Expression of Toll-like receptors and antimicrobial peptides during Eimeria praecox infection in chickens

[Display omitted] ► A high infection load (>500,000 oocysts) of Eimeria praecox may result in downregulated TLR expression. ► Antimicrobial peptide expression behaves differently in response to an E. praecox infection than in response to a bacterial infection. ► E. praecox may induce non-specific immunity during a mild to moderate infection. Intestinal colonization of avian species by Eimeria parasites results in the enteric disease, coccidiosis. A study was carried out to assess the immunologic effects of Eimeria praecox infection on the gut of infected chickens. In Experiment 1, birds were orally gavaged with 50,000 E. praecox oocysts; in Experiment 2, an infection dosage of 500,000 E. praecox oocysts was used. Duodenal and jejunal intestinal sections were sampled consecutively on days 1–7 post-infection. Intestinal expression of innate immune gene transcripts was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). Analysis of relative gene expression in Experiment 1 revealed an increase (P