Feed utilisation in Atlantic salmon kept at fluctuating oxygen saturation. A CREATE project

Summary

Atlantic salmon (initial weight 383 g) was kept at either stable oxygen saturation (>80%, control) or exposed to four daily drops in oxygen saturation to 70, 60 or 50% in a 68-days experiment. The fish was fed twice daily during normoxic (>80% oxygen saturation) periods. At termination of the trial, the feed intake and growth was significantly correlated to oxygen saturation during the hypoxic periods, and the SGR ranged from 1.16 (70% group) to 0.99 (50% group), and the range of TGC was from 1.97 (control and 70% groups) to 1.67 (50% group). Treatment did not significantly affect FER, apparent digestibility of macronutrients or retention of these. The growth was suboptimal in the trial, probably due to sexual maturation that was observed.