Characterization of the effects of Enterococcus faecium on intestinal epithelial transport properties in piglets

Probiotics have been shown to have positive effects on growth performance traits and the health of farm animals. The objective of the study was to examine whether the probiotic strain Enterococcus faecium NCIMB 10415 (E. faecium) changes the absorptive and secretory transport and barrier properties of piglet jejunum in vitro and thereby to verify tendencies observed in a former feeding trial with E. faecium. Further aims were to assess a potential mechanism of probiotics by testing effects of IL-α, which is upregulated in the peripheral blood mononuclear cells of E. faecium-supplemented piglets, and to test the hypothesis that IL-1α induces a change in ion transport. Sows and their piglets were randomly assigned to a control group and a probiotic group supplemented with E. faecium. The sows received the probiotic supplemented feed from d 28 before parturition and the piglets from d 12 after birth. Piglets were killed at the age of 12 ± 1, 26 ± 1, 34 ± 1, and 54 ± 1 d. Ussing chamber studies were conducted with isolated mucosae from the mid jejunum. Samples were taken for mRNA expression analysis of sodium-glucose-linked transporter 1 (SGLT1) and cystic fibrosis transmembrane conductance regulator (CFTR). The Na(+)/glucose cotransport was increased in the probiotic group compared with the control group at 26 (P = 0.04) and 54 d of age (P = 0.01). The PGE2-induced short circuit current (Isc) was greater at 54 d of age in the probiotic group compared with the control group (P = 0.03). In addition, effects of age on the absorptive (P < 0.01) and secretory (P < 0.01) capacities were observed. Neither SGLT1 nor CFTR mRNA expression was changed by probiotic supplementation. Mannitol flux rates as a marker of paracellular permeability decreased in both groups with increasing age and were less in the probiotic group at the 26 d of age (P = 0.04), indicating a tighter intestinal barrier. The ΔIsc induced by IL-1α was inhibited by bumetanide (P < 0.01), indicating an induction of Cl(-) secretion. Thus, in this experimental setup, E. faecium increased the absorptive and secretory capacity of jejunal mucosae and enhanced the intestinal barrier. Furthermore, the results indicated that IL-1α induces bumetanide-sensitive chloride secretion. The effects of cytokines as potential mediators of probiotic effects should, therefore, be the subject of further studies.