Effects of different levels of lipid on growth and body composition of Siberian sturgeon Acipenser Bearii Brandt, 1869

In a feeding trial, the effects of four levels of lipid (10, 15, 20 and 25%) and raw energy (including 18.8, 19.9, 21.4 and 22.5 kJ) with the same protein (45%) were evaluated to determine the appropriate level of lipid and dietary energy on growth performance and carcass composition of Siberian sturgeon (A. bearii). A total of 120 fish (15.6 ± 0.33 g) were randomly assigned to 12 fiberglass tanks of 500 liter (n=10 per tank) and fed manually 3 times per day for 12 weeks with ad libitum feeding. Results of growth trend at the end of the period showed that the fish fed with lipid content of 10 to 15 percent obtained significantly more weight gain (WG) and specific growth rate (SGR) than the fish fed with diet containing 20 and 25 percent of lipid. However the feed conversion ratio of fish fed with lipid content of 10 to 15 percent was significantly lower than other treatments. Analysis of fish carcasses indicated the significant differences in the composition of lipid, protein and ash. According to the results of present study, increasing of the lipid levels in diet of Siberian sturgeon (A. bearii) up to 15% can cause an improvement in growth rate, diet efficiency and carcass composition.