Bioavailability of phosphorus in corn gluten feed derived from conventional and low-phytate maize

Young chicks were used to determine phosphorus (P) bioavailability in corn gluten feed (CGF) derived from a conventional maize hybrid (CCGF) or one containing higher protein, higher oil, and lower phytate content (LPCGF). The nutritionally-enhanced maize used to produce LPCGF contained higher CP, total P, available P, and oil concentrations but less starch content compared to the hybrid used to produce CCGF. Similarly, LPCGF contained slightly higher CP and total P compared to CCGF. From 8 to 22 days of age, female chicks were fed a cornstarch–dextrose–soybean meal basal diet containing 1 g available P/kg, or the basal diet supplemented with two concentrations of P (0.5 and 1.0 g/kg) from KH2PO4 or two concentrations of the CGF samples (75 and 150 g/kg). Bioavailability of P based on tibia bone ash was much higher for LPCGF than for CCGF. Bioavailability of P relative to the KH2PO4 standard was 0.464±0.13 for CCGF and 0.898±0.12 for LPCGF based on slope-ratio methodology. The results indicated that P bioavailability in CGF is about twice as high as that in maize, and also that LPCGF has roughly twice as much bioavailable P as CCGF.