In order to “move the needle” on US soy, one is left with but two options: increase the inclusion rate of soy products in existing formulations destined to major commercial species, or develop new markets (“new” species, life stages, or products) where soy can be introduced. This proposal addresses both of these options. First, our test species is the California yellowtail (Seriola dorsalis), which as a member of the genus Seriola, represents a high value species with an existing market for fresh sushi-grade product and successful rearing methods in hatchery and growout. Furthermore, HSWRI is currently involved in efforts to permit a commercial yellowtail farm in federal waters off the coast of southern California. Secondly, our technology partner providing the soybean meal, Benson Hill, is now in commercial production of two high protein soy varieties, including one that has ultra-low oligosaccharide levels to promote acceptability and performance. These varieties need market outlets like those that could be provided my marine finfish aquaculture.
Seafood is responsible for one of the largest natural resource trade deficits in the U.S., exceeding $15 billion and second only to that of oil and gas. There remains a great need for U.S. aquaculture production to fill the domestic seafood void, both in terms of production volume and diversity. Most of this growth is projected to occur with marine fish species, in which a vast research effort for development of plant-based feeds has been, and still is, undertaken. California yellowtail is a highly valued commercial and sport fishes in southern California and is considered an excellent food fish. Farmed yellowtail have previously been provided to commercial growers, primarily in Mexico, as part of demonstration trials. The results from these trials have been very promising and yellowtail are now available as a commercially farmed product for the first time. Great potential exists to expand commercial culture in both northern Baja California, Mexico and Southern California, especially as SoCal was recently announced as one of the first of two Aquaculture Opportunity Areas (AOAs) in the country by NOAA Fisheries. This reinforces the notion that a good opportunity exists right now to demonstrate the effectiveness of diets based on soy protein, coinciding with the developing offshore aquaculture industry in this region. A growing body of research has been developed over recent years, during which standard protocols of reproduction (Stuart and Drawbridge, 2013), larval rearing (Hawkyard et al., 2016; Rotman et al., 2017), and juvenile nutrition (Jirsa et al., 2011; Rombenso et al., 2016 and 2018; Trushenski et al., 2014; Buentillo et al., 2015; Bergman et al., 2018) have been established for yellowtail. Of particular importance, limiting nutrients have been identified: in soy-based formulations, taurine is the first-limiting essential amino acid, followed by methionine (Jirsa et al., 2014). Past research from our group established the taurine requirement for yellowtail at 0.23% (Salze et al., 2015 and 2018). With all of these research results in place, the time is right for a final optimization of one or more soy-based diets, followed by testing in a growout simulation as proposed here.
Proposed Methods/Tactics:
Feeding trials will be conducted at HSWRI’s research facility in San Diego, CA. For the laboratory trial lasting 8 weeks, yellowtail will be fed three different graded formulations of each soy protein variety provided by Benson Hill and a commercial control. Dietary formulations and feed will be provided by Dr. Allen Davis’ laboratory at Auburn University. Each treatment will be replicated three times for statistical validity. Biochemical composition of the feed and fish fillets will be determined at the end of the study, along with growth and survival metrics, and health assessments via necropsy and histopathology.