Abstract
During two feeding trials, the effect of dietary phytogenic mixture on the performance and oxidative stress biomarkers in the liver of broilers reared under thermoneutral conditions (TN) and heat stress (HS) was studied. A number of 60 Cobb 500 chicks/trial were sheltered in environmentally-controlled digestibility cages. On the 14 days of age, the chicks were weighted and assigned to four groups (2 groups/trial with 30 chicks/group). In the first trial, two groups (C-TN and PM-TN) were kept in thermoneutral conditions. In the second trial, other two groups were kept (C-HS and PM-HS) in heat stress (32 ±1 °C). The structure of diets was the same in both experiments. Compared with the control diet (C), the experimental diet (PM) contained the addition of 1% phytogenic mixture (bilberry leaves, peppermint leaves, fennel leaves and sea buckthorn meal). Irrespective of temperature conditions, dietary PM did not affect broiler’s performance. The dietary supplementation of PM delayed protein and lipid oxidation in the liver tissue of broilers in both trials by increasing the hepatic catalase, glutathione and superoxide dismutase activity.