ONTOGENIC CHANGES IN METABOLIC-ACTIVITY AND BIOCHEMICAL-COMPOSITION IN THE SHRIMP, METAPENAEUS-ENSIS

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.