Osmoregulatory actions of growth hormone in juvenile tilapia (Oreochromis niloticus) |
| |
| Authors: | B Xu H Miao P Zhang D Li |
| |
| Institution: | (1) Fisheries College, Ocean University of Qingdao, Qingdao, 266003, P.R. China;(2) Marine Life Sciences College, Ocean University of Qingdao, Qingdao, 266003, P.R. China;(3) Laboratory of Experimental Marine Biology, Institute of Oceanology, Academia Sinica, Qingdao, 266071, P.R. China |
| |
| Abstract: | Growth hormone (GH) effectively promotes seawater (SW) adaptation in salmonids, but little is known of its effect in tilapias. Experiments were performed to investigate the effects of recombinant eel GH (reGH) on osmoregulatory actions and ultrastructural features of gill chloride cells in juvenile tilapia, Oreochromis niloticus. Tilapia showed a markedly improved SW survival, when directly transferred from freshwater (FW) to 62.5% SW 24h after a single reGH injection (0.25 or 2.5 µg g-1) or 3 reGH injections (0.25 µg g-1 every other day). Plasma Na+ and Mg2+ levels were significantly reduced by reGH (0.25 and 2.5 µg g-1) compared with saline injections; Ca2+ concentrations were reduced significantly by high dose of reGH (2.5 µg g-1) after SW transfer. However, fish failed to survive more than 24h when directly transferred to 70% SW, although the fish treated with reGH could survive longer than the controls. When examined by electron microscopy, the chloride cells were identified as mitochondrion-rich and an extensive tubular system was induced by GH treatment. The results of the present study suggest that, similar to its effect on salmonids, GH also exerts acute osmoregulatory actions and enhances SW adaptation in juvenile tilapia. GH also stimulates the differentiation of chloride cells toward SW adaptation. |
| |
| Keywords: | tilapia Oreochromis niloticus osmoregulation growth hormone seawater adaptation plasma ions gill chloride cells mitochondrion-rich tubular system |
| 本文献已被 SpringerLink 等数据库收录！ |
|
