AbstractIn two feeding trials conducted with juvenile Atlantic cod Gadus morhua (initial mean weight = 87.9 or 15.92 g), soy protein concentrate (SPC) was used to replace fish meal in isonitrogenous, isocaloric diets. In the first trial, five experimental diets (47% protein, 15% fat; calculated gross energy = 5,059 kcal/kg) were formulated to replace 28, 60, 80, and 100% of dietary fish meal. In the second trial, three diets were formulated with SPC to replace 0, 25, and 50% of the fish meal in a modified commercial diet for marine finfish (50% protein, 15% fat; calculated gross energy = 4,900 kcal/kg; calculated digestible energy = 3,570 kcal/kg). Upon conclusion of the studies, no differences in survival, growth, hepatosomatic index, or viscerosomatic index were found among the treatment groups. The fish attained mean weights of 162.7 and 39.1 g in the first and second trials, respectively, with specific growth rates of 0.76% and 1.12% and feed conversion ratios of 1.28 and 1.29, respectively. No consistent pattern of enteritis was observed in the histological sections taken from fish in either study. These results indicate that SPC can entirely replace fish meal in diets of juvenile Atlantic cod or can be combined with other common feed ingredients to replace up to 50% of dietary fish meal.
