Effect of essential oils (EO) on mRNA expression of antiviral and pro-inflammatory innate immunity genes on chicken macrophages infected with IBDV

A study was conducted to assess the effects of a single (Lippia origanoides) or blend (Lippia origanoides and Rosmarinus officinalis) of essential oils supplementation on immune innate response in chicken macrophages infected with Infectious Bursal Disease Virus (IBDV).

Methods: Chicken macrophages (HD-11) cell line were cultured by triplicate at a concentration of 5x105 cells / well in plates of 24 wells. Macrophages were divided into six groups: 1. Negative control (No virus, no EOs); 2. No virus + EO (Lo); 3. No virus + EO (Lo + Ro); 4. Positive control (Virus, no Eos); 5. Virus + EO (lo); 6. Virus + EO (Ro). After 12h of culture, cell were inoculated as a modified intermediate live vaccine of IBDV (UNIVAX-BD®) with a MOI=1 (Groups 4, 5 and 6). Followed of 1 h of virus absorption, the macrophages received media supplemented with 50 ppm of Lippia origanoides (groups 2 and 5) and with 10-ppm Lippia origanoides and 100 Rosmarinus officinalis (groups 3 and 6). This study evaluates periods of time 0, 6, 12 and 24 hours post-infection (p.i). The research tested the effect of EOs single or blended supplementation on chicken macrophages gene expression of toll-like receptors 3 and 21, MDA5, cytokines IL-1β, IL-10, IRF-7, IFN-β, OAS and PKR as indicators of immunological cell activation. An ANOVA model was calculated to determine the effect of Treatment group, gene and Time on the natural logarithm of CT values; a pairwise comparison was determined on the marginal predictions for the six treatment groups using Tukey adjustment.
Results showed that there were not statistically significant differences for the contrasts: 2 vs 1, 6 Vs 1, 6 Vs 2 and 5 Vs 4 (P > 0.05), however the rest of the contrasts showed significant differences (P < 0.001). There was a significant difference (P < 0.001) between EO blend (group 5) and single (group 6) affecting virus replication, and gene expression of TLR3, IL-1β, IFN-β, OAS and PKR.

Conclusion: The supplementation with a blend of EOs has shown to reduce virus attachment and replication, and reduction of IFN inducible antiviral effectors pathway in chicken’s macrophages. Key words: Innate immunity, macrophages, IBDV, Essential oil and health.

Key words: Innate immunity, macrophages, IBDV, Essential oil and health