Do delivery rate and pellet size affect growth rate in Atlantic salmon (Salmo salar L.) raised under semi-commercial farming conditions?

Abstract

Abstract How the daily feed ration is presented is an important aspect of feed management. In order to evaluate the effects of delivery rate and pellet size, Atlantic salmon ( Salmo salar L.) were raised in small (5×5×10 m), semi-commercial cages and were fed using 14 combinations of pellet sizes (0.03–2.68 g) and delivery rates (82.5–1320 g·min −1 (0.1–31.1 pellets·fish −1 ·min −1 )). Treatment groups were compared using the growth rate (Thermal Unit Growth Coefficient, TGC). No significant linear effect on growth due to pellet size or delivery rate could be detected. For pellet size, however, indications point to a non-linear relationship with growth rate. Salmon grew well (mean TGC (±S.D.)=2.68±0.49) irrespective of treatment indicating a high level of plasticity in the salmon's ability to adjust to changes in pellet size and delivery rates within the ranges used and under the conditions tested here.