Effects of Dietary β‐1,3 Glucan and Feed Stimulants in Juvenile Olive Flounder, Paralichthys olivaceus

Abstract

Abstract.— The present study was conducted to investigate the effects of dietary supplementation of β‐1,3 glucan and a laboratory developed feed stimulant, BAISM, as feed additives for juvenile olive flounder, Paralichthys olivaceus. Eight experimental diets were formulated to be isonitrogenous and isocaloric and to contain 50.0% crude protein and 16.4 kJ of available energy/g with or without dietary β‐1,3 glucan and BAISM supplementation. β‐1,3 glucan (G) and BAISM (B) were provided at 0% in the control diet (G0B0) and at 0.05% G + 0.45% B (G0.05B0.45), 0.05% G + 0.95% B (G0.05B0.95), 0.1% G + 0.90% B (G0.1B0.9), 0.10% G + 1.90% B (G0.1B1.9), 0.15% G + 1.35% B (G0.15B1.35), 0.15% G + 2.85% B (G0.15B2.85), and 0.30% G + 2.70% B (G0.3B2.7) in experimental diets. After the feeding trial, fish fed G0.1B0.9, G0.1B1.9, and G0.15B1.35 diets had higher percent weight gain (WG), feed efficiency ratio (FER), specific growth rate (SGR), protein efficiency ratio (PER), and condition factor (CF) than those fed G0B0, G0.05B0.45, G0.05B0.95, G0.15B2.85, and G0.3B2.7 diets (P < 0.05); however, there was no significant differences among fish fed G0.1B0.9, G0.1B1.9, and G0.15B1.35 diets. Fish fed G0.1B0.9 and G0.1B1.9 diets had higher chemiluminescent responses (CL) than those fed the other diets (P < 0.05). Lysozyme activity of fish fed G0.1B0.9 diet was significantly higher than that of fish fed the other diets (P < 0.05). These results indicated that the optimum dietary supplementation level of β‐1,3 glucan and BAISM could be approximately 0.10% β‐1,3 glucan + 0.90% BAISM (G0.1B0.9) of diet based on WG, FER, SGR, PER, CF, CL, and lysozyme activity in juvenile olive flounder, P. olivaceus.