Effects of dietary propolis and vitamin E on growth performance and antioxidant status in blood of juvenile Rainbow trout, Oncorhynchus mykiss (Teleostei: Salmoniformes) under different flow rates

the present study investigated the effects of propolis and vitamin e supplementation in diets of juvenil rainbow trout subjected to two different flow rates with or without flow stress (0.9 and 2.1 l/min, respectively) on final weigth (fw), condition factor (cf), feed conservation ratio (fcr), protein efficiency ratio (per) and vitamin a, c and e concentrations and malondialdehyde (mda) levels in serum as well as plasma superoxide dismutase (sod) activity. the experimental groups were as follows: group c was fed a basal diet, group p10 was fed a basal diet supplemented with 10 g propolis/kg, group p30 was fed a basal diet supplemented with 30 g propolis/kg, group e60 was fed a basal diet supplemented with 60 mg vitamin e/kg. cf and per were not different among all diets groups for both flow rate treatments (p > 0.05). the fcr improved in p10, p30 and e60 diet groups compared to c diet group at 2.1 l/min flow rate (p < 0.05). the fcr of e60 and p30 were found to be better than c and p10 diet groups at 0.9 l/min flow rate (p < 0.05). vitamin e and propolis supplementations did not affect vitamin a concentration of serum for either flow rate (p > 0.05). fish fed with diet e60had higher serum vitamin e concentration than other groups (p < 0.05). serum vitamin c concentration was only affected by the propolis supplemented diets. mda level of e60 group was found significantly lower comperad to other groups for both flow rate (p < 0.05). plasma sod activity significantly decreased in the e60 group compared to other groups at 2.1 l/min flow rate (p < 0.05). but plasma sod activity was not different among all diets groups at 0.9 l/min flow rate (p > 0.05).