Regulatory effects on inflammatory signaling by a phytogenic feed additive assessed in vitro and in vivo including RNA-sequencing

The worldwide trend towards a more prudent use of antibiotics has sparked the demand for alternative products to mimic the beneficial effects of feed additives. Restriction of the innate inflammatory response of animals might be one of the key mechanisms responsible for the observed growth promotion. Phytogenic feed additives harness the chemical richness offered by plants, which many are known to possess anti-inflammatory properties.

In the present study a phytogenic feed additive has been assessed for potential inflammation-restricting properties both in vitro and in vivo, the latter including novel RNA sequencing technology. First evidence for potential anti-inflammatory properties was obtained from TNF-α-stimulated IPEC-J2. Subsequently, a feeding trial with broiler chickens was conducted with an inflammatory challenge (coccidiosis vaccine overdosing) in order to compare effects on cecal gene expression when feeding the phytogenic product or a anticoccidial drug (positive control).

The inflammatory challenge significantly affected the expression of more than 500 genes compared to non-challenged birds. ost of these genes belonged to innate immune system or cytokine signaling pathways. This effect was almost completely reversed by feeding an anticoccidial additive, while in the phytogenic group approximately half of the genes were regulated back to the normal level of the unchallenged control group.

The findings corroborate the relevance of limiting inflammatory processes by phytogenic feed additives. Next-generation sequencing opens opportunities for studies on mechanisms of action of feed additives and may assist in further development.

Funding by the Austrian Research Promotion Agency (FFG) is gratefully acknowledged.

Fig. 1. Principal component analysis of cecal gene expression (RNA-Seq).