effects of different levels of cinnamon powder, antibiotic and probiotic on performance, blood parameters and immune system in broiler chickens

introduction: dietary supplementation of medicinal plants as antibiotic replacement is a new approach in modern poultry farming systems. in poultry production, the main effects of medicinal plants are focused on the intestinal tract and its microbial flora. one of these medicinal plants is cinnamon that is known with scientific name cinnamon zeylanicum. cinnamon verum (syn. cinnamomum zeylanicum) is a native of sri lanka and south india, but bark and leaf are widely used as a spice throughout the world. cinnamaldehyde and eugenol are two very important terpenoids found in cinnamon, which are known as bioactive substances with potential health effects. they have intense antimicrobial, antifungal, and antioxidant properties. cinnamon constituents possess antioxidant action and may prove beneficial against free radical damage to cell membranes. materials and methods: this study was investigated the comparative effects of different levels of cinnamon powder (cnp), antibiotic (virginiamycin) and probiotic (primalac) on blood parameters and immune system in broiler chicks for 42 days using a completely randomized design. a total of 384, day-old male broiler chicks (ross 308) were randomly assigned into 8 treatments with 4 replicates and 12 chicks each. the experimental treatments consisting of: basal diet (bd), bd + 0.1% cnp, bd + 0.2% cnp, bd + 0.3% cnp, bd + primalac, bd + 0.2% cnp + primalac, bd + virginiamycin and bd + 0.2% cnp + virginiamycin. virginiamycin was supplemented at 15 g/ton to the starter and 10 g/ton to the grower and finisher diets. also primalac was added at 900 g/ton to the starter, 454 g/ton to the grower and 225 g/ton to the finisher diets. at the end of each phase, the average daily feed intake (adfi), average daily weight gain (adwg) and feed conversion ratio (fcr) for each group of birds were calculated and mortality was daily weighed, recorded and used to correct the fcr. at 42 d of age, one bird from each replicate with average pen weight was selected, blood samples were taken from wing vein and determined triglyceride, total cholesterol, alt, ast, total protein and glucose in blood serum samples. srbc (sheep red blood cell) and cbh (cutaneous basophil hypersensitivity) test were used to assessment of humoral and cellular immunity, respectively. results and discussion: apart from feed intake at starter period, dietary treatments had no significant effect on performance characteristics at starter, grower and finisher periods. the humoral immunity results showed that in first and second titer of srbc test, igg had lonely significant difference. in second titer of srbc test, the response against antigen is faster and more powerful. birds fed bd + 0.1% cnp had high second titer of igg compared to treatments containing antibiotic and probiotic. hypersensitivity test showed the treatment bd + 0.2% cnp + probiotic (primalac) increased toe membrane thickness at 24 hours after injection pha-p solution. as cinnamon has potential broad antimicrobial and antioxidant activities, immune responses were expected to be elevated. it has been proved that herbal extracts increase anti-body titration against srbc which herbal extracts stimulate immune response by increasing vitamin c and phagocytic cells activity. immune responses using probiotics, medicines and plant extracts in the diet increases that were consistent with the results obtained in this study. serum glucose and cholesterol levels were reduced with levels of 0.2% and 0.1% of cnp respectively. cinnamon zeylanicum inhibits the hepatic 3-hydroxy-3-methylglutaryl coa (hmg-coa) reductase activity, resulting in lower hepatic cholesterol content and suppresses lipid peroxidation via the enhancement of hepatic antioxidant enzyme activities. it is known that an unidentified factor present in cinnamon as methyl hydroxy chalcone polymers (mhcp). it was reported that mhcp presented in cinnamon increased insulin dependent glucose metabolism roughly 20 fold in vitro. reduce serum glucose indirectly reduce the production of cholesterol, thereby reducing glucose to pyruvate production and reduced coa which is a precursor of cholesterol. conclusion: this study showed that inclusion of cnp in broiler diets had not remarkable effects on performance, but the use of herbal additives such as cinnamon and probiotics as alternatives to antibiotics into diet may improve humoral and cellular immune responses and decreased serum glucose and cholesterol levels in the broiler chicks, thereby it can be useful meat quality of bird and human health.