Sustainable Ingredients for Aquafeeds

The aquaculture industry will be a major contributor to feeding the world’s growing human population. The industry’s output in Norway alone is projected to increase six-fold by 2050, but this will depend on several factors, including the supply of feed resources. Conventional sources like fish meal and fish oil are limited resources, so it is pivotal for future growth to develop alternative and sustainable high-quality feed resources using advanced technology. The basic nutritional needs of fish, e.g. amino acids, lipids, and energy, can be met by a wide range of alternative feed ingredients. However, the fish feed of the future needs to be based primarily on ingredients not directly used by humans for food. Until now, plant ingredients such as soybean-based products, are important alternatives, as these are available in large quantities. Introducing new ingredients into fish feed represents opportunities and challenges that differ for each type of ingredient. Some may contain a wide range of bioactive components that may have health-promoting effects. Others, such as certain plant sources, contain antinutritional factors and antigens. These factors reduce nutrient digestibility and may cause acute intestinal inflammatory responses as seen with soybean meal and other legumes in diets for salmonids. These problems can be overcome by targeted processing techniques. For example, recent advances in processing technology have made it possible to produce protein concentrates that are more suitable for aquaculture than conventional meals. Protein concentrates from field peas and co-products from biofuel production, such as distillers dried grains with soubles (DDGS), have shown to be potential protein sources for salmonids. In the future, fish feed needs to be increasingly based on non-food raw materials, such as by-products from plant crops and animal by-products that are not edible for humans, and through developing new ingredients based on single-cell organisms. Single-cell organisms like bacteria and yeast represent potentially sustainable ingredients due to their ability to convert natural gas or low-value biomass from forestry and agricultural industry into high-quality feed ingredients. A bacterial meal produced by aerobic fermentation of natural gas by Methylococcus capsulatus and yeast produced from easily fermentable sugar have shown to be suitable protein sources for farmed salmonids. New ingredients for fish feed based on these sources and new technologies can help secure a high-quality, sustainable food source for an ever-growing world population.