The Effect of Different Levels of Spearmint (Mentha Spicata) Extract on Immune System and Blood Parameters of Broiler Chickens

The study was conducted to evaluate the effects of Mentha spicata extract and an antibiotic -virginiamycin- on immune system, blood factors in broiler chickens. A total of four hundred 1-day old chicks (Ross 308) were allocated to five treatments with four replicates based on a completely randomized design. The dietary treatments consisted of the basal diet (control), basal diet supplemented with 10 ppm of virginiamycin (antibiotic), basal diets with a 0.2%, 0.4% and 0.6% doses of Mentha spicata extract in the drinking water. At 21 and 42 days of age, two birds per pen were selected, weighed and killed by decapitation to obtain the immune organs relative weight such as spleen, thymus and bursa fabricius. Consequently blood samples were collected and blood serum was separated to measure of Newcastle and influenza viruses and also SRBC antibody titers. All experimental data were subjected to the GLM procedure of SAS as a complete randomized design and the mean values were compared by Duncan multiple tests. No significant difference between treatments was observed for the measured factors at 21 and 42 days of age. The results of this study revealed that Mentha extract consumption in drinking water could not stimulate the immune system response in broiler chickens. (C) 2012 Published by Elsevier B. V. Selection and/or peer review under responsibility of Asia-Pacific Chemical, Biological & Environmental Engineering Society