Effect of LED light spectra on reproductive performance of Koi carp (Cyprinus carpio)

The present study aimed to evaluate the reproductive performance of Koi carp, Cyprinus carpio exposed to different light spectra using light-emitting diodes, LEDs: blue (peak at 450nm), green (530 nm), yellow (580nm) and red (630nm) within a visible light under long photoperiod (16h, light: 8h, dark) at ≍0.9 W/m² lightintensity. White fluorescent light (simulated natural photoperiod, SNP) was used as control. The last 30 days of total experimental period (120 days), fishes from all the groups were uniformly exposed to green-LED light to assess the reproductive recovery. The highest levels of both male and female GSI, ova diameter, VTG and sex steroid hormones on 90^th day were recorded in green-LED fish group. In case of male the highest concentration of 11-KT hormone was also found in green-LED fish group on 90^th day. Yellow and red-LED fish groups showed significant lower level of above parameters compared to control (SNP) group. Yellow and red-LED fish group showed significant retrieval in gonadal maturation during the recovery period. Therefore, the present study indicates that green light accelerates gonadal maturation of koi carp and use of particular spectrum light likely to facilitates the more-energy efficient aquaculture practices.