Ž . Aquaculture 180 1999 237–246 www.elsevier.nlrlocateraqua-online Feed intake, growth and feed utilization of offspring ž from wild and selected Atlantic salmon Salmo / salar Jørn Thodesen, Barbara Grisdale-Helland ) , Stale J. Helland, ˚ Bjarne Gjerde ( ) AKVAFORSK Institute of Aquaculture Research , N-6600 Sunndalsøra, Norway Accepted 26 April 1999 Abstract Ž The aim was to assess whether selection for increased growth rate in Atlantic salmon Salmo . salar is associated with increased feed intake andror better feed utilization. Growth responses of Ž offspring from selected and wild lines of Atlantic salmon initial weight 814 "14 g and 533 "12 . g, respectively were tested in a 14-week experiment. Selected and wild salmon increased body Ž . weight by 79 and 39%, respectively, during the experiment. Relative feed intake DFI , thermal Ž . Ž . growth coefficient TGC and feed efficiency ratio FER were significantly higher in the selected Ž y1 y3 . Ž DFI: 0.67% BW d , TGC: 2.96 =10 and FER: 1.16 , than in the wild, line DFI: 0.48% BW y1 y3 . d , TGC: 1.39 =10 and FER: 0.93 . FER was positively correlated with mean growth rate Ž . r s0.90, n s6, P -0.05 , and differences between the 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 energy per kilogram gain, so the higher growth rate of the selected line was the result of both greater feed consumption and more efficient feed utilization for growth. This implies that selection for increased growth rate in Atlantic salmon may improve both of these traits. q 1999 Elsevier Science B.V. All rights reserved. Keywords: Feed intake; Growth; Feed utilization; Digestibility; Protein and energy budget; Atlantic salmon Ž . Salmo salar ) Corresponding author: Tel.: q47-71-69-53-12; fax: q47-71-69-53-01; E-mail: barb.grisdale@akvaforsk.nlh.no 0044-8486r99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved. Ž . PII: S0044-8486 99 00204-5