Relationship Between Bone Morphology and Bone Quality in Female Femurs: Implication for Additive Risk of Alternative Forced Molting

Abstract

Calcium (Ca) storage in bone has a relationship with eggshell production. Forced molting by feeding restriction for older hens improves eggshell quality but leads to a decline in the bone quality. Dietary minerals improve the eggshell and bone quality; however, the effect on bone quality post-molting has not been clarified. This study evaluated the effects of dietary Ca and minerals on the eggshell and bone quality during both pre-and post-molting periods. The bone quality was evaluated by measurement of bone density and Fourier transform infrared spectroscopy (FT-IR) analysis. The eggshell quality was evaluated by morphological observation of the mammillary cores by scanning electron microscope and FT-IR analysis. The high Ca concentration feed group showed a low bone density post-molting and a high carbonate/phosphate ratio pre-molting. In high mineral concentration feed group, the eggshell strength, the thickness, and the proportion of large mammillary core areas were significantly higher (p < 0.05) than control group post-molting. These results suggest that the eggshell strength increases as the proportion of mammillary core areas increases. Furthermore, the high carbonate/phosphate ratio promoted a decrease in bone density. Therefore, the concentration of dietary mineral is strongly related with the maintenance of eggshells and bone quality post-molting.