Over the past 30 or so years, a global endeavour to find and develop alternative ingredients for use in aquaculture diets has taken place. Now, at a time when farmed fish contributes more to global food supply than wild fish or beef, we are also seeing the benefits of that earlier endeavour with a large range of alternatives being adopted and used worldwide across most aquaculture species.

However, a problem with many of the alternative ingredients being developed and/or used is that they compete directly with human food supply. That is, we are producing food to feed our food. The net result of this of course, based on simple trophodynamics, is a net loss in resources. However, the production of non-competitive protein supply is possible, and it is happening now.

Single-cell protein technology, the cultivation of microorganisms like yeasts and bacteria, offers the chance to use inorganic resources to produce “new” protein. In this regard there are several emerging technologies out there that are now producing single-cell protein resources at commercial scale.

FeedKind® by Calysta is one of the front-runners in realising a commercial product. This product boasts compositional characteristics very similar to fishmeal with high (>60%) protein levels and about 10% lipid, which provides a lot of formulation flexibility. Backed up by a suite of excellent research on Atlantic salmon, trout, halibut and shrimp, FeedKind is produced from a Methylococcus fermentation system where methane is used to supply the carbon and inorganic nitrogen is used to create amino acids. One of the observations noted by Overland et al (2010) was that in some instances there was an improvement in performance with the inclusion of the single-cell biomass that was beyond expectations. This has some similarities to another single-cell technology being produced for shrimp.

The other single-cell product emerging in the market is Novacq™ by Ridley AgriProducts. This product has taken a slightly different approach to the other products in the market and is not touted as a “protein-source”, but rather as a “bioactive source”. Originally developed and patented by Australia’s CSIRO, the Novacq™ product is based on a broad suite of bacterial classes and inputs of cellulosic waste streams and inorganic nitrogen. Like the Feedkind product it too has demonstrated some remarkable nutritional results with shrimp including the ability to offset protein reductions in the diet, help sustain the complete replacement of all marine product (fishmeal and fish oil) inclusion, improve shrimp resilience to viruses, and improve growth rates.

These are only two of a raft of single-cell products now emerging in the market. New products seem to be arising on a regular basis now and it looks likely soon that this will be a competitive area of new technology going forward.

Brett D. Glencross
Institute of Aquaculture, University of Stirling, Stirling, United Kingdom

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