The effect of dietary lipid level on the growth of kutum fry (Rutilus frisii kutum)

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.

Keywords:

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