EVALUATION OF THREE TYPES OF CORN PROTEIN CONCENTRATES FOR FUNCTIONALITY DURING EXTRUSION AND DIGESTIBILITY IN RAINBOW TROUT
Small Grains and Potato Germplasm Research
2012 Annual Report
1a.Objectives (from AD-416):
1) Determine if corn protein concentrate contributes to pellet binding strength when extruded.
2) Determine the nutrient digestibility of three type of corn protein concentrate using extruded feeds with rainbow trout.
1b.Approach (from AD-416):
Each of three variants of corn protein concentrate, standard, high lysine and low pigment, will be tested for nutrient digestibility using standard laboratory practices. The effect of each variant on feed consumption will also be determined. The effect of each variant on the pellet strength will also be determined through a series of experimental extrusion runs. The corn protein concentrate variants will be added at different levels to the diets, substituting for ingredient with high binding capacity (i.e. wheat gluten, wheat flour) or low binding capacity (soy protein concentrate). All pellets will be tested for oil absorption capacity and durability.
This is the final report for this project. This research links to the parent project through objectives 2. Communication and coordination was achieved with personnel visiting each other’s facilities and through frequent emails and phone conversations. In addition, in person meeting were held in conjunction with the World Aquaculture Society Meetings. During the life of the project several important findings were determined. Extrusion studies demonstrated that corn protein concentrate (CPC) does contribute to the binding capacity of a pellet that contains low carbohydrate levels or low wheat gluten levels. The amount of nutrients found in the products that the fish were actually able to digest and absorb was determined. Compared to fish meal, all three corn protein products were highly digestible. Fish feeding studies also showed good growth and survival when feeding high levels of the corn protein concentrates. These results demonstrate that the experimental corn products can be good replacements for fish meal.