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DOI: 10.1055/s-0035-1565605
Phytogenic substances modulate intestinal permeability – porcine intestinal epithelial cells as model system for gut health
Antibiotic Growth Promoters (AGP) were banned in the EU in 2006. Since then, phytogenic feed additives are being studied with considerable focus on their potential application in livestock feeding. Phytogenics include a broad range of plant materials, able to improve gut health and performance in animals and are therefore conceived as an alternative to AGP.
The intestinal epithelial barrier serves as the first line of host defense against potentially harmful stressors taken up with feed from the environment. It is primarily formed by epithelial cells, connected by tight junctions (TJs). To test for intestinal integrity, an in vitro cell culture model, using an intestinal porcine epithelial cell line (IPEC-J2) has been established. Cells were differentiated for 8 days in Transwell® membrane inserts (1.12 cm2), allowing the formation of TJs and the build-up of a representative intestinal layer which can be observed by an increased transepithelial electrical resistance (TEER). Phytogenic test substances were added and cells were incubated for 72 hours, while TEER was measured every 24 hours.
20 ethanolic plant extracts were tested in triplicate – three of them (grape seed, apple pulp, and Echinacea herb extract) were chosen, representative of positive, negative, and marginal effect on the TEER values, respectively. Grape seed extract increased TEER by ˜ 26%. Echinacea extract decreased TEER by 6% at all tested time points and apple extract marginally affected TEER causing a 7% increase. Cell viability was checked at the end of each experiment via the neutral red assay and always exceeded 90%.
Phytogenics include a broad range of plant materials, known to possess, amongst others, antimicrobial, antiviral, antifungal, and antioxidant properties. In this study, positive and negative modulation of gut health is shown by different phytogenic components. Further studies are needed to elucidate the underlying mode of action and the comprised active compounds.