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.
3. Progress Report
This research relates to the parent project through objective 3, “Determine nutritional value of alternative ingredients (protein, lipid, energy) and develop practical feed formulations for improved strains of fish”. Corn gluten meal contains 60% protein but a new process to increase protein content to 75% has been developed by Cargill. The research collaborators have developed three different types of corn protein concentrates and we are evaluating them for functionality during extrusion and digestibility in rainbow trout. The products will also be evaluated for their effect on pellet quality through a series of processing studies using different extruder conditions. Communication and coordination was achieved through frequent emails and phone conversations and scientists from Cargill visited ARS laboratory for several days.