The effect of polyphenols and vitamin E on the antioxidant status and meat quality of broiler chickens exposed to high temperature.

The aim of this study was to determine the effect of a polyphenol product (PP) (Proviox) and vitamin E on the antioxidant status and meat quality of broiler chickens exposed to high temperature. The experimental materials comprised 120 ROSS 308 broilers (6 treatments, 10 replications, 2 birds per replication). Dietary supplementation with vitamin E and PP was applied in the following experimental design: group I (negative control) - without supplementation; group II (positive control) - without supplementation; group III - supplementation with 100 mg vitamin E/kg; group IV - 200 mg vitamin E/kg; group V - 100 mg vitamin E/kg and 100 mg PP/kg; group VI - 200 mg PP/kg. In groups II-VI, broiler chickens aged 21-35 d were exposed to increased temperature (34°C for 10 h daily). In chickens exposed to high temperature, dietary supplementation with antioxidants, mostly PP, improved growth performance parameters, including body weight, body weight gain and feed intake until 28 d of age. Vitamin E added to broiler chicken diets at 200 mg/kg and vitamin E combined with PP was most effective in improving the total antioxidant status of birds, enhancing blood antioxidant enzyme activities and increasing vitamin E concentrations in the liver and breast muscles. Broilers fed diets supplemented with 200 mg/kg of vitamin E alone and vitamin E in combination with PP were characterised by a higher percentage content of breast muscles in the carcass. Dietary supplementation with antioxidants improved the water-holding capacity of meat, reduced natural drip loss and increased the crude ash content of meat. The breast muscles of chickens fed diets supplemented with PP had a lower contribution of yellowness. The breast muscles of chickens receiving diets with 100 mg vitamin E/kg(group III) and diets supplemented with PP (groups V and VI) were characterised by the highest concentrations of polyunsaturated fatty acids. The PP can be a valuable component of diets for broiler chickens exposed to high temperature.