The objective of this study was to determine the apparent and true digestibility coefficients and relative bioavailability of charru mussel, maçunim (Anomalocardia brasiliana) and oyster shells as organic calcium sources for meat quail. In the digestibility trial, 240 quail were distributed in a completely randomized experimental design with five diets (calcitic limestone, calcium carbonate and three marine calcium sources), five replicates and eight quails per experimental unit. The relative bioavailability of calcium was determined by the standard-curve and slope ratio methods in a growth trial in which 288 European quail were distributed in completely randomized experimental design. Treatments consisted of basal diet with a low calcium concentration (0.166%) that was supplemented with two levels of calcium (0.342% and 0.684%) derived from different calcium sources. The apparent and true digestibility coefficients of calcium from charru mussel-, maçunim- and oyster-shell meals for meat quail were 91.85 and 92.04%; 91.71 and 91.90%; and 89.39 and 89.63%, respectively. The relative bioavailability of calcium from charru mussel-, maçunim- and oyster-shell meals obtained using standard-curve and slope ratio methods were 133.22 and 119.18%; 140.05 and 113.69%; and 141.73 and 106.22%, respectively, allowing the use of these organic calcium sources in diet formulations for meat quail.

No abstract