Profiling phytogenic inclusion level effects on the intestinal antioxidant capacity and the expression of protective genes against oxidation, stress and inflammation in broilers
The effects of a phytogenic premix (PP) inclusion level on an array of genes relevant for host protection against oxidation (CAT, SOD1, GPX2, HMOX1, NQO1, Nrf2 and Keap1), stress (HSP70 and HSP90) and inflammation (NF-κB1, TLR2 and TLR4) were evaluated along the broiler intestine in combination with determination of total antioxidant capacity (TAC).
The proprietary PP “gut agility activator” used comprised of functional flavoring substances of ginger, lemon balm, oregano and thyme. One-day-old Cobb broiler chickens (n=500) were assigned into the following four treatments, depending on PP inclusion level in the basal diets (i.e. 0, 750, 1000 and 2000 mg/kg diet): CON, PP750, PP1000 and PP2000. Each treatment had five replicates of 25 chickens with ad libitum access to feed and water. Data were analyzed by ANOVA and means compared using Tukey HSD test. Polynomial contrasts tested the linear and quadratic effect of PP inclusion levels.
Overall, except for CAT, the inclusion of PP up-regulated (P≤0.05) the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) / antioxidant response element (ARE) pathway genes (SOD1, GPX2, HMOX1, NQO1, Nrf2 and Keap1) evaluated. In particular, the majority of these genes were up-regulated primarily in the duodenum and the ceca and secondarily in the jejunum. Moreover, genes were mostly up-regulated in a quadratic manner with increasing PP inclusion level with the highest expression levels shown in treatments PP750 and PP1000 compared to CON. Similarly, intestinal TAC was higher in PP1000 in the duodenum (P = 0.011) and the ceca (P = 0.050) compared to CON. From the genes relevant for inflammation and stress assessed, NF-κB1, TLR4 and HSP70 were down-regulated with increasing PP level, the first one according to a quadratic pattern and the latter two linearly.
As a conclusion, PP primed the expression of cytoprotective genes and down-regulated stress and inflammation related ones, the effect being dependent on PP inclusion level and the intestinal site. Further investigation under stress-challenge conditions is warranted.
by Konstantinos C. Mountzouris, Vasileios V. Paraskeuas and Konstantinos Fegeros
presented at: Symposium on Gut Health in Production of Food Animals, St. Louis, USA 4-6th November 2019
Other scientific abstracts published in 2019