Use of Distillers Dried Grain as a Cost Effective Ingredient in the Diet of Juvenile Olive Flounder (Paralichthys olivaceus)

This study assessed the effects of the dietary inclusion of distillers dried grain (DDG) on growth performance, feed utilization, body composition, and antioxidant activity in juvenile olive flounder (Paralichthys olivaceus). Five diets (DDG0, DDG1, DDG2, DDG3, and CF) were formulated to contain 0% (DDG0), 20% DDG (DDG1) replacing wheat flour only, and 20% DDG (DDG2) and 28% DDG (DDG3) partially replacing both fishmeal and wheat flour. Experimental diets were also compared with a commercial feed (CF) diet. Three replicate groups of fish average weight 16.0±0.04 g were fed each of the diets to apparent satiation twice a day for 7 weeks. Weight gain of fish fed the DDG1 and DDG2 diets was the same as fish fed DDG0 diet, but there was less weight gain in fish fed the DDG3 diet than those fed the DDG0 and CF diets. Feed efficiency, daily feed intake, daily protein intake, and protein efficiency ratio were not affected by dietary DDG and CF diets (P>0.05). Whole body content (WBC) of crude lipid in fish fed the DDG1 and CF diets was the same as fish fed DDG0 diet. WBC was higher in fish fed the DDG2 and DDG3 diets than in fish fed the DDG0 diet. Amino acid composition of whole body was not affected by dietary DDG and CF diets (P>0.05). Plasma content of total protein, cholesterol, and triglyceride, tended to decrease with dietary DDG level, and was lower in fish fed the DDG3 diet than fish fed the DDG0 and CF diets. DPPH, hydroxyl, alkyl and superoxide radical scavenging activities in the plasma of fish were not affected by dietary DDG and CF diet (P>0.05). The results suggest that up to 20% DDG in the diet could be used to replace plant components such as wheat flour and corn gluten meal, without negatively affecting growth performance of juvenile olive flounder.