사료의 종류 및 공급 비율이 넙치 치어의 암모니아 배설과 분 배출에 미치는 영향

Abstract

An experiment was carried out to investigate the effect of feed type and feeding ratio on daily pattern and rate of total ammonia nitrogen (TAN) excretion and feces production in juvenile olive flounder Paralichthys olivaces (mean body weigh: 44.7±1.8 g). Fish were acclimated over 10 days under&nbsp;two different feeding ratio (1.0 and 2.5% per day) with dry pellet (DP) and moisture pellet (MP). Fish were fed two times daily 08:00 and 16:00 h with each diet.&nbsp;Water was sampled for both the inlet and outlet of chamber every 2 h over a 24 h period. A peak post-prandial TAN excretion rate occurred after 10 hours from the first feeding at feeding ratio of 1.0% (mean 71.8 mg TAN kg fish-1 h-1), 2.5% (79.4 mg TAN kg fish-1 h-1) in DP, 1.0% (92.8 mg TAN kg fish-1 h-1) and 2.5% (101.1 mg TAN kg fish-1 h-1) in MP, respectively. Post-prandial TAN excretion increased with the increase of feeding ratio in each diet (P<0.05). Mean post-prandial TAN excretion rates at feeding ratio of 1.0 and 2.5% were 31.2 and 48.4 mg TAN kg fish-1 h-1 in DP, and 33.8 and 53.7 mg TAN kg fish-1 h-1 in MP, respectively. Mean feces production rates at feeding ratio of 1.0% and 2.5% were 122.3 and 301.4 g kg feed-1 d-1 in DP and 144.3 and 311.2 g kg feed-1 d-1, respectively. Feed type and feeding ratio had significant influence on the ammonia excretion (P<0.05). However, only feeding ratio had significant influence on the feces production. As overall results, feed ratio exerts a profound influence on the nitrogen metabolism of juvenile olive flounder.