Effects of centaury (Hypericum perforatum) and marsh mallow (Althaea officinalis) aquatic methanolic extracts on growth performance, digestive enzyme and some immune parameters of rainbow trout (Oncorhynchus mykiss)

In this study, effects of centaury (Hypericum perforatum) and marsh mallow (Althaea officinalis) aquatic methanolic extracts on growth performance, digestive enzyme and some immune parameters in rainbow trout were investigated. Fish with an average initial weight 13,99±0,11 g, were divided into 7 groups in 21 mesh cages with stocking density of 50 fish/cage (triplicate tank were ass,gned for each experimental group). The experimental diets were prepared with control (only commercial feed) and three different concentration of aquatic methanolic extract of centaury (0%, %0.1, %0.5 and %1) and marshmallow (0%, %0.1, %0.5 and %1) added to the commercial feed by spray. Fish were fed with the diet for 75 days. The weight values, blood and tissue samples (intestine, stomach and liver) were taken from each experimental groups at every 15th, 45th and 75th day of the study. Nitroblue tetrazolium (NBT), lysozyme, myeloperoxidase (MPO) actvities and heamatological profile; red blood celss (RBC) count, hemoglobin content (Hb), haematocitr value (Hct), mean red blood cell mass (MCV) and mean red blood cell hemoglobin (MCH) were determined from blood. Digestive enzyme (amylase, lipase, pepsin and trypsine) and antioxidant enzyme activity (SOD and CAT) were performed to determine from intestine, stomach and liver tissues. At the end of the study, the experimental groups of growth performance, the final weights, weight gains and specific growth rates of fish were higher than the control (P<0.05). According to the results of NBT, lysozyme and MPO activities, values of H0.1, H0.5 and H1 groups were found higher than control and cantonal groups at the end of the experiment (P<0.05). Digestive enzymes of fish were evaluated, no statistical difference was observed in all experimental groups (P>0.05) in lipase activity. It was found that amylase activity was increased in K0.5 group compared to other groups (P<0.05). It was observed that the pepsin activities of the control, H0.1, H0.5 and H1 groups were significantly decreased with time. At the end of the study, SOD activity were significantly increased in the K0.5 and H0.5 groups compared to the 15th and 45th days (P<0.05). CAT activity of the control and H0.5 gropus depending on time were decrased. However, other experimental groups of CAT activities were increased at the end of the study (P<0.05). As a result of this study, addition of centauray and marshmallow aquatic methanolic exracts to diets of rainbow trout positive effects on the growth performance, digestive enzymes, antioxidant enzyme and some immun parameters.