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United States Department of Agriculture

Agricultural Research Service

Research Project: INTEGRATION OF NUTRITIONAL, GENETIC AND PHYSIOLOGICAL APPROACHES TO IMPROVE PRODUCTION EFFICIENCY OF RAINBOW TROUT
2009 Annual Report


1a.Objectives (from AD-416)
Objective of this research are; 1)Develop a series of trout feeds that replace fish meal and fish oil with novel and traditional plant-derived ingredients. .
2)Determine optimal supplementation levels of vitamins and limiting amino acids for plant-based feeds. .
3)Identify and evaluate genetic, biochemical and physiological responses of trout fed grain-based feeds. .
4)Identify rainbow trout families with improved phenotypes for growth and utilization of an alternative plant-protein fish feed through a genetic selection program. New funds will be used to expand objective one of the project plan: 1) Objective 1 of the project consists of developing trout feeds formulated with traditional plant-derived ingredients in place of fish meal and fish oil. Within this area of research the experimental diets are to be tested to determine the optimal supplementation level of vitamins and limiting amino acids necessary to obtain maximal growth. The financial increase to the project will aid in developing ingredient enhancement through the development of biological and mechanical concentration methods for the formulation of nutrient complete feeds.

New funds will be used to expand Objective One of the research project plan: 1) Develop a series of trout feeds that replace fishmeal and fish oil with traditional and enhanced plant-derived ingredients. The focus should be on ingredient enhancement through biological and mechanical concentration of required nutrients for complete feed development. Expedite expanded capacity to increase select cultivars in trout feeding trials. This includes expanding strains being developed at Leetown, WV. Dr. Keshun Liu: Objectives include;.
1)evaluate current methods of dry and wet fractionization for ways to improve performance or reduce cost of production;.
2)evaluate chemical and enzymatic treatments for effectiveness and production costs,.
3)evaluate nutritional quality of protein concentrates, and.
4)develop improved analytical methods for some key grain nutrients, such as beta-glucan, protein, to assist breeding screen for improved grain quality. Dr. Frederic Barrows Objectives;.
1)identify the most effective organism and blend of grains to result in a high protein low carbohydrate ingredient, 2) identify optimal processing and incubating conditions, 3) evaluate digestibility and palatability of each ingredients with in-vivo testing, 4) evaluate effect of long term feeding of experimental ingredient on growth, and product quality. Dr. Kenneth Overturf Objectives: .
1)installation of 10 heath tray incubators for hatching and isolating individual families, 80- 4'x15" troughs for rearing fry, and 25- 5' circular for holding individual families and mixed tagged families. Also included with this is the necessary infrastructure such as securing adequate water to the tanks and electrical and lighting for rearing and handling of the fish.


1b.Approach (from AD-416)
This research will benefit fish farmers, grain farmers and assist in protecting the environment by reducing nutrients in hatchery effluents, and reducing exploitation of ocean fisheries. A series of plant-based feeds will be eveloped, replacing fish meal, and containing the proper balance of essential nutrients. New cultivars of barley and oats will be evaluated as a fish feed ingredient along with alternate crops such as flax, sunflower and safflower. A breeding program will be used to develop new strains of rainbow trout that are better able to utilize plant-based feeds, grow faster and more efficiently and have improved product quality characteristics. Traditional methodologies to determine metabolic scope for a given nutrient or ingredient will be used to evaluate the relative contribution and metabolic efficacy of nutrients supplied in plant-based feeds. Information developed concerning the genetic, biochemical, and physiological responses of rainbow trout to consumption of various plant-derived ingredients will be used as a basis for developing future feed formulations and to develop improved selection parameters for trout breeding programs. An ARS scientist: Use 4 approaches to address this problem. .
1)evaluate and further process protein-rich by-products of current ethanol or beta-glucan production,.
2)develop modified and novel methods to fractionate grain proteins for trout feed ingredients,.
3)evaluate and process current improved cultivars of barley and oats, such as low-phyate cultivars for making fish feed ingredients, and.
4)select and breed new cultivars of barleys and oats with enhanced composition through collaborating with plant scientist at the ARS, Aberdeen ID (Project # 5366-21000-024-00D). An ARS scientist: Solid substrate culture (SSC) has been proven to be an effective method for fungal production on a commercial scale. The effectiveness of this approach is due to the relatively low capital costs and low energy costs. This approach has not been used for the development of animal feeds before, but preliminary studies are quite promising. Utilizing different organisms and different blends of grains, a variety of products will be produced. Dr. Kenneth Overturf: Genetic selection programs for trout have been initiated at the NCCCWA and at the HFCES (through Aberdeen). The goal of the HFCES program is to select fish with an enhanced ability to utilize a plant based feed more efficiently. The goal of the NCCCWA is to select trout for superior growth performance. Improved strains will be reared and analyzed in Idaho.

FY99 Program Increase $225,000 Add 1 SY for research on cereal grains & fish FY03 Program Increase $223,537 Add 1 SY FY04 Program Increase $241,566 Add 1 SY FY04 Program Increase $584,232 Add 1 SY FY05 Program Increase $111,600 Replaces 5366-21310-002-00D (12/04). FY06 Program Increase $89,100


3.Progress Report
Quality characterization of grain by-products and technology development for dry fractionation. Distiller Dried Grains with Solubles (DDGS) is a co-product of ethanol production from corn and other cereal grains. It is a mixture of particulate matter and can have a protein content as high as 30%, and has potential as a protein ingredient for trout feed. Two experiments were conducted to investigate.
1)factors affecting fat analysis of DDGS, and.
2)changes in chemical composition and phosphorus profile during dry grind process of corn into ethanol and DDGS. In addition, a separate study was completed to investigate factors affecting sieving efficiency since sieving is one of the common methods to fractionate dry materials, such as DDGS and barley meal. Nutri-genomics. Twenty seven new gene expression assays were developed for genes related to muscle development, protein turnover, metabolism and nutrient partitioning. These assays will be incorporated into our existing battery of gene expression assays used to evaluate muscle development, protein degradation and accretion, metabolism, energy portioning, immunologic status, and nutrient utilization in rainbow trout fed diets formulated to contain protein and oils from sustainable sources. Forty families fed a plant based diet and varying in growth rate were evaluated for relative changes in expression for regulatory metabolic and growth genes to determine how relative changes in energy portioning affects growth on diet formulated to replace fish meal with sustainable plant products. Twenty-three families were tested for resistance to bacterial and viral pathogens and then analyzed for correlations with gene diversity and growth. Thirty families were tested for variation in their ability to convert plant oils and deposit healthy omega-3 fatty acid in their fillets. Assessment of the utilization of lysine supplements in plant based trout feed. A study is underway to evaluate graded lysine levels in plant based trout diets when protein levels are reduced from 45 to 35% of the diet. Traditionally trout feeds contain up to 45% protein to meet the amino acid demands for growth and metabolism. Previous research has indicted that dietary protein levels can be reduced when amino acid supply is balanced on a digestible basis. Growth data indicated that supplemental lysine levels may be lower than expected based on an ideal amino acid ratio but higher levels may be needed for optimal feed conversion ratios. Laboratory analysis is ongoing to address these effects on protein and energy retention efficiencies. Refining the amino acid balance in trout diets will allow for increased production efficiencies with reduction in waste loads to the effluent water. Performance testing a Trout-Grains Project plant-based diet against a commercial trout diet. A study is underway to test our current ARS plant based trout diet compared to a commercial formulation containing 45% protein and 20% fat. Traditionally trout feeds contain fish meal to maintain optimal fish performance.


4.Accomplishments
1. A Vitamin Premix for Extruded, Plant-based Feeds for Rainbow Trout. The last open-formula premix for trout was released 20 years ago. ARS scientists in Aberdeen, ID, developed new feed processing methods and new sources of vitamins. They developed a vitamin premix, ARS 702 that is adjusted for losses during processing and is designed for use in alternative feeds of today. A 15 week feeding was conducted and demonstrated the importance of complete, balanced vitamin premix for plant based trout feeds. The formulation is now being commercially produced, fed to a variety of species, and used by several commercial feed manufacturers.

2. Macro-minerals Determined to be Lacking in Fish-meal Free Trout Feeds. As dietary fish meal is reduced in the diet of carnivorous fish like rainbow trout, several nutrients become limiting. ARS scientists in Aberdeen, ID, conducted a study which results demonstrated that rainbow trout fed fish meal free, plant based diets, supplemented with potassium chloride, sodium chloride and magnesium oxide, had improved feed efficiency and fish health. These minerals had not been supplemented to trout diets in the past due to their abundance in fish meal. As a result supplementation of these minerals is now done in all fish meal free trout feeds, for both research and commercial production of ARS formulations.

3. Determined that overall Genetic Variability Does Not Enhance Disease Resistance to Certain Viral and Bacterial Pathogens. Diseases are a major economic cost for aquaculture operations and several discrepancies exist in the literature regarding the effect that overall genetic diversity plays in combating pathogens. ARS scientists in Aberdeen, ID, evaluated twenty-three families for their resistance to the viral pathogen IHNV and the bacterial pathogen F. psychrofilum and then analyzed for overall diversity within and between families. While it was determined that some genetic markers may be linked to resistance, overall genetic diversity did not correlate with improved disease resistance for either the viral or bacterial pathogen. This information is being used directly by a major trout production company in developing their broodstocks.

4. Quantification of Available Amino Acids from Feedstuffs for Rainbow Trout. Formulation of diets to meet the nutritional need of the growing fish and flexibility in utilizing alternative ingredients requires that information in amino acid availability from alternatives be known. ARS scientists in Aberdeen, ID, conducted an in vivo digestibility trial to determine the apparent amino acid availability from a wide assortment of 24 feed ingredients either commonly used in formulating trout feeds or with future potential. The ability of rainbow trout to digest and absorb the essential amino acids was determined. This information has been transferred to 4 commercial feed manufacturers and is being used to reduce feed costs while maintaining fish performance.

5. Changes in composition and phosphorus profile of Dried Distillers Grains with Solubles (DDGS). Dry grinding has been the primary process used to convert corn to bio-ethanol, resulting in a large volume of dried distiller grains with solubles (DDGS) as a co-product. The process consists of grinding, cooking, liquefaction, saccharification/fermentation, distillation, and co-product recovery. ARS scientists in Aberdeen, ID, monitored changes in proximate composition (protein, oil, ash, carbohydrate, and starch) and different types of phosphorus (P) in DDGS from 3 commercial plants in Iowa. During the dry grinding process of corn, only small changes in proximate composition and P profile before saccharification were observed. Large changes in nutrient composition and distribution were observed. This information adds to our understanding of phosphorus distribution in feed ingredients and will help to reduce phosphorus released from farms.


5.Significant Activities that Support Special Target Populations
Demonstration Project; Feeding Plant-based Diets to Rainbow Trout and the Effect on Product Quality. Production scale groups of rainbow trout were fed either a fish meal based or plant-based diet for 16 weeks. This collaborative project between ARS, University of Idaho Extension, and the College of Southern Idaho provided the opportunity to local trout producers (many small farms) to taste trout fed fish-meal free diets. Over 30 producers attended and tasted the fish. Fillet samples were prepared by food technologists, and farmers could not detect a difference in the flavor or texture of the fish fed the different diets. This project provided a demonstration of the effect, or lack there of, of removing fish meal from rainbow trout diets.


6.Technology Transfer

Number of Active CRADAs2

Review Publications
Campbell, N.R., Overturf, K., Narum, S.R. 2009. Characterization of 22 novel single nucleotide polymorphism markers in steelhead and rainbow trout. Molecular Ecology Resources 9:318-322.

Liu. K.S. 2009. Effects of particle size distribution, compositional and color properties of ground corn on quality of distillers dried grains with solubles (DDGS). BioResource Technology. 100: 4433-4440.

Liu, K.S. 2009. Some factors affecting sieving efficiency and performance. Powder Technology. 193:208-213.

Overturf, K. & Gaylord, T. 2009. Determination of relative protein degradation activity at different life stages in rainbow trout (Oncorhynchus mykiss). Comparative Biochemistry and Physiology Part B 152:150-160

Foltz, J., Overturf, K.E., Plant, K., Clemens, K., Powell, M. 2009. Detection of Nucleospora salmonis in steelhead,Oncorhynchus mykiss (Walbaum), using quantitative polymerase chain reaction(qPCR). Journal of Fish Diseases. 32:551-555.

Sealey, W., Barrows, F., Hang, A., Johansen, K., Overturf, K.E., Lapatra, S., Hardy, R. 2008. Evaluation of the ability of barley genotypes containing different amounts of ß-glucan to alter growth and disease resistance of rainbow trout Oncorhynchus mykiss. Animal Feed Science And Technology 141: 115-128.

Gaylord, T.G., Barrows, F., Rawles, S.D. 2009. Apparent Amino Acid Availability from Feedstuffs in Extruded Diets for Rainbow Trout Oncorhynchus mykiss. Aquaculture Nutrition. doi: 10.1111/j.1365-2095.2009.00678.x

Gaylord, T.G., Barrows, F. 2009. Multiple Amino Acid Supplementations to Reduce Dietary Protein in Plant-Based Rainbow Trout, Oncorhynchus mykiss, Feeds. Aquaculture. 287:180-184.

Gaylord, T.G., Barrows, F., Rawles, S.D., Liu, K., Bregitzer, P.P., Hang, A., Obert, D.E., Morris, C.F. 2009. Apparent digestibility of nutrients in extruded diets from cultivars of barley and wheat selected for nutritional quality in rainbow trout Oncorhynchus mykiss. Aquaculture Nutrition. 15:306-312.

Last Modified: 10/25/2014
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