Superior Nutrient Availability, Reduced Metabolic Waste and Increased Energy Efficiency in Aquafeeds

In November 2011 the worlds human population reached 7 billion. Concurrent role shifts in world economies (e.g., competition for seafood products with China) make it necessary for aquaculture to grow at a pace much faster than previously estimated. In addition, the American seafood trade deficit now exceeds $10 billion per year. Clearly, we are at a point when new technologies are desperately needed to aquaculture food production. It is clear that future aquaculture expansion cannot rely on resources which are static at best - if not declining - as is the case of fishmeal. Soybean meal (SBM) is an excellent source of dietary protein. However, possible SBM inclusion levels in fish/shrimp feeds are limited due to the presence of both heat-resistant and thermo-labile anti-nutritional factors (ANFs) in SBM. While solvent-extracting and cooking significantly reduce the biological activity of protease inhibitors, this processing also renders protein less available for absorption at the intestinal level. Likewise, the preparation of soy protein concentrates (SPC) uses ethanol (or acid) percolation to displace soluble/indigestible carbohydrates (oligosaccharides) but, in doing so it also drives out minerals and vitamins of which SBM is considered a rich source. Moreover, the use of heated alcohol further denatures protein reducing solubility/dispersibility values (indicative of a diminished protein bioavailability). Recent advances in soy breeding have allowed for the development of non-genetically modified cultivars with enhanced nutritional characteristics. Reduced trypsin inhibitors, reduced oligosaccharides and high protein are traits that have been achieved with more improvements being constantly developed. Building on progress to date we have tested several unconventional, not-thermal (energy-saving), nutrient-preserving treatments to process aquafeed-oriented soybean cultivars into novelty meals. The proposed work will quantify - in Atlantic salmon, hybrid striped bass, tilapia and Pacific white shrimp - the effects of using these novel ingredients on waste generation and water quality of recirculating culture systems. Measurable quantities of waste materials generated by fish fed diets based on conventional SBM, SPC and/or fismeal will be contrasted with those produced by fish fed the test ingredients. Apparent digestibility coefficients, fish performance indicators, gut histology and changes in enteric populations of bacteria will be evaluated as well. We envision that the synergy between enhanced soybean cultivars processed under unconventional non-thermal methods will allow for higher inclusion rates in fish/shrimp feed formulations resulting in increased sales of American soy products worldwide. The production of alternative, soy-based aquafeeds will have a significant and positive impact in American aquaculture as well as on American seafood supply and availability.