Effect of different levels of peppermint and rosemary herbal powder mixture on performance, carcass characteristics and some blood parameters of Japanese quails challenged with dexamethasone

This study was carried out to investigate the effect of different levels of peppermint and rosemary powder mixture on performance, carcass characteristics and some blood parameters of Japanese quails challenged with dexamethasone from 21 to 35 days of age using 96 female birds in 6 dietary treatments with 4 replicates birds in each replicate. The experimental treatments consisted of the control group (basal diet without any injection), saline injection, injection of 0.4 mg/kg dexamethasone and 0.25, 0.5 or 1% of herbal mixture challenged with injection of 0.4 mg/kg dexamethasone. The results showed that body weight gain (BWG) and feed conversion rate (FCR) of quails, respectively, decreased and increased significantly by dexamethasone injection, but inclusion of 1% of herbal mixture significantly improved these indicators from 29 to 35 days of age. Quails fed 0.4 mg/kg dexamethasone alone or together with 0.25, 0.5 or 1% herbal mixture had higher alanine aminotransferase (ALT) and aspartate aminotransferase (AST) on 35 d. Moreover, the utilization of 1% peppermint and rosemary mixture together with 0.4 mg/kg dexamethasone significantly decreased malondialdehyde (MDA) of serum compared to control group and groups containing saline, 0.4 mg/kg dexamethasone or 0.4 mg/kg dexamethasone + 0.25% herbal mixture. In conclusion, the results of current study showed that consumption of 1% of rosemary and peppermint powder mixture could partially decrease unfavorable effects of dexamethasone administration in Japanese quails.