The Influence of Feeding Level on Growth Performances of European Catfish (Silurus glanis L., 1758) Juveniles under Recirculating Water Conditions

The study was carried out with one summer-old Silurus glanis juveniles, having the mean size 23.04±2.05 cm and weight 73.84±19.12 g, reared in recirculating water condition, in order to assess the impact of feeding level on growth performances and body size variation of fish. Two feeding levels were tested (R1=1.5% BW/day and R2=2.5% BW/day), in duplicate, during 6 weeks, and the biomass gain (BG), feed conversion ratio (FCR), specific growth rate (SGR), protein efficiency ratio (PER), morphometric relationship between length-weight (LWR) and coefficient of variation (CV) were assessed. Data revealed that the overall mean weight of the biomass was doubled during the trial, from 14.92 kg to 31.17 kg, and the body growth significantly increases with the increment of the feeding rate (13.48 kg in R1 and 17.70 kg in R2), underlying the good potential of the species, at this life stage, for fast-growing under intense conditions. The calculated SGR in R1 was 1.43%/day and in R2, significantly higher, as 2.05 %/day, for the almost similar values of FCR (0.74 g/g) and PER (2.50 g/g) recorded between the treatments.