Decoding the pituitary response to photoperiod in geese: Central role in regulating reproduction.

Photoperiodic regulation is a key technique in modern poultry farming. In geese, however, the molecular pathways by which the pituitary gland transduces photoperiodic signals remain incompletely understood. Therefore, this study aimed to identify key factors by analyzing the pituitary transcriptome of female Yangzhou geese subjected to a short photoperiod and a long photoperiod. RNA-seq analysis showed that the prolactin (PRL) gene was the most highly expressed among all DEGs in the pituitary, and its dynamic expression pattern was closely associated with reproductive status. Furthermore, the neuroactive ligand-receptor interaction pathway was significantly enriched. Within this pathway, we identified key receptor genes, including neurotransmitter receptors (e.g., Gamma-Aminobutyric Acid Type A Receptor Subunit Gamma1 (GABRG1), Gamma-Aminobutyric Acid Type B Receptor Subunit 2 (GABBR2), Glutamate Ionotropic Receptor NMDA Type Subunit 1 (GRIN1), Opioid Receptor Mu 1 (OPRM1)) as well as neuropeptides and their receptors (e.g., Adenylate Cyclase Activating Polypeptide 1 Receptor 1 (ADCYAP1R1), Galanin Receptor 1 (GALR1)). Our results established the pituitary transcriptomic profile of geese under photoperiod-mediated reproduction, underscoring its role as a critical neuroendocrine center. It regulates reproductive activity primarily through PRL signaling and through specific neural pathways that receive and integrate diverse neural signals.