Effects of Thymus vulgaris and Mentha pulegium on colour, nutrients and peroxidation of meat in heat-stressed broilers

This study was designed to investigate the effects of Thymus vulgaris (thyme) and Mentha pulegium (mentha) powders on meat colour, nutrient composition and malondialdehyde (MDA) where broiler chickens were under heat stress. Two hundred one-day-old male chicks were used in a completely randomized design with four treatments and five replicates each (10 birds per replication). Treatments were the control diet, 0.5% mentha, 0.5% thyme and 0.5% mixture of the two plants. The results showed no effect of dietary supplements on thigh meat redness and yellowness. Both plant products diminished the thigh lightness significantly compared with the control. No significant differences between treatments were observed for the ash, ether extract and crude protein content of the thigh muscle. Supplementation of thyme and mentha separately or together increased the moisture of the thigh muscle significantly, compared with the control. The combination of the plant products resulted in a higher thigh pH and significantly lower malondialdehyde (MDA) concentration in the thigh muscle compared with the control. In conclusion, dietary supplementation of thyme and mentha separately or in combination improved the meat quality of broiler chickens under heat stress through decreasing the MDA concentration and increasing the pH and moisture content of the thigh muscl