Influence of water temperature on oxygen consumption and ammonia excretionof juvenile pikeperch, Stizostedion lucioperca (L.) reared in arecirculating system

摘要

The oxygen consumption and ammonia excretion rates of fed and starved fingerling pikeperch, Stizostedion lucioperca (L.), reared in a recirculating system were measured at water temperatures of 20 and 24 degrees C. The fish were fed a commercial trout diet for 18 h day(-1) (0900-0300 h) at daily rations of 3.0% and 3.5% body weight at 20 and 24 degrees C, respectively. The mean rates of oxygen consumption (OC) (mg O-2 kg(-1) h(-1)) of fed fish were 225.3 at 20 degrees C and 356.2 at 24 degrees C, and were significantly different (P < 0.001). The mean OC rates (mg O-2 kg(-1) h(-1)) of starved fish were 106.3 at 20 degrees C and 145.9 at 24 degrees C, and these values also differed significantly (P < 0.001). The average ammonia excretion (AE) rates of fed fish were 14.1 and 18.3 mg TAN kg(-1) h(-1) at 20 and 24 degrees C, while the rates for the starved fish were nearly 10-fold lower, i.e. 1.4 and 2.0 mg TAN kg(-1) h-(1). These rates differed significantly with temperature for both the starved and fed groups of fish (P < 0.01). The mean oxygen:feed ratio (OFR) for fish cultured at 20 degrees C was 0.172 kg O-2 kg(-1) feed fed day(-1), while at 24 degrees C, it was 0.234 kg O-2 kg(-1) feed fed day(-1). The ammonia:feed ratios (AFRs) were similar for the fish held at the two temperatures, i.e. 0.011 and 0.012 kg TAN kg(-1) feed fed day(-1). [References: 25]