3.6. Power production

Of the earlier mentioned parameters, the mass of heart and pectoral muscle, as well as the chemical composition, glycogen, and protein contents of the tissues may be of value in estimating the birds’ ability for power production and flight. In addition to these, the cytochrome-c oxidase (COX) activities of pectoral muscle and heart (from both the homogenate and the mitochondrial fraction) were analysed from wild and hand-reared capercaillies (I), because cytochrome-c oxidase activity can be considered an indicator of the aerobic capacity of a tissue. The method originally described by Rafael et al. (1970) and later modified by Saarela et al. (1989) was used.