Size-related oxygen consumption and ammonia excretion of Eurasian perch (Perca fluviatilis L.) reared in a recirculating system

摘要

Oxygen consumption (OC) and ammonia excretion rates (AE) of perch were measured under commercial-like conditions (temperature 23.3 pC) in both fed (F) and feed-deprived groups (D). Measurements were taken in triplicate in six sized batches of perch ranging from 44.8 to 336.2 g. The mean daily OC was 288.3-180.6 mg O kgp# hp# for group F fish ranging in size from 44.8 to 279.4 g body weight. The mean daily AE expressed as total ammonia nitrogen (TAN) was 13.8-5.2 mg TAN kgp# hp# in the same groups. Daily peaks of OC in group F perch were observed 6 h after the onset of feeding for each size group with relatively stable values up to the end of feeding. Peaks of daily AE in group F perch were observed 10 h after the onset of feeding in each size group, with a rapid decrease up to 16 h after onset. In group D, OC was 181.1-110.5 mg O kgp# hp# in the weight range 57.9-336.2 g. The daily mean AE was 1.7-0.5 TAN kgp# hp# in this group. No dramatic peaks of OC and AE were observed in group D perch.