The effects of dietary Myrtle (Myrtus communis L.) supplementations on growth performance and some innate immune responses in rainbow trout (Oncorhynchus mykiss)

This study investigated the effect of dietary Myrtle (Myrtus communis L.) powder on the growth performance, immune responses and haematological parameters of rainbow trout fingerlings. Twelve cages were assigned to four treatments in triplicate and thirty fish (6.50±0.55g (were stocked. Treatments were different levels 0 (control), 0.5 (M0.5), 1 (M1) and 1.5% (M1.5) of Myrtle powder. The highest weight gain and specific growth rate and lowest feed conversion ratio were observed in fish fed with 1% Myrtle. The RBC, WBC and haematocrit were higher in the Myrtle fed treatments compared to the control group. The results showed increased total protein in M1.5 and M1 treatments compared with the control and M0.5 treatment. Also, the highest and lowest albumin were observed in M1.5 treatment and control group. Furthermore, serum ALP decreased along with the increasing Myrtle levels in diet, and lowest level was observed in M1 treatment. Lysozyme activity increased with increasing dietary Myrtle inclusion levels, although no significant difference was noticed when compared with control. These results revealed the potential growth enhancing and health promoting effects of Myrtle powder.