D.T. Haghighi
C.R. Saad
H. Hosseinzadeh Sahafi
D. Mansouri

The study was conducted with a completely randomized design consisting of four treatments in triplicates. Experimental diets were formulated to contain four different lipid levels (۸, ۱۰, ۱۲ and ۱۴%) at constant protein level (۴۶.۸%) and different gross energy of ۴۳۱۴, ۴۴۱۷, ۴۵۱۹ and ۴۶۲۲kcal/kg, respectively. Kutum fry (average weight, ۲۰۳±۴mg) were randomly assigned and distributed at a density of ۲ fish/l into twelve ۸۰ liter fiberglass tanks equipped with a tap-freshwater system and water temperature of ۲۲-۲۴oC. Fish were fed the experimental diets thrice a day at ۱۰% of body weight for ۸۱ days. Statistical analysis indicated that fish fed the lowest lipid level of ۸% showed significant differences (p<۰.۰۵) with other treatments. Fish growth, survival, protein and energy retention showed a marked decrease with an increase of dietary lipid level. Crude lipid of carcass composition increased, but ash and moisture decreased with an increase of lipid levels.

Rutilus frisii kutum, Dietary lipid, Nutritional performance, Feed conversion ratio