Fish consumption has increased dramatically over the last 20 years. Unfortunately, this increase in demand for fish has resulted in an alarming depletion of the natural fisheries. With the closure of many marine fisheries due to over-harvesting and the increased domestic demand for fish it is evident that alternatives to harvesting fish from the wild need to be developed. Aquaculture is a rapidly growing alternative to harvesting wild fish. The increase in aquaculture has required an increase in the production of manufactured feeds. The main ingredients in traditional aquafeeds include fish meal and fish oil. Several kilograms of wild fish are required to produce each kilogram of farm-raised fish, which accounts for 40% and 60% of the global fish meal and oil production, respectively. In marine aquaculture, the importance of dietary omega long chain fatty acids is well-known. High value, marine carnivores require the omega-3 highly unsaturated fatty acids (HUFA) as essential fatty acids (EFA) that are major constituents of marine fish oils. Alternative sources are needed to replace the fish oil used in aquafeeds if aquaculture is to remain competitive and sustainable. An alternative source of fish oils in aquafeed may be algae. Algae are high in HUFA, and provide a high quality source of dietary lipids. A limitation to their widespread use in feeds is economic: the cultivation, harvesting and processing of algae is very expensive. The goal of this USDA SBIR Phase 1 Grant is to develop a continuous system for extracting lipids from algae directly into soybean oil using ultrasonics. The soy-algal oil product, including the remnant biomass, will be directly added with other ingredients during the manufacturing of the feed. We believe that this process will result in lower cost of supplementing feeds with algal oils due to higher bioavailability of algal oils in diets and reduced algal processing steps. This extraction and processing methods developed in this proposal are components of an integrated algal production system designed to further reduce the cost of the algal product.
