This study was evaluated individual growth and hematological changes of young starry flounder, using hyperpigmentation marks on the blind side of body after feeding extruded pellet (EP) and moisture pellet (MP) for 45 days. As a result, the fish grew up to 220.1±47.8 g in the EP treatment and 224.7±42.4 g in the MP treatment, so the weight gain was significantly higher in the MP treatment (74.6±17.3%) than in the EP treatment (63.7±16.9%) (P<0.05). Osmolalities of flounder after 45 days culture were similar between the treatments (P>0.05), showing values of 359.8±4.2 mOsm kg-1 in the EP treatment and 358.5±6.2 mOsm kg-1 in the MP treatment. Similarly, other blood chemistry indicators such as sodium, chloride, total protein, albumin, glucose, total cholesterol, BUN, creatinine, ammonia, triglyceride, cortisol, GOT, GPT and hematocrit showed no differences between the treatments. However, the free fatty acid concentration was significantly higher in the MP treatment than in the EP treatment (P<0.05).

A field study was conducted to compare growth, feed utilization and nutrient excretions by feeding extruded pellet (EP) and moist pellet (MP). Slow growing flounder were used as the experimental animal to find out a prominent result in terms of growth and feed utilization. Weight gain of fish fed the experimental diets for 8 weeks reached 105.3 g for EP and 107.1 g for MP, while fresh feed intake was 98.7 g for EP and 279.4 g for MP. Feed conversion ratio was 0.94 and 2.61 for EP and MP, respectively which was 0.77 and 0.94 when corrected on dry matter basis. Even though protein efficiency ratio (2.26 vs 2.21), specific growth rate (0.69% vs 0.70%), daily weight gain (2.06 g vs 2.10 g) and mortality (4.0% vs 4.1%) were similar between EP and MP, protein retention efficiency of fish fed EP was superior (53.3%) to that of fish fed MP (39.6%). Protein intake of fish for 8 weeks was similar from 52.3 g for EP to 53.3 g for MP, while protein gain was higher in fish fed EP (27.9 g) than in fish fed MP (21.1 g). Protein excretion by feeding EP and MP reached 232 g and 300 g, respectively per kg gain, suggesting that protein loads could be greatly reduced in practical culture system through the use of EP. Phosphorus (P) intake was much lower in fish fed EP (1.63 g) than in fish fed MP (2.18 g), while retention of P was higher in fish fed EP (0.88 g) than in fish fed MP (0.78 g), showing the retention efficiency of 54.0% and 35.9%, respectively. Fish fed EP excreted 7.1 g of P per kg gain which was much lower than that of fish fed MP (13.1 g). The present results clearly showed that EP feeding for flounder is not only productive but also environmentally friendly.

본 연구에서는 단백질(51~5%) 및 지질(9~15%) 함량이 다른 배합사료(EP)와 생사료(MP)를 공급하면서 사육한 양식넙치의 육질을 비교해 보고자 하였다. 사육실험은평균체 중 106g의 넙치를 원형수조에 40마리씩 실험구별로 2반복으로 수용하면서, 단백질 및 지질 함량이 서로 다른 실험 배합사료(EP1, EP2, EP3)와 수입산 상품 배합사료(EP4) 및 MP를 16주간 공급하면서 사육하였다. 수분함량은 생사료(MP)를 공급한 넙치의 등근