Meeting Abstract
Specific dynamic action (SDA) is the rise in metabolism associated with processing a meal and can be a substantial metabolic cost in teleost fishes. SDA is commonly quantified as the peak postprandial metabolic rate, time to peak rate, time to return to standard metabolic rate (SMR), and metabolic expenditure above SMR. Cobia, a popular sport fish, is now widely cultured for food partially due to its fast growth rate. In culture, cobia have been reported to grow up to 8 kg in a year. Protein synthesis has been shown to be the cause for up to 44% of the metabolic increase of SDA in fishes, and many researchers have posited that an increased rate of protein synthesis increases growth potential. A faster and larger SDA may lend a higher rate of protein synthesis that in turn increases the growth potential of fishes. Here we test the hypothesis that cobia exhibit a shorter duration and larger magnitude of SDA than other species reported in the literature. Using respirometry, the oxygen consumption rates of juvenile cobia were measured either after a 24-hour starvation period or immediately after being fed to satiation. Fed cobia did not have a substantially faster nor larger SDA than many values found in the existing literature. From the starved cobia, SMR was 10.6 ± 0.2 (mean ± s.e.) mmol kg -1 hr-1, which is similar to SMR values found present in the literature. In cobia, the fast growth may be more related to high food consumption rates than to specialization of digestive metabolism.
