Measurement of true ileal calcium digestibility in meat and bone meal for broiler chickens

• Calcium digestibility of meat and bone meal for broilers was determined.
• Regression method was used for digestibility determinations.
• True ileal calcium digestibility coefficients ranged between 0.46 and 0.60.
• These values were lower than generally assumed.

The objective of the present experiment was to determine the true ileal calcium (Ca) digestibility in three samples of meat and bone meal (coded as MBM-1, MBM-2 and MBM-3) for broiler chickens. Four experimental diets, containing graded concentrations of Ca, were formulated from each MBM sample with inclusion levels of 20, 40, 60 and 80 g/kg diet. Each experimental diet was randomly allotted to four replicate cages (six birds per cage) and fed for three days from day 28 post-hatch. Apparent ileal digestibility coefficient of Ca was measured by the indicator method and linear regression analysis was used to determine the true Ca digestibility coefficient. Apparent Ca digestibility was unaffected (P > 0.05) by increasing Ca concentrations. The apparent digestibility coefficients in MBM-1, MBM-2 and MBM-3 were 0.50, 0.44 and 0.45, respectively. Significant linear (P < 0.001) relationship was observed between dietary Ca intake and digesta Ca output for MBM-1, MBM-2 and MBM-3 with R2 values of 0.82, 0.93 and 0.95, respectively. The true ileal digestibility coefficients of Ca in MBM-1, MBM-2 and MBM-3 were determined to be 0.60, 0.46 and 0.50, respectively. The corresponding ileal endogenous Ca losses were 292, 123 and 174 mg/kg dry matter intake, respectively.