Effect of food deprivation on oxygen consumption and body composition of growth-enhanced transgenic Atlantic salmon (Salmo salar)

The influence of food deprivation on the rate of oxygen consumption and the rate of mobilization/utilization of energy reserves in F-2 generation grow th-enhanced transgenic Atlantic salmon were compared relative to their non- transgenic counterparts, over a pre-smelt weight interval of 8 to 55 g. Throughout most of the 8 weeks of food deprivation, transgenic fish exhibit ed a greater rate of oxygen consumption compared to control salmon, but als o exhibited a more rapid decline in oxygen consumption as starvation progre ssed. Consequently, depending on initial weight and length of food deprivat ion, the rate of oxygen consumption of transgenic fish declined to where it equaled or was less than the oxygen consumption of control fish. Transgeni c fish depleted body protein, dry matter, lipid and energy at a faster rate than did the controls. Additionally, in both groups, lipid was catabolized raster than was protein. Although transgenic fish demonstrated the ability to reduce their metabolic rate during starvation, as also observed in the non-genetically modified c ontrol salmon, their persistence in maintaining a higher metabolic rate, co mbined with their lower initial endogenous energy reserves, suggests that t he likelihood of growth-enhanced transgenic salmon achieving maximum growth or even surviving outside intensive culture conditions may be lower than t hat of non-transgenic salmon. (C) 2000 Elsevier Science B.V. All rights res erved.