Title Physiological Studies on Nutrition-Reproduction Network ofTropical Sapphire Devil Damselfish (Chrysiptera cyanea)( Abstract_論文要旨 )
Author(s) Angka, Mahardini
Citation
Issue Date 2020-09-18
URL http://hdl.handle.net/20.500.12000/47148
Form 3 Abstract Title Physiological Studies on Nutrition-Reproduction Network of Tropical Sapphire Devil Damselfish (Chrysiptera cyanea) 熱帯性スズメダイ Chrys1pteracyaneaの栄養一生殖システムに関する生理学的研究 In fish reproduction, photoperiod and water temperature have been well-proven to be the principal factor that could determine its success. However, the stimulation of these factors become ineffective without sufficient nutrition intake. In addition to provide evidences regarding the critical involvement of nutrition in the tropical fish reproductive success, this study aims to discover the possible physiological mechanism of this nutrition-reproduction network. To address these point, closer attention was taken on the possible role of nutrition or growth-related genes from two potential axes, the growth (growth hormone [gh] insulin-like grow出 factors [igfs]) and hypothalamic-pituitary~thyroid (HPT; iodothyronine deiodinase type 2 [ dio2] and'3 [ dio3]) axes. The results of this study sh9wed that; ovarian activity d田ingthe spawning season was maintained by high food S1Jpply (HH) for 30 days, although it was sup -pressed in the food-restriction treatment (LL) and restored in the re-feeding treatment (LH). The transcript levels of igfs in the-brain, but not in the liver, in LH were lower than those in prolonged satiation and starving groups (HH and LL, respectively). Moreover; the transcript levels of dio2 in the liver and dio3 in the ovary increased as vitellogenesis progressed, suggesting that, through the metabolism of THs, _dio2 and dio3 play a role in vitellogenin synthesis in the liver and・yolk accumul_ation/E2 synthesis in the ovary. Additionally, fish were kept under long-days and 25-2~°C failed to perform vitellogenesis under low food (LF) condition. Food limitation lowered hepatic ig/1 and dio2, suggesting that the TH-IGFl signaling system functions in the liver, and that food availability altered hepatic deiodination・activities related to intercellular levels of thyroid hormones. In conclusion, IGFl is a potential regulator for the cross-interaction between nutrition and reproduction.・Moreover, it could be concluded that the nutrition-stimulated vitellogenes1sinsapphire devil seems to be mediated by the crosstalk between TH and IGFl in the liver and the protein metabolism with certain variable including ATP is potentially involved in this mechanisms. Name Angka Mahardini
