Effects of Dendrobium officinale Leaf Powder on Bone Health and Bone Metabolism in Laying Hens

<i>Dendrobium officinale</i> Kimura et Migo (<i>D. officinale</i>) is a traditional Chinese medicinal herb with recognized anti-inflammatory, antioxidant, and immunomodulatory properties. This study evaluated whether dietary supplementation with <i>D. officinale</i> leaf powder could influence bone mass, mechanical strength, and molecular markers of bone metabolism in caged laying hens. A total of 192 healthy 19-week-old Jinghong No. 1 hens were randomly assigned to three dietary groups: a control group fed a basal diet and two treatment groups supplemented with 1200 or 3600 mg/kg of <i>D. officinale</i> leaf powder for 16 weeks. Tibial and femoral bone strength and mineral density did not differ significantly among treatments (<i>p</i> > 0.05). However, tibial breaking strength displayed upward trends in both supplemented groups (<i>p</i> = 0.08), and similar tendencies were observed for femoral bone mineral content and bone density (<i>p</i> = 0.08). At the molecular level, dietary supplementation produced selective changes in gene expression. The low-dose diet significantly increased VEGFA expression (<i>p</i> < 0.05), whereas the high-dose diet resulted in significantly higher TGF-β1 expression (<i>p</i> < 0.05). Several other genes related to bone formation, bone resorption, or cytokine signaling exhibited numerical increases but did not reach statistical significance. These findings indicate that <i>D. officinale</i> leaf powder may modulate bone metabolic processes at the transcriptional level, although these molecular alterations were not accompanied by significant improvements in bone mass.