The study aimed to evaluate the effect of 4 levels of dietary protein (20, 30, 40 and 50%) and lipids (2, 4, 8 and 16%) on the magnitude and duration of specific dynamic action (SDA) and postprandial nitrogen excretion in the subadult white shrimp Litopenaeus vannamei using computer-controlled metabolic chambers (continuous-flow respirometer). We determined the oxygen consumption rate at 1 h intervals until the postprandial oxygen consumption rate returned to the pre-feeding level. Shrimp fed all the diets had significantly higher respiration rates after feeding due to the SDA. Oxygen consumption, the SDA coefficient and the SDA magnitude increased notably with increasing dietary protein content. Shrimp fed the 20% protein diet had the lowest levels of pre- and post-feeding respiration and the smallest SDA. A significant change in the SDA coefficient relative to each lipid level was not demonstrable. Additionally, nitrogenous excretion increased with an increase of dietary protein but not with an increase of lipid level. By estimating the SDA of subadults, the response to standard metabolic rate (SMR) was lower than that reported for juveniles and postlarva white shrimp.
