Histology of jejunum and some blood metabolites of broiler chickens fed with olive (Olea europaea L.) leaf extract and sesame (Sesamum indicum L.) oil under heat stress

This study was designed to investigate the synergic effects of adding sesame oil (SEO) and olive leaf extract (OLE) as sources of natural antioxidants to the diet on the histology of the jejunum, some blood parameters and immunological responses of broilers under heat stress. Three hundred Ross male broilers were randomly distributed into 30 experimental units and 6 dietary treatments (5 replicates with 10 birds in each). The completely randomized design with factorial arrangement 3×2 with 3 levels of OLE (0, 200 and 400 mg/kg of diet) and 2 types of vegetable oil (crude corn oil (CRO) and SEO) were used. Broilers were exposed to heat stress (33±1°C) for 8 h from 29 to 42 days. Chicks fed with diet containing CRO and supplemented with 200 mg/kg OLE had the highest jejunum villi length (1699 µm) and cutaneous basophil hypersensitivity (CBH) response (0.37mm). The usage of OLP in the diet significantly decreased the serum concentrations of cholesterol, triglyceride and uric acid and increased serum alkaline phosphatase (ALP) activity. These results indicated that the use of OLE up to level of 200 mg by increasing antioxidant compounds in the diet may lead to an increased villus height and balance of blood parameters and thus reduce the negative effects of heat stress in broiler chickens.