The Israeli Journal of Aquaculture – Bamidgeh 57(4), 2005, 231-240 
 
NITROGEN EXCRETION PATTERNS AND POSTPRANDIAL AMMONIA PROFILES IN BLACK SEA TURBOT (SCOPHTHALMUS MAEOTICUS) UNDER CONTROLLED CONDITIONS

Murat Yigit1*, Muammer Erdem2, Orhan Aral2 and Burcu Karaali2

1 Department of Aquaculture, Faculty of Fisheries, Canakkale Onsekiz Mart University, Canakkale 17100, Turkey
2 Department of Aquaculture, Sinop Faculty of Fisheries, Ondokuz Mayıs University, Sinop 57000, Turkey
 
(Received 29.5.05, Accepted 4.7.05)

Key words: ammonia, Black Sea turbot, intensive fish culture, nitrogen excretion, Scophthalmus maeoticus
 
 
Abstract



Measurements of the rate of nitrogenous excretion were carried out in two batches of young Black Sea turbot (small 42 g, large 72 g) at 12±1°C under natural light conditions (10 h light:14 h dark and 13 h light:11 h dark, respectively). The ammonia nitrogen excretion rates of fish starved for 48 hours were 0.20±0.05 mg-N for the small fish and 0.18±0.09 mg-N/100g fish/h for the large. Fish were then fed a pellet diet containing 8.3% nitrogen at average rations of 0.67% and 0.59% of the body weight, respectively, for four days. On the fourth day, ammonia nitrogen excretion rates were evaluated. In both batches, the rates were 2-3 times higher immediately after feeding than in the starved fish, reaching a peak 3-6 hours after feeding and declining afterwards. For the small and large fish, respectively, 21% and 20% of the consumed nitrogen was excreted as ammonia nitrogen, 6% and 7% as urea nitrogen, and 8% and 4% as feces nitrogen within 24 hours after feeding.


* Corresponding author. Tel: +90-286-2180018 (ext. 1571); fax: +90-286-2180543; e-mail: muratyigit@ttnet.net.tr

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