Feed intake, growth and feed utilization of offspring from wild and selected Atlantic salmon (Salmo salar)

The aim was to assess whether selection for increased growth rate in Atlant ic salmon (Salmo salar) is associated with increased feed intake and/or bet ter feed utilization. Growth responses of offspring from selected and wild lines of Atlantic salmon (initial weight 814 +/- 14 g and 533 +/- 12 g, res pectively) were tested in a 14-week experiment. Selected and wild salmon in creased body weight by 79 and 39%, respectively, during the experiment. Rel ative feed intake (DFI), thermal growth coefficient (TGC) and feed efficien cy ratio (FER) were significantly higher in the selected (DFI: 0.67% BW d(- 1), TGC: 2.96 x 10(-3) and FER: 1.16), than in the wild, line (DFI: 0.48% B W d(-1), TGC: 1.39 x 10(-3) and FER: 0.93). FER was positively correlated w ith mean growth rate (r = 0.90, n = 6, P < 0.05), and differences between t he lines indicated a 4.6% increase in FER per generation of selection. Fish of the selected line had a significantly lower intake of protein and energ y per kilogram gain, so the higher growth rate of the selected line was the result of both greater feed consumption and more efficient feed utilizatio n for growth. This implies that selection for increased growth rate in Atla ntic salmon may improve both of these traits. (C) 1999 Elsevier Science B.V . All rights reserved.