Abstract: This study was designed to investigate the effect of collagen peptides (CPs) on calcium absorption in mice. The animals were randomly divided into normal control group, low calcium model group, calcium carbonate (CaCO3) group, low- (500 mg/kg mb + CaCO3) and high-dose (1 000 mg/kg mb + CaCO3) CPs treatment groups and casein phosphopeptides (CPPs) control group. After 6 weeks of oral administration, the serum levels of calcium, phosphorus and alkaline phosphatase (ALP), calcium absorption rate, bone indices, bone microstructure and trabecular bone morphological changes were measured. The results showed that ALP activity of the CPs treatment groups was significantly lower than that of the low calcium model group (P < 0.05), while bone length, dry mass index, bone calcium content, bone mineral density (BMD), and bone mineral content (BMC) were significantly higher (P < 0.05). CPs at low dose could reverse almost all indexes of the low calcium model group to normal. We observed a significant decrease in ALP activity and a significant increase in bone calcium content, BMD and BMC for the low dose CPs group compared with the CaCO3 group (P < 0.05), suggesting that supplementation of both calcium carbonate and CPs could promote calcium absorption and improve bone microstructure and trabecular morphology. Therefore, CPs could increase calcium absorption rate by increasing the number and intensity of trabecular bone and promoting bone growth.

Key words: Carassius auratus skin, collagen peptides, calcium absorption, calcium deficiency model, bone microstructure