Resources

Language
English

Date Published
October 29, 2012

Author
Mark Drawbridge
Description

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.

Language
English

Date Published
October 16, 2011

Author
D. Allen Davis, Ph.D.
Description

A shrimp feeding trial was run at INMARLACA Farm, located in Maracaibo, Zulia State, Venezuela to replace Fish Meal (FM) with Soybean Meal (SBM).

Language
English

Date Published
October 23, 2011

Author
United States Soybean Export Council
Description

Aquacultural production of trout and salmon, collectively referred to as salmonids, is one of the largest global aquaculture industries and currently uses a disproportionately high amount of fish meal in dietary formulations. Sustainable production and growth in salmonid culture demands identification of alternative high-protein feed ingredients. The chemical composition of soy protein concentrate (SPC) suggests it has potential has an ingredient in diets fed to salmonids. There have been over 30 published studies of SPC use in diets for rainbow trout and Atlantic salmon. The data indicate small trout and salmon are more sensitive to SPC inclusion in diets than larger fish. SPC can provide up to 50% of the dietary crude protein in diets for small fish. Fish meal can be completely replaced in diets for larger fish. Results from digestibility studies indicate high nutrient availability from SPC. Methionine supplementation appears necessary for salmonids and taurine supplementation was recently identified as beneficial in SPC-based diets for trout. The form of phosphorus in SPC remains problematic, but incorporation of phytase or pretreatment of SPC with phytase improved phosphorus availability. Sensory characteristics of salmonid fillets fed SPC have been lighter in color than those from fish fed fish meal, but texture and flavor have not been adversely impacted. Several dietary formulations are available that have been tested in the target species. Ingredient cost hampered use of SPC in the 1990’s and remains an issue in the 21st century. However, given the escalating price of fish meal and demand for that commodity, use of SPC in salmonid diets appears promising.

Language
English

Date Published
October 29, 2011

Author
United States Soybean Export Council
Description

Florida pompano (Trachinotus carolinus) is a carnivorous marine finfish with commercial aquaculture potential. While the price of fishmeal has never been higher, soy has long been considered a cost-effective potential replacement candidate for aquacultured fish. However, there are many products on the domestic and international market with varying nutritional profiles that may or may not be well-utilized by carnivorous fish. Examples include a variety of refined soy protein concentrates (SPCs) and more cost-effective fermented soy proteins, several of which could hold promise for the aquaculture industry. Through a methodical experimental approach at the University of Miami Experimental Hatchery (UMEH), three soy protein products were evaluated for potential incorporation into feeds for Florida pompano.

Language
English

Date Published
October 29, 2011

Author
United States Soybean Export Council
Description

Selecting a new fish species with a potential value for aquaculture has essential importance for the future development of the aquaculture industry. In the United States, Florida pompano, Trachinotus carolinus, is among the marine fish species with aquaculture potential that has caught the interest of the industry for being a truly euryhaline species. Research is needed to complete our knowledge of the nutritional requirements of Florida pompano at different ages in order to develop cost-effective and environmentally-friendly diets. With the recent interest in high market-value carnivorous species, cost concerns are extremely important since carnivorous fish require greater amounts of protein and fishmeal represents the primary protein source in feeds formulations. A review of the literature confirms the importance of completing the nutritional requirements for Florida Pompano at different ages in the development of cost-effective and environmentally-friendly diets. Our goal was to examine the nutritional requirements in terms of protein and energy for Florida Pompano close to its typical marketable weight, which is between 400 and 600 g. To date, only the nutritional requirements for juvenile fish weighing up to 45 g have been examined. Since nutritional requirements have been well described to change as a fish grows and develops, it is essential that the requirements for larger Pompano, which consume greater quantities of foods than their smaller counterparts, be elucidated. This is most important for protein and lipid levels as they are the most expensive dietary components.

Language
English

Date Published
October 16, 2011

Author
Matthew C.J. Taynor a, Jorge A. Suareza, Carlos Tudelaa, Gerard Cuzonb, Ronald Hoeniga and Daniel D. Benettia
Description

Since 2007 Kampachi Farms (formerly Kona Blue Water Farms) and the University of Nebraska Lincoln have been working to reduce the use of fishmeal and fish oil in the diets of Seriola rivoliana, by substituting soy-based proteins and oils. These efforts are intended to reduce the need for wild-caught fishmeal (FM) and fish oil (FO). Results of previous years’ trials have shown that fish consuming a diet containing 40% soy protein concentrate (SPC) and a high omega-3 soy oil (STA), maintain growth rates comparable to fish eating the standard commercially prepared diet used to raise Kona Kampachi® (Seriola rivoliana) as long as supplementary taurine (a non-essential amino acid) is included in the SPC based diets. In 2011 two trials took place in order to continue this research and expand upon results.

The first of the two trials (designated as the “growout” trial) expanded upon a short-term study performed in 2010, when commercially viable growth rates and food conversion ratios (FCR) were achieved with a SPC/STA based diet. The 2011 growout trial used the same feed formulation for an eight month period, such that S. rivoliana could be reared to a marketable size (≥1.5kg) in land-based tanks. The growout trial then culminated in a consumer taste test. The consumer panel participated in a sensory evaluation to note detectable differences (if any) between the two types of fillets and to assess the palatability of SPC fed fish fish versus fish fed the standard control diet. In addition a questionnaire was included to garner consumer perceptions of aquaculture and soy-fed fish.

The second trial (referred to as the “fish oil reduction” trial) focused on further decreasing the amount of fish oil in Kampachi diets. All experimental feeds in this trial contained 40% SPC, with ascending levels of stearidonic acid (STA)-rich soybean oil. The results of this trial will indicate the changes of the fatty acid profiles of the fish (and thus marketability of health aspects of marine fish) and also if there may be any unforeseen fish health issues with the reduction in fish oil.

Results from both trials are outlined within this report. Overall health, growth, feed conversion ratios and final weights were used to compare the effectiveness of the soy-derived feed with that of the standard diet currently used by Kona Blue. The consumer panel taste test was conducted by Oregon State University’s Food Innovation Center, whose responsible parties provided all taste test related results and statistical analyses, presented herein. Tissue analyses of fish fed all diets used throughout the year are also included.

Language
English

Date Published
October 29, 2011

Author
United States Soybean Export Council
Language
English

Date Published
October 29, 2011

Author
Mark Drawbridge
Description

This project has demonstrated the technical feasibility of replacing up to 50% of the fish oil (FO) with high omega-3 soy oil (STA) in the diet of S. rivoliana. The question posed in this part of the study is whether this is likely to be a profitable substitution, and if so, what is the potential size of the world aquaculture market for STA oil and the engineered soybeans required to produce it.

The profitability of substitution depends on the price of STA relative to that of FO, and the physical rate of substitution of one for the other. The growout trial of the project demonstrated that if fish must be fed for a fixed period of 238 days, it requires about 1.24 kg of STA to substitute for 1 kg of FO. (The “oil reduction” trials imply roughly similar rates of substitution.) Thus only if the price of FO is more than 24% above the price of STA would the substitution to be profitable under this fixed 238-day production period.

The price of commercial STA oil will certainly be higher than commodity soy oil because of the strict market segregation required for a genetically engineered product such as this. We estimate that STA oil will sell at a 22-40% premium over commodity soy oil, depending on volume, yield drag and other factors. We also expect that the current 3% FO premium over commodity soy oil is likely to persist. If so, the price of STA oil will be 19-37% higher than FO, which would certainly result in losses from substituting STA for FO in a fixed-period production plan of 238 days.

Language
English

Date Published
October 29, 2011

Author
R. Perrin and L.Fulginiti
Language
English

Date Published
October 29, 2011

Author
Mark Drawbridge
Description

The ultimate goal of the project is to advance practical diet development for California yellowtail (CY). This is important given the great potential to expand the culture of CY commercially. The specific goals of this project are to (1) develop and validate an open formulation for the CY based on modifications of the existing commercial diet being fed to CY; (2) evaluate the response of CY to a diet with increasing levels of soy protein concentrate, and (3) evaluate the response of CY to a diet with increasing levels of soy oil as a fish oil replacement while keeping other nutritional factors constant.

Language
English

Date Published
October 29, 2008

Author
Mark Drawbridge Allen Davis2 Dave Jirsa
Description

The ultimate goal of the project will be to advance practical diet development for this white seabass (WSB). This is important for both the culture of this species for stock enhancement as well as the great potential to expand the culture of this species commercially. The specific objectives of this research will be to: 1) Evaluate the response of WSB to a modification of the existing commercial diet being feed to WSB, 2) Evaluate the response of WSB to a diet with increasing levels of soy protein concentrate, 3) Evaluate the response of WSB to a diet with increasing levels of soy oil as a fish oil replacement.

Language
English

Date Published
October 29, 2008

Author
Mark Drawbridge Allen Davis2 Dave Jirsa
Description

Salmonids (primarily Atlantic salmon and rainbow trout) are the most cultured family of carnivorous fishes in the world, with 2004 production values of approximately two nmillion metric tonnes (mmt) valued at US $6.5 billion (FAO 2006). The salmonid industry accounts for approximately 3% of total global aquacultural production, but its value is nearly 10% of total global aquacultural value (FAO 2006). Over the past ten years, the industry has more than doubled production output. Norway and Chile are the two primary producing countries, accounting for approximately 60% of global salmonid production (FAO 2006).

Commercial feed formulations for salmonids currently incorporate 30 to 45% fish meal (New and Wijkstroem 2002). Global fish meal production typically ranges between 6-7 mmt annually (FAO 2006). The salmonid industry is utilizing about one third of the total amount of fish meal used in aquaculture feeds (Hardy 2002). However, recent declines in the harvest of fishes utilized to produce fish meal (primarily in Peru) lead to an historic high of $1,600 per metric tonne of fish meal in the summer of 2006 (Hardy 2006). As fish meal prices climb, production costs for salmonid farmers increase as well (New and Wijkstroem 2002). Additionally, as fish farmers increase production, the economic return per unit of production decreases. For Atlantic salmon, the return per unit has decreased by 20-40% since 1986-1987 (FAO 2006). If the salmonid industry is going to continue to grow, alternative proteins will need to be incorporated into their feed formulations.

As the salmonid industry incorporates changes to their feed formulations, they need to assure that these changes have a minimal impact on fillet quality. Salmonid fillets are an excellent source of high quality protein. In addition, they contain high amounts of the n- 3 fatty acids eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Farmed salmonids contain slightly higher levels of EPA and DHA than wild harvested salmonids, with farmed rainbow trout containing 1.15 g EPA and DHA per 100 g serving, compared to 0.99 g EPA and DHA per 100 g serving of wild caught rainbow trout. Farmed Atlantic salmon contain 2.15 g EPA and DHA per 100 g serving, compared to 1.80 g EPA and DHA per 100 g serving of wild caught Atlantic salmon (all values are cooked edible portion) (USDA/ARS 2006). The Food and Drug Administration (FDA) and American Heart Association (AHA) recommend two meals (one meal is 170.1-226.8 g) of fish per week, especially fatty species such as salmonids, to maintain a healthy lifestyle. In 2004, the FDA allowed a qualified health claim for reduced risk of coronary heart disease on conventional foods that contain EPA and DHA (FDA 2004). As the salmonid feed industry transitions to alternative protein and lipid sources, EPA and DHA levels in the diet and fillet will need to be considered.

Soybean meal (SBM) is an alternative protein ingredient currently of great interest to the aquaculture industry. In 2005, global production of soybean seeds was estimated at 218 mmt, but more importantly, global production of SBM was estimated to be 145 mmt, more than 20 times greater than the average global production of fish meal (USDA 2006). SBM prices can vary, but typically cost around US $200 per metric tonne (www.aquafeed.com). Dehulled SBM contains approximately 48% crude protein, one of the highest protein contents of all plant-based protein ingredients (NRC 1993). When used as a primary protein source, the essential amino acid profile of SBM, with the exception of methionine, is adequate to meet the known requirements of salmonids (NRC 1993).

Despite the global availability and nutritional characteristics of SBM, it has not been incorporated into salmonid diets at high inclusion rates. SBM is typically incorporated at 10-30% of the diet depending on species and feed manufacturer (Hardy 2002; Pillay and Kutty 2005). The relatively high concentration of carbohydrates and presence of antinutritional factors (ANF) are believed to be the primary factors limiting the amount of SBM used in salmonid feeds (Francis et al. 2001; Hardy 2002). Lectins, oligosaccharides, saponins and trypsin inhibitors are all present in SBM and have the ability to act as ANF when fed to fish. Soy isoflavones (also called phytoestrogens) may also exert negative effects when fed to fish by exerting estrogenic effects; however, isoflavones may also have a beneficial effect by acting as an antioxidant. Researchers have attempted to identify the specific components of SBM that are limiting its use in salmonid diets; however, most of this research evaluated SBM that had been subjected to various extraction techniques that removed several potential ANF instead of evaluating purified ANF derived from SBM (Francis et al. 2001). Consequently, the specific antinutritive compounds present in SBM that are exerting negative effects on salmonids have not been identified.

In 2002, the United Soybean Board (USB) and the Indiana, Illinois and Ohio State Boards funded the Soy-in-Aquaculture (SIA) Managed Aquaculture Program. SIA was established to overcome the barriers limiting the amount of soy ingredients in aquaculture feeds. The initial SIA initiative contained two separate but related programs. The goal of the first component focused on increasing the amount of soy inclusion in feeds used by well-established, intensive aquaculture industries that were underutilizing soy in their feed formulations. Specific objectives were to systematically evaluate specific ANF and determine which ones were causing problems when fed to salmonids. This research was conducted at seven institutions, led by Purdue University (West Lafayette, IN, USA). The second program was international marketing led by the American Soybean Association/United States Soybean Export Council. The primary objective of that program was to increase usage of soy-based formulations by fish farmers in Southeast Asia and India. The remainder of this document will focus on the research portion of the SIA initiative.

Language
English

Date Published
October 29, 2006

Author
Steven D. Hart (Purdue University), Frederic T. Barrows (Agricultural Research Service, Hagerman Fish Culture Experiment Station), Konrad Dabrowski (Ohio State University), Siddhartha Dasgupta (Kentucky State University), Donald L. Garling (Michigan State)
Description

Increasingly, plant protein sources including soybeans are being evaluated as replacements for fish meal in the diets of farmed carnivorous fish. Many plant protein sources contain factors that can exert nutritional and antinutritional effects in fish, and alter other developmental processes including reproduction.

Genistein is an isoflavone that is found in significant concentrations in soybeans. Genistein can have both estrogenic and antiestrogenic effects, either of which, in turn, can have stimulatory or suppressive actions on growth and reproduction in fish. The purpose of this study was to assess the effects of genistein on the growth, development and reproduction of rainbow trout and Atlantic salmon, to clearly elucidate the potential positive and negative effects of this isoflavone before large-scale attempts are made to incorporate increasing amounts of soybean products into commercial salmonid diets.

In rainbow trout, for a one year period fish were fed diets containing genistein at four concentrations: 0 (control), 500, 1,000 and 3,000 ppm. At all doses tested, genistein had no effect on growth or feed conversion. Serum levels of vitellogenin, measured at four times during the treatment period, were higher in genistein-treated fish (all doses) than controls. We found no effects of genistein on serum levels of reproductive hormones, morphology and histology of the gonads (both sexes), egg production, fertility rates, fry size nor viability. Accordingly, we suggest that the genistein content of soy products should not be a factor in determining their incorporation into the diets of rainbow trout.

In Atlantic salmon parr, for a six-month period fish were fed diets containing genistein at four concentrations: 0 (control), 500, 1,000 and 3,000 ppm, and a fifth group of fish were fed estradiol-17β (E2) at 20 ppm as a positive control. At all doses tested, genistein had no effect on growth or feed conversion. At the end of the treatment period, serum levels of vitellogenin were higher in the E2 and genistein treated fish than in controls. E2 and genistein at all doses tested inhibited the process of smoltification, as measured by 24-hr seawater challenge tests. Accordingly, the incorporation of genistein into the diets of Atlantic salmon parr may be contraindicated.

We suggest that further studies be conducted to evaluate the effect of genistein on Atlantic salmon smolts, to determine the appropriateness of high soybean meal content on Atlantic salmon grow-out diets.

Language
English

Date Published
October 29, 2005

Author
Jeffrey A. Malison*, Luciene C. Lima, Yuliana, Terence P. Barry and James A. Held
Description

World shrimp production has been increasing for the past four decades. In 2004, production reached over 6 million tons. This unprecedented expansion has been primarily attributed to increased production from the shrimp farming activities. In 2004, more than 41% (2.5 million tons) of the world’s total shrimp production was from farming. The primary cost of production in shrimp farming is feed, with protein being the most expensive macronutrient in these diet formulations. Although marine fish meals and fish oils provide excellent sources of high quality essential amino acids, lipids, vitamins, minerals and attractants in aquaculture diets, we must consider the finite availability these resources and the impact their procurement has on the environment. In addition, demand for fishery products from other high profit sectors, such as the pet food industry, will force fish meal prices up until its usage in aquatic feeds will no longer be economically feasible. If aquaculture is to continue to be an increasing contributor to the human food supply, it is critical that aquaculture feeds become less reliant on marine fisheries products. Due to both economic pressures from high fish meal and fish oil prices and pressures from buyers and consumers requiring sustainable practices, the use of high levels of fish meal and fish oils is no longer acceptable. Currently, feed mill manufacturers and producers are taking a pragmatic approach by looking into practices that will not only reduce feed production costs, but also improve their public image. Increasing the use of soybean meal and other soy products in shrimp diet formulations should reduce feed costs and improve both the image and sustainability of this growing industry.

This study was part of a continuing project focusing on developing plant-based feeds for aquaculture; the current work was geared toward enhancing the lipid component of plant-based feeds. A systematic, stepwise approach has been developed to produce good scientific data and to ensure that larger scale pond based trials can follow with the highest potential for success. The ultimate goal of the research was to provide adequate information to the feed formulators to allow them to use the maximum level of soy products (soybean meal, soybean oil, and soy lecithin) in their feed formulations.

Previous studies have shown that fish meal can be replaced either singularly with animal by-product meal or in combination with plant protein sources without affecting the physical and nutritional quality of the feeds. However, the use of alternative protein sources is often done in combination with the use of marine oils to supply essential fatty acids and enhance the palatability of the diet. Soybean meal has been identified as a good alternative protein source due to its high protein content and relatively balanced amino acid profile. In previous studies we have maximized the use of soybean meal in shrimp feeds, however, there are numerous other products derived from soybeans that can be utilized in aquaculture diets including soy oil and soy lecithin which have yet to be optimized. Although it is unlikely that soy oil will be suitable as a complete fish oil replacement due to a lack of essential fatty acids, it may be possible to reduce fish oil use in plant-based shrimp feeds by diluting fish oil with soy oil. Another approach to enhancing the lipid component of plant-based feeds is the inclusion of soy lecithin. Phospholipids play an important role in maintaining cellular structure. They also enhance cholesterol transport, increase lipid retention, and may facilitate the pelleting process by acting as a lubricant. Soy lecithin, a primary source of phospholipids, has the potential to improve the lipid component of plant-based feeds.

The objectives of this study were: 1. To evaluate the response of Pacific White Shrimp to diets with increasing levels of dietary lecithin (0-2%) in conjunction with decreasing levels of fish oil to maintain the same dietary lipid level, 2. To evaluate the response of the shrimp to diets with decreasing levels of fish oil supplemented with increasing levels of soybean oil to maintain the targeted lipid content.

Language
English

Date Published
October 29, 2005

Author
AgriLife Research Mariculture Laboratory
Description

The Soy-in-Aquaculture Managed Research Program is working to determine the chemicals in soybean meal that can limit the greater use of soy meal in feeds for varied aquaculture species. Initial work with the salmonid industry found problems related to soy lectins and trypsin inhibitors, but determined benefits from saponins and isoflavones.

Language
English

Date Published
October 29, 2005

Author
Steven Hart Paul Brown, Ph.D.
Description

In compliance with the 2003-2004 USB Managed Aquaculture Program, researchers at Michigan State University (MSU) developed a 2-phase experimental design with the goal of examining the effect of trypsin inhibitors in SBM based diets on Atlantic salmon. Phase I focused on the effect of growth, feed consumption, digestibility, and pancreatic proteolytic enzyme activity of juvenile and smolting Atlantic salmon (Salmo salar) fed purified diets with graded levels of trypsin inhibitors. Two feed trials were completed in 2003 under phase I of this project.

The second phase of MSU’s research was initially designed to examine effects of trypsin inhibitors in SBM based diets containing practical feed ingredients under different processing conditions. Based on results obtained from other researchers in the Managed Aquaculture Program in 2003, and an extensive literature review, MSU expanded the focus of this research towards the development of an open formula practical diet, containing 5-30% SBM, that is nutritionally acceptable for young Atlantic salmon. Our objective is to develop a practical diet containing the highest level of SBM possible, based on best available knowledge, which would be available for incorporation by commercial feed suppliers for use with not only Atlantic salmon, but other picivorous fish as well (e.g. salmonids).

Phase II research was initiated in spring of 2004. Diets were formulated to contain 0- 30% SBM, which according to literature, is the range in which SBM diets appear to have anti-nutritional characteristics affecting Atlantic salmon. An open formula practical diet developed by the Ontario Ministry of Natural Resources (OMNR) for Atlantic salmon was used as a baseline diet formulation. In late May of 2004, a setback was encountered. The well pumps which supply water to the MSU Aquaculture Lab had a variable frequency drive malfunction. The repair was rather extensive and wasn’t completed in September.

The Atlantic salmon available for the study were donated from the Michigan Department of Natural Resources. Prior to pick up, we learned that these fish had Bacterial Kidney Disease (BKD). The fish were transported to MSU in late October, 2004, and were treated with erythromycin for BKD under the direction of Dr. Mohammod Faisal, MSU faculty member and State Fish Health Specialist. An INAD was not required since these fish are to be used solely for research and not human consumption.

The phase II feed trial began after the erythromycin treatments were completed on 1/11/05. The trial is designed to evaluate the potential effects of long term feeding (3-4months) of SBM diets on young Atlantic salmon.

Language
English

Date Published
October 29, 2004

Author
United States Soybean Export Council
Description

The overall objective of our portion of the collaborative soybean study is to evaluate the quality of market sized rainbow trout and salmon reared on diets containing significant levels of soybean meal as a primary protein ingredient. In year 2, we completed the following: 1) quality evaluation of rainbow trout reared on experimental genistein-containing diets for 12 months, and 2) quality evaluation of rainbow trout reared on soy-containing diets.

Language
English

Date Published
October 29, 2004

Author
Denise Skonberg and Natasha D’Souza
Description

A feeding trial was completed several quarters ago in which diets containing high quantities of soybean meal were subjected to extreme processing conditions during pelleting, using a Buhler Twin-Screw Extruder (DNDL 44). Three processing variables were studied: (1) pre-conditioning or no pre-conditioning; (2) extruder barrel temperature (low or high); and (3) time during which the feed mixture was in the barrel (short or long). Various combinations of processing conditions were employed to produce rainbow trout feeds, which were subsequently used in a 12-week feeding trial to evaluate the effects of processing conditions on the nutritional value of the diets for the trout. These results have been reported, and initial diet analysis has been completed, but an error in feed sample handling in our laboratory made it impossible to conduct analysis for protein dispersibility index (PDI) and trypsin inhibitor activity (TIA). Activity and accomplishments during the quarter

1. Experimental diets used for the rainbow trout growth study were re-manufactured using the same equipment, ingredients, and processing conditions as were used to produce diets for the rainbow trout feeding trial. Samples of these diets were analyzed again for proximate composition and energy content to ensure that they were essentially identical to earlier diets. Diet samples are currently being analyzed for PDI and TIA, with analysis scheduled for completion early next quarter.

2. Rainbow trout were fed control and high-soybean meal diets (40%) for six months to produce market-sized trout (>500g). These fish were killed, gutted, chilled, and sent by overnight courier to the Dr. Denise Skonberg, University of Maine, for sensory and nutrient analysis. Twenty fish from each dietary treatment group were sent.

Work planned for next quarter
1. Complete PDI and TIA analysis on feed samples and complete report on feeding trial.

2. Begin feeding trial with rainbow trout fed high-soybean meal diets supplemented with various volatile fractions of fish meal production to determine if they affect intake. Previous work on another project demonstrated that partial hydrolysis of fish meal increased intake of high-soy diets by rainbow trout.

Language
English

Date Published
October 29, 2004

Author
Ronald W. Hardy1 and Frederic T. Barrows2