Objective To study the calcium supplementation effect of octopus protein calcium (OP-Ca) in mice.

Methods Sixty ICR mice were randomly divided into 5 groups: normal control (with deionized water), low calcium (with deionized water), calcium carbonate (at dosage of 119.7 mg/kg), and low- and high-dose OP-Ca groups (with OP-Ca of 39.9 and 119.7 mg/kg) and the treatments were carried out by gavage once a day for 4 weeks. All the mice were supplied with low-calcium feed except for normal control mice. Calcium content in feces and urine of the mice were measured to calculate calcium absorption and retention rate for assessing calcium metabolism of the mice. Eyeball blood and the bilateral femurs samples of the mice were collected by the end of intragastric administration to detect serum and bone calcium.

Results The serum calcium (1.98 ± 0.10 mmol/L) and femur calcium content (217.24 ± 13.30 mg/g) in the mice of low calcium group were significantly lower than those in the mice of low- and high-dose OP-Ca groups (both P < 0.05). Compared with calcium carbonate group, the mice of high-dose OP-Ca group had significantly increased apparent calcium absorption rate (76.30 ± 2.44 %), calcium retention rate (75.29 ± 2.11%), serum calcium (2.23 ± 0.10 mmol/L) and femur calcium content (249.12 ± 12.39 mg/g) (P < 0.05 for all).

Conclusion With a high bioavailability and a better supplement effect than calcium carbonate, octopus protein calcium could significantly increase bone calcium content and improve calcium nutritional status in mice.