Effect of bovine lactoferrin on performance of Japanese flounder Paralichthys olivaceus

This work aimed to determine the effect of dietary bovine lactoferrin (LF) on performance of juvenile Japanese flounder Paralichthys olivaceus. Five isocaloric, isonitrogenous diets containing different levels of LF (0, 300, 700, 1,000 and 2,000 mg/kg) were fed to juvenile Japanese flounder (6.6 +/- 0.2 g/fish) during a 30-day feeding trial. Growth, survival and tolerance to exposure to the air were statistically analysed. Recovery percentage was significantly lower and time to death after air dive test was shorter in fish fed the diet without LE Furthermore, higher percentages of red spots in the ventral side of the body were found when fed the diet without LE Percentages of stiffness and curvature of the body were statistically lower in fish fed LF at 1000 and 2,000 mg/kg than in fish fed the diets without LE Higher mucus secretion was observed in fish fed the diet without LF, than fish fed with LF-containing diets. The present study demonstrated that dietary LF may enhance the biodefense ability of juvenile Japanese flounder supporting a better condition of this species, which is one of the most important goals in programs of restocking natural populations through releasing, and aquaculture activities.