Fish, seafood, and algae are farmed in aquaculture facilities for human consumption as food, dietary supplements, and cosmetics, as well as for use in pharmaceuticals and medicine. However, the farmed animals and plants are often only partially utilized. Organisms from a mussel and algae farm are to be used more holistically within the framework of this project idea through new applications in order to make the farm more economical and sustainable.
Mussels (Mytilidae) are only used once they reach a certain size; the rest are returned to the sea. In the case of macroalgae (here: Saccharina latissima), a large proportion of the algae is left over as unused residue, known as algae pomace, during the production of extracts. Algae pomace and mussel meal offer great potential for use in fish feed adapted to recirculation systems.
On the other hand, these and other by-products are to be processed into innovative foods for human consumption and, in some cases, brought to market maturity. Land-based recirculation systems, aquaculture facilities in coastal areas for fish production, and marine integrated multitrophic culture of mussels and algae, as well as consumers of fish, mussel, and algae products, will benefit from the results of this project. The scientific results of the project will be shared and, where possible, published in scientific journals and conferences. The proposed project will also make business models for aquaculture operators more viable, particularly for multitrophic facilities. The aim is to ensure that these methods for the more efficient use of farmed aquatic resources can be transferred to other aquaculture facilities that exist or are being developed in the BaMS region.
Fraunhofer IMTE's role in LaMuOpt is to conduct trials on the use of by-products in food. In the food technology center, initial prototypes are produced from algae pomace and mussel meat, and their shelf life and other relevant parameters are analyzed. Promising variants are tested for consumer acceptance in hedonic sensory tests.
In addition, Fraunhofer IMTE is responsible for coordinating the procurement and processing of mussel meat and meal, as well as the provision of mussel biomass.
CRM's task in LaMuOpt is to provide and optimize algae pomace for further use as fish feed and food.
The pomace is produced during the production of algae extracts, which in turn are used in cosmetic products by the sister company oceanBASIS GmbH (www.oceanbasis.de). In order to make optimal use of the pomace in fish feed and food, new processes must be developed in some cases, particularly with regard to feed and food conformity. The development is accompanied by analyses of the ingredients and nutrient composition of the pomace.
Fraunhofer IMTE's task at LaMuOpt is to carry out the experiments planned by the consortium to empirically record the effects of algae pomace and mussel meal on fish and the water body. Fraunhofer IMTE owns and operates a modern aquaculture research infrastructure with a wide variety of rearing systems for freshwater and saltwater fish. This allows them to simulate any practical fish farming situation and at the same time deliver scientifically validated study results.
Furthermore, Fraunhofer IMTE carries out the overarching analysis for the nutritional characterization of the various sample materials (fish, raw materials, feed, etc.). In addition, functional evaluations of the various feed rations are carried out at the Büsum institute at the level of molecular stress parameters.
There is close cooperation between the Chair of Marine Aquaculture and the GMA. The practical work of the Chair of Aquaculture at Kiel University is carried out entirely at GMA. Building on the resources, experience, and expertise of both institutions, the practical and theoretical aspects are successfully combined.
Kiel University's role in LaMuOpt is to investigate nutrient supply and feces stability, as well as the health and stress-relieving effects on fish. To this end, specific experiments are carried out at the GMA and scientifically monitored by the CAU.
The focus is on identifying functional components of the algae residue. Based on this, new innovative and animal health-promoting products are to be developed from this new and sustainable raw material.
What is LaMuOpt actually doing?
A lot has happened again in the LaMuOpt project over the past year.
Among other things, further fish feeding trials were carried out. In addition to undersized mussels, algae residues from two different extraction methods (aqueous extraction and fermentation) were tested as fish feed additives. The trials showed that mussels can be a suitable additive, but algae pomace is not.
Due to its favorable sugar composition, a by-product from the aqueous extraction process became the focus of the feeding trials. The extract appears to have a positive effect on fish health. Final investigations are still pending.
The use of pomace in fish feed now seems to be off the table, but not for the production of pesto for human consumption. Pesto was produced from the pomace of the aqueous extraction process in various flavors, and an extensive tasting was carried out with many test subjects and a professional evaluation form. The evaluation showed that algae pomace is definitely suitable as a pesto ingredient. But more on that later... ;-)
In addition to many online meetings, we also met in person again. This time we were at CRM in Kiel-Holtenau, more precisely at the Holtenau seaside resort... again in perfect weather. :-)
Kiel-Holtenau seaside resort in beautiful weather
First in-person project meeting after a year and a half!
Over the past year and a half, the project team has been meeting online about every two months to bring everyone up to speed and discuss the next steps. If we had reported on each of these meetings, this project page would have quickly become very full.
However, we would like to mention this meeting on September 28, 2021, as it was the first in-person meeting in a long time. (For those who have forgotten what that is: people meeting in the real world without a screen in front of their faces, without a shaky internet connection, without sound interference, without frozen images.)
We were guests of our partners at GMA, enjoying beautiful late summer weather (a slight sunburn was reported) against the idyllic backdrop of the North Sea dike in Büsum. In addition to the joy of reunion and the enjoyment of an excellent fish sandwich lunch snack, technical matters were of course also discussed.
The next fish feeding trials are currently being planned. As in the first trials, undersized mussels will be used as feed, but this time with different processing steps to produce the feed. Furthermore, in contrast to the last trials, which used algae residue, an algae extract rich in algae sugars will now be used. These algae sugars are said to have a positive effect on fish health.
We are eagerly awaiting the results, which we will report on here again.
Live and in color “behind the dike”
Initial results from 2020
Prototypes of undersized mussels have been produced on a pilot plant scale (including storage trials and sensory testing) in the form of mussel paste, and food approval has been tested so that upscaling by a food manufacturer is possible. The sugar kelp extraction process has been optimized so that the residual algae pomace can be used for other purposes. A comprehensive data evaluation of the feeding trials is planned. The aim is to implement functional components in commercial feed to develop a feed concept for closed-loop systems and/or a functional feed for suboptimal rearing environments in traditional aquaculture farms. On this basis, an algae residue product with specific recommendations for use is to be developed, which will be available on the market within a short period of time. If the results of the experiments are positive, certification of mussels as animal feed will also be sought.
Fish feed pellets made from mussel meal and algae pomace
Rainbow trout above: at the start of the feeding trial; below: at the end of the feeding trial
Shellfish paste in various flavors
