In conclusion, this study showed that juveniles of Nile tilapia up to±
150 g can be cultured in nearly closed recirculating systems (withwater
exchange rates of 30 L/kg feed/day) without a decrease of feeding
motivation, feed intake/efficiency and growth. On the contrary, larger
individuals (±300 g) may exhibit growth retardation. Further studies
should be considered to further explore this hypothesis and to identify
the underlying factors responsible for growth retardation in RAS.