Evaluating Growth Performance, Amino Acid Profile and Biochemical Changes in Juvenile Olive Flounder, Paralichthys olivaceus under Partial Feeding with Fermented Soybean Meal

This study was carried out to investigate the effect of replacing fish meal protein with fermented soybean meal (FSM) in diets on growth performance, feed utilization, morphological parameters, body composition, activities of antioxidant and digestive enzymes and also blood biochemistry of juvenile olive flounder (Paralichthys olivaceus). Five isonitrogenic and isolipidic diets were prepared to contain 0 (control), 80, 160, 240 and 320 g kg-1 FSM in diets. Triplicate groups (30 fish for each tank) of juvenile olive flounder averaging 11.9±0.19 g were fed each diet to visual satiation at two meals per day for 8 weeks. The fish fed diets containing up to 240 g kg-1 FSM had no significant differences in the survival, final growth, specific growth rate, feed efficiency and protein efficiency ratio compared with control group. Fish fed diet containing 320 g kg-1 FSM showed significantly lower survival, growth, specific growth rate, feed efficiency and protein efficiency ratio than in control group. Triglyceride and total protein contents of plasma in fish fed with the FSM diets as well as hepatosomatic indices were greater in fish fed with diets containing 240 and 320 g kg-1 FSM than in control. Proximate composition, amino acid profile of dorsal muscle, activity of digestive enzymes in intestine and activity of antioxidant enzymes in liver and plasma were not affected by different levels of FSM compared with control group. This study showed that FSM has potential to replace fish meal up to 240 g kg-1 diet for growth of juvenile olive flounder but better growth performance obtained with 80 g kg-1 diet.