EN
The aim of this study was to determine the effect of breed on the changes of antipyrine pharmacokinetics in calves receiving high-carbohydrate food. The experiment was carried out on 40 calves (bulls) cross-breed (20 calves - 25% HF and 20 calves 75% HF) 20 animals in the control group and 20 animals in the experimental group. During the experiment the calves from the control group were fed a food ration containing: 250 g of protein, 400 g of carbohydrates and 250 g of lipids. The calves from the experimental group received the high-carbohydrate food: 250 g of protein, 500 g of carbohydrates and 250 g of lipids. The antipyrine test in the experimental group was carried out at 0 and 7 days after administering the food ration with the carbohydrate supplement. The pharmacokinetics of the model drug was calculated based on the plasma concentration (C) versus time (t) curves (TopFit 2.0 software). Statistical analysis was performed by a paired Student-t-test. The increase of carbohydrate content in food rations did not significantly influence the volume of distribution (Vd) of antipyrine in comparison to the control group. We observed, however, a significant (P<0.01) increase of biological half-life, t₀,₅, and a decrease of metabolic clearance (Clm) of antipyrine in calves receiving high-carbohydrate food. The obtained results indicated that calves receiving the high-carbohydrate food were slower metabolizers of antipyrine, but the genotype had no influence on this process (inhibition of activity enzymes of MFO-CYP450 complex) which is evidenced by statistically insignificant differences of pharmacokinetics parameters of antipyrine between 25% and 75% HF cross-breed calves.