Effect of zinc imprinting and replacing inorganic zinc with organic zinc on early performance of broiler chicks.

The goal of this study was to determine the effects of feeding a zinc (Zn) deficient diet to broiler chicks for 96 h post-hatch followed by feeding diets with different Zn sources and supplemental levels (5 to 21 d) on the growth performance, tissue, and excreta Zn content. At the start of the study, four hundred 20-day-old male broiler chicks were divided into two groups. One group was fed a corn soybean meal based diet containing 25 mg of Zn/kg (imprinting diet, ID). The second group was fed the basal diet supplemented with 40 mg of Zn/kg from Zn oxide (ZnO) (non-imprinting diet, NID). Both groups were fed these diets for 96 h. At d 5, chicks from each group were randomly assigned to the dietary treatments consisting of the basal diet alone or the basal diet supplemented with 8 or 40 mg/kg Zn as ZnO or Zn proteinate. Main effects of post-hatch Zn ID were observed on feed intake and G:F. ID decreased (P < 0.05) feed intake and improved (P < 0.05) the gain to feed ratio (G:F) of 14 and 21 d old chicks compared to G:F of chicks fed NID. Additionally, G:F for 14 and 21 d was improved (P < 0.05) by interaction of Zn source × level. Furthermore, at d 21 chicks fed the ID had a lower (P < 0.05) Zn content in the tibia ash and excreta, and a higher (P < 0.05) Zn content in the pancreas tissue compared to chicks fed NID. These results suggest that Zn imprinting can affect body Zn stores and early performance.