Effect of Starvation on Free Fatty Acid Level in Blood Plasma and Muscular Tissues of Rainbow Trout (Salmo gairdneri)

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.