Small RNA-seq reveals the effect of formaldehyde exposure on chicken embryo liver microRNA profile
Formaldehyde (FA) is commonly used for hatchery disinfection, but its effects on embryonic development remain unclear. MicroRNAs (miRNAs) regulate gene expression post-transcriptionally and may mediate FA-induced transcriptional responses. This study investigates the impact of FA exposure on the miRNA landscape in chicken embryo liver. Small RNA-seq libraries were constructed and sequenced using the Illumina NextSeq platform. Reads were trimmed and quantified. Differential expression analysis was performed with DESeq2. Target genes of differentially expressed miRNAs (DEMs) were predicted (miRDB), and GO/KEGG/Reactome enrichment was conducted. A total of 662 mature miRNAs were detected. Differential expression analysis identified 30 DEMs (11 up-regulated, 19 down-regulated).  FA exposure at the embryo stage may significantly alter miRNA expression, affecting pathways involved in epigenetic, oxidative stress, and immune regulation. These results warrant reconsidering FA use in poultry hatcheries and further functional validation of miRNA-target interactions. Overall design: miRNA expression profiling by high throughput sequencing between FA-treated and control samples