Objectives: The purpose of this study was to determine the effects of using caffeine and trans-Cinnamaldehyde (TC) humeral immunity response on male broiler chicks under stresses induced by dexamethasone. Materials and Methods: This experiment was conducted in a completely randomized design with 200 of broiler (Ross-308) in 4 treatments and 5 replicate (with 10 hens in each replicate) from 1 to 42 days and included: 1) control group without any additives, 2) 0.5% caffeine powder 3) 1% TC 4) 0.5% caffeine powder + 1% TC. At 30 and 36 day of the experiment, chicks were injected with 0.1 mL of BW 0.25% SRBC in 0.9% saline into the brachial vein of 2 chicks per cage. The same birds were vaccinated with SRBC at both time points. Six days after each immunization, blood was collected by puncturing the brachial vein. Individual serum samples were analyzed for circulating anti-SRBC antibody titers by ELISA technique using commercial kits, and the plates were read at 405 nm on an ELISA reader. All titers were expressed as the log2 of the reciprocal of the serum dilution. Results and Conclusion: The result of this experiment showed that caffeine and TC had no significant effects on immuonoglobin levels on 36 and 42d. In summary, our study demonstrated that caffeine, TC and mixture of caffeine + TC had no significant effects on humeral immunity in chicks under stresses induced by dexamethasone.

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