effect of dietary free l-lysine on growth performance and muscle composition of beluga huso huso (linnaeus 1785) juveniles

effect of dietary free l-lysine on growth, food intake, and muscle composition of beluga juveniles were investigated over 6 weeks. control diet lysine content was 2.1% of dry matter (4.4% of dietary protein). three experimental diets were prepared by adding lysine (0.5, 1 and 1.5%) to control diet to obtain diets containing 2.6, 3.1 and 3.6% of dry matter lysine (corresponding to 5.5, 6.6 and 7.6 of dietary protein). fish were fed 2.6% of dry matter lysine showed significantly higher final weight, weight gain and sgr and lower fcr compared to other treatments. there was no significant change in food intake and survival between treatments. lysine supplementation resulted significantly in increase and decrease in muscle protein and lipid, respectively. dietary lysine has no effect on muscle ash and moisture content. results showed that lysine supplementation had no significant effect on food intake in beluga juveniles. it seems that dietary lysine level of 2.6% of dry matter (corresponding to 5.5% of dietary protein) is suitable for growth of beluga juveniles.