Effects of Sheep Bone Peptide-Chelated Calcium on Calcium Absorption and Bone Deposition in Rats Fed a Low-Calcium Diet

Sheep bones, as the main byproduct after sheep slaughter, are rich in proteins, but their utilization in deep processing is relatively low. Currently, calcium deficiency is a common health issue that can lead to metabolic bone diseases. Peptide calcium chelate is considered a superior substance, having a significant effect on improving the absorption and utilization efficiency of calcium in the human body. This study used sheep bone byproducts as the raw material to prepare sheep bone peptide-chelated calcium (SBP-Ca) and its structure was characterized and analyzed in depth. SBP-Ca was supplemented in a low-calcium diet to assess its effects on calcium absorption and bone formation in a rat model experiencing calcium deficiency. The results showed that under optimal preparation conditions for SBP-Ca (peptide-calcium ratio set at 1 : 1, pH maintained at 7, temperature set to 45°C, and duration of 60 min), calcium could chelate with sheep bone peptide (SBP) at the sites C=O, -NH2, and -COOH sites, forming a structurally dense SBP-Ca with a chelation rate of up to 89.24%. In rats fed a low-calcium diet, SBP-Ca significantly improved the rat femoral diameter, dry weight, trabecular bone structure, bone density, and bone volume fraction ($P<0.05$). A decline in serum alkaline phosphatase levels ($P<0.05$), elevation in bone calcium content, and a rise in serum osteocalcin levels ($P<0.05$) were observed. Furthermore, morphological studies on bone tissue suggest that SBP-Ca has the ability to restore trabecular bone structure. In conclusion, SBP-Ca has been successfully prepared as a novel calcium absorption promoter. By improving the bioavailability of calcium, bone formation was facilitated, demonstrating a significant application value in the prevention of calcium deficiency disorders.