Research On Bioavailabilities Of Minerals In Feedstuffs For Broilers

Two experiments were conducted in the present study to determine bioavailabilities of minerals in feedstuffs and check reliabilities of these bioavailability data used for diet formulations for broilers.In Exp.1, an experiment was conducted using a total of 96 36-d-old Arbor Acres commercial male chicks to determine bioavailabilities of minerals in soybean meal (SBM), rapeseed meal (RBM), cottonseed meal (CSM), fish meal (FM), Normal corn (NC), wheat bran (WB), rice bran (RB), and wheat middling meal (WM) using a rapid procedure proposed by Nwokolo (1976). Chicks were randomly allotted to one of eight treatments for six replicates of four birds each, and were fed the test diets mixed with the former eight feedstuffs and a synthetic diet. Feed and water were available ad libitum. Results showed that as for the majority of minerals tested, the true availabilities were usually higher than their apparent availabilities. The FM had higher mineral availabilities (60% to 95%) than other plant original feedstuffs, however, there were big differences between the apparent and true availabilities of FM. As for the plant original feedstuffs of SBM, RSM, WB, and WM, the apparent and true availabilities of calcium ranged from 56% to 70%, and the apparent and true availabilities of phosphorus in SBM and NC ranged from 71% to 84% with a range of 47% to 62% in other plant original feedstuffs. Magnesium, calcium, and copper in all feedstuffs of plant origin were highly available with a range of 61% to 86%, and iron lowly available (14% to 41%) except for the higher apparent and true availabilities (60.1% vs 61.2%) of iron in RSM. Availabilities of manganese, zinc, and selenium showed greater variations among the plant feedstuffs tested with ranges of 30% to 76% for manganese, 50% to 77% for zinc, and 51% to 90% for copper.Exp. 2 was conducted to check reliabilities of the true bioavailability data of minerals in feedstuffs from Exp. 1. A total of 420 d-old Arbor Acres commercial broilers were randomly allotted by bodyweight to one of 7 treatments with 10 replicate cages of six birds (3 males 3 females) each for each treatment. The 7 treatments included: the control (Trt. 1)---the corn-soybean meal basal diet formulated to meet a non-phytate phosphorus requirement of NRC (1994) and supplemented with inorganic trace elements (copper, iron, and zinc as sulfate forms, and selenium as sodium selenite ) at a 100% NRC (1994) requirements of the above trace elements for broilers except for inorganic manganese as sulfate form at a supplemental level of 100 mg/kg; Trt. 2---the corn-soybean meal basal diet formulated to meet a non-phytate phosphorus requirement of NRC (1994) and supplemented with inorganic copper as tribasic...