The effects different levels of vitamin e added to the ration of freshwater crayfish (Astacus leptodactylus Esch. 1823)living in Keban Dam Lake

This study was carried out between July 2002- August 2003. In the present study, the effectsof different levels of vitamin E added to the ration of freshwater crayfish (Astacus leptodactylus),which will be sexually mature first time, were investigated. The live weight gain, relative growth rate,specific growth rate, condition factor, montly food intake, daily food intake, food conversion ratio,food efficiency ratio, protein efficiency ratio and survival rate were taken montly and hepatosomaticindex, the levels of lipid peroxidation and vitamin E content in the abdomen muscle andhepatopancreas of crayfish were investigated at the end of the study. In addition to these parameters,the effects of dietary vitamin E on the abdominal eggs and stage 1 juvenile numbers were alsoresearched.For this aim, a control (K) and there treatment (D1, D2, D3) rations were prepared. The controlration constituted 65.83 mg/kg vitamin E. 34.17 mg/kg, 84.17 mg/kg and 134.17 mg/kg vitamin E (α-tocopherol acetat) were added to the control ration in order to prepare the treatment rations D1, D2, D3respectively. The study was carried out with 3 replicates for each dietary treatment.In conclusion, it was found that the different levels of vitamin E added to the ration of crayfishdid not have an impact significantly on the values of live weight gain, relative growth rate, specificgrowth rate, condition factor, montly food intake, daily food intake, food conversion ratio, foodefficiency ratio, protein efficiency ratio, survival rate and hepatosomatic index (p>0.05). The bestresults for abdominal eggs and first stage juvenile number, and for the level of vitamin E content in theabdomen meat and hepatopancreas were obtained from the treatment 2 (D2) containing 150 mg/kgvitamin E (p<0.001). On the other hand, it was found that 100 mg/kg vitamin E is enough to preventlipid peroxidation in the muscles of abdomen and hepatopancreas. In addition, the present studyshowed that there was not a significant difference between the high levels of vitamin E (150 and 200mg/kg) in the preventation of lipid peroxidation.Key words: Freshwater crayfish, Astacus leptodactylus, vitamin E, growth performance, lipidperoxidation, abdominal eggs, first stage, juveniles.