An in vitro cell culture model using IPEC-J2 to assess the anti-inflammatory and anti-oxidative effects of phytogenic feed additives

Disproportionate inflammatory reactions in the intestine of livestock are a threat in livestock production, as they contribute to gut disorders and animal health impairment. Driven by the resulting reduction of animal growth performance and consequently economic losses, the investigation of inflammation restricting feed additives is of particular importance. The pro-inflammatory transcription factor NFkB is regarded to be a key factor in the development of intestinal inflammation, whereas the anti-oxidative transcription factor Nrf2 features cytoprotective activity. Thus, the study evaluated the anti-inflammatory (NFkB down-regulation) and anti-oxidative (Nrf2 activation) potential of three phytogenic (plant based) feed additives (PFAs): PFA1 (including thymol and cinnamaldehyde as major active substances), PFA2 (including menthol and eugenol as major active substances) and PFA3 (including trans-anethole and carvone as major active substances), on intestinal porcine epithelial cells (IPEC-J2), a non-tumorigenic and non-transformed cell line from the jejunum of a neonatal, unsuckled piglet.

IPEC-J2 were differentiated in 100 mm dishes for eight days and then stimulated by TNF-α [10 ng/mL] to activate pro-inflammatory NFkB. Ethanolic extracts of the test products were added to see putative anti-inflammatory effects (TransAM NFkB p50 ELISA).

Non-cytotoxic test concentrations (Neutral red assay) were tested and PFA2 and PFA3 significantly decreased NFkB transactivation. None of the PFAs showed NFkB transactivation when applied without stimulation by TNF-α. Up-regulation of anti-oxidative Nrf2 was observed for PFA1.

All three PFAs exhibited protective properties on IPEC-J2. Further experiments to elucidate the component(s) most relevant for the observed activity of the PFAs are in progress and confirmation of the effects in vivo is planned.