Summary:
The protein requirements of Atlantic halibut (Hippoglossus hippoglossus L) were tested in two trials for fish with initial size of 564 g and 973 g. The fish were fed near isocaloric diets with crude protein in dry matter (CP) between 35% and 53%. There was no significant effect of CP on weight development or SGR, daily feed intake or protein efficiency ratio in either trial. However, CP significantly affected the feed conversion (FCR) of the smaller fish with FCR increasing at lower CP. The CP did not affect the final protein or lipid content of the fish. The results of the study suggest that the minimum CP for maximum growth is 41% and 35% for 560 g and 970 g halibut respectively.