Dietary encapsulated Bacillus subtilis and essential oil supplementation improves reproductive performance and hormone concentrations of broiler breeders during the late laying period

This study was conducted to evaluate the effects of increasing inclusion rates of Bacillus subtilis and essential oil (BSEO) on egg production, hatching traits, egg quality, plasma antioxidant capacity, immune response, and hormone concentrations of broiler breeders during the late laying period. A total of 576 broiler breeders at 54 wk of age were randomly allocated to 4 treatments with 6 replicates of 24 broiler breeders per replicate. The experiment lasted for 12 wk and dietary treatments included corn-soybean meal-based diet supplemented with 0, 300, 600, and 900 mg/kg of BSEO. The BSEO supplementation decreased linearly (P