The feasibility of partial or total replacement of fish meal by soybean meal in diet for turbot

Four experimental diets containing a gradient of soybean meal are fed to turbot over 50 days at 18℃.Digestibility of protein and starch of the diets decreased with the increase of levels of dietary soybean meal.Turbot fed a diet containing 20% of soybean meal had the growth performances comparable to those fed a fish meal based diet.The weight growths of the group 1 and 2 are 85.3% and 82.25% respectively;the special growth ratios are 1.23 and 1.19 respectively;the feed coefficients are 1.28 and 1.35 respectively;and the protein efficiency ratios are 1.49 and 1.44 respectively.There has no great difference between the group 1 and 2.Higher level soybean meal adversely affected growth.The weight of digestive organs in percentage of body weight and the activity of protease and amylase tend to decrease with the increase level of dietary soybean meal.Based on the test result,20% of fish meal can be replaced by soybean meal with no effect on turbot growth.