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 (8, 10, 12 and 14%) at constant protein level (46.8%) and different gross energy of 4314, 4417, 4519 and 4622kcal/kg, respectively. Kutum fry (average weight, 203±4mg) were randomly assigned and distributed at a density of 2 fish/l into twelve 80 liter fiberglass tanks equipped with a tap-freshwater system and water temperature of 22-24oC. Fish were fed the experimental diets thrice a day at 10% of body weight for 81 days. Statistical analysis indicated that fish fed the lowest lipid level of 8% showed significant differences (p<0.05) 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.