Propolis or bee glue is a resinous hive product collected by honey bees from plant exudates and contains more than 160 constituents. The ethanolic extract of raw propolis (balsam) has some activities such as anticancer, antibacterial, antioxidant, antiviral, anti-inflammatory, antifungal, local-anaesthetic, and hepatoprotective. It has been suggested that the presence of a large number of flavonoids, aromatic acids and phenolics compounds are responsible for the most biological and pharmacological activities of propolis. This experiment was conducted to investigate the effects of Ethanolic Extract of Propolis (EEP) on the cellular and humoral immunity, performance and egg quality of laying hens from 24-36 weeks of age. One-hundred forty four white leghorn hens. divided into 6 experimental groups of 24 birds each. Experiment was carried out in a completely randomized design with 6 treatments (different levels of propolis) and four replication of 6 birds per each replicate. The birds were fed on the basal layer diet supplemented with six levels of propolis (0, 100, 250, 500, 750 or 1000 mg/kg diet), for 12 weeks from 24 to 36 weeks of age.At the end of experiment antibody titres of NDV were measured by ELISA procedure and histological section of small intestine were investigated. Also, at the end of experiment electrophoresis of serum proteins were measured. The performance of laying hens was evaluated in terms of egg production rate, mean egg weight, egg mass, daily feed intake and feed conversion ratio. Antibody titer of NDV and gamaglobulins percentage had no significantly differences, but tended to increase with increasing levels of propolis supplement (P 0.05). Average feed consumption, egg production, egg mass and feed efficiency were significantly higher for propolis fed birds (P 0.05), and inclusion of propolis also increased egg weight, but showed no statistical differences (P 0.05). During the 84d of the experiment, the shell thickness, shell strength and shell egg weight among different treatments showed no statistical differences (P 0.05), but tended to increase with increasing levels of propolis supplement. Haugh unit among different treatment had no significantly differences (P 0.05). Results obtained here indicated that addition of 250 mg/kg or higher propolis may be beneficial in improving laying hens performances and immunity response.
