RESUMO
The contents of manganese, zinc, copper, and iron in the liver and kidney of laying hens (Shaver), kept on modern large-capacity poultry farms, were determined under the conditions of a normal and increased supply of these microelements to the organism. The content of the mentioned trace elements was determined by means of atomic absorption spectrophotometry, flameless technique, and with the use of graphite cell. In the layers fed a diet with a normal content of trace elements the average concentrations of the microelements in the liver were the following: manganese: 15.8 +/- 8.8 mg kg-1, zinc: 35.0 +/- 5.1 mg kg-1, copper: 19.9+/- 2.8 mg kg-1, and iron: 761.6 +/- 245.8 mg kg-1. When increased amounts of microelements were added to the diet, their average content generally increased just in the kidneys, whereas their average concentrations in the liver remained the same, with the exception of iron, the content of which showed an increase.