Evaluation of Varying Levels of Soy Protein Concentrate in the Diet of L. vannamei
As shrimp prices have fallen and production costs increased, shrimp farmers are more concerned with economic efficiencies of the feed. This means they are quite receptive to moving away from traditional high fish meal diet to less expensive protein sources. Additionally, there are social pressures to minimize the use of fish meal and other marine ingredients in shrimp feed formulations. The most logical replacement for protein from fish meal is to increase the level of protein originating from soybeans which means that inclusion levels in shrimp feeds will need to be increased. To date we have identified most of the limiting nutrients in soy based diets and we have increased the inclusion levels as high as 58% of the ration. Although some nutrient restriction still need to be defined, nutrient density of the diet is a problem as the level of soybean meal is increased. This simply means, that a high protein ingredient is required to provide room in the formulations. Soy protein concentrate (SPC) can meet this need as it is suitably priced to not only replace fish meal but also provide the required room in diet formulation. Hence, the objective of this project was to evaluate the feasibility of diets formulated to contain increasing percentages of SPC (0%, 4%, 8%, and 12%), in production diets for L. vannamei reared under production conditions. Consequently, two parallel growth trials were conducted in outdoor tanks and ponds to evaluate the production potential of the various diets. In both trials, growth, feed conversion and survival were good and there were no significant differences between the four open formulation feeds containing up to 12% SPC. Based on present results, growth, feed conversion, survival and production yields were not effected by the use of SPC up to 12% of the diet. Hence, once can recommend that levels up to 12% are reasonable to use in commercial feed formulations for shrimp.