Fig. 2

Diurnal rhythms of MB remodeling in 40-week-old Hy-Line Brown laying hens. A) Serum TARP (n = 9 per group); B) serum CTX-I (n = 9 per group); C) area percentage of MB analyzed by toluidine blue staining (n = 3 per group); D) representative images of toluidine blue staining of femur transverse sections, bar represents 100 µm. White and black bars represent the light and dark. Data are presented as the mean ± SEM. P < 0.05 by one-way ANOVA followed by Duncan's multiple range tests and the letters (a–c) indicate significant differences among all treatment groups (P < 0.05). CTX-I, C-terminal telopeptide of type I collagen; MB, medullary bone; TRAP, tartrate-resistant acid phosphatase