Transcriptomic analysis of pigeon retina and pineal gland illuminated with red light

1. This study investigated the transcriptomic expression of the pigeon retina and pineal gland when exposed to red light (RL). Light is a crucial environmental factor influencing poultry production, physiology and behaviour. Different wavelengths of light have distinct effects on photoreceptors, including those in the retina and pineal gland, ultimately regulating various production benefits.2. Using transcriptome sequencing, this trial examined the gene expression profiles of the retina and pineal gland of White King pigeons exposed to either red light (RL; 660 nm) or White light (WL; 400-760 nm) for 6 months. In total, 12 RNA-seq libraries were constructed and sequenced on an Illumina Novaseq 6000 platform. This identified 2305 and 635 differentially expressed genes (DEG) in the retinal and pineal gland, respectively. Gene Ontology (GO) analysis showed a total of 466 and 235 GO terms were identified in retina and pineal gland (p < 0.05).3. In these two tissues, three common GO terms were identified, including nervous system development, glutamatergic synapse and structural constituent of ribosome. Functional enrichment analysis revealed that DEG in retina were enriched in pathways related to metabolism, genetic information processing and environmental information processing. However, DEG in the pineal gland were enriched for hormone metabolism and retinol binding.4. Through integrated analysis of a protein-protein interaction (PPI) network and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway maps, four DEG (optic protein-related genes OPN5 and EGR1 in retina, melatonin-related genes SNAT and ASMT in pineal gland) were identified, which play crucial roles and affected breed performance between RL and WL. These findings provide insights into the molecular mechanisms by which RL modulates the transcriptome of pigeon retina and pineal gland, potentially influencing poultry production and physiology.