1a. Objectives (from AD-416)
The objective of this research is to improve the competitiveness of rainbow trout production by reducing feed costs through the development of improved ingredients, feeds, and strains of rainbow trout.
1b. Approach (from AD-416)
Ingredients will be selected based upon nutrient and anti-nutrient profiles, and cost on a protein unit basis. Special emphasis will be placed upon barley and oat cultivars, but any ingredient that has favorable profiles will be considered. Some marine oils and proteins maybe evaluated at low inclusion levels to enhance feed palatability and the final product fatty acid profile. Practical feed formulations, will be produced using cooking extrusion (commercial conditions) for rapidly growing juvenile fish. Traditional evaluation procedures, including growth performance and nutrient retention, and cost per unit gain, will be used to evaluate the improved diet formulations. Additional evaluation procedures will be developed and applied to fish feeding trials as follows: (1) clinical assays of blood plasma for electrolyte levels, cholesterol, triglycerides, ASAT, ALAT, and routine plasma parameters; (2) whole blood analysis for hematocrit percentages; (3) gene expression activities for genes associated with protein synthesis and degredation, fatty acid elongation and desaturation, bone and/or cartilage metabolism and energy metabolism plus cellular redox status. Reproductive performance of rainbow trout fed diets containing plant-derived ingredients in place of fishmeal and fish oil (partial replacement or total replacement for selected growth periods) will be assessed by measuring fecundity, egg fertility, and egg hatchability, plus chemical analysis of eggs to determine effects of diet on nutritional content. Bone density and imaging may be explored for fish fed diets lacking fishmeal to determine if replacement mineral supplements in plant-based feeds support normal bone development and absence of skeletal deformities.Documents SCA with U. of ID. Formerly 5366-21310-002-04S (1/05). Replacing 5366-21310-003-02S (6/17). Formerly 5366-21310-003-09S (2/10).
3. Progress Report
A collaborative study was conducted to determine the nutritional value of fish bone (recovered from sea food processing waste) as a mineral source for rainbow trout. These fish bone products show promise but nutrient digestibility was not improved and growth performance was poor. Further modification of the bone meals is underway. Fish meal based and two fish meal free diets were fed to select families of trout in order to determine if there is a genetic ability to utilize non-fish meal diets in some families of trout. This project is currently underway. A study was conducted to determine if corn products in the ARS plant based trout diet could be replaced with other non-pigment containing ingredients. Corn gluten meal can be replaced by poultry meal or barley protein concentrate without reducing growth rate. Frequent site visits were made along with conference calls and email correspondence.