Relative Bioavailability of Zinc-Methionine Chelate for Broilers Fed a Conventional Corn-Soybean Meal Diet

An experiment was carried out to determine the bioavailability of the organic Zn-methionine chelate relative to inorganic Zn source (ZnSO(4)aEuro cent 7H(2)O) for broiler chicks fed a conventional corn-soybean meal diet. A total of 504 1-day-old Arbor Acres commercial male broiler chicks were randomly allotted to one of seven treatments in a completely randomized design involving a 2 x 3 factorial arrangement with three levels of added Zn (30, 60, or 90 mg of Zn/kg) and two Zn sources (Zn-methionine chelate and Zn sulfate) plus a Zn-unsupplemented control diet containing 29.2 mg of Zn/kg by analysis for an experimental phase of 21 days. Bone and pancreas were collected for testing Zn concentrations and pancreas metallothionein (MT) messenger RNA (mRNA) level at 7 or 21 days of age. The results showed that bone and pancreas Zn concentrations and MT mRNA level in pancreas increased linearly (P < 0.0001) at 7 or 21 days of age as added Zn level increased. Based on slope ratios from multiple linear regressions of the pancreas, MT mRNA level at 7 days and pancreas Zn concentration at 21 days on added Zn level and the bioavailability values of the Zn-methionine chelate relative to ZnSO(4)aEuro cent 7H(2)O (100 %) were 120 and 115 %, respectively (P > 0.22). The results indicated that the Zn from the Zn-methionine chelate was just as bioavailable as the Zn from Zn sulfate for broilers.