The aim of the study was to determine the effect of a phytogenic additive on blood serum indicator levels and faecal nutrients digestibility. The experiment was realized in Riding Centre of the Department of Animal Husbandry, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture in Nitra. Total 14 warmblood sport horses (geldings) were used (7 horses in control group, 7 horses in experimental group respectively); Slovak warmblood bred, average body weight 525±75 kg and 6.8±3 Years. The control group of horses were fed by crimped barley, meadow hay and mineral feed mixture. Feed rations in experimental group were supplemented with a phytogenic additive containing a blend of essential oils from origanum, anise and citrus, as well as a prebiotic rich in fructooligosaccharides. Blood serum was collected 3 times during the experiment, in the beginning of the experiment, and every 45 days. The experiment lasted 90 days. After the 45 days of phytoadditive supplementation we found a tendency of lower concentrations of serum triglycerides (0.07 vs. 0.23 mmol.l-1) and total cholesterol (2.18 vs. 2.27 mmol.l-1) in experimental group of horses (P>0.05). In serum concentrations of glucose, total proteins and urea we find similar values in all of groups. The same tendency we analyzed in activity of AST, ALT, and ALP enzymes (P>0.05). After the 90 days of the phytoadditive supplementation in feed rations of sport horses, we detected a tendency of lower serum triglycerides concentration in experimental group of horses and higher cholesterol, glucose, total protein and urea concentrations (P>0.05). We didn´t find a significant effect of a phytoadditive supplementation on blood serum indicator levels. Higher faecal digestibility coefficient of dry matter was found in experimental group of horses (62.98%) in comparison with control group (56.87%). In control group of horses we detected tendency of lower crude protein digestibility (71.36%) in comparison with phytogenic additive group feeding (72.86%). We analyzed a positive effect of phytogenic additive on organic matter digestibility of feed ration. In experimental group of horses we found significantly (P<0.05) higher organic matter faecal digestibility coefficient (73.31%) in comparison with control group (68.32%). We analyzed insignificant (P>0.05) effect of a phytoadditive on blood serum concentrations during 90 days of experiment. We found positive effect of phytoadditve supplementation on total faecal digestibility of organic nutrients.
