Comparative influence of oral administration of Shirazi thyme and vitamin E on health and growth in common carp juveniles exposed to the cadmium

The comparative effects of Shirazi thyme (Zataria multiflora Boiss) on growth and health status of common carp juveniles exposed to the cadmium is the aim of current study. 225 juveniles (34±3g) were divided into five groups as followed: the first (control) and second (metal only) group feeding were done based on standard diet for common carp. Third group juveniles fed with diet containing 1 percent Shirazi thyme, for forth group excess amount of 100 mg/Kg dry weight of diet from vitamin E and about the last group combined level of Shirazi thyme and vitamin E as a same level with previous groups were used. Then all of the experimental group (except control) were challenged with sublethal concentration of cadmium (1.5 mg/L) and growth and health parameters were evaluated 3, 7, 10 and 15 days after experiment initiation. Hepatosomatic, viscerosomatic and bile somatic index showed significant improvement in juveniles which gain thyme in their diet based of our obtained results. Weight gain (%), feed conversion ratio, specific growth rate, feed conversion efficiency and protein efficiency ratio were also showed more recovery in thyme group (P<0.05). Generally it can be concluded that incorporating of Shirazi thyme in carp diet can decrease the harmful effect of cadmium and improve fish growth parameters. Juveniles which received by 1 percent Shirazi thyme in their diet showed more improvement related to the vitamin E group in the most examining parameters.