Effect of different levels of Salvia mirzayanii essential oil on performance, some blood and immunity parameters of broiler chickens under heat stress conditions

An experiment was conducted to evaluate different levels of Salvia mirzayanii essential oil on performance, blood and immunity parameters of broiler chickens under heat stress condition. Completely randomized design with four treatments (0, 150, 300 and 450 ppm of Salvia mirzayanii essential oil) was used for 42 days. Broilers were under heat stress conditions from 22 days of age. Increasing levels of essential oil in the diet significantly decreased feed intake in comparison with the control at the starter period. But level of 450 ppm essential oil had the highest feed intake during grower period and total of experiment. Feed conversion ratio significantly decreased by increasing levels of essential oil compared with the control. Triglyceride and LDL cholesterol concentration were significantly decreased at the level of 450 ppm essential oil. Percentage of heterophile, heterophil/lymphocyte ratio (H/L) decreased, and percentages of lymphocyte and monocyte increased by increasing levels of essential oil at 21 days of age (P