EN
The aim of this study was to analyse the physiological values of Ca+2-ATPase catalytic activity in the muscles of 8-, 12- and 18-week-old Polbar breed chickens of both sexes. The material for the analysis consisted of actomyosin homogenate sampled from the greater pectoral muscles (Musculus pectoralis maior) of 20 Polbar hens and 20 Polbar cocks, divided into three groups of 8-, 12- and 18-week-old birds. The studies proved the dependence of the calcium ATPase activity level on the sex and age of the birds examined. Among the three age groups the highest ATPase activity was observed in the birds in their 8th and 12th weeks of life. In the case of the cocks the highest level of the activity was determined in the 8th week of age, with a mean value of 0.37 U/mg, and in the case of the hens in the 12th week, when the mean value amounted to 0.39 U/mg. These results for the ATPase activity in a genetically consolidated hen breed can be used for comparisons with other poultry breeds. The preliminary studies to establish reference values are useful for diagnostic purposes.