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Protein to carbohydrate ratio in high‐energy diets for Atlantic salmon ( Salmo salar L.)
Author(s) -
Hillestad Marie,
Johnsen Freddy,
Åsgård Torbjørn
Publication year - 2001
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1046/j.1365-2109.2001.00569.x
Subject(s) - salmo , biology , starch , carbohydrate , zoology , meal , fish meal , feed conversion ratio , flesh , food science , nitrogen , fish <actinopterygii> , body weight , fishery , biochemistry , chemistry , endocrinology , organic chemistry
The effect of dietary protein to carbohydrate ratios (P/CH, weight percentage) of P34/CH21, P39/CH15 and P44/CH10 was studied in Atlantic salmon ( Salmo salar L.) with respect to growth and feed conversion ratio (FCR) in one medium‐scale experiment (Experiment 1) and to slaughter quality in two production scale experiments (Experiments 2A and 2B). The dietary fat was maintained at 290 g kg −1 whereas the protein (fish meal) was exchanged with carbohydrate (wheat). Fish grown from approximately 1 to 4 kg were fed a restricted diet (iso‐energetic on gross energy basis) or to satiation. Nitrogen, fat, starch and energy digestibilities were measured in a separate experiment. There were slight tendencies for lower growth ( P = 0.06) and for higher FCRs ( P = 0.06) in Experiment 1, and a slight tendency for a lower dress‐out percentage in Experiments 2A and 2B ( P = 0.10 and 0.20 respectively) with decreasing P/CH. The P/CH had no effect on the fat concentration of fillets, flesh colour or sexual maturation. The digestibility of starch decreased from 62.1% to 46.1% and the digestibility of energy from 84.9% to 79.5% when P/CH decreased from P44/CH10 to P34/CH21. Growth per unit digestible protein increased with decreasing P/CH. Feeding to satiation improved the growth but the FCR was higher than it was for restricted feeding. The calculated starch load per kg of fish growth increased with decreasing P/CH, whereas the effluent nitrogen decreased.