Evaluation of different feeding frequencies in RAS-based juvenile pikeperch (Sander lucioperca) aquaculture

Feeding regime, which involve selection of appropriate diet and application of feed itself is a decisive factor in intensive, RAS-based production system – more so, for carnivorous fish culture. It is critical for the economics, resource (feed/nutrients) use efficiency and final profit yield. The present study examined different feeding strategies in juvenile pikeperch reared in RAS for growth performance, survivability, feed utilization, and fish welfare. Juvenile pikeperch (106.59 ± 24.84 g) were cultured in RAS for 112 days and fed at five different feeding intervals (2-h, 4-h, 6-h, 8-h and 12-h) using automatic feeder Imetronic® (Pessac, France). Fishes were fed a commercially standardized pikeperch diet. A higher degree of growth heterogeneity was observed in groups fed in shorter feeding intervals (2-h, 4-h and 6-h). At the end of the experiment, slightly higher fin damage was observed in all tested groups compared to fin conditions of stocked fish especially for dorsal and caudal fins. No significant differences were observed in selected biochemical parameters indicating liver, pancreas, and intestinal function. All tested fish were adequately fed providing sufficient nutrients for proper pikeperch growth and welfare. Nevertheless, the feeding interval 8-hour was evaluated as optimal. This frequency supports higher fish conditions (Fulton's coefficient) and the specific growth rate (SGR), survival rate (SR), weight heterogeneity (CV2), lower fin erosion compared to the other tested frequency and optimal level of biochemical parameters in blood plasma.