Ontogenetic changes in metabolic activity and biochemical composition in the shrimp, Metapenaeus ensis

Abstract

The shrimp Metapenaeus ensis (de Haan) were reared from eggs to postlarvae (PL). Biochemical composition, oxygen consumption, and ammonia excretion were quantified at selected developmental stages. The nauplius V–VI, with a lower weight than the egg, also has reduced amount of protein, lipids, carbohydrates and water. The nauplius exhibited higher weight-specific oxygen consumption and ammonia excretion rates than the egg and the protozoeal larva. From protozoea III to 3-day PL, there was a general increase in weight-specific oxygen consumption rate while ammonia excretion rate remained relatively stable with age. A lower oxygen consumption in the 9-day PL was possibly associated with the shift to a benthic mode of life. There was a general rise in oxygen consumption in all feeding stages upon food intake but ammonia excretion rates were unaffected. A lower O:N ratio under starved condition suggested the catabolism of constituent protein, which was the principal biochemical constituent of all stages. There was a general increase in ash and decrease in water, lipid and carbohydrate levels during larval and postlarval development.