Abstract

The objective of this research was to identify metabolites produced by commensal bacteria that enhance the integrity of the gastrointestinal barrier (GIB). The integrity of the GIB is mainly determined by the complexity of interactions between tight junctions of opposing epithelial cells of the GI wall. This was measured using an in vitrobioassay, consisting of a monolayer of intestinal epithelial cells grown on a membrane. The trans-epithelial electrical resistance (TEER) across this monolayer was measured to determine the strength of the tight junctions. Preliminary results showed that a commercial probiotic product caused an increase in TEER across non-differentiated and differentiated monolayers by 178 ± 61% and 40 ± 9%, respectively. The maximum increases in TEER obtained with conditioned media fractions (media fractions containing components secreted by the probioticproduct) was between 23 ± 6% and 43 ± 4%. The conditioned media fraction containing components less than 3 kDa accounted for the total activity of the whole conditioned media. Metabolite profiling ofactive conditioned media compared to inactive conditioned media using fast-LCMSMS identified numerousmetabolites that may be responsible for this positive effect. Future work will isolate the candidate metabolites and screen them for GIB enhancing activity both in vitroand in vivo.

L, Li, VH Oddy, I Godwin, J Hegarty, and JV Nolan

Proceedings of the New Zealand Society of Animal Production, Volume 66, Napier, 200-205, 2006