dc.description.abstract | Broiler chickens are very sensitive to environments with high temperatures which cause heat stress. Heat stress in broiler chickens is characterized by decreased growth rate, decreased meat quality, increased feed conversion ratio, and can cause death. This study aims to determine the effect of using mangosteen peel extract on the performance of broiler chickens (feed consumption, body weight gain and feed conversion). This research was carried out from 11 January to 15 February 2024 in Lubuk Pakam, Jalan Banjar Negoro A, Sidodadi Ramunia Village, Beringin District, Deli Serdang Regency. The design used in this research was a Completely Randomized Design (CRD) with 4 treatments and 4 replications. Each replication contains 5 broiler chickens. Treatment consisted of administering mangosteen peel extract P0 = 0%, P1 = 4%, P2 = 5%, P3 = 6%. The parameters observed were the performance of broiler chickens for 35 days. Based on the research results, it shows that 4% mangosteen peel extract + 500 ml drinking water has a significant effect (P<0.05) on the performance of broiler chickens. The best average results were feed consumption with values (89.71 ± 1.39), body weight gain (60.02 ± 0.43) and feed conversion (1.49 ± 0.02). The performance value is influenced by the antioxidant content in mangosteen peel extract which helps reduce heat stress, increase the body's immunity in stressful conditions, maintain health and increase growth | en_US |