Profiling pro-inflammatory cytokine and chemokine mRNA expression levels as a novel method for selection of increased innate immune responsiveness

Abstract

Previous studies using F1 reciprocal crosses and two parental lines of broilers show the sire is instrumental in determining the in vitro leukocyte function and cytokine/chemokine profile. Since the innate immune response is the primary means young chickens have to protect themselves, we hypothesize utilizing a novel genomics approach to select sires based on an elevated pro-inflammatory cytokine and chemokine profile. By identifying sires with increased pro-inflammatory cytokine (interleukin [IL]-1β and IL-6) and chemokine (CXCLi2 and CCLi2) mRNA expression levels, we expect the progeny will also have elevated profiles. We characterized the pro-inflammatory cytokine and chemokine profile of 119 sires using quantitative real-time RT-PCR (qRT-PCR) and identified two populations with inherently high and low mRNA expression levels of IL-1β, IL-6, CXCLi2, and CCLi2. Select high and low sires were then used to produce progeny for the second phase of the trial. Blood samples were collected from 214 progeny and the cytokine and chemokine mRNA expression levels determined. Progeny from high sires had significantly ( P ≤ 0.02) higher cytokine (IL-1β and IL-6) and chemokine (CXCLi2 and CCLi2) mRNA expression levels compared to progeny from low sires. We have identified a broiler population of sires with higher and lower than average pro-inflammatory cytokine/chemokine mRNA expression levels and used them to produce progeny with similar profiles.