of nine days. At the end of the first period (day 5), three pigs were sacrificed for digesta and tissue sampling (see Bruininx et al, 2009). The remaining five piglets per group and treatment remained for the second period.…”

Higher prevalence ofBacteroides fragilisin Crohn’s disease exacerbations and strain-dependent increase of epithelial resistance

“…However, short chain fatty acids, including acetate, and lactate are reported to rather strengthen the epithelial barrier. 13,41 The lower acetate and lactate concentrations found in the supernatant of TEER-enhancing strains are therefore unlikely to explain the TEER-enhancing effect.…”