Effect of different dietary protein levels on growth, survival and body composition ofHediste diversicolor

The aim of this study was to investigate the effect of different dietary protein levels on growth, survival and body composition of Hediste diversicolor. Three isocaloric diets with three different protein levels containing high protein (50%), medium protein (35%) and low protein (20%) were designed in three replicates in completely randomized design. Hediste worm larvae weighing 0.02±0.005g were distributed into nine 40-L tanks with a density of 500 worms (2500 worms per m2). The worms were fed for 77 days. Results showed that final weight, final biomass (g/m2), biomass gain, specific growth rate, body weight increase and average daily growth in worms fed high protein (50%) were significantly higher than in comparison with other experimental treatments (p<0.05). The highest survival rate was recorded in worms fed medium protein (35%) (p<0.05). Worms fed 50% and 35% protein levels had the highest content of carcass protein that showed significant difference (p<0.05). Significant differences were observed in contents of lipid and ash (p<0.05). Worms fed protein at the level of 35% showed the highest level of carcass moisture (p<0.05). The lowest (p<0.05) feed conversion ratio and economic conversion ratio were seen in worms fed protein at the level of 50%. According to obtained findings, protein at the level of 50% (high) can be effective in enhancing of growth performance, feed efficiency, body composition of Hediste diversicolor and economic efficiency.