STUDY ON EFFECTS OF GREEN LIGHT EMITTING DIODES ON GROWTH OF OLIVE FLOUNDER Paralichthys olivaceaus

In recent years, the use of light emitting diodes is gaining increasing attention due to its potential antimicrobial activities without adverse effects. Besides, previously studies clearly indicated that the effects of light wavelength are probably species specific. Since data related to light wavelengths and olive flounder are still few, the aims of this study were to determine the effects of LED with different wavelengths on growth performance of olive flounder, the most economical fish species in Korea.

Six hundred fish (34.3±4 g) were randomly divided into 4 groups (exposed to ambient light, 405 nm, 520 nm, and mixed lights (simultaneously exposed to 405 nm and 520 nm) for 12 weeks under 12L: 12 D photoperiod with light intensity of 10 and 20 μ.mol.m^-2.s^-1 for 405 nm and 520 nm, respectively. Fish were hand-fed to satiation every two days. Fish weight were measured at 0, 4, 8, and 12 wpe for calculating growth performance. At 0 and 12 weeks, 10 fish were sacrificed for determining the expression level of growth hormone (GH), stress (HSP70), and immune-related genes (SOD, caspase-3, and catalase).

Present results show that all growth parameters in fish exposed to 520 nm and mixed lights groups was significantly higher than those of fish in the control group (Table 1). The expression level of growth hormone in fish under 520 nm was significantly higher than other groups (Figure 1). There were no significant differences in expression levels stress and immune-related genes (SOD, caspase-3, and catalase). In addition, fish exposed to LED did not induce any change in serum glucose level and histological in eye compared to the control group. Present results indicate that olive flounder under 520 nm and mixed lights had favorable effects on fish growth without effect on their immune system. In addition, growth hormone would play an important role on enhancing the growth of olive flounder