Effects of Myrtus (Calendula officinalis) extract on Immunological and some blood factors of Goldfish (Carassius auratus)

Effect of myrtus extract (Calendula officinalis) at concentrations of 0.5, 1 and 1.5% in diet was studied on some growth performance, survival and immunological variables of gold fish (Carassius auratus) weighing 8.5±1 g for 60 days using a complete random design. A number 63 fish were used per treatment and growth parameters consisting of percent body weight increase, specific growth rate, daily growth rate and condition factor were evaluated. The blood samples were obtained at the end of trial and levels of hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, heterophil, lymphocyte, and complement activity were also measured. The obtained results showed that an insignificant increase was seen in level of complement component when the concentration of myrtus extract was increased in the fish diet (p>0.05). The amounts of C3 and C4 were also higher in treatments containing the extract than control group but they had on significant different (p>0.05). Generally, the results of this experiments showed that Calendula officinalis extract had positive effect on some immunological parameters of fish and it could act as immonostimulator in this fish species.