Protein synthesis and specific dynamic action in crustaceans: effects of temperature

Temperature influences the specific dynamic action (SDA), or rise in oxygen uptake rate after feeding, in eurythermal and stenothermal crustaceans by changing the timing and the magnitude of the response. Intra-specific studi es on the eurythermal crab, Carcinus maenas, show that a reduction in accli mation temperature is associated with a decrease in SDA magnitude, resultin g from an increase in SDA duration but a decrease in peak factorial scope ( the factorial rise in peak SDA over prefeeding values). Inter-specific feed ing studies on stenothermal polar isopods revealed marked differences in SD A response between the Antarctic species, Glyptonotus antarcticus and the A rctic species, Saduria entomon. Compared to S. entomon held at 4 and 13 deg reesC, the SDA response in G. antarcticus held at 1 degreesC was characteri sed by a lower absolute oxygen uptake rate at peak SDA and an extended SDP; duration. At peak SDA, whole animal rates of protein synthesis increased i n proportion to the postprandial increase in oxygen uptake rate in the Anta rctic and the Arctic species. Rates of oxygen uptake plotted against whole animal rates of protein synthesis gave similar relationships in both isopod species, indicating similar costs of protein synthesis after a meal, despi te their differences in SDA response and thermal habitat. (C) 2001 Elsevier Science Inc. All rights reserved.