EN
The aim of the study was to compare the breeding efficaciousness of chicken broilers, physicochemical and sensory quality of meat and composition of fatty acids of fat from three breeding lines of chicken served feed with or without growth stimulator (control group). It was found that adding an antibiotic growth stimulator increased the production efficiency of Hubbard and ISA 215 lines. Free-range chickens, certified I 957, scored the lowest production effects (in both feeding groups) when compared to the remaining breeding groups, but at the same time were healthier and there was a lower percentage of death rate amongst these birds. The breast muscles of Hubbard line chickens where antibiotics were contained in their feed were found to have significantly more protein and less fat than the control group. Additionally, breast muscles displayed the best technological properties in both feeding groups independent of stimulator addition. The sensory quality of meat was not influenced by the breeding line or addition of antibiotics. Intramuscular fat from chickens fed with the addition of growth stimulator contained a slightly lower amount of saturated and monounsaturated fatty acids, but at the same time a higher amount of polyunsaturated fatty acids. The oxidation rate was fastest in the abdominal fat from the Hubbard line fed with the addition of antibiotics. This was probably due to a higher content of polyunsaturated and lower monounsaturated fatty acid content as mentioned above.