Aquaculture Studies 2020, Vol 20, Num, 1     (Pages: 11-18)

Effects of Long-Afterglow Phosphorescent Pigments on Somatic Growth in Juvenile Goldlined Spinefoot Siganus guttatus

Chihiro Yamauchi 1 ,Yuki Takeuchi 1-2 ,Akihiro Takemura 1

1 Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan
2 Okinawa Institute of Science and Technology Graduate School, 1919-1 Tancha, Onna, Okinawa 904-0495, Japan
DOI : 10.4194/2618-6381-v20_1_02 Viewed : 1008 - Downloaded : 2143 The purpose of the present study was to examine effectiveness of light emitted by long-afterglow phosphorescent pigments (LAPP) on the somatic growth of juvenile goldlined spinefoot. Comparison was done between juveniles in the aquarium with LAPP (exposure group) and those in the aquarium without LAPP (control group). When juveniles were reared under these conditions for more than 1 month, relative increase in somatic growth and average of specific growth rate of the juveniles (1-month-old, but not 9-month-old) in the exposure group were significantly higher (P < 0.05) than those in the control group. These results suggest that wavelength (520 nm) and period (at least 3 hours) of light emitted from LAPP after dusk stimulate the somatic growth of younger juveniles. The qPCR revealed that mRNA abundance of growth hormone (GH) in the pituitary was significantly higher (P < 0.05) in the control group than that in the exposure one, while an opposite effect was seen in that of insulin-like growth factor-I (IGF-I) in the liver. It is suggested that mRNA expression of IGF-I, but not GH, was stimulated by light from LAPP. It is concluded that LAPP becomes a useful tool for aquaculture promotion through stimulation of somatic growth in juveniles. Keywords : Growth hormone, Growth rate, Insulin-like growth factor, LumiNova