Effects of tetra (Cotinus coggygria) and common mallow (Malva sylvestris) plant extracts on growth performance and immune response in Gilthead Sea bream (Sparus aurata) and European Sea bass (Dicentrarchus labrax)

In this study, effects of tetra (T) (Cotinus coggygria) and common mallow (CM) (Malva sylvestris) aqueous methanolic extracts on growth performance and immune response in gilthead sea bream, Sparus aurata (19.92 +/- 0.40 g) and European sea bass, Dicentrarchus labrax (18.66 +/- 0.86 g) were investigated. The experiment was designed as 5 treatment groups: control (0 mg/kg), 500 mg kg(-1) (CM500, T500) and 1000 mg kg(-1) (CM1000, T1000) for each fish species. Fish were fed the diet supplemented with tetra and common mallow extracts for 60 days and blood samples were collected on the 30th and 60th days of the study. Immunological parameters, such as respiratory burst, phagocytic, lysozyme, myeloperoxidase and bacterial killing activities were determined. At the end of feeding trial, fish were challenged with Vibrio anguillarum infection and survival rate was recorded. Final weight of the both experimental fishes were significantly increased in CM treatment groups compared to control (P < .05). No difference was observed in FCR values in sea bass (P > .05), whereas a decrease in FCR was noticed in CM treatment groups of sea bream (P < .05). Moreover, oxidative radical production was significantly increased in sea bass in all treatment groups at all sampling times. In sea bream, it increased in T500 and CM500 groups on 30th day, and only in CM groups on 60th day compared to control (P < .05). Phagocytic activity was significantly increased in sea bass received only tetra extract on the 30th day compared to control (P < .05) and in all treatment groups except T1000 on 60th day. In sea bream, phagocytic activity was enhanced in all treatment groups on 30th day and only in CM500 and T1000 groups on 60th day. Lysozyme activity was elevated in all treatment groups at all sampling times in sea bass, and in T500 and T1000 groups of sea bream. Myeloperoxidase activity increased in both the fish species at any sampling time compared to that of control (P < .05). Survival rate was significantly higher in treatment groups compared to control of both fish species. These results suggest that both tetra and common mallow could be used as immunostimulants for European sea bass and sea bream with an added advantage of common mallow as a growth promoter.