| Brown trout and rainbow trout (average weight 100 g) were reared in fresh water at 12 degrees C under the same conditions before transfer of brown trout to sea water, in order to compare nitrogen utilisation in the two species. Apparent protein digestibility (ADC), nitrogen (ammonia and urea) excretion, protein productive value (PPV) and actual observed nitro en mass balance were determined. Rainbow trout raised in fresh water had a higher growth rate (1.1 vs 0.8%. d(-1)), better food conversion ratio (0.7 vs 1.0), better ADC (91 vs 85%) and PPV (45 vs 35%) and lower ammonia excretion rates than brown trout reared in fresh water. Transferring brown trout to sea water induced lower PPV (30%) and ammonia and urea excretion. Salinity did not modify metabolic... |
