Quality Evaluation of Commercial Extruded Pellet Diet for Olive Flounder, Paralichtys olivaceus

This study evaluated the quality of commercial extruded pellet (EP) diet of five companies (A, B, C, D and E) for olive flounder Paralichtys olivaceus by biochemical analyses, physical properties and growth performance. The proximate analyses of five EP diets showed of moisture, of crude protein, of crude lipid, of crude ash, of crude fiber, of itrogen free extract (NFE), 304.3-395.4kcal/100g of digestible energy (DE) and 6.1-7.1 of calorie/protein ratio (C/P). Peroxide value (POV) was highest in diet D (47.4 meq/kg) as compared to other diets which in the range of 4.0-11.7 meq/kg. Total amino acid contents were ranged from 46.54 to with the highest content in diet B and the lowest content in diet C. Essential amino acid of diet C was lowest as compared to other diets which in the range of . Saturated fatty acid was higher in diet A followed by diet B , diet E, diet C and diet D. EPA+DHA were highest in diet E and lowest in diet C. The floating rate after 6 hours on the sea water was highest in diet C followed by diet B and A. However, diets D and E were completely settled down after 1 and 2 hours, respectively. The range of relative expansion rate was for all diets and all reached the peak at 2-3 hours. The water absorption rate of diets C and D was lowest, and diet E was highest at 1 hour after deposition of sea water. Growth rate was higher in diet B and E. Feed efficiency was higher in diet A and E and was significantly lowest in diet D. The protein efficiency ratio was highest in diet E (2.72) and lowest in diet D (1.76). These results suggest that there is a necessity for improvement of nutrients balance and feed physical properties to fulfill the nutrient requirements and digestive characteristics of fishes in commercial EP diets.