Jul, 1997
Physiological and respiratory responses of the Mozambique tilapia (Oreochromis mossambicus) to salinity acclimation
Comparative Biochemistry and Physiology - A Physiology
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- Volume
- 117
- Number
- 3
- First page
- 391
- Last page
- 398
- Language
- English
- Publishing type
- DOI
- 10.1016/S0300-9629(96)00261-7
We have examined several physiological variables related to salinity acclimation in the euryhaline tilapia, Oreochromis mossambicus. Tilapia reared in fresh water (FW) were transferred to FW, isosmotic salinity (ISO, 12‰%) and 75% seawater (SW, 25‰). Oxygen consumption, plasma levels of cortisol, growth hormone (GH), prolactins (tPRL177 and tPRL188), glucose, ions (Na+, K+, Cl-), and gill Na+,K+-ATPase activities were measured for up to 4 days in each salinity treatment. Plasma Na+ and Cl- concentrations were elevated 1 day after transfer to SW, but returned to FW values on day 4. Plasma cortisol and glucose levels were higher in FW and ISO than in SW 1 day after transfer. Plasma GH levels of tilapia in SW increased above FW and ISO values after 4 days, whereas plasma PRL levels decreased in ISO and SW compared to FW at 4 days. These results are consistent with the possible osmoregulation roles of GH and PRL in SW and FW, respectively. Gill Na+,K+-ATPase activity of tilapia in SW increased more than 2-fold over the FW value after 4 days, but activity of this enzyme did not change in ISO. Oxygen consumption rates of tilapia in SW were significantly elevated 4 days after transfer compared to FW and ISO. The results of this study indicate that the physiological changes associated with SW acclimation in tilapia represents a significant short-term energetic cost, and may account for as much as 20% of total body metabolism after 4 days in SW.
- Link information
- ID information
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- DOI : 10.1016/S0300-9629(96)00261-7
- ISSN : 0300-9629
- SCOPUS ID : 0031195087