The effects of stress, Escherichia coli, dietary ethylenediaminetetraacetic acid, and their interaction on tissue trace elements in chicks.

The present study determined effects of Escherichia coli infection, crowding stress, and EDTA supplementation on Cu, Fe, and Zn levels in the serum, liver, bursa of Fabricius, and spleen of chickens. Organ weights as a percentage of BW were affected by treatments prior to and after infection. Liver and spleen weights as a percentage of BW increased with infection but bursa weight decreased. One week of stress increased hepatic Cu, but 3 wk of EDTA ingestion increased serum Cu and serum, hepatic, bursal, and splenic Fe. These elemental changes resulting from EDTA may have predisposed the chicks to a higher mortality rate from E. coli compared with controls. Peak mortality occurred 2 days after infection, coincident with an increased serum Cu, decreased serum and bursal Fe and Zn, and increased hepatic and splenic Zn. At 7 days postinfection, recovering chicks experienced decreased hepatic Fe, elevated hepatic Zn, decreased bursal Cu, Fe, and Zn, and increased splenic Cu, Fe, and Zn. The current study demonstrates the interactive effects of EDTA, stress, and E. coli infection on serum and organ trace element concentration.