Commercial Scale Evaluation of Practical Extruded Pellet Feed for the Olive Flounder (Paralichthys olivaceus)

This study was conducted to evaluate the effects of extruded pellet (EP) diets, as compared to a raw fish moist pellet (MP) diet for olive flounder, Paralichthys olivaceus, grown in commercial-scale aquaculture for 1 year. Four diets with duplication per diet were formulated for this experiment: two experimental EP diets (EP1 and EP2), one commercial EP diet (CEP), and a raw fish MP diet (MP). The MP diet consisted of 80% frozen horse mackerel and 20% commercial binder meal. Fish weighing () were distributed randomly to each aquarium as a group of 2,600 fish. Weight gain (WG) and feed efficiency ratio (FER) of fish fed EP2 and MP were higher (P0.05) from those fed EP2 and MP. However, fish fed the MP diet had a higher survival rate than fish fed the other diets. Fish fed EP2 had higher serum, phospholipids and total protein levels, and lower levels of serum glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), and total cholesterol than fish fed MP (P0.05). These results strongly suggest that EP1 could be developed to replace MP for grow-out stage production of olive flounder without adverse effects on growth performance.