The assessment of certain minerals content in mixed feeds in relation to the laying hens' exploitation system (organic vs. conventional).

Feedstuffs grown in certain geographic areas may be marginal or deficient in specific elements. Thus, poultry diets usually require supplementation to ensure an adequate intake of trace minerals. The aim of this paper was the assessment of calcium (Ca), phosphorus (P), magnesium (Mg) and sodium (Na) content in the mixed feeds from two different production systems (organic and conventional). Were analyzed ten samples of mixed feed used for the feeding laying  hens from Brown hybrid at the age of 27 weeks in two units in Romania. Sampling and the preparation of samples were performed in compliance with the rules of the standards in force in Romania and harmonized with EU legislation (ISO 6869:2002); the method for the determination used was spectrophotocolorimetry method (UVmini 1240 SHIMADZU) for P, and for Ca, Mg and Na was was assessed by atomic absorption spectrometry method. Analysis of mixed feed samples revealed statistically significant differences (p≤0.05) between the two systems (organic vs. conventional) for the P content (0.25 vs. 0.26 %) and Mg content (0.26 vs. 0.28 %). Statistically insignificant differences (p≥0.05) between the two systems (organic vs. conventional) were found for the Ca content (2.93 vs. 2.97 %) and Na content (1.706 vs. 1.712 % ).