Differential gene expression in heterophils isolated from commercial hybrid and Thai indigenous broiler chickens under quercetin supplementation

Chicken heterophils serve as the first-line defence in chicken innate immunity. The present study aimed to explore the effects of quercetin, a herbal phenolic substance known for its inflammatory modulation, on mRNA expression patterns in chicken heterophils. Isolated heterophils from two genetically distinct chicken lines, hybrid commercial and Thai indigenous chickens, Pradu Hang Dam, were <i>in vitro</i> co-cultured with live intestinal pathogenic <i>Salmonella enteritidis</i> under Phosphate-buffered saline (PBS) or quercetin supplementation. Quantitative real-time RT-PCR was performed to investigate the effects of quercetin on mRNA transcripts of 12 genes. The results showed that heterophils from hybrid chickens treated with quercetin had higher relative expression levels of <i>IL6</i>, <i>IL8L1</i>, <i>IL8L2</i>, <i>IL18</i>, <i>CCL4</i>, <i>LITAF</i>, and <i>MIF</i>. Unlike hybrid chickens, Pradu Hang Dam chickens had down-regulation of cytokine genes, <i>IL1B</i>, <i>IL6</i>, <i>IL8L1</i>, <i>IL8L2</i>, <i>IL12B</i>, and <i>IL18</i>, and chemokines, <i>CCL4</i> and <i>MIF</i>. In addition, <i>NOS2, IL17A</i>, and <i>TGFB1</i> were up-regulated in this lineage. In conclusion, our findings emphasize the modulatory effects of quercetin to down-regulate most pro-inflammatory genes, whereas it up-regulates anti-inflammatory gene (<i>TGFB1</i>) in Pradu Hang Dam chickens.