Combinational use of Malt Protein Flour and Soybean Meal as Alternative Protein Sources of Fish Meal in Fingerling Rainbow Trout Diets

Abstract

A 6-week feeding experiment was conducted to determine the optimum combinational ratio of soybean meal (SBM) and malt protein flour (MPF) as alternative protein sources of fish meal in fingerling rainbow trout diets. In the control diet, brown fish meal (BFM) was used as the sole protein source to be 43% crude protein. In the experimental diets, 60% of BFM protein was replaced by proteins from SBM and MPF. The combinational ratios of SBM and MPF were varied as 60:0, 40:20, 30:30, 20:40, and 0:60 in the percentage of total dietary protein. In the fish fed the diet with the ratio of 30:30, almost similar levels of weight gain and protein retention with the control diet were noted, and moreover the energy retention based on digestible energy was higher than that of the control. These findings suggest that an equivalent combination of both alternative proteins can maximize the rearing performance of fingerling rainbow trout. © 1995, The Japanese Society of Fisheries Science. All rights reserved.