In the present study, differences in oxygen consumption, may be related to postlarvae
behavior and differences in energy demand in the different stages. This could also
explain the absence of a decrease in the weight-specific respiration rate with increasing
animal size, as is generally found in crustaceans.
A change in ammonia excretion according to the diet fed and stages was observed. A
higher ammonia excretion was observed in all stages when animals were fed MCD
compared to postlarvae fed with the other diets. These differences could be explained as
a result of deamination of amino acids derived from the diet, which are related both to
quality and quantity of dietary protein. According to Claybrook (1983), deamination
occurs when dietary protein is deficient in one or more essential amino acids or there is
poor amino acid balance, when excess amounts of protein have been ingested, or when
there is insufficient energy from lipids and carbohydrates to support body processes.
Higher ammonia excretion observed in postlarvae fed on MCD could be related to some
deficiency in the protein balance of the diet, which when mixed with live food produced
a decrease in ammonia excretion by L. setiferus postlarvae.