Illumination of different light wavelengths on growth performance and physiological response of juvenile sweetfish, Plecoglossus altivelis

Abstract

Light-emitting diodes (LEDs) have gained increasing popularity in fish farming because certain wavelengths of light may promote the growth and innate immune system of fish. In this study, we reported the effects of different LED wavelengths on growth performance, antioxidant defense, and innate immune responses in sweetfish. According to the results, the blue-light group showed significantly increased body weight and length after 12 weeks. In contrast, the red-light group showed significantly inhibited growth performance and decreased feeding motivation. There was no difference in survival rate among the groups during the 12-week experiment. The antioxidant defense analysis results showed that red light may cause increased splenic oxidative stress. Splenic tnf-α mRNA expression increased in the blue-light group at weeks 4, 8, and 12; however, in the red-light group, this increase was significant only at week 12. il-1β mRNA level increased at week 4 in both groups. The lysozyme mRNA expression was downregulated in the blue-light group after 4 weeks, but it decreased only at week 12 in the red-light group. Histological sections of the ovary in the blue-light group showed a higher synchronization of oocyte development compared with the red-light group. In summary, light wavelength in a captivity environment can influence the physiological response of sweetfish. This study thus demonstrated that blue LED has a positive effect on fish growth performance, antioxidant ability, innate immunity, and reproduction.

Keywords

• Sweetfish
• Antioxidant
• Innate immunity
• Light-emitting diodes
• Spleen