EN
Modification of the composition of the carcass, especially reduction of the fat depot and enlargement of the musculature mass have been recognized as a main feature of the action of beta-2-adrenergic agonist clenbuterol. As a result of a dietery treatment with clenbuterol significant decreases of chylomicrons, VLDL and LDL2 in the plasma of chickens were observed. There was a tendency for a diminishing of saturated fatty acids (palmitic and stearic acids). Simultaneously, an increase in the content of unsaturated fatty acids (linoleic, linolenic and arachidonic acids) was observed. Compared to control chickens, those fed 5 mg clenbuterol/kg had decreased total content of fatty acids in fatty tissue from 686.99 to 563.50 mg/g, respectively. The ratio of insaturated to saturated fatty acids in plasma and adipocytes increased in the treated groups. On the basis of histochemical differentiation of fibre types it was established that type II В fibres were most pronounced in clenbuterol treated groups.