Selected metabolic aspects of pike-perch, Stizostedion lucioperca (L.) reared in a water recirculation system

Abstract

The aim of the present study was to evaluate the effect of fish size (BW 11.7 g in the PS group, and 28.1 g in the PL group), feeding (SDA effect), and starvation (4, 13, 19 or 26 days in the PS-S group, and 4 or 13 days in the PL-S group) on oxygen consumption (OC, mg O2 kg^-1 h^-1), and ammonia excretion (AE, mg TAN kg^-1 h^-1) of the juvenile pike-perch Stizostedion lucioperca (L.) reared in water recirculation systems. The fish were fed high-protein commercial trout pellets for 18 h d^-1 at daily rates of 2.5% (PS) or 1.2% (PL) of stock biomass. The average OC and AE values of the fed pike-perch from the PS group were equal to 355.70 mg O2 kg^-1 h^-1 and 21.21 mg TAN kg^-1 h^-1, respectively, and were 35% (OC) and 62% (AE) higher than in the PL group (P < 0.05). The metabolic rate of the starved fish was also inversely related to fish size and showed significant differences (P < 0.05). The energetic value of SDA was 62.8 kJ kg fish^-1 d^-1 (7.3% of feed digestible energy content) in the PS group, and 31.6 kJ kg fish^-1 d^-1 (5.2% of digestible energy) in the PL group. The starvation period of four days was too short for O^oC and AE stabilization. The values of both parameters stabilized in the second and third week of starvation.