The effects of three diets on some growth performance of whitefish (Coregonus lavaretus) fry

In a 3 months experiment, the effects of three different kinds of food rations including culture rotifers, commercial food and the equal amount mixture of these two foods were studied on some growth specifications and survival of the whitefish (Coregonus lavaretus) fry. The initial average weight and length of the fry were 0.009 g and 4 mm, respectively. The period of experiment was among April to July 2003. The assessed characteristics variance analysis showed that the different food treatments caused very significant differences among the all averages (p < 0.01). Comparing the characteristics averages showed that during the first month of experiment, the best results of weight (0.029 g), total length (8.78 mm), specific growth rate (5.36%) and food efficiency (63.48%) were obtained in live food treatment, whereas the weakest averages of referred characteristics were observed in commercial food treatment. During the last month of experiment, some of the above results reversed so that the best averages of specific growth rate (3.73%) and food efficiency (44.3%) were observed in commercial food treatment. The results of this study showed that the use of rotifer as live food for fry has provided better survival rate than the other two treatments. However, this food could not provide the best results for the all measured characteristics in all of the experiment period, for the reason that during the third month of experiment period, using commercial food treatment which consist of more miscellaneous nutrient components, created better results for some fry's characteristics than the live food.