Effects of Water Temperature and Post-Feeding Period on Postprandial Ammonia Excretion and Oxygen Consumption by Larval Pacific Cod (Gadus macrocephalus) Fed Rotifers (Brachionus plicatilis)

摘要

Postprandial ammonia excretion and oxygen consumption of 15-d post-hatch larval Pacific cod (Gadus macrocephalus), rotifer-fed (Brachionus plicatilis) since their first feeding, were studied in stationary cultures at 10oC, 13oC, and 16oC for 48 h. Postprandial ammonia excretion and oxygen consumption rates were determined after 2, 4, 6, 8, 10, 12, 18, 24, 36 and 48 hours. The 48-h post-feeding weight-specific ammonia excretion and oxygen consumption rates increased until 4 h postfeeding, decreased to 18 h post-feeding, and remained relatively stable until 48 h post-feeding. The highest weight-specific ammonia excretion and oxygen consumption rates were 215±19.8 μg NH₃-N g^–1 h^–1 and 1,778±55.6 μg O₂ g^–1 h^–1 2–4 h postfeeding at 13oC. The higher (P<0.05) resting ammonia and oxygen consumption at 16oC 12-h post-feeding indicate that this temperature is not appropriate for inducing higher growth of rotifer-fed pacific cod larvae.