Hypothermal Effects on Energy Supply for Ionocytes in Gills of Freshwater- and Seawater-Acclimated Milkfish, Chanos chanos

The milkfish, Chanos chanos , is an important aquaculture species that can be cultured in freshwater (FW) and seawater (SW) ponds because of its high euryhalinity. In winter, cold snap leading to mortality this tropical a critical issue for the industry Taiwan. Under hypothermal stress, however, changes energy supply osmoregulation euryhaline intriguing. study, we used antibody against glycogen phosphorylase (GP) identify glycogen-rich (GR) cells distributed adjacent mitochondria-rich (MR) ionocytes milkfish gills. Glucose transporter 1 (GLUT1), which plays major role supply, was also identified localized GR cells. Moreover, expression indicators aerobic metabolism production, citrate synthase (CS) cytochrome c oxidase (COX), were analyzed gills FW- SW-acclimated reveal different strategies utilization under stress. When exposed low-temperature environment, SW individuals branchial lactate match demands ionocytes, elevated capacity support maintain normal functions However, mainly FW not utilized Meanwhile, similar level COX activity COXIV protein abundance at low temperatures between indicated requirements This suggested another source, but glycogen, maintained demand milkfish. present study illustrated differential SW- FW-acclimated temperatures.