Abstract
The concentration of free fatty acids (FFA) in blood plasma of rainbow trout (Salmo gairdneri) maintained without food for 1–70 days averaged 424 (range 160–1003) μ equivalents FFA per liter plasma. The effect of starvation on the level of plasma FFA was limited, showing a more significant increase during the first 2 weeks without food than during prolonged periods of starvation. FFA in lateral line muscle averaged 147 (range 27–258) μ equivalents per 100 g wet tissue and during starvation a trend generally similar to that found for plasma FFA was observed. Starvation had no effect on the amounts of FFA in white dorsal muscle which averages 37 (range 13–73) μ equivalents per 100 g wet tissue. The results are discussed in relation to the mechanism of utilization of fat reserve in fish.