The mixture of plant extracts (Herbiplant CS) in amount of 125 and 500 mg/kg was added to feed mixtures of starter, grower and finisher type for fatteners from 20 to 100 kg of body weight. The research material were 27 fatteners divided into 3 groups, 9 individuals in each group. After 85 days of fattening, the blood from jugular vein was collected, and biochemical indices as well as macro and microelements concentration was determined. Herbiplant CS did not influence the crude protein, albumin and urea level in blood serum, while it significantly influenced the increase in glucose level that may profitably influence the energy balance. Applied phytopreparation did not influence the enzymatic (ATP, ALT and GGT), but had a beneficial effect on lipid balance, what was confirmed in lowered level of total cholesterol and its LDL fraction. The level of macroelements (Ca, P, Na, K, Cl) in blood serum was not dependent on used phytopreparation, however, the supplement significantly influence the increase in copper and zinc level in blood serum. No significant differences in the level of analysed parameters depending on used Herbiplant CS doses in mixtures for fatteners (125 and 500 mg/kg) were observed.

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