Nitrogenous excretion of Penaeus monodon postlarvae fed with different diets

This study is designed to determine ammonia and nitrite excretion by Penaeu s monodon 25-30 day old postlarvae fed with different diets (artificial and natural). Shrimps were fed with Chaetoceros calcitrans (phytoplankton), ch ironomid larvae (benthos), Brachionus sp. (rotifer) and artificial diet. In the control treatment, shrimps were not fed. The highest concentration of ammonia was excreted by shrimps fed with artificial diet and the lowest by that of control treatment. All treatments except where shrimps fed on C. ca lcitrans showed a sudden increase in ammonia-N excretion after 36 h. C, cal citrans contributed to high ammonia excretion only after 61 h. Shrimps fed with Brachionus sp. (rotifer) showed significantly higher nitrite excretion rate compared to other treatments. Shrimps fed on C. calcitrans depicted t he lowest nitrite excretion. This experiment indicated that nitrogenous exc retion was predominant in shrimps fed with artificial diets. Live food like algae and chironomids, despite a high protein content, contribute to low n itrogenous excretion and hence pose less adverse effects on water quality c ompared to artificial diets, (C) 1999 Elsevier Science Ltd. All rights rese rved.