Establishing an innovative and transnational feed production approach for reduced climate impact of the aquaculture sector and food supply

CLIMAQUA aims to develop a sustainable aquaculture based on the total utilization of locally produced feed raw materials of high quality. In collaboration with Sintef, researchers in Germany (DIL, ILU) have developed and established a pilot process for the transformation and recycling of aquaculture side streams from rainbow trout (sludge) as growth substrate for a microalgae (Galdieria sulphuraria). Nofima has analysed the algae product, which has been shown to be of high quality, and to contain a lot of protein (66.7%), and some levels of fat (11.7%). The protein is well balanced with a composition of amino acids consistent with that found in an ordinary fishmeal. The microalgae have been mill-dried to break down the thick cell wall and to release the nutrients. The algal suspensions have been added at graded levels to 5 different experimental diets, where the algal protein was replaced with equal amounts of fish meal protein, at levels corresponding to 0, 1.5, 3.0, 4.5, and 6% of the marine protein. In a freshwater feeding trial with small salmon (initial weight: 7.5 g), good growth conditions were achieved in all dietary groups with at least a 4-fold increase in body weights (final mean weight: 30.8 ± 1.4 g). Salmon fed with microalgae had somewhat lower feed intake and growth as compared to the control fish, possibly explained by lower digestibility of protein and energy, while at the same time no differences in protein utilization was found. On the other hand, the results may suggest oxidative stress in the fish, with reduced levels of micronutrients (vitamins, minerals) well known to be important to counteract oxidative stress. Histological examination of the intestinal system showed some negative effects in fish fed with the highest substitution level of the algae meal, but these changes were of a moderate character and at the same time no indications of intestinal inflammation were found. Despite general good growth conditions in the fish trial, the results also suggests that the algae meal may induce oxidative stress in salmon. This has to be further investigated and solved in order to realise the commercial potential. The CLIMAQUA project involves partners from Norway, Germany, Kenya and South Africa, and have possibility evaluate the climatic impacts in different geographical zones. The CLIMAQUA project will also carry out an investigation of social, economic and environmental aspects of microalgae production that can be valuable in the effort to explore the potential for locally production of new feed raw materials with high quality.

CLIMAQUA results in an innovative process for converting and recirculating aquaculture side-streams (sludge and wastewater) in algae (Arthrospira platensis)-based feed production for aquaculture. In conventional aquaculture, feed production is responsible for 50% of greenhouse gas (GHG) emission. The aim is to substantially reduce GHG emission by considering geographic and site-specific characteristics (temperature, sunshine duration etc.) and to design site-specific phototrophic or heterotrophic A. platensis cultivation for use as a highly digestible feed ingredient. CLIMAQUA builds on knowledge gained regarding aquaculture and feed production, and involves partners from Norway, Germany, Kenya and South Africa in order to broaden the applicability, not limiting the approach to a certain geographic area and assessing climate impact of feed production in different climate zones. CLIMAQUA will consider both technological aspects resulting in low carbon footprint solutions and reduced environmental impact as well as non-technological aspects resulting in changes in supply chains and food system resilience by climate adapted production of feed and fish. The transnational cooperation is characterized by mutual knowledge exchange that involves on-cite solutions to meet the future climate situations challenging the supply of food. This cooperation strengthens regional capabilities and contributes to food security under climate change within 1.5 or 2 °C until 2050 and beyond. The project will enable an assessment of future climate impact and an investigation of social (Aquaculture farmers, feed and food processors, consumers), economic and environmental aspects. The regional results obtained, including the role of food losses and waste management and feedback of stakeholders will be used to further improve resource efficiency and nutritive quality of produced feed and food in the southern and northern parts of the world to strengthen regional food supply.