Adult Chicken Bone-Derived Components Reverse the Impaired Calcium Homeostasis and Bone Mass in Mice Lacking 1,25(OH)2D3-VDR Signaling.

Female adult chickens, known as laying hens, possess a distinctive bone structure in the intracortical region, which is responsible for storing calcium. Given the cyclical nature of calcium storage and demand during the egg-laying cycle, the medullary bone of laying hens plays a crucial role in maintaining calcium homeostasis. In this study, we examined the potential of orally administered components derived from adult chicken bones to improve calcium homeostasis and bone mass in mice. Samples from adult chickens and young chickens without egg-laying experience were prepared by pressing meat parts, including bones, and administered to wild type (WT) and vitamin D receptor knockout (VDRKO) mice respectively. The phenotypes observed in VDRKO mice, such as severe reductions in serum calcium concentration and bone mass, were normalized in mice fed the adult chicken bone-containing diet to the same extent as in WT mice. These effects were not observed in mice fed a young chicken bone-containing diet. The adult chicken bone-containing diet increased apparent calcium absorption in VDRKO mice compared to other dietary groups. To determine the effects on bone metabolism, osteoclasts activity was evaluated by histological measurements and the quantification of serum osteoclast marker, and it was restored by the adult chicken bone-containing diet. In addition, the treatment of adult chicken bone-derived components increased osteoclasts differentiation in vitro from cultured bone marrow macrophage. These results show that adult chicken bone-derived components improve calcium and bone homeostasis in mice lacking vitamin D action through combined effects that target calcium metabolism and bone turnover.