Response to T3 treatment and changing environmental salinity of liver lipid composition, mitochondrial respiration and (Na++ ++ K++)-ATPase activity in rainbow trout Oncorhynchus mykiss Walbaum |
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Authors: | M Pirini A Pagliarani V Ventrella F Trombetti G Trigari & A R Borgatti |
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Institution: | Centro di Ricerca Interdipartimentale delle Scienze del Mare –Laboratorio di Biochimica Marina, Universitàdi Bologna, Italy |
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Abstract: | Rainbow trout Oncorhynchus mykiss Walbaum were fed a pelleted diet (14.3% wet weight lipid) containing 9 p.p.m. 3, 5, 3′‐triiodo‐l ‐thyronine (T3) for 1 month and then transferred from fresh water to brackish water (average 22 p.p.t. salinity), where they were maintained untreated for 22 days. Trout fed a control diet were subjected to the same protocol. For both treated and control trout, liver lipid and fatty acid composition, mitochondrial respiratory activity and oxidative phosphorylation and (Na+ + K+)‐ATPase activity were monitored in fish sampled periodically throughout the trial. No differences between treated and control trout occurred in liver total lipid, phospholipid and cholesterol content or fatty acid composition. Conversely, irrespective of T3 administration, the trout from the two habitats showed adaptive changes to salinity, differing in phospholipids and in the fatty acid composition of total and neutral lipids and selected phospholipids. Liver membrane permeability and mitochondrial respiratory activity were affected by both T3 treatment and salinity transfer. The latter was apparently greater than the former in affecting mitochondrial respiratory activity. The higher (Na+ + K+)‐ATPase activity in T3‐treated trout after 22 days in brackish water may reflect long‐term effects of the hormone linked to salinity adaptation. |
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Keywords: | liver lipids mitochondrial respiration (Na+ + K+)-ATPase rainbow trout salinity adaptation T3 treatment |
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