Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853
Performing Department
Animal Science
Non Technical Summary
The vast majority of targeted wild fisheries are exploited to maximum levels, and cannot keep up with the seafood demand of the growing human population. Aquaculture will necessarily provide nearly all future increases in seafood production; however, fish require high-protein diets, and the industry must identify economically and environmentally sustainable feeds to grow fish. Fishmeal, in particular, has become a prohibitively expensive and controversial source of dietary protein, and acts as a persistent stigma on aquaculture for catching wild fish to grow farmed fish. Alternately, processed fish carcasses, which also possess high-quality protein, could be used more extensively in place of fishmeal in aquafeeds if a means of salvaging the perishable material were available. Utilizing abundant seafood waste streams to help reduce aquafeed prices would furthermore be a major step toward creating a viable domestic aquaculture industry that could counteract our $15B seafood trade deficit. In response to these issues, our project goal is to develop and implement a silage-based aquafeed formula that converts ensilated fish processing byproducts directly into pellets. Early attempts to make aquafeed from fish silage required up to a 50% rate of binder, which dilutes the valuable fish protein content. Our lab is pioneering a novel "cold-gelling" feed system capable of solidifying fish silage into water-stable feed pellets using a much lower (< 5%) level of binding agent. Ensilation stabilizes fish tissue at low pH rather than freezing, making it cheap and easily accessible, while also avoiding the cost and carbon footprint of transportation and rendering that currently inhibit broad use of fish processing byproducts in aquafeeds. The current proposal is aimed at optimizing the silage-based feed system, testing growth performance of fish cultivars, and transferring the technology to industry.
Animal Health Component
75%
Research Effort Categories
Basic
(N/A)
Applied
75%
Developmental
25%
Goals / Objectives
Aquaculture pioneers in New York, a growing number of which are multimillion-dollar operations, are desperate to reduce production costs to better compete with cheap seafood imports. Cheaper aquafeed for fish farming is imperative for reducing variable costs, and hence increasing profits to recoup large capital investments in industrial-level aquaculture facilities. For smaller-scale fish farms who cannot even buy feed in bulk at discounted rates, feed cost is prohibitive. Meanwhile, seafood processors must sometimes pay to dispose of fish carcasses into landfills, such that giving away waste material - or even selling it - to regional fish farms would also be an upstream economic boon. Redirecting fish offal from the dump into feed would therefore solve two problems simultaneously.In response to these problems, the goal of the proposed project is to develop a technology that makes it possible to salvage large volumes of perishable protein from seafood processors, at low cost, for use in aquafeeds. This objective will be accomplished by first optimizing a novel silage-based aquafeed formula that allows fish carcasses to be used in aquafeed, then further developing variations of the feed using readily available, sustainable ingredients. The proposed project represents one iteration of many possible formula modifications using a wide variety of seafood processing byproducts, protein supplements, and target fish species. Experimental feeds will be evaluated for growth performance and production qualities (fish flavor, yield, etc.). The ultimate objective will be to create protocols for anyone in the industry, i.e. fish processors, feed manufacturers, or aquaculturists, to begin making and using the feed. Aquaculturists will help guide the implementation process to make it practical for industry use. The economy of the feed will also be roughly assessed so that we can begin mapping out a logistical map of where the feed system might be most practical, accounting for raw material availability, transportation costs, and seafood markets in the region. The current budget will allow us to assess the utility of a silage-based feed in a representative carnivorous fish relevant to New York aquaculture, such as trout or salmon. To the extent resources allow, we will begin similar studies on a representative omnivore, e.g. tilapia.Research objectives:Optimize silage-based feed formulas using three protein supplements.Evaluate growth performance of fish grown on silage-based feeds relative to conventional feed.Evaluate growth performance of fish using silage-based feeds in tandem with a regimen of conventional feed.Evaluate production characteristics of fish and fish flesh produced using silage-based diets.Disseminate findings on the utility of silage-based feed to industry, and produce protocols for manufacturing feed on site.Cheap, high-quality feed made from local seafood byproducts would help U.S. farms and processors cut production costs, and reduce our dependence on costly seafood and fishmeal imports. Salvaging fish offal would also have positive environmental impacts extending to coastal stakeholders in New York and beyond. Fishmeal fleets have plundered the marine food web base, undermining valuable food-fish stocks and lucrative recreational fisheries. In many states, including New York, extension services are pushing for local seafood branding that would be aided by touting sustainable production practices, e.g on the popular Monterey Bay 'Seafood Watch' consumer guide, or in some cases even lead to an Organic certification. Replacing fishmeal with an industry side stream will result in more sustainable aquafeeds, benefitting farms, fisheries, coastal stakeholders, as well as seafood consumers who increasingly want local, sustainable seafood.
Project Methods
Research will be carried out in three progressive phases to 1) optimize and expand the feed formula to meet a range of farm needs; 2) test silage-based feeds for growth performance in fish; and 3) assess cost effectiveness and develop manufacturing protocols.1) Feed formulation: The feed system involves adjusting silage pH and levels of an alginate binder in the presence of calcium ions to "stiffen" the wet silage into pellets. Fish silage tends to have a higher relative fat content than needed for feed, however. Removing fat from silage is not practical for on-farm use, although adding protein is a viable option to adjust the protein:lipid ratio. We will test soy protein concentrate (SPC), defatted microalgae, and blood meal as supplements to fish silage, representing a range of available plant and animal protein commodities.Silage production: Fish byproducts (head, frame, viscera) will be acquired from collaborators, Haskell's Seafood (LI, New York), Cortland Seafood (Cortland, New York) and/or Hudson Valley Fisheries (Hudson, New York). Typical northeastern species include porgy, pollock and haddock (wild), or trout (farmed). Carcasses will be ground (Insinkerator SS-1000) to release enzymes from the gut and maximize surface area of tissue for digestion. The pH will be lowered to 4.0 using phosphoric acid, and the tissue allowed to liquefy for 1-2 weeks at 22°C. Propoionic acid (0.25%) will be added to restrict fungal growth.Each batch of silage and supplements will undergo proximate analysis for crude protein, lipid and energy content, and mixed as needed to make isonitrogenous, isocaloric experimental feeds. Target protein:lipid ratios will be based on established fish nutrition standards (e.g. 42%:15% for trout). Silage will be pelletized by raising pH to 5.0, 5% sodium alginate added by weight, and the mixture extruded and cut into a calcium ion bath. Pellets will be dried and stored at 4°C. Crude proximate composition and energy content of feeds will be verified prior to feed trials.2) Growth performance trials: Experimental feeds will be evaluated in a progressive series of growth trials. First, growth elicited by silage-based diets using various protein supplements will be compared to a typical commercial feed. Next, the best-performing silage-based feed from the first trial will be evaluated in conjunction with a normal feeding regimen. Finally, in an extended growth trial, production qualities and economy of the experimental feed will be evaluated. Analyses details are found below. Growth trials will proceed as follows.Trial I: Trout will be acclimated for two weeks in a 12-tank RAS array (120 L/tank) at Cornell University (15° C; 12L:12D photoperiod). Groups will be randomly assigned to tanks (n ≥ 3 tanks/group), and fed either pellets (e.g. Zeigler Gold)silage-based diets supplemented with either SPC, microalgae, or blood meal. Although compositionally different than a silage-based feed, pellets are a justifiable control for comparison because they represent the industry standard (experimental feeds have no commercial analog). Regimen will be based on the species and size of fish available in order to stimulate competitive feeding behavior. Groups will be fed at consistent rates and grown to at least double their initial size. Biomass of each tank will be weighed every two weeks to track specific growth rate (SGR) and to update feeding regimen as a percentage of body weight per day (BW/d; e.g. rainbow trout: 1.5-3%). Total feed intake of each tank will be recorded to calculate feed conversion ratio (FCR) for each treatment, and proximate composition of flesh and morphometrics for each group calculated to provide a basis for comparison.Trial II: Because it might not be practical for some farms to derive their entire feed requirement from silage, we will also assess if a silage-based feed can be used in tandem with commercial feed. The best performing experimental feed from the initial trial (determined primarily by growth rate; also considering other relevant metrics) will be further evaluated as a dietary supplement. Groups will be fed a commercial pellet, a silage-based feed, or be fed between the two diets in variable proportions to test if the silage-based feed can totally or partially supplant conventional pellets during grow out. Regimens with silage-based feed rates of 0% (control), 33%, 66% and 100% will be fed to groups of fish (n ≥ 3 tanks/group), and fish allowed to double in weight. SGR will be tracked in two-week intervals, and FCR, proximate composition, and morphometrics for each group calculated to provide a basis for comparison.Trial III: The utility of a silage-based feed as a total or partial diet for farmed fish will be validated, and production quality and cost-benefits assessed. The best regimen using the highest level of silage-based feed, as determined by the previous trial, will be used in a larger-scale follow up study in a six-tank RAS array (400 L / tank; n = 3 tanks/group). A commercial pellet will be used as a control. Fish will be stocked at industrial density, and fed as % BW/d. Fish will increase 3-4X in weight to provide a reliable assessment of growth. SGR will be tracked in two-week intervals, and FCR, flesh composition, somatic indices and morphometrics for each group calculated to provide a basis for comparison. By better approximating production conditions, and having a longer growth period, this trial will provide a more definitive evaluation of the relative growth promoting capacity and economy of the silage-based diet. Sensory trials will be held to determine if silage affects fish meat characteristics. Prior to harvest, fish will be purged for a week. Panelists will be given unseasoned, poached fillet and asked to rate flavor and other sensory qualities to gauge if the experimental feeds impact the final product.Analyses: Specific growth rate [(ln W2 - ln W1)/(T2 - T1) * 100, where W1 is the initial weight at the start of the growth interval, W2 is the end weight and T2-T1 is the duration (days) of the interval] and FCR (feed intake / weight gain) will be tracked for all trials. At the end of the trials, a pooled sample of muscle will undergo proximate composition analysis, including amino acid and fatty acid profiles, to compare the protein and lipid in the flesh between diets. Somatic (fillet, liver, viscera, muscle) indices [(organ weight / total BW)*100] will be calculated to determine yield, or otherwise characterize the partitioning of somatic growth. Differences between group means for SGR will be analyzed by two-way ANOVA (time × treatment) to track growth across time within groups and between groups at given intervals. Other terminal data, including FCR, proximate analysis, and body composition between groups, will be analyzed by one-way ANOVA (treatment). Hedonic sensory ratings will be taken on a scale of 1-10 for meat from each diet and averaged among panelists (n ≥ 10).3) Protocols and economy: Although extension is not an element of this project, the goal is nonetheless to share our findings to farmers and implement the feed system. Putting a rough cost to the silage-based feed and providing manufacturing instructions to industry will help farmers decide how, or if, to proceed with using this technology based on their resources and proximity to raw materials. The cost of producing a given unit of feed from fish offal will be estimated based on the price of raw materials, transportation, labor, and equipment. The cost per kg of fish produced using silage will be estimated based on feed cost and FCR. Protocols for making fish silage, and for converting silage into fish feed, will be compiled. We plan to work with several fish farms to manufacture the feed on site, and to get feedback on how the system might best be implemented. Once practical methods have been decided upon, protocols will be made available to the public (e.g. Sea Grant).