Transcriptomic landscape reveals segment-specific molecular mechanisms underlying honeycomb-enhanced egg quality in laying hens.

Honeycomb is rich in bioactive compounds with anti-inflammatory, antioxidant, and immunomodulatory properties. However, its effects on the poultry oviduct (magnum, isthmus, and uterus) remain poorly understood. This study investigated the effects of dietary honeycomb powder supplementation at 0, 0.5, 1.0, and 2.0 g/kg on egg quality, oviduct histomorphology, and transcriptomic profiles in 240 laying hens. Among them, 1.0 g/kg honeycomb powder produced the most pronounced improvements in egg weight, eggshell weight, and albumen weight. Histological analyses revealed segment-specific remodeling of the oviduct, including enhanced tubular gland development in the magnum, increased secretory cell abundance in the isthmus, and more developed mucosal folds with higher glandular and secretory cell densities in the uterus. Transcriptomic analysis further indicated that honeycomb supplementation was accompanied by segment-specific functional remodeling of the oviduct, involving mechanistic target of rapamycin (mTOR) and Wingless/Integrated (Wnt) -related signaling pathways associated with epithelial secretion, extracellular matrix organization, and eggshell mineralization. Collectively, dietary honeycomb powder supplementation was associated with improved egg quality and accompanied by region-specific oviduct adaptations, including structural changes and transcriptomic alterations related to albumen secretion in the magnum, extracellular matrix (ECM) organization in the isthmus, and eggshell mineralization in the uterus. These findings provide new insights into the nutritional regulation of oviduct function and support the potential application of honeycomb powder as a functional feed additive in laying hens.