The Link Between Inflammation, Gut Health, Phytogenics and Performance

Link to gut health

Inflammation and a bird’s antioxidant status are decisive criteria for gut health. Inflammation leads to decreased gut protection in the intestinal tract resulting from infections or feed-dependent changes. Intestinal disorders often cause damage in the bird’s intestinal mucosa. Changes in the intestinal mucosa or gut morphology influence the development and differentiation of villi cells at the epithelial surface. The subsequent reduction in villi length results in decreased nutrient absorption capacity. Furthermore, low digestibility exacerbates inflammatory processes and reduces the antioxidant potential in the intestinal tract.

Phytogenics exert anti-inflammatory and antioxidative effects

The anti-inflammatory activity of selected phytogenic additives (PFAs) can be attributed to their antioxidant activities and their interactions with signaling cascades involving cytokines and regulatory transcription factors, favoring the expression of pro-inflammatory genes.

Transcription factor NF-KB (nuclear factor KB) is a major mediator of inflammatory processes. The activated form of NF-KB results in an increase in pro-inflammatory gene-expression. Nrf2 (nuclear factor erythroid 2 – related factor 2) is an antioxidant transcription factor involved in cell protection that increases the expression of several antioxidant enzymes.

To further investigate the influence on inflammatory response pathways an in vitro cell test with CaCo-2 intestinal epithelial cells was conducted at the Justus-Liebig-University Giessen, Germany, to measure the effect of a select phytogenic feed additive on an inflammatory stimulus.

As shown in Figure 1, the phytogenic feed additive reduced the mRNA expression of NF-KB target genes significantly compared to the positive control, indicating a significant positive influence by down-regulating the pro-inflammatory NF-KB pathway.


Figure 1. Down-regulation of NF-κB target genes

The cytoprotective effect of the PFA on intestinal epithelial cells was also assessed by measuring the Nrf2 target genes CYP1A1 (Cytochrome P450 1A1), HO-1 (Heme oxygenase 1) and UGT1A1 (UDP-glucuronosyltransferase 1A1), as shown in Figure 2. The mRNA-expression of those anti-oxidant and cytoprotective target genes of the Nrf2 pathway showed a significant increase compared to the control.


Figure 1. Down-regulation of NF-κB target genes

Conclusion

This study shows that a PFA inhibits the NF-KB pathway and down regulation of pro-inflammatory cytokines and stimulates the Nrf2 pathway. This results in lower inflammation and an improved anti-oxidative and cytoprotective status. Therefore, regular PFA supplementation can act against inflammatory reactions in the gastrointestinal tract, allowing birds higher feed intake, dietary energy and nutrients to put towards performance.