This study aimed to investigate the impacts of dietary Moringa oleifera leaves (MOL) and Saccharomyces cerevisiae (SC) supplementation on growth performance parameters, some blood biochemical findings, antioxidant status, mRNA of HSP70 and HSP90 expressions and quality and antioxidant properties of breast meat in broilers exposed to heat stress (HS). For this purpose, 120 one-day-old chicks were randomly allotted into 6 groups (T), 20 chicks each, which were fed for 35 days with a basal diet. At the 21st day, T1 was unexposed to HS (21-22 °C). While, T2 was exposed to heat stress (33-35 °C) and relative humidity (64± 2).While, Groups T3, T4 and T5 were exposed to HS (33-35 °C) and humidity (64± 2) and supplemented with 2%, 4% and 6% of MOL, respectively, and T6 was exposed to HS (33-35 °C) and humidity (64± 2) and supplemented with SC 5%. The obtained results showed that T3, T4, T5 and T6 provoked increased final B.W, BWG and F.I, improved liver and kidney function (reduced AST, ALT, creatinine and uric acid level), improved antioxidant status (reduced serum MDA levels and increased serum CAT, SOD and GPx activities), decreased HSP70 and HSP 90 mRNA expressions and improved breast meat compared to T2. In conclusion, the (MOL) and SC dietary supplementation to basal diet of heat-stressed broilers mitigated HS negative impacts: enhanced growth performance, antioxidant capacity, controlled HSP70 and HSP 90 mRNA expressions and improved breast meat quality.
Key words: Heat stress, Growth performance, Antioxidant capacity, meat quality, Moringa olifera, Saccharomyces cerevisiae.